Progressive Design in the Digital Age

-Pete Hanlin, ABOM

Overview

Importance of the Design

Potential of the DS Process

Design Formats & Capabilities

Introducing

Introducing

Importance of the Design

Design is everything!

...poor design leads to poor performance...

(Somehow, designer forgot to leave his name on the base...)

Importance of the Design

New processing technologies do enhance great designs...

...but they cannot make an average design exceptional!

Importance of the Design

There are several fundamentals a PAL design must provide- to name a few:

–Natural Reading Posture (rate of progression)

–Properly Placed Near Zone (correct inset)

–Binocularity (balanced peripheral vision)

–Central Focus (sharp vision in all zones)

–Natural Reading Posture (rate of progression)

–Properly Placed Near Zone (correct inset)

–Binocularity (balanced peripheral vision)

–Central Focus (sharp vision in all zones)

Natural Reading Posture

Natural reading posture characteristics:Head tilts down 40°

Eyes vertically scan 15°

PALs should require at most 25° downward gaze

No Eyewear Non-Optimal PAL Optimal PAL

Natural Reading Posture

The ideal progression length is around 12mm to 85% of the ADD power

>12mm requires eye to look downward >25°

<12mm increases peripheral astigmatism

Patent FR 2 699 294 "...a very low sphere gradient for a so short power progression and a maximum gradient value located in the intermediate vision zone"

Properly Placed Near Zone

The near zone must be optimally placed

Convergence inset is determined by:Prismatic effects of the Rx

Convergence required at focal length of ADD

0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50

BASE ONE 1.81 1.92 1.98 2.09 2.29 2.29 2.29 2.29 3.05 3.05 3.05 3.05

BASE TWO 1.94 2.03 2.09 2.09 2.29 2.29 2.29 2.29 3.05 3.05 3.05 3.05

BASE THREE 2.09 2.09 2.09 2.09 2.29 2.29 2.29 2.29 3.05 3.05 3.05 3.05

BASE FOUR 2.69 2.71 2.72 2.74 2.80 2.95 3.11 3.21 3.51 3.72 3.90 4.10

BASE FIVE 2.92 2.94 2.97 2.99 3.00 3.04 3.29 3.39 3.70 3.90 4.17 4.30

Patent FR 2 683 643 "...a near zone which gets higher and more nasally decentered with the increase of the addition"

Binocularity

The optics of a PAL must be similar in every viewing position

The eyes must work together to maintain stereopsis (depth perception)

Dissimilar Similar

Binocularity

Even low levels of astigmatism will disrupt vision if it is imbalanced

The visual system can handle peripheral aberration- as long as it binocularly equivalent

Patent EP 0 994 375 "...a very low difference in sphere for two corresponding points of the right and left lenses, and this for all points of the space"

Central Focus

The central zones of the lens must provide sharp focus

Astigmatism is usually located in the periphery

Higher order aberrations (HOAs) reduce sharpness in the central zones of a PAL

Central Focus

Control of the wavefront results in the sharpest possible central vision

W.A.V.E. Technology™ provides clinically proven improvements in vision

Patent FR 05 07378 "In a wide angular zone (150 to 160) with a vertex 4 below the fitting cross, the high order aberrations, including coma, are reduced, allowing a clear far vision zone. At the same time, the near vision zone is easily accessible at 25 of gaze excentricity downward"

Varilux Physio Comp A Comp B

Importance of the Design

ALL of the fundamentals of design can be delivered by ANY processing format:

Traditional Surfacing

Digital Surfacing

Potential of Digital Surfacing

Limitations ofTraditional Surfacing

•Tooling required for each shape(designer is limited by # of tools)

•Tooling limits accuracy of lens

•Only one surface can be used for the progressive design

Solutions ofDigital Surfacing

•Tool can create unlimited shapes (designer is not limited by tools)

•Tool is exceptionally accurate*

•Both surfaces can be used for the progressive design

How Digital Surfacing Works

A DS generator is similar to a lathe

Lens starts as a block of material...

...a single point cutter removes material from the spinning blank to create a 3D surface...

...finished surface can be virtually any shape- with the potential for great precision.

In digital surfacing, the cutter is precisely controlled by motors which follow a path contained in the form of a computerized (digital) file.

