To report a case of deterioration of a retinal arterial macroaneurysm after panretinal photocoagulation (PRP) for diabetic retinopathy.

A 70-year-old woman visited our clinic for evaluation of diabetic retinopathy. Fundus examination and fluorescein angiography showed severe non-proliferative diabetic retinopathy and PRP was planned for the patient. In addition, the patient was found to have a retinal arterial macroaneurysm on the superotemporal area of the retina on her right eye. However, the lesion was small and was located far from the macula, causing no symptoms; thus we decided to observe the patient over a period of time. Two months after PRP, the patient revisited the clinic complaining of acute visual loss. Fundus examination showed vitreous and retinal hemorrhage and optical coherence tomography revealed subretinal fluid in the corresponding area. This was considered to be due to aggravation of the pre-existing macroaneurysm. Intravitreal Bevacizumab injection, C₃F₈ gas injection, and pars plana vitrectomy were performed. After absorption of the hemorrhage, barrier photocoagulation was performed around the retinal macroanerysm. The visual acuity improved and the retina remained stable through the most recent follow-up.

We experienced the rupture of a preexisting retinal arterial macroaneurysm in an asymptomatic patient after panretinal photocoagulation. PRP in diabetic patients could aggravate retinal arterial macroaneurysms. Therefore, it is necessary to carefully examine the patient for retinal macroaneurysms when planning a PRP for diabetic retinopathy.