Glycated hemoglobin as a continuous metabolic determinant of intraocular pressure independent of diabetic status: a prospective observational study in Kosovo

Background Elevated intraocular pressure (IOP) has been associated with diabetes mellitus; however, the role of chronic hyperglycemia in both diabetic and non-diabetic patients remain a topic of exploration with regard to dysregulation of trabecular meshwork and humor aqueous drainage especially in understudied regions such as Kosovo and Southeast Europe. Objective To evaluate glycated hemoglobin (HbA1c) as a continuous metabolic determinant of intraocular pressure independent of diabetes mellitus diagnosis. Methods In this prospective observational study, 150 participants (100 with diabetes and 50 non-diabetic controls) were enrolled. HbA1c values obtained within three months of ocular examination were analyzed as a continuous variable. IOP was measured using applanation or non-contact tonometry. Associations between HbA1c and IOP were assessed using correlation and linear regression analyses. Results Mean IOP was significantly higher in diabetic participants compared with controls (p < 0.001). Across the entire cohort, HbA1c demonstrated a significant positive association with IOP, including within the non-diabetic range. Linear regression confirmed HbA1c as an independent predictor of IOP in both diabetic (R² = 0.10, p = 0.0011) and non-diabetic individuals (R² = 0.15, p = 0.0059). Conclusion Chronic hyperglycemia is associated with intraocular pressure across diabetic and non-diabetic populations, suggesting that chronic glycemic exposure may influence ocular physiology beyond conventional disease classifications. These findings support the consideration of metabolic glycemic status in glaucoma risk assessment in this population.