Contrast sensitivity and photostress recovery time in diabetics with and without diabetic retinopathy

Diabetes mellitus (DM) is a major public health concern and a leading cause of diabetic retinopathy (DR), a condition that can lead to vision impairment and blindness. Early detection of retinal changes is essential in preventing vision loss.

Purpose. This study investigates the relationship between photo-stress recovery time (PSRT) and contrast sensitivity (CS) in diabetic patients with and without DR compared to healthy controls.

Material and methods. A hospital-based comparative cross-sectional study was conducted at Al-Shifa Trust Eye Hospital, Rawalpindi, Pakistan. A total of 60 participants (age range: 40–75 years) were included, comprising 40 diabetic individuals (20 with DR and 20 without DR) and 20 healthy controls. Visual acuity, CS (using the Pelli — Robson chart), and PSRT (using a direct ophthalmoscope) were assessed. The correlation between DR and PSRT/CS was analyzed using the Spearman’s correlation test, with a significance level set at p < 0.05.

Results. The study found significantly lower CS and prolonged PSRT in diabetic individuals compared to controls (p < 0.05). Diabetic individuals with DR showed the most significant delay in PSRT. A weak negative correlation was observed between CS and DR, and a moderate positive correlation was found between PSRT and DR (p < 0.05).

Conclusions. PSRT is significantly prolonged in diabetic patients, particularly those with DR, compared to non-diabetic controls. The results suggest that PSRT could serve as a reliable and simple clinical tool for early detection of DR, potentially aiding in the prevention of vision loss. Further studies with larger sample sizes are needed to explore mechanisms and therapeutic interventions to improve PSRT and CS in diabetic retinopathy patients.

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