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OPTICALABBREVIATIONS

& GLOSSARY

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OPTICAL ABBREVIATIONS

20/20 best vision

≈ approximate

∆ prism diopter  

º degree of prism

< less than

> greater than↑ increase

↓ decrease

♀ female

male

combined !ith

" infinit#

$ pl%s

& min%s

'() hori*ontal box meas%rement

a applanation tension

ac before meals

acc accommodation

 (++ add po!er ,m%ltifocal-

 (. anti&reflective coating

ax axis

') vertical box meas%rement

bbl barrel of hinge

base c%rve

+ base do!n prism

1 base in prism

bif bifocalbid t!ice dail#

base o%t prism

distance bet!een optical center

and top of segment

3 base %p prism

45 bac6 vertex distance

c !idth

cc c%bic centimeter  

cc comfort cable temple

cc !ith correctioncf co%nt fingers

cl contact lens

cm centimeter  

.&78 plastic lens material

conv convergent

.5 orneal reflection p%pilometer 

c#l c#linder  

+ diopter  

+5 distance portion of lens

+9 distance bet!een lenses ,bridge-

+ distance bet!een centers

div divergent

+x diagnosis:5 e#ecare professional

:+ effective diameter  

eom extraoc%lar movements

eso tendenc# to t%rn in

exo tendenc# to t%rn o%t!ard

exam examination

et esotropia

:; edge thic6ness

fb foreign bod#

+ frame distance center 

5 far point

t flat top bifocal

= geometric center  

gtts drops

+ hori*ontal decentration of

optical center 

hgt height

1 hi&index lens material

hm hand motion

hori* hori*ontal

hs at bedtimeh#per %p

h#po do!n

hx histor#

ic bet!een meals

15 intraoc%lar press%re

19 intraoc%lar lens

15+ interp%pillar# distance

9 left

lib librar# temple

lp light perceptionm meter  

mc mechanical center  

?+5 monoc%lar p%pillar# distance

mm millimeter  

?.5 ma@or reference point

n index of refraction

Aeg negative

 __ 

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Alp no light perception

nn nanometer  

np near point

nrp near reference point

nv near vision

Ava near vis%al ac%it# optical center  

+ oc%l%s dexter & right e#e

B+B +octor of ptometr#

9 overall length

5 optical prod%ct code

pht ophthalmic&pertaining to the e#es

rtho straight

C oc%l%s sinister & left e#e

3 oc%l%s %niter & both e#es

o* optical *one

5(9 progressive addition lens

5c after meals

5+ papillar# distance

ph pinhole

5l plano

po per os & orall#

prn as needed

5.5 prism reference point

Dd ever# da#

Did E times a da#

D2h ever# 2 ho%rsDh ever# ho%r  

Dod ever# other da#

. right

.ef refraction

.x prescription

s !itho%t

sc !itho%t correction

seg segment

seg ht segment height

C1 segment inserts6 s6%ll

Cph sphere

C5 standard operating proced%re

C. scratch resistant coating

Ctat at once

C4 single vision

Cx s#mptoms

t tension

temp temporal to!ard the temple

tid 7 times a da#

tri trifocal

34 %ltraviolet

v A% val%eF (: val%e4( vis%al anal#sis ,e#e examination-

4+ vertical decentration of optical center 

vert vertical

vf vis%al field

GA9 !ithin normal limits

x axis

xp exophoria

xt exotropia

*#l plastic frame material

 __ 

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Air ,empering H ;he strengthening of a lens as a

res%lt of cooling a heated lensB

Albinism H 5igmentation is deficient or absentB

?a# occ%r in s6inF hairF and e#esB c%lar albinism

is a pigmentation deficienc# occ%rring mainl# in the

e#esB 1ndivid%als !ith albinism incl%ding oc%laralbinism commonl# have decreased vis%al ac%it#

,20/N0 H 20/200-F strabism%sF photophobiaF and

n#stagm%sB ;here is no 6no!n treatmentB

1ndivid%als ma# benefit from lo!&vision aidsB

;reatment options for strabism%s and n#stagm%s

does appl# to these individ%alsB

Alignment H ;he placing of the retinal D%adrants of

the e#e so that the light stim%l%s is eD%all#

distrib%ted on all fo%r D%adrantsB

Ambl!opia & +efective vision that cannot be

corrected b# e#eglasses or contact lensesB ftenreferred to as 'la*# e#e)B

Ametropia H :#e disorders that prevent a clear

image from forming on the retina ,m#opiaF

h#peropiaF astigmatism-B

Ambl!opia -xanopsia $la.! e!e% H 3ncorrectable

bl%rred vision d%e to a lac6 of %seL the vis%al

path!a# fails to mat%reL an e#e can become

ambl#opic from being crossedF having a large

refractive error or having the brain s%ppress its

visionB orrective lensesF vision therap#F or

patching therap# ma# be prescribedBAM H (ge related mac%lar degenerationF a

disease that damages the mac%laF the central part

of the retinaF leading to loss of central vision and

leaving onl# the peripheral or lateral vision in tactB 

Amplitude +unctional $or anal!tical% H ;he range

over !hich clearF binoc%lar vision can be

maintained %pon reading material of 20/E0 ang%lar

si*e placed at a fixed distance ,%s%all# K7 inches-B

Amplitude o( Accommodation $AA% H (

meas%rement of the e#eJs abilit# to foc%s clearl# on

ob@ects at near distancesB ;his e#e foc%sing rangefor a child is %s%all# abo%t 2&7 inchesB or a #o%ng

ad%ltF it is E&I inchesB ;he foc%s range for a EO&

#ear&old ad%lt is abo%t 20 inchesB or an P0ear&

old ad%ltF it is I0 inchesB

Anal!sis H ( scientific proced%re for dividing a

complex experience into simpler constit%entsB

Anal!tical -xamination H ( 2K&point optometric

examinationB :ach point is a meas%rement of

performance of a vis%al behavior patternB ;hese

meas%rementsF made thro%gh the application of

prism and sphereF sho! the absorption of the

potential of inhibitionF meas%re the existing learnedassociations bet!een patternsF and probe for the

degree or organi*ation existing in the vis%al patternB

Anisei1onia H ;he image of an ob@ect as seen b#

one e#e is different in si*e and shape from the

other oneB

Anisometropia H 3neD%al different refractive

errors of the t!o e#esB

Annealing & ;he heating of a material to a

s%fficientl# high temperat%re !ith s%bseD%ent

controlled cooling to relieve an# internal stress and

strainsBAnomal! H (n# stri6ing deviation from t#pical or

normalB

Anomalous Retinal Correspondence $ARC% H (

t#pe of retinal pro@ectionF occ%rring freD%entl# in

strabism%sF in !hich the foveae ,center of the retina

that prod%ces the sharpest e#esight- of the t!o

e#es do not facilitate a common vis%al directionL the

fovea of one e#e has the same f%nctional direction

!ith an extrafoveal ,non&fovea- area of the other

e#eB

A'* $American 'ational tandards *nstitute% H:#e!ear that meets this standard is considered

safer than e#e!ear that does notB

Anterior egment H ;he space in front of the iris

and behind the corneaF !hich incl%des corneaF

con@%nctivaF irisF lens and aD%eo%s h%morB

Antimetropia H ne e#e m#opic ,near sighted-F the

other h#peropic ,far sighted-B

Anti)Re(lective Coating H ( m%lti&la#er thin

coating applied to the lens s%rface to red%ce the

amo%nt of reflection from the lens and increase light

transmissionBApex H ;he thin edge of a prismBApa1ia H ( condition ca%sed b# the removal ofthe cr#stalline lens most often d%e to cataractsB

Aperture H ;he opening in an ophthalmic frame

front into !hich the lens is insertedB (pert%re

dimensions ,in millimeters- do not incl%de the depth

of the lens groveB

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A3ueous 4umor  H ( clear !ater# liD%id in the

chamber of the e#e that flo!s bet!een the cornea

and the cr#stalline lens and no%rishes bothL

secreted b# the ciliar# processesB

AR tac1 H ombined la#ers ma6ing %p an (.

coating ,%s%all# five or more-B omposition ofla#ers can var# bet!een (. coatersB

Asepsis H ree fromF absence of infection or

infectio%s materialB

Asperic H ( lens that is not sphericalB ;he lens

s%rface is mar6ed b# a variet# of ellipticall#

changing c%rvat%resB (n aspheric design allo!s a

lens to be m%ch flatter !itho%t compromising the

optics of the lensB ;he benefitsM flatter lenses are

less noticeable in framesF and ma6e the !earerJs

e#es loo6 more nat%ral and less magnified or

minifiedBAsperic Compensation o( "o#er  H 5o!er is

compensated in each area of the lens b# appl#ing

aspheric principlesB

Astenopia H C#mptoms of 'e#e&strain) incl%ding

headachesF tearingF itchingF b%rningF and bl%rred

visionB

Astigmatism H ( condition !here a misshaped

cornea ca%ses light to be foc%sed over a range of

distances rather than on a pointB ;his can be

corrected b# a lens !ith c#linder po!er in a certain

directionBAs!mmetrical esign H ( lens design that has

conto%r line patterns positioned differentl# into the

nasal and temporal area to prod%ce a right and left

lens designB ;his is e#e specific so the lens can not

be rotated to ma6e a right or left lensB

Atoric Lens H 9ens !ith astigmatic po!er in !hich

at least one principal meridian is not sphericalB

Automated Re(ractor  H ;his method determines

the e#eJs refractive error and the best corrective

lenses to be prescribed b# %sing a comp%teri*ed

device that varies its optical po!er mechanicall#and prints o%t the res%ltsB

Axis C!linder  H ;hat principal meridian !hich

contains onl# the spherical po!er component of a

sphero&c#linder lensB (xis !ill intersect a spherical

lens of min%s po!er at its thinnest point and a

spherical pl%s lens at its thic6est pointB

Axis 5ptical ) ,Q- H (n imaginar# line at right

angles to the s%rface of a lensF !hich passes

thro%gh the optical centerB ;he meridian of least

po!er 80º a!a# from the meridian of greatest

po!er in a c#lindrical lensL %sed in correcting

astigmatismBAxis Aligner "lier  H (n# device %sed for aligning a

c#linder axis of a spectacle lens at its proper angleB

Axis *ndicator o( Lensometer  H ( device in !hich

a scale from 0º to KP0º can be aligned to give the

axis of c#linder po!er on a spectacle lensB

B

“B” Box Measurement H 1n lens meas%rementF

the longest vertical distance from the %ppermost

point to the lo!ermost point of a shapeBBac1 +ocal Lengt H ;he distance from the bac6

s%rface of a lens to the image of an infinitel# distant

ob@ectB

Balance Lens H ( lens placed in a frame !hich

loo6s li6e the lens for the opposite e#e to balance

cosmeticsL similar in thic6ness and st#le !ith no

specific .x po!erB

Barium 6lass H ommonl# %sed for a t#pe of

cro!n glassF one of the ingredients is bari%m oxide

added for the p%rpose of increasing refractive

indexF !hile maintaining relativel# lo! dispersionBBarrel ) ,bbl- H ,K- ;he component of a hinge that

interloc6s !ith the mating component of the hinge

setF ,2- ( threaded clos%re device attached to a

metal e#e!ireB

Bar!ta 6lass H ( t#pe of glass containing lead for

increasing the index together !ith bari%m to

increase refractive indexF !hile maintaining a

relativel# lo! dispersionB

Base Curve H ;he sing%lar dioptric c%rve on the

front s%rface of a lensB ;his c%rve is generall# in

place !hen the lens blan6 is man%fact%red and ass%ch !ill control the selection of bac6 c%rves

necessar# to prod%ce a given prescriptionB ;his

s%rface c%rve becomes the basis from !hich the

other remaining c%rves are meas%redB Ghen

applied to lenses in generalF the base c%rve is the

gro%p c%rve or the c%rve common to a gro%p of lens

po!ersB

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Base o#n $B% "rism H ( !edged shaped lens

