Evaluation of corneal biomechanical properties on ocular response analyzer and their correlation with the clinical profile of the patients with thyroid-associated ophthalmopathy

Abstract

ABSTRACT Purpose: The study evaluates the corneal biomechanical properties on Ocular Response Analyzer (ORA) and aims to establish their correlation with the clinical profile of patients with TAO. Methods: A tertiary care centre-based cross-sectional observational study was conducted. Eighty patients with stage I and II TAO (EUGOGO classification), categorized as group A, were age and sex matched with 85 controls constituting group B. The disease activity was assessed using clinical activity score (CAS). The thyroid hormonal profile of within one-week duration was recorded for each patient of group A. Mean IOP-GAT (IOP using Goldmann applanation tonometer), IOPg (Goldmann-correlated IOP value), IOPcc (cornea-compensated IOP value), CRF (corneal resistance factor), and mean corneal hysteresis (CH) of group A and B were compared. The variation of CH with disease severity, activity, and thyroid status in group A was evaluated. Results: Mean GAT, IOPg, and IOPcc of group A were significantly higher than that of group B (p < .001). Mean CH of group A i.e the visco-elastic dampening ability of cornea was significantly lower than that of group B (p < .001). In group A, mean CH of patients with stage 1 disease severity and CAS<3 was significantly higher than that of patients with stage 2 severity and CAS≥3 (p < .001). CH of hyperthyroid patients was significantly lower than CH of hypothyroid patients (p < .01). Conclusion: TAO affects the biomechanical properties of the globe as reflected by the corneal biomechanics on ORA. The disease severity, activity, and hyperthyroid status are negatively correlated with the CH.