The impact of diabetes mellitus on the development of dry eye syndrome

Abstract

Introduction: Diabetes mellitus (DM) is a major systemic risk factor affecting ocular health, involving both the ocular surface and the lens. Chronic hyperglycemia induces metabolic and oxidative changes that accelerate lens opacification and contribute to the development of dry eye syndrome (DES). The aim of this study was to evaluate the impact of diabetes mellitus on the prevalence and severity of DES in patients undergoing surgery for complicated cataracts. Materials and Methods: A prospective study was conducted on a cohort of 26 patients (30 eyes) with complicated cataracts (mean age 67.38 ± 7.32 years). The evaluation included a review of the relevant literature and clinical assessment through patient history and the Schirmer test, performed preoperatively and 14 days postoperatively. The data were statistically analyzed using the t-test, Chisquare test, with a significance threshold set at p<0.05. Results: Diabetes mellitus was identified as the most aggressive risk factor, with a prevalence of DES of 81.25%, significantly higher than the 45.00% observed in hypertensive patients. Pathophysiologically, diabetes induces corneal denervation through peripheral neuropathy, disrupting the neuro-lacrimal feedback. This vulnerability led to a decompensation of ocular surface homeostasis under the mechanical and inflammatory stress of phacoemulsification, exacerbating hyposecretion in 46.6% of eyes, with Schirmer test values dropping from 7.8 mm to 4.1 mm (p < 0.0001). This reduction correlated with debilitating symptoms (foreign body sensation, burning). At the molecular level, activation of the polyol pathway and accumulation of sorbitol generate osmotic stress, reactive oxygen species (ROS), degrading lens proteins (α, β, γ-crystallins), accelerating opacification on an already compromised biological substrate. Conclusion: Diabetes mellitus is the most important systemic risk factor for the onset and exacerbation of dry eye syndrome in patients undergoing cataract surgery. The results highlight the need for monitoring function and implementing preventive measures to protect the ocular surface during the perioperative period.