!hich is thic6er at the bottom of the lensB 5risms

bend light in the opposite direction from its thic6er

edge so base do!n prism t%rns the light %p!ard

th%s ca%sing the e#e to also move %p!ardB ;his

prism is %sed to meas%re an e#e alignment and /ortreat a binoc%lar d#sf%nction ,e#e teaming

problem-B 5risms are sometimes added to glasses

to help improve e#esight d%e to a misalignment or

vis%al field lossB

Base *n $B*% "rism H ( !edged shaped lens !hich

is thic6er at the nasal area of the lensB 5risms bend

light in the opposite direction from its thic6er edge

so base in prism t%rns the light o%t!ard ,to!ard the

ear- th%s ca%sing the e#e to also move o%t!ardB

;his prism is %sed to meas%re an e#e alignment

and /or treat a binoc%lar d#sf%nction ,e#e teamingproblem-B 5risms are sometimes added to glasses

to help improve e#esight d%e to a misalignment or

vis%al field lossB

Base 5ut $B5% "rism H ( !edged shape lens

!hich is thic6er on the o%t!ard edge of the lensF

closest to the earB 5risms bend light in the opposite

direction from its thic6er edge so base o%t prism

t%rns the light in!ard th%s ca%sing the e#e to also

move in!ardB ;his prism is %sed to meas%re an

e#e alignment and /or treat a binoc%lar d#sf%nction

,e#e teaming problem-B 5risms are sometimesadded to glasses to help improve e#esight d%e to a

misalignment or vis%al field lossB

Base 7p $B7% "rism H ( !edged shape lens !hich

is thic6er on the %p!ard edge of the lensB 5risms

bend light in the opposite direction from its thic6er

edge so base %p prism t%rns the light do!n!ard

th%s ca%sing the e#e to also move do!n!ardB ;his

prism is %sed to meas%re an e#e alignment and /or

treat a binoc%lar d#sf%nction ,e#e teaming

problem-B 5risms are sometimes added to glasses

to help improve e#esight d%e to a misalignment orvis%al field lossB

Basic +ormula H ;he s%b@ectiveL it is the lens

po!er that alters the light ra#s entering an e#e and

ca%ses a change in the foc%sing mechanism in the

greatest degree !itho%t ca%sing a s%b@ectivel#

detected alteration in the convergence mechanismB

Batc H =enerall# considered to be the n%mber of

lenses that fit into an (. chamber at one timeB

Baume 6auge H 3sed to chec6 the specific gravit#

of a polishing sol%tionB

Beam H ( gro%p of parallel ra#s of lightB

Bevel H ;he shaping of the edge aro%nd theperipher# of a lens necessar# to hold the lens !ithin

the groove of a specific frameB

Bevel -dger  H ( machine b# !hich an %nc%t lens

is given a bevel on its edge b# a special lens

grinding !heelB

Bi)centric 6rinding $lab 5((% H ;he process of

grinding base %p prism to correct vertical

imbalanceB

Biconcave H ( lens st#le !here both front and

bac6 s%rfaces are min%s ,concave-B

Biconvex H ( lens st#le !here both the front andbac6 s%rfaces are pl%s ,convex-B

Bi(ocal H ( lens !ith t!o focal pointsF one for

distance vision and one for nearB .eg%lar bifocals

have a line bet!een the prescriptionsL 5rogressive

bifocals change grad%all# from the near to far

prescriptions !ith no visible line on the lensB

Binocular " H ;he single meas%red distance

from p%pil center to p%pil centerB

Binocular $binocularit!% Vision H ;he blending of

the separate images b# each e#e into a single

imageL allo!s images to be seen !ith depthBBi)5cularit! H %sing both e#esF b%t not together as

a teamB

Bire(rigence H ;#pe of lens aberration that is

ind%ced d%ring the man%fact%ring process !hich

res%lts in chromatic aberrationB ( rainbo!&li6e effect

,sometimes called Ae!ton .ings-B

Bitoric Lens H  ( lensF both s%rfaces of !hich are

gro%nd and polishedF in toric or c#lindrical formB

Blan1 Molded H ( lens blan6 that is %nfinished on

both sides !hen it arrives from the lens factor#B

Blan1 emi)+inised H ( lens blan6 that isgro%nd and polished on one side to ma6e a

prescriptionB

Bleac H ( process to remove the tint from a d#ed

lensB

Blended Bi(ocals H ( ro%nd st#le bifocal t#pe lens

designed so that there is no discernable line of

demarcation bet!een the distance portion and the

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reading portionB ;he blended area is vis%all# non&

%sableB

Blended M!o)disc H 9enses have a f%ll field

c%rved or 5lano front s%rface !ith a high min%s

bo!l&shaped s%rface on the oc%lar side s%rro%nded

b# a 5lano s%rface called a carrierBBlemises H ,K- C%rface H present on the convex

or concave s%rface of the lensB ,2- 1nternal H

present in the material %sed for s%bstrate lens

prod%ctionB ,7- oating H formed or appearing

d%ring or in coatingB

Bleparitis H ( condition that describes an

inflammation of the e#elid margins characteri*ed b#

a stic6# cr%st that forms on the e#elidsB

Blinding 6lare H .eflected glare ca%sed b# light

reflected off smoothF shin# s%rfaces bloc6ing visionB

Blind pot H ,K- ( small area of the retina !herethe optic nerve enters the e#eL occ%rs normall# in

all e#esB ,2- (n# gap in the vis%al field

corresponding to an area of the retina !here no

vis%al cells are presentL associated !ith e#e

diseaseB

Bloc1er H ( mechanical device for affixing an

ophthalmic lens blan6 to a plastic or metal lens

carrierL %sed in lens edging and lens s%rfacingB

Bloc1ing H (ttaching lenses to a bloc6ing bod# or

handle in readiness for s%rfacing or edgingB

Blue Bloc1ers H (n orange colored tint form%latedto bloc6 o%t %ltraviolet radiation and red%ce bl%e

light !hich ma# be harmf%l to the e#eB

Blue Blur  H ;he condition of %nclear vision d%e to

the scattered bl%e light in the visible spectr%mB

Blurred Vision H lac6 of clarit# or ac%it#B

Bon! 5rbit H :ither of t!o bon# cavities in the s6%ll

containing an e#e and its external str%ct%resL an

e#e soc6etB

Box Measurement H ;he meas%rement of a lens

or frame b# incorporating it !ithin a sD%are and

then meas%ring the hori*ontal and vertical inmillimetersB

Brea1 "oint H the point at !hich a person can no

longer f%se ,%nite- t!o images into oneB ( bl%r

point !ill occ%r before this pointB

Bridge H ;hat portion of the frame that rests %pon

the !earerJs noseB ;he bridge si*e is the shortest

hori*ontal distance bet!een lenses ,+9-B

Bro#)Bar  H ( plastic or metal piece attached to the

%pper e#e!ire of a frame front to position the frame

a!a# from the !earerJs bro! or to add stabilit# to

the frame designB

Build)7p "ads H 5lastic pads that are cemented to

the bridge section of the e#e!ire to red%ce thebridge si*e and raise the frame frontB

C

C Measurement H ;he circ%mference of a lensB

Cable ,emple H (n earpiece of metalF plasticF or

combination thereofF !ith the portion in contact !ith

the ear consisting of !o%nd !ireF !ith or !itho%t a

coreB ;his portion is t#picall# bent in the shape of a

semicircle to fit sec%rel# aro%nd the earB

Calipers H ( hand&held mechanical meas%ringinstr%ment in the form of pliersF having t!o legs or

 @a!s that can be ad@%sted to determine thic6nessF

diameterF caliberF and/or distance bet!een

s%rfacesB alipers are calibrated and meas%re in

tenths of millimetersB

Cantus H ;he angle formed b# the @%nct%re of the

e#elidsB

Carrier Lens H ;he ma@or portion of a lens that has

a differing po!er component cemented or f%sed to

itF creating the combined lens po!erB

Cataract H 5artial or complete opacit# of the lens ofthe e#eF ca%sing partial or total loss of visionB

:vent%all#F the clo%ded lens in the e#e m%st be

s%rgicall# removed and an intraoc%lar lens implant

inserted to ta6e its placeB

Cataract Lens H 9enses %sed to correct vision after

cataract s%rger#B

Cellulose Acetate H ommon material %sed to

ma6e frame partsB (lso referred to as '*#l)B

Cemented egment H (n added po!er ophthalmic

lens bo%ndF %s%all# b# epox# resinF to a carrierB

Center o( Rotation H ;he imaginar# point aro%nd!hich the e#eball pivots !hen movedB

Center ,ic1ness H ;he front&to&bac6

meas%rement of a lens at its optical or geometric

centerL %s%all# expressed in 0BK mm %sing a

caliperB

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Central Retinal Arter! H ;he blood vessel that

carries blood into the e#eL s%pplies n%trition to the

retinaB

Central Retinal Vein H ;he blood vessel that

carries blood a!a# from the retinaB

Cerium H (n oxide compo%nd %sed for polishing alens s%rfaceB

Cala.ion H ( small and freD%entl# painf%l c#st of

the e#elid res%lting from a bloc6ed meibomian

glandB

Camber  H ;he vac%%m compartment of an (.

