Purpose: To report the evolution of diabetic macular edema (DME) after extensive panretinal photocoagulation in patients with Type 1 diabetes exhibiting florid proliferative diabetic retinopathy (FPDR).
Methods: This retrospective observational case series comprised 17 eyes of 10 consecutive patients (8 women and 2 men). All patients exhibited FPDR combined with severe DME, and all underwent panretinal photocoagulation. The evolution of visual acuity and progression of FPDR were evaluated. The evolution of DME during follow-up was assessed by fluorescein angiography and repeated optical coherence tomography examinations.
Results: At baseline, all eyes had diffuse DME. Mean logMAR visual acuity was 0.402 +/- 0.46. Mean central macular thickness was 468.23 +/- 113.63 microm. After panretinal photocoagulation, DME regressed spontaneously in all eyes after a mean follow-up of 7.1 +/- 2.68 months. Mean central macular thickness decreased to 268.12 +/-54.67 microm (t-test, P < 0.0001). Mean visual acuity improved significantly to 0.184 +/- 0.12 (t-test, P = 0.048). Diabetic macular edema only recurred in two eyes.
Conclusion: In DME combined with FPDR, extensive panretinal photocoagulation and glycemic control seem effective in reducing DME and improving vision. In FPDR, DME may be caused by excessive production of vascular endothelial growth factor by the unperfused retina.