To compare macular thickness and visual acuity before and after panretinal photocoagulation in patients with severe diabetic retinopathy without diabetic macular edema.

Macular thickness and visual acuity (LogMAR) of 40 eyes were compared before and after panretinal photocoagulation, for severe diabetic retinopathy. Macular thickness was measured by optical coherence tomography(OCT). In addition, changes in macular thickness and visual acuity were compared with the patient's level of HbA1c, blood pressure, and diabetic nephropathy.

Mean visual acuity before and 1.47±0.80 months after panretinal photocoagulation were 0.28±0.23 and 0.33±0.27, respectively, which was not a significant decrease ( p =0.131). However mean central macular thickness (216.98±34.09 µm to 255.22±73.40 µm), and mean peripheral macular thickness (269.26±34.59 µm to 291.96±46.49 µm) did increase significantly after panretinal photocoagulation ( p =0.001). The decrease of mean visual acuity and increase of mean macular thickness were greater in patients with high blood glucose, high blood pressure and diabetic nephropathy.

In eyes with severe diabetic retinopathy treated with panretinal photocoagulation, mean visual acuity did not decrease significantly, but mean central and peripheral macular thickness significantly increased after treatment. We posit that visual prognosis after panretinal photocoagulation in eyes with severe diabetic retinopathy without macular edema is influenced by the control of blood glucose and blood pressure and the presence of diabetic nephropathy.