coating machine into !hich the lenses are placed

for (. applicationB

Cam(ering H 3se of a tool to remove all resid%al

lens material !hen drilling a holeB

Cassis H ;he metal e#e!ire and bridge

components of a combination front that holds thelensesB

Cemical 4ardening $tempering% H ( chemical

process b# !hich the lens is strengthened b# timed

treatment in a hotF ion&exchange bath chemicall#

replacingF from each s%rface of the lensF small ions

!ith larger ions into a thinF to%ghened s%rface la#erB

Ciasm H ;he lo!er portion of the brain at !hich

point the t!o optic nerves intersectB

Coroid H ;he la#er filled !ith blood vessels that

no%rishes the retinaL part of the %vea and bet!een

the retina and the scleraBCromatic Aberration H Ghen a lens ca%ses

!hite light to be bro6en into vario%s component

colors !ith each foc%s at a different distance from

the lensF commonl# prod%cing color fringe aro%nd a

vie!ed imageB

Cuc1 H ( padded metal or plastic circ%lar piece

%sed to s%pport a lens d%ring the edging processB

Ciliar! Bod! H ( str%ct%re directl# behind the iris of

the e#e and contains the ciliar# m%scleB

Ciliar! Muscles H ( band of m%scle and fibers that

are attached to the lens that controls the shape ofthe lens and allo!s the lens to accommodate

,change foc%s-B

Ciliar! "rocesses H ;he extensions or pro@ections

of the ciliar# bod# that secrete aD%eo%s h%morB

Clip)5n H (n apparat%s that holds t!o lenses

,%s%all# colored- to filter different light !avelengthsB

 ( piece attached to a frameB

C'C H omp%ter A%merical ontrolL the process of

g%iding the position of a machine tool s%ch as a

c%tting tool of a freeform generator %sed comp%ter

controlled reading inp%t of a program fileB

Coating H (pplied to corrective lenses after

s%rfacingB ,iBeB scratch resistanceF anti&reflectiveFmirrorF colorF tintF antistaticF anti&sm%dge-

Colmascope H ( device !hich thro%gh %se of

polari*ed lightF demonstrates strain existing in a

piece of lens materialB

Color Blindness H ,color deficienc#- H ( condition

in !hich a personJs abilit# to disting%ish colors and

shades is less than normalB olor blind is an

incorrect term beca%se onl# a small n%mber of

people are completel# %nable to identif# an# colorsB

olor deficiencies are %s%all# hereditar#B (cD%ired

deficiencies ma# indicate a health problemB ( c%refor color deficienc# has #et to be discoveredB

o!everF people !ith this condition can be ta%ght

to adapt and the abilit# to disting%ish colors can be

improved !ith the %se of colored filtersB

Color)Coated Lenses H 9enses !ith a metallic

oxide coating applied to s%rfaces b# means of

vac%%m depositionB ;he coatings are deposited

evenl# across the s%rface regardless of

prescriptionF so color is %niformB

Color "erception ,est H ( test that meas%res the

abilit# to identif# and disting%ish colorsBCombination +rame H ( frame !herein the front

consists of a metal chassis !ith attached trimB

;hese trim parts are t#picall# plasticF al%min%mF or

other metalF and are attached to the top portion of

the chassisB

Compound Lens H (n ophthalmic lens containing

both a spherical and c#lindrical refractive po!erB (

sphero&c#linder lens design is %sed to correct

astigmatismB

Compensated Curve H ( c%rve comp%ted to attain

a desired vertex po!er considering the thic6nessfactorB

Computer Vision !ndrome $CV% H ;he

complex of

e#e and vision problems related to near !or6 that

are experienced d%ring or related to comp%ter %seB

1ts s#mptoms incl%de e#estrainF dr# or b%rning

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e#esF bl%rred visionF headachesF do%ble visionF

distorted color visionF and nec6 and bac6 achesB

Concave Lens H ( spectacle lens !hich is thic6er

at the edges than in the centerB ( concave or

'min%s) lens diverges ,decreases- the po!er of

incoming light ra#sF and is %sed in the correction ofm#opia ,nearsightedness-B

Cones Cone Cells H ne t#pe of speciali*ed light&

sensitive cells ,photoreceptors- in the retina that

provide sharp central vision and color visionB

Con&unctiva H ;he thinF moist tiss%e ,membrane-

that lines the inner s%rfaces of the e#elids and the

o%ter s%rface of the sclera and contains man# blood

vesselsB

Con&unctivitis H (n inflammation of the

con@%nctivaF the transparent la#er covering the inner

e#elid and the !hite portion ,sclera- of the e#eballBon@%nctivitis can be ca%sed b# a vir%sF bacteriaF or

f%ng%s ,infectio%s con@%nctivitisF or 'pin6 e#e)F ma#

be contagio%s-L allergies to pollenF fabricsF animalsF

or cosmetics ,allergic con@%nctivitis-L or b# air

poll%tion or noxio%s f%mes s%ch as s!imming pool

chlorine ,chemical con@%nctivitis-B C#mptoms

incl%de red or !ater# e#esF bl%rred visionF inflamed

inner e#elidsF scratchiness in the e#esF or ,!ith

infectio%s con@%nctivitis- a p%ss li6e or !ater#

discharge and matted e#elidsB on@%nctivitis is

%s%all# treated !ith antibiotic e#e drops and/orointmentB

Contact Lens H ( small soft or rigid corrective lens

that fits directl# on the s%rface of the e#e and floats

on tear film over the cornea to corrective vision

errorsB

Contact Lens $ail! 8ear% H ontact lenses

designed to be !orn onl# d%ring !a6ing ho%rsB

reD%ent R planned replacement contact lenses

general term %sed to refer to contact lens regimens

in !hich lenses are replaced on a planned

sched%leF ever# t!o !ee6sF monthl# or D%arterl#BContact Lens $isposable% H ontact lenses

defined b# the 3BCB +( as a contact lens that is

%sed one time and discardedB ;hese can be !orn

either for a single da# or %p to seven da#sF

depending on !ear sched%le prescribed b# the e#e

care professionalB (n# lens that is intended to be

removed from the e#eF cleanedF rinsedF disinfectedF

and reinserted does not D%alif# for incl%sion in this

categor#B

Contact Lens $-xtended 8ear% H ontact lenses

designed to be !orn aro%nd Hthe&cloc6 for intervals

of one to seven da#sB

Contact Lens $,erapeutic% 9 ontact lensdesigned to aid in protecting and helping a sic6 e#e

to healB ;hese %niD%e lenses are freD%entl#

combined !ith precise medication deliver#

sched%les to heal the e#eB

Contact Lens $,oric% H ontact lenses designed to

correct astigmatic refractive errorsB ;oric lenses are

!eighted to maintain a specific axis across the

corneaB

Contrast ensitivit! H ;he abilit# to perceive

differences bet!een an ob@ect and its bac6gro%ndB

Convergence H ;he abilit# to %se both e#es as ateam and to be able to t%rn the e#es in!ard tomaintain single vision close %pB

Coolant H ( liD%id %sed to red%ce the heat ca%sed

b# friction of a s%rfacing operationB

Cord Mount & ( frame st#le !here the lenses are

held in the frame b# a thin plastic cord !hich fits a

groove in a flat edge of a lensB

Core H ,K- ( central strand aro%nd !hich other

!ires are !o%nd in a core templeF ,2- Gire

reinforcement imbedded in plastic temples ,core

!ire-B

Cornea H ;he o%terF transparentF dome li6e

str%ct%re that covers the irisF p%pilF and anterior

chamber of the e#e that transmits light to the e#eF

and is the ma@or refraction element of the e#eB

Corneal Abrasion H ( c%t or scratch on the

corneaB

Corneal Astigmatism H +efect in the c%rvat%re of

the cornea !hereb# light ra#s passing thro%gh the

cornea prod%ce aberrations and are not foc%sed on

the retinaB

Corneal Re(lection H ?ethod of meas%ring the

distance from the p%pilF %sing light reflected from

the cornea to the center of the noseB

Corneal Re(lex H 1rritation of the cornea res%lting in

reflex clos%re of the e#elidsB

Corneal ,opograp! H ?apping or examination of

the s%rface of the corneaB

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Corrected Curve H ( c%rve designed to partiall# or

totall# correct either or both the marginal astigmatic

error and the marginal spherical errorB

Corrective Lenses H orrects e#esight disorders

and is a combination of materialF optical s%rfaceF

and coatingsBCorridor Lengt H ;he distance bet!een the fitting

cross and the point of f%ll add po!er on a

progressive lensB

Corundum H :xtremel# hard material !hich emer#

is madeB

Cover ,est H ( test of e#eball alignment in !hich

each e#e is covered !ith an occl%der ,e#e cover-

and then %ncovered to observe e#e movementsB

Convergence H ;he sim%ltaneo%s t%rning in of the

e#es to 6eep an ob@ect in sight as it comes nearer

to the e#eBConvex Lens H ( spectacle lens !hich is thic6er in

the center than at the edgesB ( convex or 'pl%s)

lens adds optical po!er to incoming light ra#s %sed

in the correction of h#peropia ,farsightedness-B

CR):; H ( thermostat resin material from !hich

plastic lenses are castB (lso called hard resin or

plasticF it !as the 78th form%la from ol%mbia

.esin and is no! man%fact%red and trademar6ed

b# 55= 1nd%striesB

Cra.ing H ( crac6ed or spider !eb appearance on

a lens s%rface or edgeBCribbing H .emoval of excess lens material on the

edgeB

Cross Curve H ;he strongest c%rve of a toric

s%rfaceL lies in the meridian 80 degrees from the

base c%rveB

Cross -!e H See strabismus.

