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About your upcoming exam
50 questions Multiple choice, four possible answers
All questions taken directly from lecture Lecture notes are available in the
optometrie section in the library and online
Similar in style to the last exam No embryology
No slides
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Lecture notes online
For those who dont have it, the URL is: http://virtmed.fg.hvu.nl/domeinen/opto
metrie/optometrie.html
The password is redeye
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About your upcoming examCOSM3
Questions per topic covered: Methods (direct and indirect examination
of the fundus, tonometry, gonioscopy): 5
Fundus Landmarks: 2
Congenital variations: 8-9
Optic Neuropathy: 13 Fundus Spots: 21-22
Total: 50
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About your upcoming examCOSMB
Questions per topic covered: DPAs: 15-16
Methods (direct and indirect examination
of the fundus, tonometry, gonioscopy): 5
Fundus Landmarks: 2
Normal fundus: 7-8 Congenital variations: 8
Optic Neuropathy: 12
Total: 50
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Tonometry
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Tonometry
One abbreviation that will be usedthroughout your career is IOP, whichstands for intraocular pressure
Get used to it
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Tonometry
Measures tension in eye The combined resistance of het oog (IOP)
and the tear film
The main reason we measure this isbecause high pressure is a key indicator
of glaucoma Pressure is elevated in most types ofglaucoma
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Tonometry
Pressure can also be high in cases ofocular inflammation
Uveitis
Perforating injuries to the globe mayresult in an abnormally low pressure
This is called hypotony
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Tonometry
Measured in mm Hg There are three ways to measure IOP
Manometry
Applanation
Indentation
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Tonometry
Manometry The most accurate method of determining
IOP
A needle connected to a column ofmercury is inserted into the eye
Not generally performed in clinical practice
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Tonometry
Applanation Based on the Imbert-Fick formula
IOP = force/area
This is the same formula used in physics
If one measure is kept constant, pressure
is directly related to the other variable The Goldmann tonometer is the one we
use, and the worldwide standard
Also using this theory is the Maklolov unit
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Tonometry
The Goldmann tonometer has aconstant area
The force required to flatten the cornea is
directly related to the IOP
The Maklokov tonometer applies a
constant force The area flattened is directly related to theIOP
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Tonometry
IndentationA constant force applied to the cornea
The cornea is pushed posteriorly
The IOP is related to the distance thecornea is pushed
Influenced by corneal rigidity Tends to be lower in high myopes, who havelarger eyes and therefore slightly softer corneas
Aqueous humor is forced from the eye
Subsequent readings will be lower
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Tonometry
Normal IOP The average IOP is 16 mm Hg
Normal IOP is anywhere from 6 to 21 mm
Hg
An eye with an IOP under 6 is consideredhypotonous
Look for a wound leak (do the Seidel test)
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Tonometry
Normal IOPAn eye with an IOP over 21 is referred to
as hypertensive
Most people with ocular hypertension do notdevelop glaucoma
What this means is that some people have
pressure which is higher than most others, butfor them this is normal
You should make sure of your diagnosis ofocular hypertension with your anamnese and
other tests
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Tonometry
Physical factors affecting IOP Pressure on Globe
Holding lids--some people just wont keep their
eyes open no matter what you say, so youhave to force them open
By doing this, you can inadvertently press onthe globe, giving a false high reading
Blepharospasm, or forceful blinking, can do thesame thing
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Tonometry
Physical factors affecting IOP Trauma/Inflammation
Damage to the trabecular meshwork will
prevent the proper drainage of aqueous fromthe eye
This happens in angle recession glaucoma
Uveitis
In the beginning of the condition, IOP is slightlylowered due to decreased aqueous production
In the later stages, IOP increases as a result of cells
and flare, clogging the trabecular meshwork
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Tonometry
Physical factors affecting IOP Medications
Steroids
Use of these over a long period of time causesin increase in IOP in about 1/3 of all people
