Purpose
To provide evidence for more accurate evaluation of refractive surgery candidates in clinics, this retrospective study investigated the effect of corneal diameter on the biomechanical indices assessed by Pentacam Scheimpflug cornea tomography (Pentacam) and corneal visualization Scheimpflug technology (Corvis ST).
Methods
The relevant data were collected of 132 eyes from 132 participants with moderate myopia who were candidates for refractive surgery. Eligible participants were apportioned to 2 groups based on the white-to-white (WTW) corneal diameter: Group A, ≤ 11.5 mm, and Group B, ≥ 11.6 mm. A single clinician performed Pentacam and Corvis ST imaging on each subject for 3 consecutive measurements, and the means were used for statistical analyses.
Results
Each group comprised 66 eyes. As measured by Pentacam, the 2 groups were comparable regarding Df and Da. For other measurements, Group A had significantly higher K1, K2, Db, Dp, Dt, Do, PPImin, PPImax, PPIavg, while Group B had significantly higher CCT, BFSf, BFSb, and ARTmax. Corvis ST data included DA ratio, SPA1, CBI, TBI, and ARTh. Only the latter showed a significant difference, with ARTh of group A (437.04 ± 76.60) larger than group B (470.46 ± 103.36, p = 0.04).
Conclusion
In a Chinese population, WTW corneal diameter showed effect on biomechanical indices assessed by Pentacam and Corvis ST. Personalized evaluation of these measurements based on corneal diameter should improve the sensitivity and specificity for screening of keratoconus by these devices.