Cro#n 6lass H ( spectacle lens material of KBO27

indexB

CR" $Corneal Re(lection "upilometer% H ( device

%sed to meas%re the distance bet!een p%pils of the

e#es in millimetersBCR, $Computer Reading ,ri(ocal% H ( m%ltifocal

design that feat%res !ider intermediate areas !ith a

N0S (dd strengthB ;he# are s%ited for arms&length

distance s%ch as comp%ter screenB

Cruxite H ;rade name of a glass pin6 tintB

Cr!stalline Lens H ( transparent biconvex lens

located behind the p%pil that helps to foc%s light on

the retinaB

C)si.e H ?eas%rement needed for acc%rate lens

si*ingB ;he millimeter reading of the circ%mference

of a given lensBC)si.er  H ( mechanical device for meas%ring the

circ%mference of a lensB

Curve ,op H ( bifocal lens !ith the top line of the

segment slightl# c%rved instead of straightB

Custom Coating H 5rescription lenses ordered

!ith a coating that is processed from a semi&

finished blan6 and then coatedB

Customi.ation H ;he act of tailoring the optical

characteristics of a progressive lens design to the

individ%al !earer based %pon information specific to

that !earerBCut < Coat H ( method of freeform s%rfacing that

relies on achieving l%ster ,transparenc#- on a

generator s%rface b# glossing the s%rface !ith a

hard coating instead of polishing the s%rface

mechanicall#B

C!cloplegic Re(raction & (n examination method

to determine the e#eJs refractive error and best

corrective lenses to prescribeB ;he e#e is dilated

!ith the m%scles of accommodation ,e#e foc%sing

m%scles- being temporaril# paral#*ed !ith special

e#e drops or spra#B ;his is a good method for non&responsive or non comm%nicative patients s%ch as

#o%ng childrenB

C!linder Axis H ;he meridian in !hich the sphere

po!er f%nctions aloneB

C!linder Lens H ( compo%nd lens !ith a toric

s%rface !ith the t!o separate dioptric meridians 80º

apartB ?a# be recorded in ,&- or ,$- po!erB 1t is

al!a#s follo!ed b# an axisF the direction in !hich

there is no po!er of the c#linderB ( prescribed

amo%nt of po!er that is added or s%btracted to the

lens sphere po!er to create t!o different po!ers inthe principal meridiansB

D

atelite => x :? ,ri(ocal H (n occ%pational trifocal

designed for comp%ter %se !ith a !ider ,7O mm-

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and deeper intermediate seg ,KEmm- !ith

intermediate po!er of O0&IIS in the trifocal areaB

atum Line H ( line at the midpoint bet!een the

top and bottom of a lensF also referred to as the

KP0º lineB 3nless other!ise specifiedF optical

centers are gro%nd on this lineB“BC” H +istance et!een entersB

“BL” & +istance et!een 9enses H ;he closest

distance bet!een lensesB ;he fig%re is needed to

comp%te decentration and is meas%red from the

closest nasal point of one lens to the closest nasal

point of the other lensB ;his meas%rement ma# be

different that the mar6ed bridge n%mber on the

frameB

ecenter  H ;o place o%t of centerB

ecentration H ;he act of moving the optical

center of a lens a!a# from the geometric center ofa shape or frame for the p%rpose of aligning the

optical center over the p%pilB ;he lens ma# also be

displaced a!a# from the !earerJs line of sight for

the p%rpose of creating prismatic effectB

egree $@% H ;he 7I0th part of the circ%mference of

a circleB ;he %nit %sed for specif#ing the position of

the axis of a c#linder or the location for the base of

a prismB

ensit! H ,K- ;he !eight of a material per %nit

vol%meL ,2- ( meas%rement of the transparenc# of

a medi%mF as related to light transmissionBept "erception H ;he abilit# to @%dge relative

distances of ob@ectsB

ept "erception ,est H ( test to meas%re the

abilit# of the vision s#stem to discern the relative

distances of vario%s ob@ectsB ,(lso called a

'Ctereopsis ;est)B-

escemets Membrane H the lining of the posterior

portion of the corneaB

evelopmental Vision Anal!sis H ?ore

comprehensive than a ro%tine e#e examF

examination !ill eval%ate all of the patientJs vis%alabilities s%ch as a vis%al ac%it#F e#e foc%sing s6illsF

e#e teaming s6illsF e#e trac6ing s6illsF vis%al motor

s6illsF and vis%al percept%al s6illsB

eviation H ,K- ;he change in direction of light d%e

to the action of a prismL ,2- a misalignment of one

or both e#es associated !ith extraoc%lar m%scle

imbalanceB

iabetic Retinopat! H Gea6ens and ca%ses

retinal changes in the small blood vessels that

no%rish the e#eJs retinaF the delicateF light sensitive

lining of the bac6 of the e#eB ;hese blood vessels

ma# begin to lea6F s!ell or develop br%sh&li6e

branchesBiagram H ( dra!ing ill%strating the basic frame

meas%rementsB

iameter  H;he length of a straight line from one

edge of a lens to the other and passing thro%gh its

centerB

id!mium H ( specific tinted glass lens %sed for

!earer exposed to a soda ash or sodi%m flareB

ften %sed for 'glass blo!er) occ%pationB

ielectric Mirrors H ( mirror coating %sing

bet!een O R KK la#ers of virt%all# colorless

materialsF precisel# appliedF !hich res%lts in abrilliant color mirror effectB ;his mirror does not add

densit# to the lensB

i((raction H 9ight c%rves or travels aro%nd small

circ%lar ob@ectsB

i((usion H ;he scattering of light ra#s that ca%ses

a bl%rred image d%e to the imperfect refractionB

igital ur(acing H 5recise s%rface c%tting %sing

single point t%rningL c%tting height is controlled at all

points of the lensB

ilation H ( process b# !hich the p%pil is

temporaril# enlarged !ith special e#e drops,m#driatic-L allo!s the e#ecare specialist to better

vie! the inside and bac6 of the e#eB

iopter $% H ( %nit of meas%rement of the

refractive po!er of the lensB ( lens !hose focal

point is one meter has a po!er of one diopterB (

lens !hose focal length is one&fo%rth of a meter has

a po!er of fo%r dioptersB

iplopia H +o%ble visionL normall# the ob@ect !hich

is being observed is single and ob@ects in front and

behind this ob@ect are seen do%ble ,diplopia-B

i((use 6lare H .eflected light that does notprod%ce a clearl# discernible imageF iBeBF a ha*#F

bright lightB

irect +ield o( Vision H ;hat portion of the field

!hich is seen b# the mac%laB

irect 6lare H .elativel# bright light that is not

reflectedF b%t emanates from a so%rce s%ch as the

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s%nF oncoming a%tomobile headlightsF or other light

so%rceB

irect 5cclusion H overing the non&ambl#opic

e#eB

ispensing H ;he art of selecting a frameF ta6ing

meas%rementsF filling the lens prescriptionF andfitting a pair of glassesB

ispersion H ;his occ%rs !hen !hite light is split

into separate !ave lengths and component colorsB

istance Acuit! H ;he e#eJs abilit# to disting%ish

an ob@ectJs shape and detail at a far distanceF s%ch

as 20 feet ,I meters-B

istance Vision H 4ision !hen loo6ing at distance

ob@ectsB

istometer H ?eas%res vertex distances ,front of

the e#e to the bac6 of the lens-B

istortion H (n aberration !hich occ%rs as lightra#s move from the center of the lens to!ard the

peripher#B (s ra#s approach the edgeF the lensJs

increasing magnification ca%ses a distorting of the

imageB

ivergence H ;he abilit# to %se both e#es as a

team and be able to t%rn the e#es o%t to!ard a far

ob@ectB

ominant -!e H ;he e#e that 'leads) its partner

d%ring e#e movementsB %mans also have a

dominant handF footF e#eF and side of brain ,not

necessaril# all on the same side-Bouble Concave Lens H ( biconcave lens of

special form having hollo! s%rfaces of eD%al radii

on both sides of the lensB

ouble Convex Lens H ( biconvex lens of special

form having b%lging s%rfaces of eD%al radii on both

sides of the lensB

ouble egment Bi(ocals H 9enses !ith

segments at the top and bottom of the lensB C%ited

for those !ho reD%ire near focal length above and

belo! the headB

o#n Bend H ;he drop or do!n!ard bend of thetip end of a temple ,earpiece- to fit over and aro%nd

the earL also 6no!n as the ear bendB

rilling H ;he process of ma6ing a hole in a lens

for mo%nting on a frameB

rop Ball ,est H ( lo!&velocit#F impact resistant

testF commonl# %sing a solid steel sphere free&

falling O0 inchesB or (BABCB1B T&P0 standardsF a

O/P inch steel ball falling O0 inchesL for (BABCB1B

TPNstandardsF a K&inch steel ball falling O0 inchesB

rusen H ;in# #ello! or !hite deposits in the retina

or optic nerve headB

r! -!e !ndrome 9 1tchingF b%rningF and irritation

of the e#esB a%sed b# lac6 of D%alit# or D%antit# oftears to l%bricate e#esB ?a# prescribe 'artificial

tears) to alleviateB

uction ,est H ( test of the e#eJs abilit# to t%rn

in!ard or o%t!ard !hile maintaining singleF

binoc%lar vision !ith the grad%al introd%ction of

progressivel# stronger base&in or base&o%t prismsB

!seidetic H 5oor sight recognition of !ordsB (

form of d#slexiaB

E

-arpiece H ( component of a spectacle frame

designed to assist its stabili*ation b# extending over

the external earB

-ccentric +ixation H ;he person fixates the image

of regard !ith an area other than the fovea ,center

of the retina that prod%ces the sharpest e#esight-

area of fixationB

-C" H (bbreviation for e#ecare professionalB

-dge H 1n lens opticsF the flat or angled s%rface

!hich limits the refracting s%rfaces of a lensL the

edge determines the peripheral shape of a lensB-dge Coat H Colid color coat applied on the edge

of a lens to hide thic6ness and eliminate ring

reflections seen in the lensB 3s%all# color selected

matches the frame color closel#B

-dge "olising H ;he grinding process on edge of

lenses leaving a finished clear edge rather than a

!hite frostB

-dged Lens H ( lens that has been gro%nd to

prescription and c%t to the si*e and shape of an

e#eglass frameB

-dger  H ( machine %sed to red%ce a lens to adesired si*e and shape of a frame !ith a desired

edge conto%rB

-dging H :dging a lens means hogging it do!n

from its original circ%lar shape to the precise si*e

and shape needed for it to fit into the !earerJs

frameB

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-((ective iameter $-% H ;!o times the longest

radi%s of an# given shape or lensB ;his val%e !ill

give the smallest theoretical diameter needed to c%t

o%t an# given shapeF ass%ming the center of that

blan6 !as s%perimposed over the geometric center

of the shapeB :+Js are especiall# critical in high.xs to determine appropriate blan6 si*e and lens

thic6nessB

-((ective "o#er  H Cee vertex po!erB

-lectromagnetic pectrum H ;he entire range of

radient energ#F incl%ding x&ra#F visible lightF

infraredF radiationF radio !avesF etcB

-mer! H ;he abrasive %sed for grinding a lens

s%rfaceB

-mmetropia H ;heoreticall# normal e#esightB

.efractive condition of the e#e in !hich the ra#s of

light come to a point of foc%s perfectl# on the retinaB-ndotelium H ;he inner most la#er of the corneaB

