Abstract
Purpose: :
To determine the frequency, associated local and systemic risk factors for macular edema secondary to pan-retinal photocoagulation (PRP) in diabetic patients.
Methods: :
40 eyes of 20 patients with severe non-proliferative diabetic retinopathy (SNPDR) and proliferative diabetic retinopathy (PDR), treated with PRP with baseline visual acuity ≥20/40. Fasting glucose, lipid profile, urea, creatinine, urine protein, fluorescein angiography and color fundus photographs and OCT measurements were obtained at baseline. Imaging studies were evaluated to establish de presence of lipid exudate, staging of diabetic retinopathy, presence of angiographic edema (leakage), and area of capillary non-perfusion. Macular volume was evaluated using OCT. PRP was done in three sessions with an interval of two weeks. OCT and BCVA were obtained at baselines, 1mo, 3mo and 6mo after the completion of PRP.
Results: :
Results: 40 eyes of 20 patients were evaluated. All of the patients developed an increase in macular volume (MV) (mean baseline 10.88 µm vs. 12.28 µm at 3mo, 11.84 µm a 6mo). Mean BCVA at baseline was 80.3 letters, 72 letters at 1mo and 77 letters at 3mo and 6mo. Patients with proteinuria had a mean increase of MV of 2.07 cubic microns versus an increase of 0.67 cubic microns in patients without proteinuria. Patients with severe capillary non-perfusion (>10DA) had a mean increase of 1.43 cubic microns versus 0.93 cubic microns in patients without capillary non-perfusion. (p<0.05)
Conclusions: :
Macular edema secondary to PRP and its consequent decrease in visual acuity are most apparent at 1 and 3mo post-treatment. Improvement in macular volume and BCVA is seen at 6mo but they do not return to baseline levels. Proteinuria and capillary non-perfusion were associated with a greater increase in macular volume and decrease in visual acuity.
Keywords: macula/fovea • edema • diabetic retinopathy