Silicone Oil Droplets in the Vitreous After an Anti-vascular Endothelial Growth Factor (VEGF) Injection: A Complication of Syringe Lubrication

Intravitreal anti-vascular endothelial growth factor (VEGF) injections are a cornerstone treatment for various retinal conditions, including diabetic macular edema and age-related macular degeneration. While generally safe, these injections can introduce unintended substances, such as silicone oil droplets, into the vitreous cavity due to the silicone-based lubricant used in syringe manufacturing. Although frequently asymptomatic, silicone oil droplets can occasionally cause significant visual disturbances and discomfort. We report a rare case of symptoms caused by silicone oil droplets following a single intravitreal bevacizumab injection. A 54-year-old diabetic male patient presented with pain and iridescent floaters in his right eye, which began immediately after receiving an intravitreal bevacizumab injection and persisted for four weeks. The patient, with a 20-year history of diabetes and prior scatter laser photocoagulation, exhibited a visual acuity of 20/80 in the right eye or oculus dexter (OD) and 20/40 in the left eye or oculus sinister (OS), with an elevated intraocular pressure (IOP) of 24 mmHg in the right eye. Dilated fundoscopy revealed multiple silicone oil droplets floating in the vitreous cavity, alongside severe non-proliferative diabetic retinopathy and macular edema. The patient was started on anti-glaucoma medications, brimonidine, and timolol, which effectively reduced his IOP to 18 mmHg within a week. Despite IOP control, the patient remained distressed by persistent floaters, which gradually became less symptomatic with time. This case is unique because the symptoms due to the silicone oil droplets occurred after a single injection, unlike most reports of asymptomatic presentations or those arising after multiple injections. The disproportionate amount of silicone oil observed raises concerns about syringe design and transport conditions. While silicone oil is inert, its presence can cause the patient anxiety and visual disturbances.