Blood pressure medication
Beta blockers, alpha agonists, and carbonicanhydrase inhibitors can lower IOP
Marijuana/alcohol
The effect is gone when it leaves the body
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Tonometry
Physiological factors affecting IOP Diurnal variation
IOP is highest at around 10AM, and lowest in
the late avond Normal variation is 4mm Hg per day, but may
be twice that in glaucoma
If you suspect glaucoma in a patient with highpressure, get a morning reading
If still unsure, you can do a diurnal curve
Start in the morgen, and read IOP every 1-2uur
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Tonometry
Physiological factors affecting IOP Vascular integrity
In cases of hypoxia, there will be low IOP from
decreased aqueous production Since this occurs throughout the eye, there
may be nerve damage despite low IOP
Patient position for measurement IOP is 2-3 mm higher lying down
This is not a problem with current techniques
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Tonometry
Techniques Finger tensions (digital IOP)
Goldmann
Perkins
Non-contact
Pulsair Tonopen
Pneumotonometer
Maklakow Glaucotest
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Tonometry
Finger tensions (digital IOP) Not accurate
Should only be done when all other
methods are not possible
Lightly push on the closedeye
Compare each eye to the other
Rate whether soft, normal, or hard
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Tonometry
Goldmann applanation tonometry Is the gold standard because of its
accuracy and repeatability
The only method used to diagnose andtreat glaucoma
Used with the spleetlamp
There is also a hand-held version made bymany companies, including Perkins
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Tonometry
Goldmann applanation tonometry Uses a tip which has prisms inside
The tip is 7mm in diameter, but only 3.06mm
of the cornea is applanated (flattened) by thetip
The prisms split the image horizontally topermit a proper measurement
Each half of the image contains a semi-circle,which is called a mire
When the mires are aligned properly, you have
determined the IOP
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Tonometry
This is what the mires look like whenthe unit is properly aligned and the IOPreading is correct
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Tonometry
Procedure for Goldmann tonometry Disinfect tonometer tip
Soak in 3% peroxide solution (contact lens
solutions work well) for tien minutes and thenrinse with saline solution
Place tip in holder
Align 180 mark of tip with horizontal line If the patient has more than drie diopters of
corneal astigmatism, place the minus cylinder
axis along the red line of the tonometer
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Tonometry
Procedure for Goldmann tonometry Place a drop of anesthetic in het oog
Instill fluorescein
Switch to diffuse illumination of maximumintensity with the cobalt blauw filter
Observe cornea for staining
Start with the right oog
Pull spleetlamp back
Place illumination system at 60 temporally
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Tonometry
Procedure for Goldmann tonometry Set measuring drum at 10
Note: the drum has numbers 0-8 on it. These
stand for 0 through 80. There are four linesbetween each number. These correspond totwee mm Hg each.
The line by the number 1 is 10 mm Hg. Theline after that is 12mm Hg. If the reading isbetween the first and second lines after thenumber 1, this is a reading of 13 mm Hg.
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Tonometry
Procedure for Goldmann tonometry Place tip in position, directly facing the
patient
Have the patient look straight ahead Bring tip toward het oog, looking from
outside the spleetlamp
When the limbus has a blauw glow, lookthrough the eyepieces
Move spleetlamp forward until you see themires
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Tonometry
Procedure for Goldmann tonometryAdjust the mires until they are centered
Turn the drum until the mires are properly
aligned Remove tip
Check for staining again
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Tonometry
To properly align the mires vertically, movethe spleetlamp in the direction of the largermire. In the picture on the left, you would
lower the spleetlamp, and this would alignthe mires. In the picture on the right, youwould have to raise the instrument. To alignthe mires horizontally, move the spleetlampin the direction of the mires. So in thepicture on the right, you would have to movethe instrument to the right as well as up.
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Tonometry
To have a proper reading, the inside edges ofthe mires should touch. The picture on theleft requires you to increase the reading on
the power drum. The picture on the rightrequires a decrease in the reading. Thepicture in the center shows a tonometerwhere the power is correct.
