GRAVITY OF GRAVES' ORBITOPATHY: IMPACT ON VISION, OPTIC NERVE FUNCTION AND PERIPAPILLARY BLOOD FLOW

Background: Graves' Orbitopathy (GO) is the inflammation of the orbital, ocular, and periocular tissues associated with thyroid autoimmunity and is primarily linked with hyperthyroidism. Its pathogenesis involves orbital fibroblast stimulation leading to increased adipocyte proliferation and hyaluronan synthesis, eventually compressing vital orbital structures. Despite its low risk of vision loss (4-8%), GO imposes a substantial socioeconomic and psychological burden, impacting quality of life. To correlate the severity of GO with Objectives: the following parameters: vision, optic nerve function and peripapillary hemodynamic alterations. In addition, the study aimed to compare the above-mentioned parameters with those of healthy controls. Hospital-based analytical cross-sectional study recruiting 50 eyes from Methods: 25 adults diagnosed with GO and 50 eyes from appropriately matched controls between December 2023 and July 2024. Comprehensive ocular examination was performed, including best corrected visual acuity (BCVA), optic nerve function tests, and OCT-A imaging to quantify peripapillary vessel densities. Subsequent classification as per European Group on GO (EUGOGO) was done. ImageJ software was used to analyze the vessel densities across key regions of the optic disc among various GO severity groups and controls. Among the cases, majority (80%) had m Results: ild GO and were hyperthyroid. BCVA and optic nerve function tests were similar amongst controls, mild GO and moderate-severe GO, but those with sight-threatening GO showed reduced BCVA, defective colour vision, poor contrast sensitivity and visual field defects. Detailed OCT-A analysis showed a generalized reduction of vessel densities (VDs) in cases. A statistically significant decrease in VD (P < 0.001) was found in two niche regions (intrapapillary small VD and peripapillary superior hemifield all VD), with the reduction becoming more pronounced as GO severity worsened and in cases of active disease. This study found significant reductions in peripapillary vessel densities using OCT- Conclusion: A across progressive GO stages, suggesting OCT-A as a potential prognostic tool, detecting changes overlooked by routine clinical exmination.