Optical Assessment of Corneal Endothelial Morphology in Treatment-Naïve Dysthyroid Patients: A Specular Microscopy Analysis

To evaluate corneal endothelial morphology in treatment-naïve dysthyroid patients using age-adjusted analysis and identify diagnostic thresholds.

This prospective case-control study enrolled 46 treatment-naïve dysthyroid patients (27 hyperthyroid, 19 hypothyroid) and 48 controls. Optical imaging of endothelial parameters (ECD, CV, hexagonality, average cell area, CCT) was performed using non-contact specular microscopy, a non-invasive optical assessment technique. Age-adjusted ANCOVA with formal assumption testing, ROC analysis with bootstrap confidence intervals, and a left eye sensitivity analysis were performed.

Hexagonality was significantly lower in both hyperthyroid (56.56±7.19% vs 62.54±4.30%; d=-1.09; p=0.003) and hypothyroid groups (56.42±8.01% vs controls; d=-1.10; p=0.027). Average cell area was elevated in both groups (d>1.1; p≤0.014). After age adjustment, HEX (p=0.0006) and AVG (p<0.0001) remained significant. ROC analysis yielded optimal cutoffs (HEX≤57%, AVG≥275μm²) with a combined model AUC of 0.828 (optimism-corrected 0.812). Left eye sensitivity analysis confirmed the concordance of HEX and AVG findings across both eyes, while CV showed discordant laterality. ECD and CCT were preserved.

Treatment-naïve dysthyroid patients showed age-independent endothelial morphological alterations despite preserved cell density. Optical assessment via specular microscopy with ROC-derived cutoffs offers preliminary clinical utility for preoperative risk stratification in dysthyroid patients, pending external validation. Findings in the hypothyroid subgroup, which did not reach the planned sample size, should be considered hypothesis-generating.