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Tonometry
15
16
1 Oxybuprocaine 16 30
To properly record, you must document thetest used, the drop used, the IOP reading,the time it was done, the fact that you told
the patient not to rub their eyes, and if thelids were held. If multiple readings weretaken, write them all down and averagethem. The method we use here is below.
lidsheld
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Tonometry
If there is too much fluorescein, as in thepicture on the left, the mires will be too thickand you will get a false high reading
If there is not enough fluorescein, as in thepicture on the right, the mires will be too thinand you will get a false low reading
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Tonometry
If you are pushing too hard on the eye, as inthe picture on the right, you will havedistorted mires which will not move when youchange the reading drum
If you are not pushing hard enough, as in thepicture on the left, the mires will go in and
out of view
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Tonometry
Things to remember Alignment for excessive corneal cylinder
If a patient has an ocular pulse (also called
a hippus) then the reading will fluctuate Set the reading so that the center of this
movement will be where proper alignment is
If you must hold the lids, you must movethe spleetlamp and the power drum withyour other hand
Scarred corneas give distorted mires
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Tonometry
The hand-heldtonometer works thesame way as theGoldmann tonometer
The power wheel iscontrolled by yourthumb
You should also recordthe patients position
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Tonometry
Non-contact tonometry (NCT) Works by applanation (by air)
A puff of air flattens a fixed area of cornea
The air stops when the cornea is flattenedenough to allow a light to be reflected to areceiver
The amount of air needed is related to theIOP, and the machine displays the nummer
Must average drie readings per oog
OK for screening purposes
T
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Tonometry
air pulse
Monitoring
mirror system
Light source
Air pulse
Non-Contact Tonometer (NCT)
T t
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Tonometry
Non-contact tonometry procedure Disinfect chin & headrest
Demonstrate puff
Switch instrument to regular mode
Align patient comfortably
Patient closes eyes
Set and test safety lock
Pull instrument slightly back
Have patient open their eyes
T t
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Tonometry
Non-contact tonometry procedure Direct fixation
Align targets
Instrument may shoot automatically ormanually
Take drie readings and average
Documentation is the same as with theGoldmann
T t
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Tonometry
Keeler Pulsair non-contact tonometer We have one of these in the preclinic
Hand held
Portable
Can be used in any position
Requires a steady hand
Machine averages vier readings
T t
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Tonometry
Tonopen Uses a combination of applanation &
indentation techniques
Hand-held, portable, digital, quick, welltolerated
Excellent back-up for Goldmann
Tonometry
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Tonometry
Tonopen procedure Calibrate instrument
Place sterile disposable cover over tip
Anesthetize eyes
Direct fixation
Press reading button listen for beep
Hold instrument perpendicular to cornea
Tonometry
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Tonometry
Tonopen procedure Gently tap the cornea 3-5 times
The instrument makes a sound every time
it gets a reading If it is not reliable, then you should repeat
the procedure
It tends to overestimate low IOP andunderestimate high IOP
Tonometry
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Tonometry
Im still trying to figure out why the Schiotz,Pneumotonometer, and Heine-Maklakowinstruments are in the module.
