Photocoagulation of diabetic macular oedema; complications and visual outcome

. Purpose: To describe complications and visual outcome of photocoagulation for clinically significant macular oedema. Subjects and Methods: Evaluation of macular oedema and complications of photocoagulation in 194 eyes, defined as subretinal fibrosis, atrophic creep of the pigment epithelium and subretinal neovascularization was based on stereo fundus photo grading. The study included 25 patients with type 1 and 93 patients with type 2 diabetes (age 32±10 and 65±9 years, respectively). The statistical evaluations were based on one eye per patient. Results: Follow‐up time was 5.5±2.4 years (mean±SD). Complications within 1/3 ODD from the centre of the macula were seen in 4% (1/23) of eyes of patients with type 1 diabetes, compared to 26% (20/76) of eyes among patients with type 2 diabetes (p=0.02). Hard exsudates before treatment were more common in type 2 than in type 1 diabetic eyes, 70/82 vs. 11/23 (p<0.001). In all eyes, hard exsudates were more often associated with subretinal fibrosis or atrophic creep (35/133 eyes) than diffuse oedema (5/44 eyes) (p=0.04). Conclusion: Photocoagulation for clinically significant macular oedema with hard exudates, particularly when subfoveally located, was more often associated with subretinal fibrosis or atrophic creep of the pigment epithelium than photocoagulation of oedema without hard exudates. Hard exudates as well as complications after photocoagulation were more common in type 2 than in type 1 diabetes, resulting in poorer visual outcome in this group of patients.