-ndpiece H ;hat part of a frame !here the frame

front is @oined !ith the templeB

-pitelium H ;he o%ter most la#er of the corneaB

-pox! H ( t!o component organic coating applied

to frames for adding d%rable decorative colorationB

-3utin "risming H ( proced%re grinding base

do!n prism 3 ,both lenses- to arrive at a thinnerF

more pleasing lensB :D%ithin can be %sed on an#

prescription b%t is especiall# effective on pl%s

distance prescriptionsF progressive lensesF andexec%tive st#le m%ltifocalsB

-soporia H ;he tendenc# of the e#e to t%rn

in!ard or nasall#B

-sotropia H ( condition of misalignment of the

e#es in !hich one or both e#es t%rn in!ard or

nasall#B

-xecutive Bi(ocal H ( one&piece bifocal that

incorporates the total bottom portion of the lens for

close vision !ith a visible dividing line across the

entire lensB 1t is thic6er and heavier than flat top

st#les and disco%raged beca%se of thesedra!bac6sB

-xecutive )eg ,ri(ocal H ( plastic trifocal !ith a

flat top 2O mm seg st#le set inside the intermediate

exec%tive st#le areaB

-xecutive ,ri(ocal H ;here are t!o ledges across

the lens that represent the bifocal and trifocal area

for distanceF intermediateF and near vie!ing areasB

-xpanded Visual +ields H GiderF largerF or more

precise vision in the field of vie!B

-xtraocular Muscles H ;he m%scles attached to

the o%tside of the e#eball !hich control e#e

movementB :ach e#e has six m%scles that are

coordinated b# the brainB-xoporia H ;he tendenc# of the e#e to t%rn

o%t!ardB

-xotropia H +ivergent strabism%sB ( condition of

the e#e t%rning laterall# or temple!ard of one or

both e#esB

-xtraocular H %tside or external to the e#eB

-!e H ;he organ of visionL oc%l%sB 1n h%mansF a

spheroid bod# approximatel# one inch in diameterF

occ%rring in pairsF positioned in soc6ets in the front

of the s6%llF !hich foc%s lightB

-!eglasses H ( term commonl# %sed to describean ophthalmic frame !ith lenses insertedB

-!e 4and Coordination H ;he abilit# of the e#es

to g%ide the handsF also called vis%al motor

integrationB

-!e Lids H ?ovable folds of tiss%e that protect the

e#e from in@%r#F excessive lightF and distrib%te the

tear film over the cornea and con@%nctivaB

-!e "iece o( Lensometer  H ;he telescopic portion

of the instr%ment that can be foc%sed to the

individ%al e#eJs error in order to see the ad@%stment

of the po!er !heelB-!e i.e H Ci*e of lens hole meas%red !ith a

millimeter r%ler on a frame from edge to edge to

inside frameB

-!e ,rac1ing H ;he abilit# of the e#es to smoothl#

and effortlessl# follo! a moving targetB

-!e#ire H ;he part of the frame that encircles the

lens and holds it in placeB

F

+ace +orm H ;he gentle !rap of a frame frontnecessar# to parallel the ro%ndness of the headB

+aceted Lens H 5rescription lenses fabricated !ith

highl# polished and beveled edgesB

+actor! Coating H oatings applied to large

batches of lenses !here the .x is alread#

established on the lensB

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+ar "oint H ;hat point %pon the vis%al axis of the

e#e !hich is sharpl# imaged on the retina !hen the

accommodation is relaxedB ;he far point of a

normal e#e lies at infinit#B

+arsigtedness H ( condition in !hich the optics

of the e#e are not adeD%ate to foc%s on the retina ofthe e#eB ;his res%lts in bl%rred visionF %s%all# in the

near field of visionB 1t is corrected !ith pl%s po!er

lensesB ,(lso called h#peropiaB-

+ ,ri(ocal H ;raditional near flat top segment

positioned on a f%ll lo!er portion intermediate lensB

+ield o( Vie# H +istanceF intermediate and near

vie!ing areasL part of the observable !orld thatJs

seen at an# given momentB

+ilter H 1n optical scienceF a deviceF materialF or

color for restricting transmission of certain light

ra#sB+ine Motor 1ills H ;he abilit# to coordinate hand

and finger movementsB

+ining H ;he grinding proced%re #ielding a satin

smooth finish immediatel# prior to the polishing

stage of lens s%rfaceB

+inised 7ncut Lens H (n ophthalmic lens that

has been gro%nd and polished on both sides to a

specific prescription po!er and thic6nessL has been

edged rendered impact resistantF if necessar#F and

prepared for insertion or mo%nting into a frameB

+itting H ;he meas%rement and/or ad@%stment offrames or mo%nting for the specific needs of the

!earerB

+itting Cross H ;he location on a progressive

addition lens that is normall# fit in front of the p%pil

centerL denoted b# t!o U inch lines crossed at right

angles to each other on a lens la#o%t chartB 1t is

%s%all# 2&E mm above the ma@or reference point

,?.5- or optical center of the lensB

+itting ,riangle H 1n spectacle opticsF a geometric

constr%ction from the three points !here spectacles

contact or p%t press%re against the headB ;he apexof the triangle is the press%re point on the crest of

the noseF and the base of the triangle is the t!o

press%re points @%st above the external earsF on

each side of the headB Ghen nose pads are %sedF

there !ill act%all# be t!o press%re points at the

apex of the triangle rather than oneB

+ixation H ;he abilit# to aim the e#e and hold that

aim on an ob@ectF s%ch as a !ord in a line of printB

+ixation isparit! $+% H over&convergence or

%nder&convergenceF or vertical misalignment of the

e#es %nder binoc%lar vie!ing conditions small

eno%gh in magnit%de so that f%sion is presentB+las Mirror  H ( highl# reflective coating on lenses

that is added for both cosmetic and performance

reasonsB

+lat H Tero base c%rvat%re or flat s%rfaceB

+lat),op Bi(ocal H ( t#pe of m%ltifocal in !hich the

segment is flat on topB (lso 6no! as a '+) seg or

straight topB

+lexural trengt H ( materialJs abilit# to resist

deformation %nder loadB

+lint 6lass H ( glass to !hich lead has been

added res%lting in both higher index and dispersionB+loaters H ften called spotsF these are smallF

semi&transparent or blac6 spec6s !ithin the e#e

that becomes noticeable !hen the# fall in the line of

sightB ?edicall#F the# are deposits of var#ing

shapes and si*es present in the normall#

transparent vitreo%sB ne ma# be born !ith

floaters or develop themB loaters can be an

indication of serio%s vis%al problemsB

+luorescein Angiograp! H ( test to examine

blood vessels in the retinaF choroids and irisB (

special d#e is in@ected into a vein in the arm andpict%res are ta6en as the d#e passes thro%gh blood

vessels in the e#eB

+lux H ;he rate of flo! of fl%id or energ#B

+ocal Lengt H ;he distance from the bac6 vertex

of a lens to its focal pointB

+ocal "oint H Ghen parallel ra#s of light are

refracted b# a lens the# !ill converge or diverge

from the focal point of the lensB

+ocimeter H (n optical instr%ment for determining

vertex po!erF axis locationF optical centerF error&

free pointF and prism po!er at an# given point onan ophthalmic lensL also called lensometer or

vertometerB

+ocus H ( point thro%gh !hich ra#s of light

converge or from !hich ra#s of light appear to

diverge !hen entering or emerging from an optical

s#stemB

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+orm Constanc! H ;he abilit# to recogni*e t!o

ob@ects that have the same shape b%t different si*e

or positionB ;his abilit# is needed to tell the

difference bet!een 'b) and 'd)F 'p) and 'D)F 'm) and

'!)B

+ormer H (nother name for lens patternB+orm +it Bridge H ;he nasal bearing s%rface

consisting of t!o pads and a connecting strap or

one solid piece of plastic made of clear acr#lic or

silicone based materialB

+ovea H ( central part of the mac%la that provides

the sharpest vision and contains the most conesB

+rame H (n appliance that is designed to hold

corrective lensesB

+rame " & ;his is the distance bet!een centers of

the e#e!iresB ;o calc%late frame 5+F simpl# add

the e#e si*e and the bridge si*eB ( EPx20 frame

has a IP frame 5+B

+ran1lin Bi(ocal H ;he initial m%ltifocal lens made

b# %niting the %pper half of a distance po!er lens

and the lo!er half of a near po!er lens in one

frameL the t!o half lenses are independent of each

otherB

+resnel "rism H ( series of narro! prisms molded

into one piece of soft plastic that has the effect of

one prismB ;hese prisms are c%t and applied

directl# to the lens s%rfaceB ;he# are an alternative

!hen prism is reD%ired and a standard lens can not

be gro%nd or !hen lenses !ill be too thic6 and

heav#F if s%rfacedB 1n additionF the# can be

removed !itho%t rema6ing a lens !hen a patientJs

prism correction is %ndergoing several changes

over a period of timeB

+ringe H 3sed to denote lenses or blan6s of s%ch

po!erF c%rvat%re or t#pe that are not %sed in great

D%antit#B

+ront H ( component of an ophthalmic frame

t#picall# consisting of a bridge and e#e!iresB

+rosted Lens H ( transl%cent lens s%rface that

allo!s light to enter the e#e !itho%t crispF sharp

opticsB

+racture H ( crac6 in an ophthalmic lens s%rfaceB

+undus H ;he interior lining of the e#eballF

incl%ding the retinaF optic discF and mac%laL portion

of the inner e#e that can be seen d%ring an e#e

examination b# loo6ing thro%gh the p%pilB

+ull +ield Lens H 9ens in !hich the *one of the

prescription optics extends to the edge of the lensB

+used egment & 1s prod%ced b# imbedding a

piece of glass of greater densit# into a cro!n lensB

=enerall#F the segment is placed on the convex

side of the lens and the c%rves on this s%rface are%niform over the entire areaB

+using H ;he %niting of t!o pieces of lens material

b# means of high temperat%reB

+usion H ;he process of merging the images from

each e#e to form a three&dimensional ob@ectB

+usion ,est H +etermines the e#es abilit# to %nite

the images from each e#e into a single imageB

+usional Vergence H ( convergence response

!hich serves to maintain ,f%sion- the %nion of

images from each e#e into a single imageB ;he

e#es !ill t%rn !ith a slo! smooth tonic movementor a fast @%mping movement called phasicB

