Effect of Angle Kappa on Hyperopic LASIK
Narrative Responses:
Purpose
To determine the effect of angle kappa on the visual results and safety of hyperopic LASIK.
Methods
Retrospective review of 155 consecutive hyperopic LASIK eyes performed on AMO IntraLase FS60/ Alcon Wavelight Allegretto Eye-Q 400 wavefront optimized lasers. The hyperopic ablation was centered on the pupil per standard Wavelight tracker operation; no compensation for angle kappa was performed. Minimum follow-up was 3 months. Patient age, preoperative refraction, angle kappa and pupil size measured by Orbscan IIz, preoperative best corrected visual acuity (BCVA), postoperative BCVA, and gain/loss of BCVA were statistically analyzed for correlation (Pearson correlation coefficient, r).
Results
Patient age averaged 49 years, range 23 to 68 years. Preoperative sphere ranged from +0.25 to +5.75 D, mean +2.30 D. Mesopic pupil size ranged from 5.0 to 9.5 mm, mean 6.49 mm. Angle kappa ranged from 2.80 to 10.05 degrees, mean 6.35 degrees. The amount of angle kappa significantly correlated with age (r=-0.32; p=0.00005) and the amount of hyperopic sphere (r=0.16; p=0.047). Angle kappa did not significantly correlate with pupil size (r=-0.016; p=0.84), preoperative spherical equivalent (r=0.14; p= 0.08), gain or loss of BCVA (r=-0.001; p=0.99), or postoperative BCVA (r=0.002; p=0.98).
Conclusion
Angle kappa does not affect the visual outcome of hyperopic LASIK performed on the Alcon Wavelight Allegretto Eye-Q 400 laser. The amount of angle kappa does not correlate with postoperative BCVA, or postoperative gain or loss of BCVA.