Prevalence of tomographic features associated with subclinical oedema in Fuchs dystrophy across three commercially available corneal tomographers

Abstract

Aims/Purpose: Specific tomographic alterations suggestive for subclinical oedema have a known impact on FED prognosis. Here, we compare the prevalence of tomographic alterations associated with subclinical oedema in patients affected by Fuchs Endothelial Dystrophy (FED) imaged with corneal tomographers employing three different technologies.Methods: Patients with a clinical diagnosis of FED referred to the cornea service underwent tomography with 3 different devices: the Pentacam Scheimpflung camera (Oculus, Germany), the Casia2 AS‐OCT (Tomey, Japan), and the Precisio 2 blue‐light slit‐scanning tomographer (IVIS, Italy). All patients had confirmed corneal guttae at slit‐lamp examination. Subjects were classified into FED with no oedema, FED with subclinical oedema, and FED with clinical oedema according to a validated classification based on pachymetric and posterior elevation maps appearance on the Scheimpflung camera. The prevalence of these features was compared across the 3 devices, then two experienced ophthalmologists (M.A., M.L.P.) assigned a 0–3 score according to their evidence. A mixed‐effects binomial model estimated Odds Ratios (OR) for the scores of the 3 devices.Results: A total of 30 eyes were included: 7 eyes presented with clinically defined oedema, 18 eyes with no clinical oedema but tomographic features suggestive of subclinical oedema, and 5 eyes with no oedema and no tomographic alterations. The prevalence of Loss of parallel isopachs, Displacement of thinnest point, and Focal posterior depression did not differ between devices. However, identification of Loss of parallel isopachs was most evident on Precisio 2 compared to Pentacam (OR 9.6, p = 0.007), and the Displacement of thinnest point was most evident on Precisio 2 compared to both Pentacam and Casia2 (OR 6.9, p = 0.01 and OR 15.1, p = 0.005). 3 eyes showed alterations only on Precisio 2, one of which was later scheduled for DMEK.Conclusions: Scheimpflung camera, AS‐OCT, and blue‐light slit‐scanning based tomographers were all able to detect tomographic changes in FED. Nevertheless, our results suggest that the blue laser, slit‐scanning tomographer might be able to detect earlier, and delineate better, subclinical changes in FED.