To evaluate changes in subfoveal choroidal thickness (SFCT) and macular thickness as measured by enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) after argon laser panretinal photocoagulation (PRP) in patients with severe diabetic retinopathy.

This prospective, comparative case series included 21 patients (28 eyes) with severe diabetic retinopathy. All patients underwent three sessions of PRP. The SFCT and macular thickness were measured using EDI-OCT at baseline and one week after completion of 3 sessions of PRP.

SFCT before PRP was 318.1±96.5 µm and increased to 349.9±108.3 µm; P=0.001 after PRP. Macular thickness significantly increased at one week after PRP from 273.1±23.9 µm at baseline 295.8±25.3 µm at one week; (P<0.001). No significant relationship between the changes in macular thickness and SFCT was observed (r=−0.13, P=0.52).

PRP induced increases in both SFCT and macular thickness. Changes in SFCT did not correlate with changes in macular thickness.