Anti–Vascular Endothelial Growth Factor Crunch Syndrome in Proliferative Diabetic Retinopathy

A 33-year-old male individual with proliferative diabetic retinopathy (PDR) received a single intravitreal injection of conbercept (Kanghong Inc., Chengdu, China) for vitreous hemorrhage in his right eye. Three days post-injection, his vision deteriorated from 20/25 to hand motion, with anti-vascular endothelial growth factor (VEGF) crunch syndrome progressing to tractional retinal detachment, threatening the macula. Urgent surgical interventions, including vitrectomy, membranectomy, pan-retinal photocoagulation, and silicone oil tamponade, were performed. However, at the 3-month follow-up, visual acuity remained limited to counting fingers. This case highlights crunch syndrome as a rare but serious complication of intravitreal anti-VEGF therapy for PDR, emphasizing the need for careful patient selection and close postoperative monitoring.