Increased Tool Capability

Traditional Surfacing is limited by physical toolsMolds for complex front surfaces

Laps/Tools for simple back surfaces

Digital Surfacing uses "digitized" tools (digital files)A virtually unlimited number of shapes can be produced

Designer is free to create an ∞ number of surfaces

DistancePower

ProgressiveDesign

Distance Power and/orProgressive Design

Increased Tool Capability

The impact of DS capability is limited by:the quality of the initial design

the ability to create meaningful customization

Otherwise, digital surfacing is just another way to make a lens

=

Increased Precision

The DS process is capable of greater precision than traditional surfacing

+

DIS

TA

NC

E P

OW

ER

- - DESIGN + - DESIGN +

TRADITIONAL SURFACING Digital Surfacing

Traditional tooling creates "rounding errors" which cause up to 0.06D of distance power error

Digital tooling can be accurate to within 0.01D of target powers

+/-0.06D

+/-0.12D

Increased Precision

DS processes must be tightly controlled

+

DIS

TA

NC

E P

OW

ER

- - DESIGN + - DESIGN +

UNCONTROLLEDTRADITIONAL SURFACING

UNCONTROLLEDDIGITAL SURFACING

Process variations usually affect only the distance power of

traditionally surfaced lenses.

When DS is used to create a PAL design, process variations

will affect the design

Essilor has invested millions in DS process R&D, because an uncontrolled DS process produces unreliable product!

"6x more accurate"

DS potentially has greater accuracy- but it is harder to control.

Increased Precision

DSPC

Essilor has > 20 years invested in DS R&DEssilor Digital Surfacing Process Control (DSPC) is a complete quality assurance system

every laboratory required to test/calibrate processes daily

A "DS PAL" = design + processIf the process is bad, the design will not be accurate

All major manufacturers have a defined process

DEPARTMENT MANAGERDEPARTMENT MANAGERE. COMTEE. COMTE

AssistantM.HAGER

SURFACING MANAGERB.GELB

B.TAYLOR

B.BEESON

M.MODH

K.SCHROWANGEN

J.MONAGHAN

M.JACOB

H. NGUYEN

DALLAS

J.SHERIDAN

SURFACING MANAGER

INDUSTRIALIZATION WORKSHOPL.GRELICHE

TECHNOINDUSTRIALIZATION

G.MARTIN

PRODUCTSINDUSTRIALIZATION

B.GODEAU

P.RENAUD

Y.DUPIN

Y.FELTEN

JF. BELLY

G.BOLTEAU

B.CALLIER

M.LIBBRECHT

J. DE BARROS

D.BOULET

PH.CORNE

S.PICHOUX

M.DURANT

P.DEMION

S.SPOHR F.LAFON

TECHNICAL LEADERBLOCKINGM.LE GALL

TECHNICAL LEADERMACHINING/POLISHING

X. BULTEZ

CRETEIL OUDRY

BANGKOK

SURFACING MANAGERW.MAYUREE (TOY)

P.WASANCHAI(TA)

C.PETCHARAT(Poy)

K.SANRAYU(JOY)

C.ING ON(ING)

T.NIDA(KERNG)

K.PHANUWAT(JO)

K.CHETTHAPHON(EARTH)

A. SAUZEApprentice

Digital Surfacing Process Control

I. KATESANEE (KATE)T. TOVEY

B. LYONS

CALCULATIONT. BAUDART

J-L. ARBESSIER

D. DRUGEON

J. CONCIALDI

N. BELHACHMIApprenti

F. GAUCHI-MARTINOIntérimaire

V. MARTINConges 18 mois

N. FARIA

M. METTEL

B. ROMAIN

S. WEERAPON(MAN)

M.KALUZA

Increased Design Flexibility

Traditional surfacing is limited to one designDesign (D) placed on the front surface

Distance power (d) surfaced on the back

Traditional PAL

D d

Playing music through a single speaker system limits the ability to design sound effects...

Using only one surface for progressive design also limits the effects the designer can create...

D = Design d = distance powerD = Design d = distance power

Increased Design Flexibility

FBS PALs are also limited to one designDesign (D) placed on the back surface

Distance power (d) surfaced on the back

FBS (DRx™)

D d

The location of the speaker is changed...

