Lamina cribrosa curvature depth and index as novel parameters in Graves' ophthalmopathy

This study aims to evaluate lamina cribrosa (LC) parameters, macular ganglion cell layer thickness (GCLT) and peripapillary retina nerve fiber layer thickness (RNFLT) in Graves' Ophthalmopathy (GO) patients using spectral domain optical coherence tomography (SD-OCT). Seventy GO patients and 70 healthy subjects were included in the study. LC thickness (LCT), LC depth (LCD), LC curvature depth (LCCD), LC curvature index (LCCI) measurements, peripapillary RNFLT and macular GCLT were evaluated with SD-OCT, and proptosis was evaluated with Hertel exophthalmometer. Clinical activity was assessed using the clinical activity score (CAS). Disease severity was evaluated according to the European Group on Graves Orbitopathy (EUGOGO) stage. SD-OCT revealed significant differences in the LC morphology between the affected and control groups. LCT was significantly decreased in the GO group (236.7 ± 37.1 μm) compared to the control group (276.1 ± 36.3 μm) (p < 0.001). Median LCCD was significantly higher in the patient group [95.5 (80.5-127.5) µm] than in the control group [78 (66-90.25) µm] (p < 0.001). LCCI was 6.08 (4.7-7.5) in the GO group and 4.9 (4.3-5.6) in the control group. The difference between the two groups regarding LCCI was statistically significant (p < 0.001). The mean LCD, central foveal GCLT, peripapillary global RNFLT and central foveal thickness were not significantly different between the two groups (p = 0.124, p = 0.536, p = 0.226 and p = 0.958, respectively).LC morphology may change in patients with GO. LCT, LCCI and LCCD showed a good ability to differentiate GO from healthy controls. Therefore, they can be used as supporting parameters for diagnosis.