Prevalence of Intravitreal Silicone Oil Following Intravitreal Injections: A Meta-Analysis

Intravitreal injections (IVIs) are used for retinal diseases, but concerns emerged regarding silicone oil (SiO) contamination, which may cause floaters and inflammation. This meta-analysis evaluated the prevalence of intravitreal SiO following IVIs, its association with floaters, and contributing factors.

SiO contamination may compromise visual quality, lead to inflammation, and patient dissatisfaction.

We systematically searched PubMed, Embase, and Cochrane for studies reporting SiO prevalence after IVIs. We conducted a single-arm meta-analysis with subgroup analyses by syringe and needle types. We applied meta-regression to test whether SiO prevalence correlated with the number of injections per eye. We used a generalized linear mixed model to pool data and assessed heterogeneity with I².

We included ten studies, comprising 1583 eyes. The prevalence of intravitreal SiO following IVIs was 57.56% (95% CI: 40.45-73.03; I² = 96%; very low certainty), and floaters occurred in 27.85% (95% CI: 14.59-46.58; I² = 1%; very low certainty) of eyes. Staked-in needles showed higher SiO prevalence than attachable needles (72.33% versus 17.14%; very low certainty). The SiO prevalence did not correlate with the number of injections. Post hoc analysis showed that SiO-free syringes had significantly lower contamination rates than siliconized syringes (OR 0.05; 95% CI 0.02-0.12; I² = 0%; moderate certainty).

IVIs are frequently associated with intravitreal SiO and floaters. Siliconized syringes and staked-in needles may increase contamination risk. Utilizing SiO-free syringes and attachable needles may reduce SiO-related complications. Randomized controlled trials should confirm these preventive strategies.