The patient was a 49-year-old man with juvenile-onset (type 1) diabetes who presented with a history of an acute loss of vision in the right eye. The visual acuity was hand motion OD and 20/50 OS. He had a vitreous hemorrhage in the right eye and multiple areas of fibrosed neovascularization as well as background diabetic changes with edema in the left eye. OCTA showed mild parafoveal nonperfusion. Curiously, there was extensive hard exudate formation in the superonasal quadrant of the left eye. Ultrasound of the right eye revealed a vitreous hemorrhage and no retinal detachment or evident retinal break. The left eye was treated with Avastin and the right eye was closely monitored. After two weeks, the vision had improved to 20/30 OD and neovascularization along the temporal arcades was seen. OCT confirmed that there was no significant edema. Both eyes have subsequently received Avastin treatments, and the macular edema in the left eye has improved.
What is the most likely cause of the superonasal hard exudates in the left eye? What treatment, if any, would you recommend?