An analysis of the relationship between Q-value with parameters of corneal allterior surface before laser in situ keratomileusis for myopia

Abstract

Objective To measure the corneal Q value and other anterior surface refractive parameters in myopic population and analyze the relationship. Methods The Q valve and other related anterior comeal refractive parameters included comneal curvature, simulated keratometry, irregular index in 3 and 6 mm area and Diff value were measured with Orbscan Ⅱ anterior segment systemin on 300 myopic patients ( 600 eyes). The relationship betweend the Q value and other refractive parameters were analyzed. Results In the 600 eyes,the Q value ranged from -0.51 to 0.37 and averged -0. 17 ±0. 11 ,corneal curvature,was (43.59 ± 1.54) D, simulated keratometry was (43.89 ± 1.46) D, cornael irregular index in 3 and 5 mm area were ( 1. 324 ± 0.41 ) D and ( 1.72 ± 0.63 ) D and anterior corneal surface Diff was (0.07 ± 0.05 ) mm. Statistic analysis showed negative relationship between Q value with other refractive parameters. Conclusion In myopic eyes,the Q value has negative relationship with other corneal anterior surface refractive parameters. Key words: Corneal anterior surface; Q-value;