Evaluation of corneal endothelium and correlation with disease severity in patients with Graves' ophthalmopathy: A specular microscopy-based study.

Purpose: To investigate the possible corneal endothelial damage in Graves' ophthalmopathy (GO) and its relationship with GO activity.

Methods: This cross-sectional study included 101 eyes of 55 patients with GO. Each eye was assigned a specific clinical activity score (CAS). Accordingly, they were classified as active (CAS ≥ 3) or inactive (CAS< 3). The corneal endothelium was measured using a non-contact specular microscope (Tomey EM-4000; Tomey Corp.). Endothelial cell density (ECD), average cell area (ACA), standard deviation of cell area (SD), coefficient of variation in cell area (CV), hexagonal cell ratio (HEX), and central corneal thickness (CCT) were recorded.

Results: Among the eyes included in the study, 71 had inactive GO and 30 had active GO. ACA and HEX levels were lower (p<0,001) and CV values were higher (p<0.001) in patients with GO than in healthy subjects. Corneal endothelial cell morphology was altered in active GO compared to inactive GO. The SD (p = 0,009) and CV (p<0,001) were significantly higher in active GO than in inactive GO. When the parameters examined were correlated with CAS, a statistically significant positive correlation was observed between proptosis (p = 0,036, r = 0,385) and CV (p = 0,001, r = 0,595).

Conclusion: Our study confirmed that morphological changes occur in the corneal endothelium of patients with GO. CV and SD values, in conjunction with CAS, can be used as non-invasive and quantitative indices to examine the activity status of GO. The demonstration of endothelial changes even in GO eyes with low CAS may be considered an incentive to include non-contact specular microscopy in the routine clinical evaluation of all patients with GO.