Accuracy of Orbscan total optical power maps in detecting refractive change after myopic laser in situ keratomileusis

Purpose: To determine whether the refractive change obtained using the Orbs can-derived total optical power (TOP) map is in concordance with the manife st refractive change produced by laser in situ keratomileusis (LASIK). Setting: LASIK Vision Canada, Vancouver, BC, Canada (an ambulatory surgical center for refractive surgery). Methods: Twenty eyes of 10 consecutive bilateral LASIK patients were includ ed in the study. Orbscan topographical analysis and manifest refraction wer e performed preoperatively and at least 1 month postoperatively. The change in manifest refraction (corrected to the corneal plane) before and after L ASIK was correlated with the corneal power change averaged within the 2.0, 3.0, 4.0, and 5.0 mm diameter zones of TOP and axial power maps. Results: The central 4.0 mm zone TOP map gave the best correlation between manifest refractive change and Orbscan-measured corneal power change (r(2) = 0.835, P < .004). The correlation was higher with TOP maps than with ante rior axial power maps. Conclusion: The corneal power change measured by the Orbscan TOP maps corre lated highly with the changes in manifest refraction after LASIK. J Caterac t Refract Surg 1999; 25:1596-1599 (C) 1999 ASCRS and ESCRS.