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The following is a summary of “Risk of Endophthalmitis Based on Cumulative Number of Anti-VEGF Intravitreal Injections,” published in the June 2024 issue of Ophthalmology by Israilevich et al.

Researchers conducted a retrospective study to assess the relationship between the cumulative number of intravitreal injections (IVIs) and the risk of endophthalmitis in eyes receiving anti-VEGF therapy.

They studied patients receiving ranibizumab, aflibercept, or bevacizumab IVIs from 1 center. eyes were grouped into quartiles by the number of injections causing endophthalmitis, the interquartile clinical outcomes and cumulative risk of endophthalmitis per injection and per eye (January 2011 to June 2022). 

The results showed 43,393 eyes receiving 652,421 anti-VEGF injections, resulting in 231 endophthalmitis cases (0.035% per injection, or 1 in 2857), from which 215 were included. The cumulative risk increased from 0.0018% (1 in 55,556) after 1 injection to 0.013% (1 in 7692) after 11 injections (0.0012 percentage point [pp] change), vs. 0.014% (1 in 7143) after 12 injections to 0.025% (1 in 4000) after 35 injections (0.00049 pp change), vs. 0.025% after 36 injections to 0.031% (1 in 3226) after 66 injections (0.000017 pp change), vs. 0.031% (1 in 3226) after 63 injections to 0.33% (1 in 3030) after 126 injections (0.000042 pp change) (P<0.001). Likewise the cumulative risk of endophthalmitis increased from 0.028% to 0.20% (1 in 500) between 1 and 11 injections (0.018 pp change), vs. 0.21% (1 in 476) to 0.38% (1 in 263) between 12 and 35 injections (0.0075 pp change), vs. 0.38% (1 in 263) to 0.46% (1 in 217) between 36 and 66 (0.0026 pp change), vs. 0.465 (1 in 217) to 0.50% (1 in 200) between 67 and 126 (0.00063 pp change) (P<0.001).

Investigators concluded that the endophthalmitis risk increased with more injections, but the rise was faster early on and slowed down later in the treatment.

Source: sciencedirect.com/science/article/abs/pii/S0161642024000058