Association between metabolic control and contrast sensitivity in type 2 diabetes patients without retinopathy

Background: Diabetic retinopathy (DR) a microvascular disease, also involves early retinal neurodegeneration causing visual impairments such as reduced contrast sensitivity (CS), colour perception changes, and altered temporal perception, often before changes in visual acuity or retinal structure. Current DR screenings mainly assess retinal morphology and circulation, missing early functional visual changes. This study aims to explore the connection between metabolic status and contrast sensitivity in patients with Type 2 diabetes mellitus who are free from diabetic retinopathy.Materials and Methods: This cross-sectional study was conducted over a span of one year, comprising 106 eyes from 53 patients diagnosed with Diabetes Mellitus (DM). The assessment encompassed variables including age, gender, duration and treatment of diabetes, visual acuity, CS, and glycated haemoglobin levels. Statistical analysis included Chi-square tests for categorical variables and Pearson’s correlation analysis to assess associations between contrast sensitivity and metabolic parameters.Results: Out of 53 participants, 29 (54.7%) were males and 24 (45.3%) females with mean age of 60.16 ± 7.80 years, and the average period of diabetes mellitus 7.21±4.37 years. The mean fasting blood glucose was 127.28±40.75 mg/dl, postprandial blood glucose 174.37±59.52 mg/dl, and the HbA1c level averaged 7.72±1.85% (range 5.5 to 12.1%). A strong positive association was identified with diminished CS in both eyes and duration of diabetes (p = 0.001). Also, CS exhibited a considerable negative association with HbA1c levels (P