Intravitreal (IVT) injections have become one of the most commonly performed procedures in ophthalmology—particularly as anti-VEGF therapy continues to expand across retinal disease management.
But despite how routine these injections now are, one complication still gets outsized attention: endophthalmitis.
Tell me more.
While rare, infectious endophthalmitis can be visually devastating and may require urgent treatment with IVT antibiotics and, in some cases, pars plana vitrectomy (PPV).
With this in mind: A new study out of Bascom Palmer Eye Institute took another look at how often these infections are actually occurring in modern practice, particularly now that newer agents like faricimab and high-dose aflibercept have entered the mix.
Why has endophthalmitis remained such a concern with IVT injections?
Essentially, it's volume. IVT injections are now performed at an enormous scale worldwide, which means even extremely low complication rates still translate into real clinical concern.
And because endophthalmitis can lead to severe and permanent vision loss, retinal specialists have spent years refining injection protocols to minimize infection risk.
Go on …
At the same time, injection techniques, drug formulations, and delivery systems continue evolving. Pre-filled syringes (PFS), newer anti-VEGF agents, and changes in antiseptic protocols have all raised questions about whether infection risk could shift over time.
That’s part of why ongoing surveillance studies matter. Even when complication rates are already low, clinicians still want to know whether newer therapies or procedural changes are introducing additional risk.
So what exactly did this study investigate?
Researchers conducted a retrospective review of patients who developed endophthalmitis after intravitreal injection between January 2021 and December 2024.
The study specifically looked at:
- Incidence rates
- Culture results
- Visual acuity outcomes
- Medication-specific trends
- Outcomes following treatment
Investigators also compared the newer data against historical endophthalmitis rates previously reported at the same institution dating back to 2005.
Who ended up being included in the analysis?
Over the 4-year study period, researchers analyzed 115,367 IVT injections performed at Bascom Palmer Eye Institute.
Only 10 cases of infectious endophthalmitis were identified. The injections included a range of anti-VEGF agents, including:
- Bevacizumab
- Ranibizumab
- Aflibercept
- Faricimab
- Brolucizumab
The study also tracked how medication use changed over time, particularly as faricimab entered clinical practice and high-dose 8 mg aflibercept became available.
So what did they actually find?
The biggest takeaway was straightforward: Infection rates stayed extremely low.
The cumulative incidence of endophthalmitis across all injections was 0.0087%, or roughly 1 case per 11,000 injections.
Yearly rates ranged from:
- 0.004% to 0.014%
And importantly:
- Rates did not significantly differ between medications
- Newer agents like faricimab and high-dose aflibercept were not associated with increased risk
The researchers also found that overall rates remained consistent with historical Bascom Palmer data reported between 2005 and 2020.
What stood out about the infection profiles and outcomes?
Half of all vitreous cultures were negative, while the remaining infections involved various gram-positive organisms.
The identified organisms included:
- Streptococcus mitis/oralis
- Staphylococcus aureus
- Granulicatella adiacens
- Staphylococcus epidermidis
- Abiotrophia defectiva
Visual outcomes varied considerably after treatment.
Mean final best-corrected visual acuity (BCVA) was approximately 20/526 overall, although outcomes ranged from 20/20 vision to no light perception.
One notable exception involved a patient with S. epidermidis infection who ultimately recovered to 20/50 vision, which aligns with prior research suggesting comparatively better outcomes with that organism.
What was suggested about injection technique and prevention?
The study reinforces something retina specialists already know well: consistent antiseptic technique still matters enormously.
All injections in the study followed a standardized institutional protocol that included:
- 5% povidone-iodine preparation
- Avoidance of post-injection topical antibiotics
- Avoidance of topical lidocaine gel
- Use of topical lidocaine solution
Researchers noted that povidone-iodine remains one of the few consistently supported preventive measures for reducing endophthalmitis risk.
Interestingly, the study did not find meaningful differences in infection rates following the introduction of PFS—although investigators acknowledged the study may have been underpowered to detect smaller differences.
What limitations should clinicians keep in mind?
Like many retrospective studies, this one comes with important caveats.
For starters: It was conducted at a single large tertiary referral center using a largely standardized injection protocol. That limits the ability to compare outcomes across different techniques or practice environments.
And despite the massive injection volume, the actual number of endophthalmitis cases remained very small. While that’s reassuring clinically, it also limited statistical power when trying to detect subtle differences between medications or procedural variables.
The authors also noted that management decisions were not fully standardized across all cases, and additional non-quantifiable clinical factors may have influenced outcomes.
Why are these findings still important even with such low event rates?
Because this is exactly the kind of complication clinicians continue monitoring as intravitreal therapy evolves.
Explain, please.
The retinal treatment landscape has changed dramatically over the last several years with:
- Newer anti-VEGF agents
- Higher-dose formulations
- Increasing injection frequency overall
What this study suggests is reassuring:
- Infection rates have remained remarkably stable
- Newer therapies do not appear to be introducing new safety concerns
- Current preventive protocols continue to perform well in high-volume settings
That consistency matters, especially as IVT injections continue scaling across retinal practice worldwide.
And now: the take home.
This large retrospective analysis found that endophthalmitis following intravitreal injection remains exceedingly rare, occurring in fewer than 0.01% of cases.
Just as importantly, newer anti-VEGF therapies—including faricimab and high-dose aflibercept—did not appear to increase infection risk.
While visual outcomes after infection can still be severe and variable, the overall data reinforce the strong safety profile of modern intravitreal injection protocols when consistent antiseptic measures are used.