...and the flexibility of DS does allow the designer to customize to a limited degree

D = Design d = distance powerD = Design d = distance power

Increased Design Flexibility

Digital surfacing can support two designsDesigns (D) are placed on both surfaces

Distance power (d) is digitally surfaced on back

D

dD

Two speakers makes it possible to create stereo and other sound effects...

Using two surfaces makes it possible for the designer to create new optical effects...

DualOptix™

D = Design d = distance powerD = Design d = distance power

Increased Design Flexibility

Two designs allow the designer to address both defocus and distortion simultaneously

Patient's Blurred Vision

Management of Distortion

Management of Focus

Controlled Correction

Two surfaces can be used to control focus & distortion simultaneously...

A single surface can control focus or distortion (usually a compromise of the two)

Increased Design Flexibility

An example of two-surface design:

6B

9B

6B

6B

6B

7B

-1.00 -1.00 -1.00

+2.00 +2.00 +2.00

Rx -1.00 sph / +3.00 ADD

D d D

d

D

d

D

Single surface progressions cannot provide the optimal curvature for both the distance and the near powers (and asphericity alone cannot overcome all "base curve effects"). Disassociating the power change from the curvature change reduces distortion to levels not otherwise possible.

TRADITIONALTRADITIONAL FBS (DRx™)FBS (DRx™) DualOptix™DualOptix™

Review

Digital surfacing provides three advantagesRemoves tooling limitations

but customization must be meaningful

Potential for greater precisionbut the process must be controlled

Allows designer to use both sides of the lensallows simultaneous control of focus and distortion

New PAL Formats

D d

Traditional PAL

d

D

DRx™ (FBS) PAL

Dd

D

DualOptix™ PAL

• A single surface PAL• Design on front• Distance power on back• Compromise between control of focus / distortion

• A single surface PAL• Design on back• Distance power on back• Greater accuracy• Compromise between control of focus / distortion

• A two-surface PAL• Designs on front & back• Distance power on back• Greater accuracy• Control of both focus / distortion

D = Design d = distance powerD = Design d = distance power

Advantages of DS Formats

Benefits of both FBS and DualOptix™More precise compared to Traditional PALs

Additional Benefit of DualOptix™Control of both focus and distortion

DualOptix™

D

dD

Essilor uses the DualOptix format for customization- since it offers the greatest ability to control focus and distortion.

FBS

D

d

Types of DualOptix™ Customization

Personalization to Head/Eye Ratio (Varilux Ipseo IV)

W.A.V.E. Technology 2 (Varilux Physio Enhanced)

Maximized Zone Width (Varilux Comfort Enhanced/All Varilux)

DUAL ADD TECHNOLOGY (DEFINITY)

FrameOptimization Technology (Accolade Freedom)

Additional benefits common to ALL DualOptix PALsAtoricity (to reduce peripheral aberration)

Customized Near Zone Inset (to promote reading)

Customized to Fitting Height

Length of Progression

Distribution of Zones (wider distance angle) D

dD

DS Design Capabilities

DEFINITY- reduces astigmatism/distortion

Widest Intermediate

Least Swim

Varilux Physio Enhanced- customized wavefront

Sharpest Vision Possible

New Varilux Comfort Enhanced- peripheral width

Wide/Smooth Vision

Accolade Freedom- instant adaptation

95% adaption in first 5 minutes

Benefits of DualOptix PALs

Varilux Ipseo IV is the only PAL featuring a DualOptix design which adapts to the wearer's individual visual strategy

the design is individualized to 7 parameterswavefront correction pupil map

sphere slope management

position of wear

visual zone width

distance Rx atoricity

progression length

zone distribution

Benefits of DualOptix PALs

Varilux Physio Enhanced is the only PAL providing customized wavefront correction

W.A.V.E. Technology 2 personalizes the design to 4 parameters

wavefront correction pupil map

distance Rx atoricity

progression length

zone distribution

wavefront correctioncustomized

wavefront correction

pupil sizepupil size

Benefits of DualOptix PALs

DEFINITY is the only PAL to split addition to achieve levels of astigmatism not possible in a single surface PAL

DUAL ADD TECHNOLOGY customizes the design to 2 parametersdistance Rx atoricity

progression length

Conclusions

The foundations of PAL design can be delivered in ANY format

Two new DS formats are available:DRx™

greater precision than traditional PALs

DualOptix™greater precision than traditional PALs

unlimited ability to customize