G

6auge H ( meas%ring instr%ment or device

calibrated to a previo%sl# established standardF or

s#stem of %nitsB

6enerating H ( rapid ro%ghing process to D%ic6l#

remove material from a lensB (ccomplished b#

c%tting tools on a machineB

6enerator +ree)+orm H ( t#pe of comp%ter&

controlled generator !ith at least three axes of

movement that can c%t most contin%o%s lens

s%rface shapes to a level of precision and

smoothness that reD%ires onl# minimal polishing

!ith a free&form polisherB

6enerator ,raditional H ( t#pe of generator !ith

either t!o or three axes of movement that can c%t

onl# basic spherical and sphero&c#lindrical lens

s%rface shapes to a minimal level of smoothness

that reD%ires additional fining !ith a c#linder

machineB

6eometric Center  H ,K- ;he point of a lens that is

mid!a# bet!een the topF bottomF nasal and

temporal edgesB ;his point is most al!a#s different

from the gro%nd optical centerL ,2- the intersection

of the hori*ontal and vertical center lines of a box

that circ%mscribes the lens shapeB

6ost *mage H 1n spectacle opticsF an %n!anted

secondar# image formed b# internal reflections

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from the rear or b# reflection from the anterior

s%rface of the cornea and a second reflection from

the oc%lar ,e#e- s%rface of a spectacle lensB

6lass H ( hardF brittleF amorpho%s s%bstance made

from heat&f%sed silicates !ith soda or potashF limeF

metallic oxidesF and similar elements of transparentD%alit# %sed to man%fact%re an ophthalmic lensB

6lass Beads H Cmall balls of glass %sed in a frame

!armer to provide an evenF constant heat to the

frameB

6lare H .elativel# bright light entering the e#e

creating da**leF discomfortF or vis%al impairmentB

6laucoma H ( disease associated !ith increased

press%re of the fl%id of the e#eB ;his disease ma#

initiall# have no s#mptoms or painB ;he condition

damages the optic nerve that ma# lead to

blindnessB ?a# be treated !ith medication drops

and/or s%rger#B

6la.ing H ;he process of edging and inserting

lenses into frames or mo%ntingsB

6oggle H (n oc%lar protective device designed to

fit the orbital area of the face to shield the e#es

from a variet# of ha*ardsL ma# be ventilated or non&

ventilatedB

6onioscope H ( magnif#ing device %sed in

combination !ith strong ill%mination and a contact

lens for examining the angle of the anterior

chamber of the e#eB

6radient H 1n tinting lensesF application of d#e to a

lens ma6ing the top dar6er and fading to clear

to!ards the bottom of the lensB

6radient Mirrors H 5rimaril# %sed for driving or

reading o%tdoorsB ;his mirror helps reflect the

intensit# of the s%n above !hile leaving a slight

lighter area belo! for better visabilit# of the

dashboard or reading materialB

6re! H ondition of a lens s%rface !hen improperl#

or ins%fficientl# polishedB

6rind H ;hat process in the fabrication of a lens

!hich gives it a specific nat%reB

6roove H ;he angle formed b# the 4&shape of an

e#e!ire groove to accommodate a beveled lensB

6rooving H ;he process of c%tting a deep channel

bet!een the edges of a rimless lensB ;his allo!s

the lens to be sec%rel# mo%nted in to a frame %sing

metal or n#lon cordB

H

4al( -!e H ( frame designed in s%ch a manner that

the !earer ma# loo6 over the top %sing nat%ral

vision for distance and the correction on the bottom

for close visionB4and tone H ( rotating !heel composed of a

material than can grind a lens and not chip it %sing

the stone and appl#ing a lens edge to its s%rfaceB

4ard esign H ( progressive lens design t#picall#

having large clear distance and reading *onesB 1n

order to create these distinct areasF all of the

%n!anted s%rface astigmatism is forced to the

peripher#B ;he res%lt is a closel# pac6ed s%rface

astigmatismF on either side of the corridorF bet!een

the KP0º line and the reading areaB

4ard Resin H ( thermostat resin material from

!hich plastic lenses are castB (lso referred to

.&78 or plasticB

4a.e H 1n ophthalmic lensesF the presence of slight

scratchesF marsF coating delaminationF or similar

s%rface imperfections that interfere !ith light

transmission b# creating scatter lightF s%rface

astigmatismF on either side of the corridorF bet!een

the KP0º line and the reading areaB

4eat ,empering $ardening% H ( heat treatment

applied %nder press%re to the front and bac6

s%rface of the lens to strengthen the lens against

brea6ageB

4emeralopia H +a# blindnessL defective vision in

bright lightB

4emianopsia H lindness of half the vis%al field of

one or both e#esB

4eteroporia H ;endenc# of the e#es to deviate

from their normal position of vis%al alignmentB (

m%sc%lar imbalance existsL ho!everF a person can

overcome it and still maintain approximatel# normal

single binoc%lar visionB

4eterotropia H ;he e#es are abnormall# t%rnedB4ex 'ut H ( small hexagon n%t %sed on the end of

a post or scre! in order to retain a lens in a frame

or frame parts togetherB

4idden 4inge H (n imbedded hinge anchoring

device !hich allo!s elimination of shieldsB

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4ide)A)Bevel H ( specific t#pe of bevel %sed for

cosmetic appearanceB 1t is a flatter bevel generall#

%sed on strong min%s lensesB

4ig *ndex Lens H 9ens !ith a refractive index

greater than KBON made from this material !ith more

efficient light&bending abilit# ,high index ofrefraction- than hard resin or cro!n glassB ;he

res%lt is a thinnerF and in most casesF a lighter lensB

4inge H ?etal fastener attached to both the

endpiece of the front and the end of the templeB 1t

has 7F OF or N barrels !hich interloc6 one anotherB

4ordeolum/t!e H ( smallF sometimes painf%lF

infection of the sebaceo%s gland of the e#elidB

4ori.ontal Meridian H the KP0º meridian on a

c#lindrical s%rfaceB

4ue H ;he partic%lar aspect of color or !avelength

that enables it to be assigned a position in thevisible spectr%mB

4!dropobic H aving little or no affinit# for !aterB

4!dropobic Coating H ;he top la#er of modern

coatings designed to repel oils and dirt and other

debris on the lens s%rfaceB 1t provides sm%dge

resistanceF cleanabilit#F and s%rface d%rabilit#B

4!permetropia H .efractive error or optical defect

of the e#e in !hich parallel ra#s of lightF as from a

distant light so%rceF stri6e the retina before coming

to a foc%sB

4!peropia H arsightednessL the abilit# to seedistant ob@ects more clearl# than close ob@ectsL ma#

be corrected !ith glasses or contact lensesB

4!perporia H ( tendenc# of one e#e to t%rn

above the other e#eF ca%sing e#estrainB

Cometimes improved b# prism gro%nd in lensesB

4!pertropia H ne e#e is act%all# t%rned above

the otherB

4!po)Allergenic H 5ropert# of prod%ct offering

benefit in red%ction of sensitivit#B

4!potropia H +o!n!ard deviation of one e#eB

I

*llumination H ;he amo%nt or intensit# of light

stri6ing an ob@ectB

*mage ump H ;he apparent s%dden displacement

of an ob@ect that occ%rs !hen the fixation axis

passes abr%ptl# from one vie!ing area of a non&

progressive m%ltifocal lens to anotherB ;his ma# be

exaggerated in high po!er lensesF b%t can be

minimi*ed b# proper segment choiceB

*mbalance H ( state or condition !hen something

is o%t of eD%ilibri%m or %neD%alB

*mpact Resistance H ;he meas%red abilit# ofmaterial or lens to s%stain d#namicall# applied

external forces !itho%t brea6ingB

*n situ H 9atin for 'in the sit%ationB) (llo!s !earer to

!ear frame as the# !o%ld !ear it normall# before

ma6ing lens meas%rementsB

*n Camber H ;he action or application ta6es place

inside the vac%%m chamber d%ring coating

application processB

*ncident Ra! H ( ra# of light is said to be an

incident ra# before it stri6es a lens or prismB (fter

passing thro%gh the lens or prismF the ra# is said tobe the emergent ra#F or the refracted ra#B

*ndex o( Re(raction H ;he degree to !hich a lens

material refracts ,bends- lightB ;his res%lts from the

ratio of the speed of light in air to the speed of light

thro%gh a lens s%bstanceL the higher the index of

lens materialF the D%ic6er light ra#s are bent as the#

pass thro%gh the lensB ;he higher the indexF the

more the refractive po!er of the lensB

*nduced "rism H ;he prism po!er created !hen

the optical center of a lens is o%t of coincidence

!ith the !earerJs vis%al axesF or !hen the vis%alaxes intersects an# point on a lens !ith refractive

po!erF a!a# from the optical centerB

*n(init! H 1n optical scienceF a distance great

eno%gh so that ra#s of light from that distance ma#

be regarded as parallelL 20 feet or I meters or

greaterB

*n(rared H :lectromagnetic radiation !ith

!avelengths longer than visible lightF b%t shorter

than micro!ave radiationB

*n)mass "otocromic H 9enses in !hich the

photochromic material is dispersed evenl#thro%gho%t the s%bstrateB

*nset H =enerall# refers to the additional

decentration of a bifocal segment be#ond the

distance decentrationB

*ntermediate eg H ;he middle lens in a trifocal set

for a foc%s shorter than distance b%t longer than

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nearB ;he %s%al foc%s is half the bifocal po!erF