None of these have been used in clinicalpractice for years
Read them over once, so you have a clue if
some old-timer starts talking about them Obviously, they will not be on the exam
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Gonioscopy
Gonioscopy
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Gonioscopy
Technique used to view the anteriorchamber angle
It is impossible to directly view the
angle with the spleetlamp alone We need special lenses/prisms
Gonioscopy
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Gonioscopy
Gonioscopy
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Gonioscopy
Indications: Grade 2 or less on Van Herrick technique
Suspicion of abnormality in angle
trauma, maldevelopment, neoplasm,neovascularization
Pigment dispersion syndrome
Pseudoexfoliation, exfoliation Glaucoma has been diagnosed or is
suspected
Gonioscopy
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Gonioscopy
Contraindications: Traumatic hyphema
Corneal abrasion
Laceration or perforation Post-surgery
Gonioscopy
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Gonioscopy
Direct gonioscopy High plus lens, light source, and magnifier
You can look directly into the angle
You can view the angle 360 around It provides an erect, virtual image
The most common is the Koeppe lens,which provides 24X magnification
Patient must be lying down
This is rarely used
Gonioscopy
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Gonioscopy
Koeppe lens
Gonioscopy
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Gonioscopy
Indirect gonioscopy Mirrors and prisms are used in combinationwith the spleetlamp
The mirrors and prisms do not magnify The mirror/prism should be 180 away
from the angle you want to observe
Inverted, virtual images
Goldmann, Sussman, Posner, Zeiss makelenses for this purpose
Scleral and corneal lenses are used
Gonioscopy
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Gonioscopy
Scleral lenses There are many types available The most common is the Goldmann 3-mirror
They are larger in size than the cornea,therefore they rest on the sclera
Require a solution to keep a tight seal
It should be relatively thick
Gonioscopy
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Gonioscopy
Corneal lenses They have a smaller diameter than thecornea
They rest on the tear film They do not require a solution to stick to
het oog
There is limited lens manipulation
These are less stable than scleral lenses
Some have a handle for better control
Gonioscopy
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Gonioscopy
There are vijf major structures thatneed to be evaluated in every angle
From posterior to anterior, they are:
Iris root (IR)
Ciliary body (CB)
Scleral spur (SS)
Trabecular meshwork (TM)
Schwalbes line (SL)
Gonioscopy
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Gonioscopy
I ris root (IR) C iliary body (CB)
Scleral spur (SS)
Trabecularmeshwork (TM)
Schwalbes line (SL)
I Cant
See
This
S%@#
The easiest way to remember the structures is to
remember this statement, in which the words all startwith the same letters as the anatomical structures
Gonioscopy
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Gonioscopy
Gonioscopy
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Go oscopy
Gonioscopy
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py
There are other things that we need tolook for as well
Iris processes
Iris/angle neovascularization Peripheral anterior synechiae (PAS)
Pigment
Gonioscopy
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py
Schwalbes line The termination of Descemets membrane Where the cornea ends
Color varies from clear to light brown If anterior chamber pigment is deposited
here, it is called Sampaolesis line
There is a specific method used to see thisstructure
Gonioscopy
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py
Schwalbes line Use an optic section rather than aparallelpiped to see where it is
The light will shine on both the cornea andangle
Where they meet is Schwalbes Line
Gonioscopy
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py
Gonioscopy
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py
Gonioscopy
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Trabecular meshwork Is composed of fenestrated sheets ofepithelium
Its function is to remove aqueous from hetoog
It can be subdivided into anterior and
posterior
Gonioscopy
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Trabecular meshwork
The anterior portion is less pigmented
The posterior part does more of the work
Therefore more pigment will accumulate hier The actual color depends on the
pigmentation of the patient and the
amount of free pigment available If you push hard on the lens, you can
observe Schlemms canal, it will be red
from blood
Gonioscopy
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Gonioscopy
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Blood in Schlemms canal
Gonioscopy
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Scleral Spur
Ring of collagen and elastic tissue
Is the end of the trabecular meshwork
The longitudinal muscles of the ciliary bodyinsert here
Appears as a white line
May not be easily found in light eyes, asthere is no pigment to contrast with
Gonioscopy
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Gonioscopy
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Ciliary body
It has many functions
Aqueous production
Accommodation Point of attachment for iris
Most of it lies behind the iris
We can only see the ciliary body band The color varies depending on the patients
overall pigmentation
Gonioscopy
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Iris root
This is the end of the iris
You must observe how it attaches to the
ciliary body In cases of trauma:
The iris may be torn, which is called
iridodialysis The ciliary body may be torn, which is known
as an angle recession
