Changes in retinochoroidal thickness after vitrectomy for proliferative diabetic retinopathy

To evaluate the changes in the peripheral retinochoroidal thickness after pars plana vitrectomy (PPV) with scatter photocoagulation for proliferative diabetic retinopathy (PDR).

Small gauge PPV was performed on 22 eyes with PDR with scatter photocoagulation, and on 32 eyes with an epiretinal membrane (ERM) without photocoagulation as control. The peripheral retinochoroidal thickness was measured at 5 mm from the limbus in the four quadrants using anterior segment optical coherence tomography preoperatively, and 3 days and 1 and 2 weeks after the surgery. In eyes with a peripheral choroidal detachment, the retinochoroidal thickness and the height of choroidal detachment were measured separately. The total peripheral thickness was defined as the sum of retinochoroidal thickness and the height of choroidal detachment.

A significant larger number of eyes developed a choroidal detachment in the PDR group than in the ERM group 3 days after surgery (P < 0.001). The total peripheral choroidal thickness 3 days after surgery was significantly thicker than that before surgery in the PDR group (P = 0.009). The increase in the total peripheral thickness in the PDR group was significantly greater than that in the ERM group at 3 days after surgery (P = 0.007). The number of photocoagulation burns was significantly and positively correlated with the total peripheral thickness (r = 0.57, P = 0.006).

We conclude that the transient thickening of the total peripheral thickness in early postoperative stage for PDR was due to the intraoperative scatter photocoagulation.