Changes in macular thickness after panretinal photocoagulation in patients with severe diabetic retinopathy and no macular edema.

PURPOSE

The purpose of this study was to investigate changes in macular thickness after panretinal photocoagulation (PRP) in patients with severe diabetic retinopathy (DR) without macular edema and to compare the visual acuity outcomes.

METHODS

This prospective cohort study included 30 patients with severe nonproliferative DR or non-high-risk proliferative DR whose visual acuity was > or =0.8 before PRP. Sixty eyes of 30 patients with severe nonproliferative DR or non-high-risk proliferative DR received biweekly PRP treatment in 4 sessions. Macular thickness and visual acuity were measured before and at 1, 3, 6, and 12 months after PRP.

RESULTS

The visual acuities were 0.02 +/- 0.11 before PRP and 0.04 +/- 0.11, 0.04 +/- 0.07, 0.02 +/- 0.07, and 0.04 +/- 0.08 at 1, 3, 6, and 12 months after PRP, respectively (P > 0.05 for each). Central macular thickness was increased at 1 (223.3 +/- 40.6 microm), 3 (216.8 +/- 23.5 microm), 6 (219.4 +/- 33.1 microm), and 12 months (220.4 +/- 17.3 microm) after PRP compared with that before PRP (199.0 +/- 20.9 microm; P < 0.05 for each).

CONCLUSION

Biweekly PRP (1,200-1,600 spots) had no effect on visual acuity in patients with severe DR without macular edema, which was determined by clinical and optical coherence tomography examination, although mild macular thickening frequently persists.