9% of all patients with angle recessionsdevelo laucoma as a result
Gonioscopy
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Gonioscopy
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Iris processes
A normal finding
Are fine strands of iris that attach to the
trabecular meshwork You must distinguish from these from
anterior synechiae and neovascularization
Gonioscopy
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Iris processes
Gonioscopy
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Iris Processes
Gonioscopy
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Iris/Angle Neovascularization
Also known as rubeosis irides
New bloedvat growth
These vessels are fragile and leaky Fibrin leaks out of the bloedvat and
attaches itself to the angle structures,
stopping the flow of aqueous This happens in response to ischemia
Gonioscopy
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Peripheral anterior synechiae (PAS)
Are areas of the iris that have becomeattached to angle structures
These are irregular, thick, and oftenobscure your view of the angle
In comparison, iris processes are thin and lacy
They usually attach to the trabecularmeshwork or Schwalbes line, but mayattach to the cornea or ciliary body as well
These can close the angle completely
Gonioscopy
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Peripheral anterior synechiae (PAS)
Can be caused by angle closure,inflammation, trauma, neovascularization,and after laser procedures
You can also see tumors in the angle
Gonioscopy
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Peripheral anterior synechiae
Gonioscopy
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Gonioscopy
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Gonioscopy
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Indirect Corneal Lens
Gonioscopy
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Indirect corneal lens procedure Educate and anesthetize the patient Disinfect and rinse lens
Patient is placed behind the spleetlamp Observation and illumination systems at 0
2-3 mm parallelpiped
Pull spleetlamp all the way back
The patient should look straight ahead
Place lens on het oog
Gonioscopy
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Indirect corneal lens procedure
The lens has four mirrors, which should beat 3, 6, 9, and 12 oclock
Stabilize your hand on the head rest or onthe patients cheek
Gently press against corneal surface
Look in a different mirror to observe adifferent angle
Pull the lens away to remove it
It comes off very easily, unlike the scleral lens
Gonioscopy
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Indirect corneal lens procedure
You should use the parallelpiped toobserve the entire angle
The beam should be horizontal for the superiorand inferior angles and vertical for the nasaland temporal angles
To look for Schwalbes line, use an optic
section The beam should be vertical for the superior
and inferior angles, and horizontal for the nasal
and temporal angles
Gonioscopy
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Indirect corneal lens procedure
More difficult to use than the scleral lens
The examiner must be very steady
You must maintain good contact with thetear film without wrinkling Descemets orcausing blood to back up into Schlemms
canal If the patient has a bowed iris, have the
patient look slightly toward the mirror
Gonioscopy
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Wrinkling of Descemets membrane
Gonioscopy
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Indentation gonioscopy
Only done with corneal lenses
Used to determine if a closed angle is that
way because of synechiae or apposition You will see structures if the closure is a result
of apposition
This can be treated with a peripheral iridectomy
If none are seen, then the closure is fromsynechiae
This is not easy to treat
Gonioscopy
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Indentationgonioscopy
This angle isclosed due to
apposition
Gonioscopy
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Angle classification
There are many methods, some contradictothers
The most common and clinically usefulmethod is to:
Record the most posterior structure seen
Grade pigmenting of the trabecular meshwork Indicate any abnormalities Evaluate in all vier quadrants and record
on an X
Gonioscopy
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Angle classification
Read over the Schaffer and Scheie systems
They are actually graded opposite of the
van Herrick technique and can createconfusion for examiners
This is why the previously described
method is widely used However, a new system has emerged and
it is what we use in our clinic
Gonioscopy
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Spaeth angle classification We must determine vier things The site of iris insertion
The iris approach The angle of insertion
The amount of pigment
This system allows for recording of irisprocesses and results of indentationgonioscopy
Gonioscopy
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Spaeth angle classification
Site of insertion
Anterior to Schwalbes line
Behind Schwalbes line, trabecularmeshwork is not visible
sC leral spurDeep angle, with visible ciliary body
Extremely deep
Gonioscopy
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Gonioscopy
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Spaeth angle classification
Iris approach
queer--concave iris
regular configuration
steeply convex (bowed) iris
Gonioscopy
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Gonioscopy
Spaeth angle classification
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Spaeth angle classificationInsertion angle
(in degrees)
Gonioscopy
Recording
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Recording
OD OS
E 40 r0 pigment
B 10 s1 pigment
E 40 q
iris neorecessionC 25 r
4+ pigment
A 10 s
4+ synechiae
Normal Abnormal