Increased permeability of the blood-aqueous barrier after panretinal photocoagulation for proliferative diabetic retinopathy.

PURPOSE To measure the permeability of the blood-aqueous barrier before and after panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy. METHODS Twenty patients with diabetic proliferative retinopathy in one eye and background retinopathy in the other eye were included. PRP was performed in the proliferative eye, while the other eye served as control. Aqueous flare intensity was measured with a laser flare cell meter before, 10 and 90 days after treatment. RESULTS The flare was stable in the control eye with a flare of 4.5+/-2.3, 4.4+/-2.4, and 4.5+/-1.7 photon counts/ms (mean+/-standard deviation) on Day 0, 10 and 90. In the laser treated eye corresponding figures were 5.2+/-2.4, 9.6+/-3.3, and 7.1+/-2.8 photon counts/ms, with a significant increase in aqueous flare at 10 days (p<0.001) and 90 days (p=0.002). CONCLUSION A significant increase in aqueous flare was found 10 days after PRP, indicating a breakdown of the blood-aqueous barrier after retinal laser treatment. The breakdown was still present, however, less pronounced, after 3 months.