To investigate the changes in choroidal thickness in diabetic retinopathy patients after panretinal photocoagulation (PRP).

This retrospective study included 42 eyes of treatment-naïve, severe non-proliferative diabetic retinopathy or proliferative diabetic retinopathy patients undergoing 3-session PRP. At baseline and 1 and 2 months after completion of the PRP treatments, subfoveal choroidal thickness (SFCT) was measured using enhanced depth imaging optical coherence tomography.

The mean SFCT at baseline was 261.52 ± 77.98 µm, changing to 249.14 ± 72.23 µm and 242.95 ± 70.28 µm at 1 and 2 months, respectively ( p < 0.05). The mean central macular thickness (CMT) was increased (>10%) in 9 eyes (21.43%) at 1 month and 8 eyes (19.05%) at 2 months after PRP. The mean SFCT showed no significant difference between increased mean CMT (238.22 ± 57.59 µm and 240.00 ± 67.71 µm at 1 and 2 months, respectively) and stable mean CMT groups (252.12 ± 76.24 µm and 243.65 ± 71.84 µm at 1 and 2 months, respectively; p > 0.05).

Choroidal thickness decreased after PRP. There was no significant relationship between change in SFCT and CMT after PRP.