How to Improve your Refractive Cataract Surgery Outcomes by Skilful Interpretation of Corneal Mapping Course IC-16 ESCRS Copenhagen 10 th September 2016 Consultant for Alcon / WaveLight/TearLab Arthur Cummings FRCSEd Wellington Eye Clinic, Dublin, Ireland
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
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?
IOL Calculations Pre-Operative
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 Results Perfect eye, Mean Prediction Error ± Standard deviation Lenstar vs Pentacam
Pre-Operative IOL calculations IOL type
biconvex Results Scenario III: Average Eye, Acrylic vs. Silicone convex-plano plano-convex 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.
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 0-0.2-0.4-0.6-0.8-1 -1.2-1.4-1.6-1.8 Preoperative Week 1 Month 1 Month 3 Data courtesy of Kjell Gunnar Gundersen MD, PhD (Norway) Toric IOL`s Incisions
Superior Cataract Incision
42.1 44.2 42.5 43.3 Good placement of incision. Incision enlarged in width. Incision decreased in length. Decreased corneal astigmatism by 1.3 D
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 Good placement of incision Reduced corneal astigmatism by 0.70 D
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 mm 3 ACD < 2.1mm AC angle < 26 degrees
Post-Operative Detecting tight sutures Detecting wound gape Detecting irregular astigmatism Guiding suture removal with the Pentacam
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