: To compare the effect of pan-retinal photocoagulation (PRP) using pattern scanning or conventional laser on subfoveal choroidal thickness (SFChT). Methods : Thirty-eight patients (64 eyes) with advanced diabetic retinopathy (DR) who underwent PRP using pattern scanning or conventional laser were included. Changes in SFChT were compared with baseline values at 1, 3, 6, and 12 months after PRP using swept-source optical coherence tomography. Results : The conventional laser group showed

more »

... cally significant decrease in SFChT at 1, 3, 6, and 12 months after PRP ( P <0.001). SFChT was significantly decreased at 3 ( P = 0.025), 6 ( P = 0.004), and 12 months ( P < 0.001) after treatment in the pattern laser group. Conclusion : Eyes with advanced DR showed a significant reduction in SFChT over 12 months regardless of the type of laser used; however, the reduction was sooner after conventional laser than after pattern laser.