Anterior segment measurements using Pentacam and Orbscan II 1 to 5 years after refractive surgery

Abstract

Purpose: To compare anterior segment measurements between Pentacam and Orbscan II after laser surface ablation.

Methods: Corneal thickness, anterior elevation, posterior elevation, and anterior chamber depth more than 1 year after laser refractive surgery were measured using Pentacam and Orbscan II in 51 eyes that underwent laser epithelial keratomileusis (LASEK) and 21 eyes that underwent photorefractive keratectomy (PRK). As controls, the same comparisons were made in 52 unoperated eyes.

Results: Mean follow-up was 28.2 months in the LASEK group and 49.9 months in the PRK group. Mean corneal thickness using Pentacam was thicker than that using Orbscan by 10.4 microm in unoperated eyes, 22.6 microm in LASEK eyes, and 11.0 microm in PRK eyes, but the two devices showed good correlation in all groups. Mean anterior elevation was highly correlated between the two devices with 2.1-microm differences in LASEK eyes, but posterior elevation showed no correlation with significant discrepancies. Mean anterior chamber depth was 0.12-to 0.14-microm thicker with Pentacam than with Orbscan, and highly correlated in all groups.

Conclusions: Pentacam and Orbscan showed good correlations in corneal thickness, anterior elevation, and anterior chamber depth despite some differences in mean values. The two devices, however, showed no correlation in posterior elevation measurements, a difference that was greater in the postoperative groups.