IRIS CHANGES IN DIABETIC RETINOPATHY

Abstract

Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes mellitus and remains a leading cause of preventable visual impairment and blindness worldwide, particularly among the working-age population. While retinal changes in DR have been extensively studied, increasing evidence suggests that the iris is also significantly affected by diabetes-related vascular and neural damage. Chronic hyperglycaemia, ischemia, and autonomic dysfunction lead to a variety of structural and functional alterations in the iris, including neovascularisation (rubeosis iridis), changes in iris thickness, pupillary abnormalities, pigment epithelial instability, and microvascular leakage. Iris neovascularisation is a critical indicator of advanced diabetic eye disease and often precedes the development of neovascular glaucoma, a severe and sight-threatening complication. Recent advances in anterior segment imaging techniques, particularly anterior segment optical coherence tomography angiography (AS-OCTA), have enabled non-invasive and quantitative assessment of iris vasculature, allowing earlier detection of subtle vascular changes that may not be clinically visible on routine examination. This review summarises the anatomical and physiological features of the iris, the pathophysiological mechanisms by which diabetes affects iris structure and function, and the spectrum of iris changes associated with diabetic retinopathy. It also highlights current diagnostic techniques and management strategies, emphasizing the importance of early detection and strict systemic control of diabetes. Improved understanding of iris involvement in diabetic retinopathy may enhance disease assessment, guide timely intervention, and reduce the risk of irreversible vision loss. Future research focusing on iris biomarkers and the integration of anterior segment imaging into routine diabetic eye screening may further improve clinical outcomes.