Very High Astigmatism Outcomes With PRK and LASIK

Monday, April 28, 2014: 8:36 AM
Room 155 (Boston Convention and Exhibition Center)
Xiao-Yang Liu, PhD, McGill University, Montreal, QC, Canada
Eser Adiguzel, PhD, Lasik MD, Montreal, Quebec, Canada
Mark Cohen, MD, FRCSC, Lasik MD, Montreal, QC, Canada
Avi Wallerstein, MD, FRCSC, LASIK MD, Montreal, Quebec, Canada

Narrative Responses:

Purpose
To determine the accuracy, efficacy, safety, and stability of laser vision correction (LVC) for high astigmatism greater than -5 D.

Methods
Retrospective chart review of eyes with greater than -5 D cylinder.  All eyes underwent aspheric PRK or LASIK targeting emmetropia.  6 month or greater postop manifest refraction, UDVA and CDVA were compared to preop measurements. RM-ANOVA with Holms-Sidak post hoc tests and vector analysis (VA) were performed.

Results
208 eyes, preop sphere -0.82±2.32 D (-6.75-+5.50D) and cyl -5.89±0.77D (-5.00- -7.75D). 88 postop of 6+ months, mean FU 12.9±5.8 months. Postop sphere +0.08±0.48D ( -1.50- +1.25D), cyl -0.67±0.53 D (0- -2.25D). 46, 73, 98% within ±0.25, ±0.50, ±1.00D. Cumulative UDVA 20/20, 20/25, 20/40 in 34, 65, 94%, preop CDVA in 48, 82, 98%; efficacy index 0.9±0.2. 2 lines CDVA loss-1%, 1 line-5%, no change-55%, gain of ≥1 lines-39%. No loss >2 lines; safety index 1.1±0.2. MRSE stable. 30 (14%) had retreat. VA: correction ratio 0.95±0.10, error ratio 0.11±0.08, axis shift -3.2±36.7°. Error of magnitude and axis 0.32±0.62D and -0.44±2.65°.

Conclusion
LVC for very high astigmatism (greater than -5 D) has excellent accuracy, efficacy, and safety profiles.  Vector analysis demonstrated a high degree of precision in treating these highly astigmatic eyes.