Noncontact Evaluation of Corneal Grafts: Swept-Source Fourier Domain OCT Versus High-Resolution Scheimpflug Imaging

To study the reliability and repeatability of anterior segment measurements in patients who underwent penetrating keratoplasty with swept light source Fourier domain anterior segment optical coherence tomography (SS-OCT) in comparison with a high-resolution Scheimpflug camera.

Keratometry (K) and elevation data of the anterior and posterior corneal surfaces, central corneal thickness, and anterior chamber depth were determined in 56 postkeratoplasty eyes (mean age: 59.6 ± 16.5 yrs) with SS-OCT (CASIA SS-1000; Tomey) followed by Scheimpflug photography (Pentacam High Resolution; Oculus). Examinations were also performed on 48 right eyes of 48 age-matched healthy subjects (mean age: 66.3 ± 7.0 yrs).

A statistically significant difference was detected between both tomographers in anterior flat K [1.7 ± 4.92 diopters (D)], posterior astigmatism (1.32 ± 5.7 D) and elevation (6.65 ± 14.07 μm), and central corneal thickness (27.39 ± 90.81 μm) and anterior chamber depth values (0.14 ± 0.66 mm) in patients who had undergone corneal transplantation (P < 0.05). In the postkeratoplasty group, repeatability of SS-OCT was higher for every anterior segment parameter in comparison with the Pentacam. In corneal grafts, the variability between 3 consecutive measurements on the same subject was remarkably lower for every parameter while using SS-OCT.

In patients who had undergone corneal transplantation, SS-OCT provided more reliable and repeatable anterior segment evaluations when compared with the rotating Scheimpflug system. Our findings suggested that the tested high-resolution swept-source OCT system is a comprehensive and precise diagnostic tool for postoperative follow-up of patients who have undergone penetrating keratoplasty.