Cluster of symptomatic silicone oil droplets following intravitreal injections: a 1-year observational study

OBJECTIVE: To describe a cluster of symptomatic intravitreal silicone oil (SiO) droplets following intravitreal injections (IVIs) and assess the effect of switching to a SiO-free syringe. METHODS AND ANALYSIS: Observational quality registry study of patients receiving IVI at a large Norwegian ophthalmology centre between April 2018 (start of cluster) and November 2019 (1 year after switching to SiO-free syringes). At onset, anti-vascular endothelial growth factor drugs were administered using SiO-containing insulin syringes. From November 2018, SiO-free syringes were implemented. Spontaneously reported symptomatic SiO cases were confirmed by slit-lamp examination. A follow-up interview was performed after 1 year, assessing visual complaints. The prevalence of non-symptomatic cases was assessed in a sample of 50 eyes from 50 consecutive IVI patients. RESULTS: Among 13 429 IVIs, 50 eyes of 46 patients (29 women) with symptomatic intravitreal SiO droplets were identified. Forty-one patients reported floaters at regular appointments, whereas five patients contacted the department regarding symptoms between scheduled appointments. After 1 year, 34 patients (79%) still experienced floaters, 21 (49%) reported reduced symptoms and 3 (7%) reported worsened symptoms. Eighteen patients (42%) reported being bothered, and eight (18.6%) reported that their lives were negatively affected by the floaters. Among 50 non-symptomatic eyes that had received IVI during the same period, intravitreal SiO was found in 34 (68%). No cases of symptomatic intravitreal SiO droplets were identified after switching to SiO-free syringes. CONCLUSION: Symptomatic intravitreal SiO following IVI can cause significant and prolonged distress for affected patients. It can be avoided by using SiO-free syringes.