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FITTING THE IRREGULAR CORNEAChallenges & Solutions

Course Title:

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Lecturer: Phyllis Rakow, COMT, NCLM, FCLSA(H)

CORNEAL IRREGULARITIES

• Keratoconus

• Pseudokeratoconus

• Pellucid Marginal Degeneration

• Post-LASIK Ectasias

• Trauma

• Post-Corneal Transplant

THE CHALLENGES IS THIS A GOOD LASIK CANDIDATE?

• VA sc 20/70 OD; 20/70-1 OS

• OD -0.50 -1.25 X 75 = 20/20

• OS -0.75 -1.00 X 94 + 20/20

• Pachymetry 520 microns OU

POST-LASIK ECTASIA

• Irregular astigmatism

• Unable to achieve functional VA with glasses

• Rose K2 rigid lenses now worn

• OD 6.50 -8.37 8.7 OS 7.00 -4.00 9.3

POST-REFRACTIVE SURGERY

• Patient G.M.

• 48 y/o female

• 1996 - RK OU + AK OS for post-op astigmatism

• 2005 LASIK OS for recurrence of high astigmatism

• Hx of strabismus - OD deeply amblyopic

• c/o severe ghosting OS; fluctuating VA during day

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POST-LASIK ECTASIAPOST-REFRACTIVE SURGERY

Easy Fit!• 9/21/07 topography & diagnostic fitting

• Auto Ks 39.50@27/41.25@117

• Initial trial Rose K2 IC 8.44 (40.00) -1.00 11.2

– Aligns well

– VA 20/20-2 with -0.25 overrefraction

– Lens ordered: Rose K2 IC 8.44 (40.00) -1.25 11.2 Std. PCs BXO

PSEUDOKERATOCONUSSOFT LENS INDUCED CORNEAL WARPAGE

• Patient wore LWC torics 12 years

• Referred for keratoconus

• Refit with GP lenses

• 1 year later: ectasia resolved

ACT ENHANCEMENT KCN

• Patient W.M.

• 44 y/o male

• Advanced KCN OS

• CL Failure

• Transplant consult

• Piggyback fit suggested

• Soft lens:

– Oasys 8.4 -0.50 14.0

• GP Trial:

– Rose K 6.70 -16.00 9.3

• Well-aligned centrally

• Moderate inferior standoff

FLAT/STEEP DESIGNS

(ACT)

• Make 1 edge quadrant flatter or steeper than

the others

• Can steepen inferior portion of lens over

steepest area of cone

– EG: 1 PC at 90°; another at 270°

– Keeps normal curvature superiorly

– Minimize or eliminate lower edge standoff

– Prism ballast maintains orientation of lens

ACT DESIGN

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POST- PK

• Patient I.M.

• 89 y/o male

• Pseudophakic

• Post-PK for bullous

keratopathy 1999

POST- PK• Initial Trial

– Rose K 2 Post-Graft

– 44.50 (7.60) -1.62 10.4

– Good centration

– Mid-peripheral seal-off

– BCVA 20/50± with plano

• Trial #2

– Rose K2 Post-Graft

– 43.87 (7.70) -3.00 10.4

– Good centration

– Feather touch in ectatic area

– Standoff inferiorly

– +1.75 D overrefraction

– BCVA 20/50

POST- PK

• Final lens ordered:

• Rose K2 Post Graft

• Material: BXO

• 7.70 -1.25 10.4

Act Grade 1

• Good centration

• Feather touch inferiorly in ectatic

area

• Well aligned in mid-periphery

• No more inferior edge standoff

POST-TRAUMA & INFECTION

• Patient A.A.

• 50 y/o male

• Previous SL wearer

• CL-induced corneal

abrasion OD 2003

• 7.0 mm X 7.0 mm

central ulcer

• Pseudomonas cultured

POST-TRAUMA & INFECTION

Refraction

- OD: +1.00 -5.00 X 55

- BCVA: 20/70±

- RGP: Dyna Intralimbal

- 8.90 +0.50 11.2 9.8 OZ

- VA: 20/25

- Wears multifocal RGP OS

Can We Fit a GP Multifocal on an Atypical

Cornea?

