Impact of Diabetes Mellitus on Tear Secretion, Intraocular Pressure, and Contrast Sensitivity: A Comparative Study of Controlled and Uncontrolled Diabetics

• Ankit Sanjay Varshney,*  
• Aarchi B Saraiya,  
• Hardeepsinh B Mahida,  
• Chetna Suresh Patel,  
• Mahendrasinh Dolatsinh Chauhan

Abstract

Background: Diabetes mellitus (DM) is a prevalent metabolic disorder associated with systemic and ocular complications that impair visual function. This study evaluates the impact of DM on tear secretion, intraocular pressure (IOP), and contrast sensitivity (CS), and explores the relationship between DM duration and these parameters. Purpose: To compare tear secretion, IOP, and CS in non-diabetic individuals and diabetic patients with controlled and uncontrolled DM, and to assess the influence of DM duration on these ocular measures. Methods: This prospective observational study was conducted from August 2023 to July 2024 at a tertiary eye care center in Surat, India, with 150 participants (300 eyes). Participants were divided into three groups: 50 non-diabetic controls, 50 with controlled DM (HbA1c ≤ 7), and 50 with uncontrolled DM (HbA1c > 7). Tear secretion was measured using the Schirmer test, CS with the Pelli-Robson chart, and IOP using non-contact tonometry. Statistical analysis included ANOVA for group comparisons and Pearson correlation to assess relationships with DM duration. Results: Diabetic patients had significantly lower tear secretion (controlled DM: 12 mm; uncontrolled DM: 8 mm) than non-diabetic controls (18 mm; p <0.05). CS was also reduced in diabetic groups, with controlled DM patients averaging 1.4 log units and uncontrolled DM patients 1.1 log units, compared to 1.9 log units in controls (p <0.05). IOP was higher in diabetic groups but not statistically significant. DM duration positively correlated with reduced CS (r = 0.45, p <0.05) but not with tear secretion or IOP. Conclusions: DM significantly impairs ocular health, evidenced by elevated IOP, reduced tear secretion, and diminished CS, particularly in uncontrolled cases. While DM duration is strongly associated with progressive CS decline, it does not significantly affect tear secretion or IOP. These findings underscore the need for routine ocular assessments and effective glycemic control to prevent visual complications in diabetic patients.

Keywords

Tear secretion, Intraocular pressure, Contrast sensitivity, Diabetes mellitus, DM duration, Ocular health