The Effects of Prefilled Syringe Technology and Masking on Endophthalmitis Risk Following Intravitreal Injection of Anti-Vascular Endothelial Growth Factor Agents

The purpose of this paper is to evaluate the effect of prefilled syringe technology and different masking protocols on endophthalmitis rates following intravitreal injection (IVI). Endophthalmitis cases following IVI between 3/1/2015 and 10/31/2022 at a single institution were reviewed. Three different periods of masking protocols were evaluated: no masking (5.1 years), universal masking (2.2 years), physician masking with optional patient masking (0.5 years). A total of 63 cases of endophthalmitis occurred following 248,879 IVI’s (92,463 bevacizumab, 12,395 ranibizumab, 144,021 aflibercept), of which 177,129 used prefilled syringe technology. The use of prefilled syringes was associated with a significant decreased risk of endophthalmitis (odds ratio 0.25, 95% CI 0.15-0.42, p<0.0001). In multivariable analysis, different masking protocols had no effect on endophthalmitis risk (p=0.974). However, in culture-positive endophthalmitis cases, the use of face masks among all individuals (p=0.011) and physicians only (p=0.019) was associated with lower rates of endophthalmitis. The use of prefilled syringes of anti-vascular endothelial growth factor agents was associated with a significant decreased risk of endophthalmitis following IVI. Masking protocols had no effect on risk of infection overall although masking was associated with lower risk of culture-positive cases.