Posterior surface topography of early keratoconus patients / 复旦学报（医学版）

ABSTRACT

Objective To investigate the corneal posterior surface topography characteristics of keratoconus at early stages applying the Pentacam anterior segment analysis system. Methods The present study included 43 eyes of 43 patients with keratoconus at the subclinical stage (group A), 40 eyes of 40 suspected keratoconus patients (group B), and 143 normal eyes of 143 controls (group C). Based on an examination of the Pentacam anterior segment analysis system of each subject, a series of data, including the posterior surface refractive power, the posterior surface elevation were collected. The differences among the three groups, the correlation among indices, and the area under the receiver operating characteristic (ROC) curves were analyzed. Results The mean values of the posterior surface maximum refractive power in 3 groups were -6.2 D, Q=0.5;-5.6 D, Q=0.3;and -5.5 D, Q=0.3, respectively. The mean values of the posterior surface maximum elevation were 23 μm, Q=14;11 μm, Q=8.5;and 7 μm, Q=6, respectively. The posterior surface maximum refractive power and maximum elevation among three groups were statistically different. The area under ROC (AUR) of posterior maximum refractive power and the AUR of posterior maximum elevation were greater than that of other indices in the diagnosis of early keratoconus. Conclusions Based on the results from the Pentacam anterior segment analysis system, the changes of the posterior surface refractive power and elevation are important characteristics of early keratoconus.