Contrast Sensitivity Across Different Grades of Non-Proliferative Diabetic Retinopathy: A Cross-Sectional Study from Peshawar, Pakistan

Doi: 10.36351/pjo.v42i4.2577

Abstract

Purpose:  The purpose of this study was to assess contrast sensitivity (CS) across the spectrum of Non-Proliferative Diabetic Retinopathy(NPDR) severity and explore clinical and demographic variables associated with it.

Study Design:  Cross-sectional study.

Place and Duration of Study:  Department of Ophthalmology, Hayatabad Medical Complex, Peshawar from October 2020 to November2021.

Methods:  We enrolled 245 patients with mild, moderate, or severe NPDR, analyzing one eye per participant. Contrast sensitivity was assessed using Pelli-Robson chart, alongside a range of clinical and ocular variables including diabetic macular oedema (DME), visual acuity, HbA1c, and duration of diabetes. Differences across NPDR grades were examined using ANOVA and Kruskal-Wallis tests, while correlation analysis, multivariable linear regression, and sensitivity analyses were used to further explore the data.

Results:  Mean CS showed a declining trend across mild, moderate, and severe NPDR (1.26±0.38, 1.23±0.40, and 1.13±0.39 log units, respectively), although the difference was not statistically significant (p=0.175). CS was not significantly correlated with NPDR grade. In multivariable analysis, neither DME (β=-0.251, p=0.082) nor NPDR grade (β=-0.076, p=0.526) was independently associated with CS. Excluding eyes with DME did not materially alter the findings.

Conclusion:  CS showed a modest decline with increasing NPDR severity but was not independently associated with disease severity after adjustment for relevant clinical factors. It may provide complementary functional information but should not be considered an independent marker of NPDR severity.