Significant reduction of both peripapillary and subfoveal choroidal thickness after panretinal photocoagulation in patients with type 2 diabetes

Purpose: To evaluate changes in peripapillary choroidal thickness (PCT) and subfoveal choroidal thickness (SFCT) after panretinal photocoagulation (PRP) for diabetic retinopathy. Methods: This retrospective interventional study included 59 treatment-naive eyes of 33 patients who underwent PRP and completed $12 months of follow-up. Peripapillary choroidal thickness and SFCT were measured at baseline and 1, 3, 6, and 12 months post-PRP. Differences between baseline and 12 months (DSFCT and DPCT) and percentage changes (DSFCT or DPCT/baseline · 100%) were determined. Results: Mean SFCT was 287.7 ± 76.7 mm (139.0-469.0 mm) at baseline and 225.8 ± 62.0 mm (102.5-379.5 mm) 12 months post-PRP (P, 0.001). Mean PCT was 161.2 ± 16.5 mm (75.3-308.1 mm) at baseline and 128.4 ± 41.8 mm (73.0-212.9 mm) 12 months post-PRP (P, 0.001). DSFCT was 261.3 ± 28.7 mm (2139.5 to 217.0 mm), and %SFCT was 21.2 ± 7.2% (6.8% to 36.1%). DPCT was 236.4 ± 23.2 mm (2149.1 to 5.4 mm), and %PCT was 22.4 ± 12.0% (2.5% to 62.6%). Diabetic retinopathy severity was the only factor significantly correlated with %SFCT (b = 0.500, P = 0.004) and %PCT (b = 0.152, P = 0.024). Conclusion: Both PCT and SFCT reduced significantly after PRP. Diabetic retinopathy severity was significantly correlated with post-PRP changes of peripapillary and SFCT.