!hich allo!s the !earer to foc%s at armJs lengthB

*nterpupillar! istance H ;he linear distance

bet!een fixation axis of the !earerJs e#e or centers

of the p%pil !ith e#es foc%sed at distanceB

*nterval o( turm H Ceparation bet!een t!o focallines of an astigmatic imageB

*ntraocular Lens $*5L% H ( s#nthetic lens

implanted after cataract s%rger# to replace the

damaged cr#stalline lensB

*ntraocular "ressure $*5"% H 5ress%re of the fl%id

inside the e#eL normal 15 varies among

individ%alsB

*nverted *mage H 4is%al impression of an ob@ect as

formed b# a lens or mirrorF in !hich the %pper and

lo!er portions of the image appear as exchangedB

*ris H ;he colored ro%nd portion of the e#eF sit%atedbet!een the cornea and the lensF and perforated b#

the p%pilB .eg%lates the amo%nt of light entering

the e#e b# ad@%sting the si*e of the p%pilB

*ritis H 1nflammation of the irisB

*socromatic H 5ossessing the same color

thro%gho%tB

*socoria H :D%all# in si*e of the t!o p%pilsB

*ostropic H aving eD%al refractive po!er ,index of

refraction- in all directionsB

J

aeger ,est H ?eas%rement of vis%al ac%it# at the

reading distanceB

K

eratitis H (n inflammation of the corneaB

eratoconus H ( cone shaped protr%sion and

thinning of the corneaB

eratometer H (n instr%ment %sed to meas%re the

c%rves of the corneaL also 6no!n as anophthalmometerB

eratometr! H ?eas%rement of the c%rvat%re of

the anterior s%rface of the corneaB

e!ole Bridge H ( bridge design for a front that

does not permit contin%o%s contact bet!een the

nose and the front in the nasal crest areaB

.esembles an 6e#hole !ith a circ%lar arc at the top

of the opening in an antiD%e doorB

r!pto1 H ( f%sed lens !ith a ro%nd top bifocal 22

mm in diameterB

L

Lacrimal 6land H ;he small almond&shaped

str%ct%re

that prod%ces tearsL located @%st above the o%ter

corner of the e#eB

Lacrimation H 5rod%ct of tearsB

Lag o( Accommodation H ( meas%re of the e#eJs

abilit# to foc%s acc%ratel# on a given targetB ;he

dioptric difference bet!een the e#eJs foc%sing

response and the stim%l%s to foc%sB

Laminated Lens H ( lens formed b# t!o or morela#ers of refracting material firml# @oined together

for special optical or safet# p%rposesB

Lap H ( tool %sed in the man%fact%re of ophthalmic

prod%ctsL made from cast ironF al%min%mF brassF or

plastic forms !ith po!er c%rves on the top s%rfaceL

%sed either as grinding or polishing platforms to

prod%ce refractive or reflective s%rface po!ers on

lensesB

Lap ,ool $4ard% H ( rigid tool having a specific

c%rvat%re that is %sed in con@%nction !ith vario%s

abrasive pads to smooth and polish generated lenss%rfaces of the same c%rvat%reB

Lap ,ool $o(t% H ( flexible tool made from a

compliant foam or air bladder that is %sed in

con@%nction !ith free&form s%rfacing to polish

generated lens s%rfaces that have complex shapes

!ith var#ing c%rvat%reF s%ch as progressive

s%rfacesB

Laser -ngravings H :tchings or engravings on

progressive lenses to denote the position of the

fitting crossF add po!erF etcB

Lasi1 H ( s%rgical proced%re %sing a laser toreshape the cornea to correct refractive errorsB

Lateral 6radient ,int H ( cosmetic tint dar6er

temporall# and fades to!ard the centerB 1ts

application is for !earers !ith %n%s%all# narro!

5+sB

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La!out H ,K- ;he art or process of arrangingL ,2- 1n

opticalF the process of mar6ing a lens blan6 for

positioning in s%rfacing or edging eD%ipmentB

La.! -!e H See amblyopia. 

Legal Blindness H 1n the 3BCBF ,K- vis%al ac%it# of

20/200 or !orse in the better e#e !ith correctivelenses ,20/200 means that a person m%st be at 20

feet from an e#e chart to see !hat a person !ith

normal vision can see at 200 feet- or ,2- vis%al field

restricted to 20 degrees diameter or less ,t%nnel

vision- in the better e#eB

Lens H ,K- ;he transparentF do%ble convex

,o%t!ard c%rve on both sides- str%ct%re of the e#e

s%spended bet!een the aD%eo%s and vitreo%sL

helps to foc%s light on the retinaB ,2- ( device or

means of ca%sing the e#e to ma6e the maxim%m

change possible in the accommodative pattern!itho%t introd%cing an %ndesirable change in the

convergence patternB

Lens $Bac1)ur(ace% H ( t#pe of free&form

progressive lens that emplo#s a factor#&molded

spherical s%rface on the front and a free&form&

s%rfaced progressive s%rface that has been

combined !ith the prescription c%rves on the bac6B

Lens $ual)ur(ace% H ( t#pe of free&form

progressive lens that emplo#s a factor#&molded

progressive s%rface !ith a portion of the total

addition po!er on the front and a free&form&s%rfaced progressive s%rface !ith the remaining

addition po!er that has been combined !ith the

prescription c%rves on the bac6B

Lens Bevel H ;he edge of a lens shaped li6e a '4)B

;he bevel helps to sec%re the lens after it has been

inserted in the frameB

Lens Cloc1 H ,base c%rve cloc6- H ( smallF ro%nd

cloc6&t#pe ob@ect !ith three prongsF !hen placed on

a lens it gives the po!er of the lens s%rfaceB 3sed

to determine base c%rves primaril#B (lso called a

sagitta ga%geBLens Coating H oatings placed on a lens for

either tinting or reflection p%rposesB

Lens Corridor H ;he channel of an ophthalmic

progressive lens @oining the distance vie!ing area

and the total reading po!er areaB

Lens i((erence H 1n spectacle opticsF the

n%merical difference expressed in millimeters

bet!een the hori*ontal ( and vertical

meas%rementsB

Lens 6roove H ;he angle formed b# the 4&shape

of an e#e!ire groove to accommodate a beveled

lensB

Lensometer  H (n instr%ment to determine theprescription of an# given c%rve lensL also 6no!n as

a focimeter or vertometerB

Lens "attern H ( templateF %sed in lens edging

eD%ipment to generate correct peripheral shape

and geometric center locationB

Lens "o#er  H ;he diopter po!er or prescription of

a lensB

Lens Retention H ;he abilit# of a front to 6eep a

lens from dislodging from the e#e!ire groove %nder

forceB

Lens top H 1n a lonsometerF a mechanical holderto position the lens at a fixed positionF thereb#

providing a %niform meas%ring apert%reB

Lens 8aser  H 4er# thin n#lon beveled material to

fit bet!een a lens and an e#e !ire to hold the lens

in more sn%gl#B

Lenticular Asperic H 3s%all# plastic cataract

lenses gro%nd so that the overall !eight and

thic6ness is red%ced and to eliminate lens

distortions are eliminatedB

Lenticular Lens H ( strong po!er gro%nd into a

red%ced area of the lens to limit thic6nessB ;heremainder of the lens is called a carrier and

provides no refractive correction b%t gives

dimension to the frame for mo%ntingB efore high

pl%s asphericsF these lenses had a higher %sage

b%t the# are still often the onl# option for some

apha6ic patients !itho%t a lens implantB

Librar! ,emple H (n earpiece !itho%t an ear bend

or do!n bendB

Ligt H ,K- ;he radiant energ# !hichF after entering

the e#eF provides the initial stim%l%s for sightF ,2-

electromagnetic radiations visible to the h%man e#e!hich gives rise to the sensation of vision b#

stim%lating the rod and cone cells of the retinaL

absence of dar6nessB

Ligt Adaptation H (bilit# of the e#e to ad@%st itself

to an increase in the intensit# of lightB

Ligt "erception H ;he abilit# of a person to

recogni*e the presence of a l%mino%s so%rceB

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Limbus H irc%lar *one !here the cornea @oins the

sclera ,!hite of the e#e-B

Longe)Range Vision H 3s%all# from O0 inches to

infinit#B

Lo# Vision H 4is%al loss that cannot be corrected

!ith e#eglasses or contact lenses and interferes!ith dail# living activitiesB

M

Macula H ;he smallF sensitive area of the central

retinaL the mac%la is responsible for good vis%al

ac%it#F color visionF and central visionB

Macular egeneration H ;he deterioration of the

most sensitive and important region of the retinaF

the mac%laB ;his degeneration ca%ses significant

bl%rring of the central vision and can lead toblindnessB

Magnesium +luoride H ( metal oxide commonl#

applied to the s%rface of ophthalmic lenses to

red%ce and eliminate spec%lar reflectionsB

Magni(ication H ;he increase in the apparent or

perceived si*e or s%btended angle of an image in

relation to act%al si*e of ob@ectB

Ma&or Meridians H ;hese are the t!o meridians

made %p of the meridian of axis po!er and the

meridian that is 80 degrees from the axisB

Ma&or Re(erence "oint $MR"% H ;he point on alens that satisfies all optical D%alitiesB ;he point on

a !here the complete meas%re of a prism reD%ired

is presentB

Marginal Astigmatism H Ghen a narro! beam of

parallel ra#s stri6es a lens obliD%el#F ra#s in the t!o

opposite meridians foc%s at different pointsB ;he

distance bet!een the t!o foc%s points eD%als the

degree of astigmatism ca%sedB ;his tro%blesome

error ca%sed lens man%fact%rers to develop a

corrected c%rve lens seriesB ;he idea is if specific

c%rvat%res are controlled for specific correctionsFthen marginal astigmatism can be controlledB

Mar1ing evice o( Lensometer  H ( device

mo%nted on a lensometer that is %sed !ith an in6

pad to mar6 the center and the direction of the axis

of the c#linder in a lensB

Mar1ing "ins H Cmall metalF spring&mo%nted

pointed pins on a lensometerF in6ed and %sed to

mar6 the ma@or reference point and hori*ontal lens

bisector on an ophthalmic lensB

Mar1)up H ?ar6ing of a reference line on a lens

d%ring the s%rfacing process to define ho! optical

characteristics are to be gro%nd into a lensB

Mastoid Bend H ;he c%rvat%re in the do!n bend ofthe temple ,earpiece- adapting to the mastoid

c%rvat%re ,depression- be#ond the earB

Mecanical Center  H the geometric center of an

optical lensB

Medium H (n# material thro%gh !hich light passesB

Meibomian 6lands H ( variet# of glands located in

the e#elidB ;he# secrete an oil# s%bstance to 6eep

the e#e l%bricated and the tears from overflo!ing

the lid marginsB

Melanin H ( pigment that gives hairF s6in and e#es

its colorB Aat%re %ses melanin to protect the tiss%eof the e#e from s%nlight damageB ?elanin absorbs

the color in preportion to their potential damageB 1t

is lost !ith agingB

Meniscus H ( lens !ith a crescent&shaped profile

that is a combination of a concave and a convex

s%rfaceB

Meridian H phthalmic lens po!er is specified

according to a pattern similar to the face of a cloc6B

;he hori*ontal ,KP0- merdian !o%ld be a line

passing thro%gh the three and the nineB ;he vertical

,080- meridian !o%ld be a line passing thro%gh sixand t!elveB ;he one to seven line !o%ld be the 0I0

meridian and the ten to fo%r line is the KO0

meridianB

Metallic $Re(lexive% Mirrors H ;hese coated

lenses red%ce visible light b# 2OS to 7OS %sing K

to 7 la#ers of metalB ?etallic mirrors sho%ld be

applied to lenses !ith a base tint of at least O0S

densit# for maxim%m effectB

Mid)Range Vision H 3s%all# from 70 inches to O0

inchesL arms&length rangeB

Millimeter H ( s%b%nit of linear meas%rementL onetho%sandth of a meterL abbreviated mmB

