Ocular Hypertension and Glaucoma in Graves' Orbitopathy: A Single-Center Retrospective Cross-Sectional Study

Background/Objectives: Elevated intraocular pressure (IOP) in Graves' orbitopathy (GO) is a recognized risk factor for glaucomatous optic neuropathy, but the extent to which it translates into measurable structural and functional damage remains unclear. This study investigated structural and functional correlations in patients with GO stratified by IOP and glaucoma status. Methods: In this retrospective, cross-sectional study, 165 adult patients with GO were stratified into three groups of 55 each: normal IOP, ocular hypertension, and clinically diagnosed glaucoma. All patients underwent clinical examination, optical coherence tomography (OCT), and, where available, standard automated perimetry. Structural and functional parameters were compared across all three groups, with post-hoc pairwise testing. Multivariable logistic regression (clinical and combined models, adjusted for smoking and diabetes mellitus, restricted to the ocular hypertension and glaucoma groups) was used to identify factors independently associated with glaucoma status, with model discrimination assessed by optimism-corrected receiver operating characteristic (ROC) curve analysis. Results: IOP increased and best-corrected visual acuity (BCVA) declined progressively across groups. Most structural and functional parameters differentiated the glaucoma group from both other groups but did not distinguish normal IOP from ocular hypertension. In multivariable analysis restricted to the ocular hypertension and glaucoma groups, IOP was the factor most strongly associated with glaucoma status (odds ratio [OR] 1.44 in the clinical model and 1.61 after adjustment for structural parameters, both p ≤ 0.003), with BCVA also independently associated in the clinical model (p = 0.032). Diabetes mellitus and smoking were independently associated with glaucoma status in both models; the inverse association observed for smoking lacks an established biological explanation. Adding ganglion cell layer plus inner plexiform layer (GCL+IPL) thickness improved model discrimination (optimism-corrected area under the curve from 0.73 to 0.76) and was independently associated with glaucoma (OR 0.90, p = 0.036). Conclusions: IOP remains the factor most consistently and independently associated with glaucoma status in GO, with GCL+IPL thickness providing an additional independent contribution once smoking and diabetes mellitus are accounted for. These findings support regular IOP and visual acuity monitoring as first-line surveillance in GO, with structural OCT as a useful adjunct.