Correction of Corneal Astigmatism with AcrySof Toric IOL: Short- and Long-Term Results

1. Correction of Corneal Astigmatism with AcrySof Toric IOL:Short- and Long-Term Results Peter Hoffmann Christoph Lindemann Karl-Christoph Schulze Our research has been partially funded by Alcon

2. Introduction • Astigmatism is common and astigmatic refraction errors are routinely treated with toric spectacle glasses (69% of all prescriptions in our clinic) • Corneal astigmatism of 1,5 D or more occurs in 1 out of 6 cataract eyes • Corneal astigmatism contributes 50% or more to the postoperative defocus equivalent (size of blur circle on the retina) • Incisional methods of astigmatism correction have low predictability and limited range

3. Numbers and Facts Corneal astigmatism present in % of cataract eyes (n = 23239) Cumulative frequency based on Zeiss IOLMaster® keratometry e.g. 16,57% have 1,5 D or more, 2,65% 3,0 D or more Cylindrical part contributes approx. 50% to the defocus equivalent of 3046 refractions post cataract surgery

4. Patients and methods • Prospective, single-arm study • 84 patients with 102 eyes enrolled • 50 right, 52 left eyes • 89 eyes fully evaluated • Median 73 years (range 37-86), no „best case“ picking • 2 surgeons with 10 year, 300+ cases experience with toric IOL • Corneal astigmatism 1,25 to 3,0 D • No significant ocular pathology apart from cataract

5. IOL power spherical equivalent and torusNo. of eyes implanted Spherical equivalent (D) T3=1,5D T4=2,25D T5=3,0D Torus

6. Surgical technique • Zeiss IOL-Master® biometry + Pentacam Hires topography • IOL calculation according to Haigis • Calculation of spherical equivalent lens power • Calculation for steep and flat meridian seperately, difference = IOL torus required, always rounded down to avoid overcorrection • Marking of horizontal axis at sitting patient with Gerten marker • Microcoaxial phaco (Geuder) with 2,5 or 2,2 mm posterior limbal stab incision • Marking of cornea with Neuhann marker prior to implantation • Final rotation and positioning of the lens after removal of OVD • Crosscheck by retinoscopy („poor man‘s wavefront analysis“)

7. Results: Cylinder pre/post [dpt]

8. Visual acuity UCVA / BSCVA

9. Cylinder pre/post double angle scatter plot 4 weeks 6 months

10. Prediction error spherical equivalent / cylinder Predictability of cylindrical correction Prediction error (spherical equivalent) Haigis constants a0=−0.091 a1=0.231 a2=0.179as published on ULIB website for SA60AT + more hyoperopic − more myopic than predicted

11. Malpositioning (axis intended − achieved) Measured rotation of the lens axis Magnitude of vector change of cylinder Surgically induced astigmatism (Naeser)

12. Discussion • good refractive outcome of cataract surgery (uncorrected visual acuity) is very important for patient satisfaction • implanting a toric IOL is the most reliable option for correcting astigmatism during cataract surgery • approx. 97% of all eyes can be corrected with IOL cylinder up to 3,0 D • with proper planning and technique, median absolute positioning error of 3° or less is achievable • limbal microincisions give extremely low SIA, noise due to measuring tolerances • postop. cylinder typically reduced to 0,5 dpt • very good efficacy, UCVA typically only one line less than BSCVA • very good predictability of cylindrical effect • very good predictability of spherical equivalent, but „constants“ not identical to SA60AT, refractive results should be reviewed on a large scale and constants fine-tuned (e.g. A=118,9 instead of 118,7 for SRK/T users) • lens rotation negligible and well within measuring tolerance • stable refraction over time, no spherical shift, cylindrical vector change negligible, compares favorably to FDA trial results* * http://www.fda.gov/cdrh/pdf/p930014s015.html