ABSTRACT
Objective: To evaluate key corneal tomography parameters for screening refractive surgery patients in Pakistani population
Study Design: Cross-sectional, observation study
Place and Duration of Study: Armed Forces Institute of Ophthalmology AFIO, National University of Medical Sciences, Rawalpindi, Pakistan, from August 2013 to December 2016
Methodology: Myopic patients were evaluated by two separate observers on Allegro OculyzerII [Wavelight] for normal ocular examination. A total of 20 tomographic parameters, used for pre-refractive surgical evaluation, were included. Normality of data was evaluated using Kolmogorov-Smirnov test. Results for outliers were displayed as 2.5%, 5%, 95% and 97.5% percentiles
Results: The sample of 451 patients [895 eyes], comprised of 61% [n=277] females and 39% [n=174] males [39%]. The mean age was 26 +6.4 years [range of 18-62 years, M=F]. Normal mean anterior segment values included; flat simulated keratometry [K1] 42.9 +/-1.44 diopters [D], steep K2 43.9 +/-1.52 D, K mean 43.4 +/-1.43 D, K maximum 44.6 +/-1.56 D, astigmatism -0.96 +/-0.97 D, anterior chamber depth [ACD] 3.19 +/-0.28 mm, front elevation at the thinnest point 4.11 +/-2.44 um, and that at the back was 7.56 +/-4.52 um progression index [PI] maximum 1.14 +/-0.17, Ambrosio relational thickness maximum [ART max] 487.5 +/-89.0 and pachymetry at thinnest point 542.2 +/- 31.1 um
Conclusion: The study demonstrates key corneal tomography parameters, which can be useful for screening refractive surgery patients in Pakistani population