• Must use anterior

surface design

• Must be able to

achieve good

centration

• Lid attachment

• Good alignment

• Lenses must translate

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ANTERIOR SURFACE MULTIFOCALS

• Minimal asphericity on posterior lens surface

• Fit conventionally

• Approach true alignment fit similar to sphere

• Can be fabricated with:

– Toric posterior surfaces

– Reverse geometry curves

– Keratoconus designs

PATIENT SELECTION

• Long-term rigid lens wearers

• Mature presbyopes

• Keratoconus

• PMD

• Post-Graft

• Post-LASIK

• High astigmatism

PATIENT SELECTION

• Well-centered, large diameter current lenses

– Diameter ≥ 9.5 mm

• Average pupil size

• Lower lid able to assist in translation

• Ability to resolve simultaneous images

EXPERIENCE WITH RECLAIM DESIGN

• High definition,

aberration control

optics

• Improved contrast

• Minimal optical

confusion

• Optimal intermediate

vision

STARTING OFF SIMPLE

• M.G. 66 y/o female

• Current Rose K CLs

• OD: 7.50 -2.00 9.9

• OS: 7.50 -0.75 9.9

• Standard/steep edge lift OU

• Add +2.50 OU

• 4.0 mm Distance OZ

• Visual acuity– OD 20/20-1 J3

– OS 20/20-1 J3

PELLUCID MARGINAL DEGENERATION

• E.S. 60 y/o female

• Fitting lenses: Rose K2 Post Graft

• Best Fit parameters:– OD 7.20 -4.25 10.4

• Standard edge lift

• Grade 1 ACT

– OS 7.20 -2.25 10.4• Standard edge lift

• No ACT enhancement

– Add +3.00 OU 3.0 OZ

– VA: OD 20/25-1 J1

OS 20/25+2 J1

J1+ OU

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POST-CORNEAL TRANSPLANT

• R.D. 51 Y/O female

• Corneal transplants OU 10+ years ago

• OD: 3.12 D cyl

• OS: 8.60 D cyl

• Current CLs: Rose K2 Post-Graft– OD: 7.60 -5.50 10.4

– OS: 8.00 -2.75 10.4• Standard edge lift

• Add: +2.25 4.0 OZ OU

• VA: OD 20/20-2 J1

OS 20/20-2 J1

POST- LASIK

• J.K. 60 y/o female

• 5 yrs. Post-LASIK

• Current refraction:OD: -0.75 -0.25 X 161 = 20/40

OS: -1.25 -0.50 X 114 = 20/30

• Sim Ks OD: 38.75/38.87

OS: 38.75/39.87

• OD: RSS 8.33/7.50 -5.00 10.5

OS: RSS 8.23/7.50 -4.75 10.5

• Add + 2.50 4.2 OZ

• VA: 20/20-3 OU J2 OU

POST- LASIK

• J.K. 60 y/o female

• 5 yrs. Post-LASIK

• Current refraction:OD: -0.75 -0.25 X 161 = 20/40

OS: -1.25 -0.50 X 114 = 20/30

• Sim Ks OD: 38.75/38.87

OS: 38.75/39.87

• OD: RSS 8.33/7.50 -5.00 10.5

OS: RSS 8.23/7.50 -4.75 10.5

• Add + 2.50 4.2 OZ

• VA: 20/20-3 OU J2 OU

HIGH ASTIGMATISM

• S.N. 49 y/o male chef

• Wearing GP monovision

• Eye rubber

• KCN mentioned in past

• Topography done

• Sim Ks:

– OD: 48.71/42.97

– OS: 47.34/42.57

– Stores CLs dry

– Inserts with saliva

HIGH ASTIGMATISM

• OD: No reliable refraction

• OS: +1.75 -6.00 X 170 = 20/20

• Inquired re. GP multifocals

• Topography sent to lab (Art

Optical)

• Renovations Bi-torics requested

HIGH ASTIGMATISM

• Lenses designed:

– Art Optical Renovations Bitorics

– OD: 7.96/7.29 +2.75/-2.75 9.5

– OS: 7.96/7.29 +1.75/-3.75 9.5

• Add +2.50 OU

• VA: OD: 20/20 OS: 20/15-1

J 2 OU

• Perfect lid attachment & alignment

OU

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HIGH ASTIGMATISMFLAT CORNEAS

• N.R. 60 y/o female

• Long-term GP wear

• Current back torics

OD: 8.63/8.39 +6.62 9.8

OS: 8.95/8.31 +7.75 9.8

• Add +2.50 4.0 OZ OU

• VA: OD 20/25± J2

OS 20/25+1 J2

EVALUATING THE FIT

• Refine distance vision with loose lenses

• Place overrefraction in trial frame

• Evaluate transition from distance to near vision

• If overrefraction gives good distance but unacceptable near, reassess centration, add power, & OZ diameter

TROUBLESHOOTING

• Poor Distance Vision

– Lens decentered

– Anterior OZ too small

• Patient looking through

intermediate or near

zone

– Residual astigmatism

TROUBLESHOOTING

• Poor near vision

– Anterior OZ too large

– Not enough add

– Lens not translating

– Residual astigmatism

TROUBLESHOOTING

• Flare

– Large pupil

– AOZ too small

– Decentration

– Inferior pooling

• Ghosting

– Inability to resolve simultaneous images

– Residual astigmatism

– Decentration

CONCLUSION

• Front surface GP multifocals

– Simple to fit

– Employ conventional fitting techniques

– Can be fit on patients with atypical corneas if

good centration can be achieved