Corneal topography analysis before and after radial keratotomy.
Corneal topographic analyses were conducted on 58 eyes of 42 cases with mild or moderate myopia by computer-assisted photokeratography before and after radial keratotomy (RK). The results indicate that the corneal surfaces of most examined eyes (76%) are positive aspheric shape before RK, while after RK they are changed to negative aspheric shape. Before RK, the corneal topography of most examined eyes (67%) is symmetric bow tie pattern or asymmetric bow tie pattern; after RK, the forms of central flattened regions are mainly round or approximately round, dumbbell and belt-shaped. Before and after RK there is no significant change in surface regularity index (SRI), but surface asymmetry index (SAI) is changed significantly. RK makes the central and central peripheral parts of the cornea flattened. The most significant RK effect is found at the region 1.140 +/- 0.090 mm away from the corneal optical center. Examination and analysis on the corneal topography before and after RK not only provide an accurate and objective basis for RK operational plan, but also make it possible to objectively and quantitatively evaluate the RK effect, to accurately predict the RK clinical effects, and to effectively improve the RK clinical quality.
Lin
Y
Y
Zhongshan Ophthalmic Center, Sun Yat-sen University of Medical Sciences, Guangzhou.
Chen
J
J
Wang
Z
Z
Xuan
J
J
D000293:Adolescent; D000328:Adult; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007646:Keratotomy, Radial; D008297:Male; D009216:Myopia / Q000601:surgery; D012029:Refraction, Ocular