Miniaturi.ation  H Ghen an image is smaller

thro%gh the lens than its original ob@ect si*eB

Minimum Lens ,ic1ness H ;here is a limit to

ho! thin a lens can be s%rfacedB ;his minim%m

thic6ness is determined b# practicalit# and b#

established standards s%ch as (AC1 TP0&K888B

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Minus H ;erm %sed to indicate the po!er of a

concave s%rface of po!er of a lens !hose concave

s%rface is stronger than its convexB 3sed to correct

m#opiaB

Mires o( Lensometer  H;he bars and dots that go

in and o%t of foc%s as #o% t%rn the po!er !heel ofthe lensometerB

Mirror Mirror 6radient Mirror ouble 6radient

 H ( vac%%m applied mirror&t#pe coating placed on

the front of the lensB

Miter oint H ( @%nct%re bet!een front and temple

!here both mating s%rfaces are ang%larl# c%tB

Moisture Camber  H ( thin plastic sheet attached

to the e#e!ire of a frame and shaped to fit li6e a

safet# c%p st#le side shieldB elps to create a

chamber of moist%re for a dr# e#e conditionB

Monocle H ( single e#eglass lens designed to be!orn or hand&held in front of one e#eL %s%all#

provided !ith an attached cord or chainB

Monocular H 5ertaining to one e#e onl#B

Monocular Vision H 4ision res%lting from the %se

of one e#e onl#B

Mono)esign H ;his progressive lens t#pe %ses a

single design for a given distance base c%rve to

!hich all add po!ers are appliedB

Mounted Lens H 9ens that has been inserted into a

spectacle frame frontB

MR)=0 H 3niD%e KBIN high index resin %sed in lensman%fact%rerJs mix !ith best tensile strength for

rimless mo%ntingsB

MR" H ;he ?.5 ,ma@or reference point- is that

point in the lens that gives the prescriptionB

Multi)esign H ;his progressive lens is c%stom

designed for each base/add po!er combinationB

9ens variables are selected and controlled for all

designs maximi*ing vis%al performanceB

Multi(ocal H( lens incorporating t!o or more

different po!ers ,incl%des bifocalF trifocalF or

progressive lenses-BMulti)la!er AR H (ll modern (. coatings consist of

m%ltiple la#ers on each side of the lensF %s%all# five

or moreB

M!driatic H (n# dr%g that dialates the p%pilB

M!odisc H ( strong min%s lens that limits thic6ness

b# lentic%lari*ing the min%s po!er into a small 2O to

7O mm concave bo!l in the center of a 5lano or

pl%s lens blan6B ften an option for a ver# high

min%s patientB

M!opia H AearsightednessL abilit# to see close

ob@ects more clearl# than distant ob@ectsL a

refractive condition in !hich the point of foc%s falls

in front of the retinaL ma# be corrected b#e#eglasses or contact lensesB

N

' H ;he variable %sed to represent a materialJs

index of refractionB

'anometer $nm% H ( %nit of length eD%al to one&

millionth of one millimeter or K0 (ngstrom %nitsL

%sed to meas%re the !avelength of lightB

'arro#/stretc Bridge H ;o change the bridge

si*e b# modif#ing the shape of a lens b# c%ttinga!a# the bridge

or filling the bridge area !ith extra frame material

on a *#l frameB

'asal -dge H ;he side of a spectacle lens closest

to the noseB

'ear Acuit! H ;he e#eJs abilit# to disting%ish an

ob@ectJs shape and details at a near distanceB

'ear "oint o( Convergence $'"C% H ;he closest

point at !hich the t!o e#es can maintain a single

%nit imageB

'earsigtedness H ( condition in !hich the opticsof the e#e are too strong and foc%s in front of the

retinaF res%lting in bl%rred distance visionB (lso

referred to as m#opiaB 1t is corrected !ith min%s

po!er lensesB

'ear Vision H 3s%all# from KK inches to !ithin arms

reach ,approxB 70 inches-B

'ear Done 8idt H ;he meas%rement of the near

*one ta6en at a specified point belo! the fitting

crossB

'egative Relative Accommodation $'RA% H (

meas%re of the maxim%m abilit# to relaxaccommodation !hile maintaining clearF single

binoc%lar visionB

'eutrali.ation H 3tili*ing a lensometer to

determine the dioptric po!er of an ophthalmic lensB

'eutrali.er H ( combination of chemicals %sed to

'sta#) a color of tint on a lens s%rfaceB

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'igt Vision H ;he e#eJs abilit# to adapt to lo!

light conditionsB 3nder lo! light levelsF the p%pil

enlarges and the e#e %ses different light receptors

,rods-B +ifferent e#e conditions res%lting in night

blindness or poor night vision incl%de p%pils that

become smaller !ith ageF cataractsFnearsightednessF retinitis pigmentosaF or 4itamin (

deficianciesB

'odal "oint H ;he point on the optical axis to

!hich entering and emerging ra#s are directedB

'ominal "o#er  H ;he nominal c%rve of a semi&

finished lens mar6ed in diopters b# the

man%fact%rerB ;he difference bet!een mar6ed and

act%al tool c%rve of the s%rface represents the

man%fact%rerJs compensation for the base c%rveB

;his compensation allo!s standard tooling to be

%tili*ed over a range of prescriptions !ith little or nof%rther compensation b# the laborator#B

'ormal Retinal Correspondence $'RC% H ;he

foveas of the t!o e#es are corresponding ne%ral

points in the vis%al cortex and binoc%lar vision can

occ%rB

'ormal Vision H 4ision is clear and sharp !hen

the e#e is able to foc%s on images correctl# onto

the retinaB

'ose "ad H ;he nasal bearing s%rface member of

a frontL also called padB

'!ctalopia H Aight blindnessL impaired vision%nder red%ced lightB

'!stagmus H ;he rapid fl%ct%ation of the e#es in a

rotar# or side to side directionB ( fl%ttering of the

e#esB

O

5b&ect isplacement H ?ovement of ob@ects seen

thro%gh a prism to!ard the apex of the prismB

5b&ective Re(raction H +etermination of the

prescription %tili*ing the response of the patient todetermine the acc%rac# of the prescriptionB

5bli3ue H 1n referring to optical axisF an# axis that

is not perpendic%lar ,80- or parallel ,KP0-B

5bli3ue -rrors H bliD%e astigmatism and obliD%e

spherical po!er errorB

5ccluder H (n opaD%e plastic spat%la device %sed

to cover one e#e d%ring examinationB

5ccular 6lobe H ;he e#eballB

5ccular 4!pertension H (n increase in press%re

above the normal range !ith no detectable changes

in vision or damage to the e#eB ommon in ver#

nearsighted or diabetic patientsB

5cculist H (n earl# term for a ph#sicianspeciali*ing in the st%d# and treatment of affects

and diseases of the e#eB

5cular e(ects H ;he end res%lt of vis%al

problemsB

5ccupational egment H ( segment that is

prescribed and fit to ans!er a specific tas6B

5EE H ,K- (n abbreviation of +octor of optometr#L

,2- oc%l%s dexter in latin H meaning 'right e#e)B

5(( Center $Marginal% Astigmatism H l%rred

vision d%e to po!er error and ind%ced c#linder in

the peripher#F corrected b# introd%cing asphericit#into lens designB

5leopobic Coating H ( chemical composition top

coat consisting of h#drophobic chemicals and

oleophobic chemicals to repel dirtF d%stF s6in oilsF

and ma6e %p for effortless cleaning and sm%dge

resistanc#B

5pa3ue H 1mpenetrable b# lightF does not refract

lightB

5ptalmometer H (n instr%ment %sed to

meas%re the c%rvat%re of the corneaB

5ptalmoscop! H ;he doctor examines the insideof the e#es !ith an ill%minates and magnifies the

interior of the e#eB

5ptalmoscope H (n instr%ment containing a

perforated mirror and lenses to examine the interior

of the e#eB

5ptalmologist H ( medical doctor ,?B+B- !ho is

an e#e specialist that can diagnose and treat e#e

diseasesF perform e#e s%rger#F and prescribe

prescriptions and medicationsB

5ptical Correction H ombination of c%rvat%res of

the front and rear s%rface of the lensF meas%red indioptersB

5ptic isc H ead of the optic nerve in the e#eballB

5ptical Axis H (n imaginar# line at right angles to

the s%rfaces of a lens and passing thro%gh its

optical centerB

5ptical Center  H ;he point on an optical lens

!here the light passes directl# thro%gh !itho%t

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bendingB ;he thic6est point of a pl%s lens and the

thinnest point of a min%s lensB

5ptical Cross H ( diagram consisting of t!o

straight lines crossing each other at right angles

orientated to represent the principal refractive

meridians of an ophthalmic prescription lensL %sedto chart the axis and refractive po!ers in the

principal meridiansB

5ptic Cup H ;he !hiteF c%p&li6e area in the center

of the optic discB

5ptic isc/5ptic 'erve 4ead H ;he circ%lar area

,disc- !here the optic nerve connects to the retinaB

ptic nerve has the b%ndle of over one million

nerve fibers that carr# vis%al messages from the

retina to the brainB

5ptician H ( person trained in the dispensing and

fitting of prescription e#e!ear and/or contact

lensesB

5ptical Axis H ;he line that passes thro%gh the

center c%rvat%re of optical s%rfacesB

5ptical Center  H ;he point on a lens thro%gh !hich

light can pass !itho%t being deviatedB

5ptimi.ation H ( method of manip%lating a given

progressive lens %sing complex mathematical

algorithms in order to preserve the desired optical

characteristics of the 'ideal) or 'target) lens design

in the final lensB

5ptometric Assistant H ffice staff primaril#

involved in front&office proced%resF optical

dispensing and contact lens patient ed%cationB

5ptometric ,ecnician H ;echnicians !or6

directl# !ith optometrists in the areas of patient

examination and treatment incl%ding contact

lensesF lo! visionF vision therap#F and optical

dispensing and office managementB

5ptometrist $5EE% H ( doctor of optometr# !ho

speciali*es in vision examinations and treatmentF

prescribes spectacle and contact lensesF and also

diagnoses and treats some e#e diseasesB

5pt!l H ;he trade name for a thermo&setting epox#

resin of high stabilit# %sed in e#eglass framesB 1t

!ill ret%rn to its original shape !hen heatedB

5rbital Cavit! H on# orbits that serve as soc6ets

!hich contain the e#eballsB

5rto1eratolog! H ;he practice of correcting or

red%cing prescription needs s%rgicall# altering the

shape of the corneaB