The cornea is the eye’s primary optical interface, responsible not only for light refraction and image formation but also serving as a sensitive indicator of systemic health. Recent advances in high-resolution imaging techniques, such as confocal microscopy, have enabled clinicians and researchers to detect cellular and structural corneal changes that may reflect systemic conditions including diabetes mellitus, peripheral neuropathies, and autoimmune disorders.<br />Microscopic Corneal Changes<br />1. Epithelial Layer: Recurrent micro-erosions and epithelial irregularities often indicate compromised peripheral nerve function, commonly observed in diabetic patients.<br />2. Bowman’s Layer: Abnormal collagen or protein deposits can occur in metabolic disorders, affecting corneal transparency and biomechanical integrity.<br />3. Stroma: Microscopic fat or amyloid deposits may be detected in rare systemic conditions, such as protein storage disorders.<br />4. Endothelium: Dysfunctional endothelial pump activity can be an early sign of chronic hypertension or renal diseases, manifesting as subtle corneal edema.<br />Association with Systemic Diseases<br />• Diabetes Mellitus: Corneal nerve fiber density is often significantly reduced, and irregular branching patterns emerge, serving as early indicators of peripheral neuropathy.<br />• Autoimmune Disorders: Conditions such as Sjögren’s syndrome and rheumatoid arthritis may manifest as focal inflammatory infiltrates and disrupted cellular homeostasis within the corneal surface.<br />• Rare Metabolic Disorders: Lysosomal storage diseases can produce characteristic corneal deposits, providing a potential diagnostic marker.<br />Clinical Significance<br />Microscopic corneal evaluation offers a non-invasive and safe modality for monitoring systemic disease progression. For instance, improvements in corneal nerve morphology can serve as a biomarker for therapeutic efficacy in diabetic neuropathy. Moreover, these assessments may complement traditional diagnostic tools, offering early insights into otherwise subclinical disease states.<br />The cornea is not merely an optical structure but also a window into systemic health. Incorporating microscopic corneal imaging into routine clinical practice could significantly enhance early diagnosis, disease monitoring, and personalized management of systemic conditions, highlighting the cornea’s pivotal role in interdisciplinary medical care.<br />