How to Improve your Refractive Cataract Surgery Outcomes by Skilful Interpretation of Corneal Mapping

Arthur Cummings FRCSEd Wellington Eye Clinic, Dublin, Ireland

Course IC-16 ESCRS Copenhagen 10th September 2016

Consultant for Alcon / WaveLight/TearLab

AIMS of Course

• Help manage refractive expectations of cataract surgery patients

• Help with managing toric IOL’s

• Help with LRI’s, OCCI’s, effect of incision size and architecture

• Help with selecting multifocal IOL candidates

Why address astigmatism?

• Astigmatism is the KEY factor for success with multifocal IOL’s

• Correcting astigmatism provides better UCVA, BCVA for distance

and near

• Glasses that may be required are lighter, cheaper and easier to

wear / get used to

What is “Refractive Cataract?”

• The intended outcome is emmetropia

• The intended outcome has addressed astigmatism

• The intended outcome may have addressed presbyopia too depending

on patient wishes (multifocal IOL, monovision)

• The patient is free of glasses for at least distance vision (monofocal,

emmetropia) or completely free of glasses

Devices

• Placido disk (in relative detail)

• Scheimpflug (in relative detail)

• Cassini (Introduction)

Topolyzer (Keratograph)

• Placido disk

• Tear film reflections

• Central scotoma where camera is situated

• Auto-capture, very repeatable

Oculyzer (Pentacam)

• Scheimpflug camera

• Captures scatter so does not see tear film but

corneal surface

• No central scotoma

• Auto-capture, very repeatable

Diagnostic Applications

• Screening for IOL’s (toric, multifocal)

• Screening for corneal health

• Screening for AC parameters

Cassini Corneal Topographer

Multi-spectral LED technology from i-Optics

Given the faster acquisition time and insensitivity to radial aberrations, corneal astigmatism is measured more accurately

Cassini and Toric IOL’s

Arthur Cummings

Wellington Eye Clinic

How does the iTrace work?

• Simultaneous corneal topography and whole eye

wavefront mapping

• Refraction

• Can separate corneal from intra-ocular optics

• Can therefore help manage post-op toric IOL’s

6/10 +0.25 /+0.25 X42 6/10

Summary

• Value of adding posterior corneal data is understood

• What about the geometry and geography of the

crystalline lens and the final position and orientation of

the IOL?

• Mirricon from ClearSight may have more answers?

Pre-Operative

• IOL Calculations

Results

Lenstar radius achieves a Mean Prediction Error of -0.02±0.52 D Pentacam radius achieves a Mean Prediction Error of 0.22±0.68 D

“Perfect” eye, Mean Prediction Error ± Standard deviation Lenstar vs Pentacam

Pre-Operative

• IOL calculations

• IOL type

Results Scenario III: Average Eye, Acrylic vs. Silicone

Acrylic IOLs are considerably less affected by IOL design, whereas silicone IOLs exhibit a much higher dependency, with the poorest results obtained for convex-plano IOLs.

biconvex

plano-convex

convex-plano

Pre-Operative

• IOL calculations

• IOL type

• Incision type: Scleral, limbal, corneal

Pre-Operative

• IOL calculations

• IOL type

• Incision type

• Incision shape: 3 step, 2-step, straight-in

Pre-Operative

• IOL calculations

• IOL type

• Incision type: Scleral, limbal, corneal

• Incision shape: 3 step, 2-step, straight-in

• Incision size: <2mm, 2.2mm, 2.5mm, 2.8mm, >2.8mm

Pre-Operative

• IOL calculations

• IOL type

• Incision type: Scleral, limbal, corneal

• Incision shape: 3 step, 2-step, straight-in

• Incision size: <2mm, 2.2mm, 2.5mm, 2.8mm, >2.8mm

• Incision location: Superior, Temporal, on axis

Incisions and OCCI’s on steepest axis My OCCI nomogram: • Astigmatism < 0.8D

– Single 2.75 mm incision – Make slightly shallower to allow

slippage • Astigmatism 0.8D < X < 1.2D

– OCCI 2.2mm • Astigmatism 1.2D < X < 1.5D

– OCCI 2.75mm • Astigmatism 1.5D < X < 2.0D

– OCCI 3.0mm

OCCI = Opposite Clear Corneal Incision

Toric IOL`s vs. OCCI’s over 3 Months

-1.8

-1.6

-1.4

-1.2

-1

-0.8

-0.6

-0.4

-0.2

0

Preoperative Week 1 Month 1 Month 3

Toric IOL`s

Incisions

Data courtesy of Kjell Gunnar Gundersen MD, PhD (Norway)

Superior Cataract Incision

42.1 44.2

42.5 43.3

Decreased corneal astigmatism by 1.3 D

Good placement of incision. Incision enlarged in width. Incision decreased in length.

42.8 43.4

42.7 43.7

Increased corneal astigmatism by 0.30 D Incision incorrectly placed

Temporal Cataract Incision

39.8 41.1

40.1 40.7

Reduced corneal astigmatism by 0.70 D

Good placement of incision

44.9 46.2

44.5 46.7

Increased corneal astigmatism by 1 D Poor choice of incision

Cataract On-Axis Incision

42.5 47.1

43.2 46.5

Reduced corneal astigmatism by 1.30 D OCCI’s with 2.2mm

Pre-Operative

• IOL calculations

• IOL type

• Incision type: Scleral, limbal, corneal

• Incision shape: 3 step, 2-step, straight-in

• Incision size: <2mm, 2.2mm, 2.5mm, 2.8mm, >2.8mm

• Incision location: Superior, Temporal, on axis

Shallow Anterior Chambers

• Mostly hyperopes

• Mostly shorter eyes

• 3 critical values

– AC volume < 100 mm3

– ACD < 2.1mm

– AC angle < 26 degrees

Post-Operative

• Detecting tight sutures

• Detecting wound gape

• Detecting irregular astigmatism

• Guiding suture removal with the Pentacam

Thank You for Your Attention