Is there any role for prophylactic antibiotics in conjunction with intravitreal anti-VEGF injections?

No clear benefit

Colin A. McCannel

It is important to distinguish between peri-procedure antisepsis with povidone iodine and use of topical antibiotics for several days pre- or post-procedure. There is no controversy regarding the use of peri-procedure antisepsis with povidone-iodine. In 2004, an expert panel recommended only that povidone-iodine antisepsis and a lid speculum always be used for minimizing risk of intravitreal injections (Aiello LP, Brucker AJ, Chang S, et al. Evolving guidelines for intravitreous injections. Retina. 2004;24(5 Suppl):S3-S19). With regard to whether or not to use pre- or post-procedure antibiotics, controversy persists.

There is little evidence to suggest that antibiotics even after cataract surgery reduce the rate of postoperative endophthalmitis. Most endophthalmitis cases occur in patients who have been on prophylactic antibiotics, both postoperative and post-intravitreal injection.

Procedural technique and precautions are much more important. In a meta-analysis of the injection-related literature presented at the American Society of Retina Specialists annual meeting, I noted that there is a three to four times higher than expected rate of Streptococcus species endophthalmitis after intravitreal injection, suggesting droplet contamination of the field. This may be avoided by avoiding talking in the direction of the sterile field or by wearing a face mask.

Additionally, 65% to 85% of postoperative or post-procedure endophthalmitis cases are caused by Staphylococcus epidermidis. However, 30% to 40% of S. epidermidis isolates are resistant to fluoroquinolone antibiotics, including newest-generation ones. Yet, the most commonly used prophylactic perioperative and peri-procedure antibiotics are fluoroquinolones. In the absence of scientific proof that using the antibiotics reduces the risk of endophthalmitis, I think it is less important than good injection technique.

If a surgeon does use antibiotics, I suggest gentamicin or Polytrim (polymyxin B-trimethoprim, Allergan) drops. There are far fewer resistant isolates of S. epidermidis to these antibiotic drops, and they are broad spectrum.

Colin A. McCannel, MD, FACS, is associate professor of clinical ophthalmology at the Jules Stein Eye Institute, UCLA, in Los Angeles.

Topical antiseptic warranted

Michael D. Ober

Intravitreal injections are considered a fairly low-risk procedure to most busy retina practices but, because of the volume of injections we do, it is inevitable that we will see post-intravitreal injection endophthalmitis.

Many suspected risk factors, such as blepharitis or periocular infection, would preclude giving an injection. For most of our patients, however, people have a routine they have set up that quickly and efficiently allows us to see and treat our patients who require intravitreal injections.

The routine in my office is to give pre-injection antibiotics to reduce or eliminate the surface bacteria where the needle passes and to counter a small inoculum of bacteria that may enter the eye with the needle. The eye can tolerate a certain amount of bacteria in the anterior segment, but the threshold is low and likely to be lower in the vitreous cavity.

The one antibiotic I believe to be imperative is Betadine (5% povidone-iodine, Alcon). Even though the literature supports use of Betadine to reduce the risk for endophthalmitis in cataract surgery, there is no level 1 evidence to confirm that it reduces the risk after office-based intravitreal injection. Nonetheless, most physicians are using Betadine as an antibiotic prior to their injection. Betadine works best on surface bacteria, but does not have significant intraocular penetration. Fortunately, newer-generation fluoroquinolones and other commercially available antibiotics have excellent penetration into the eye. This intraocular penetration could at least, in theory, counteract a small amount of susceptible bacteria potentially introduced into the eye.

Michael D. Ober, MD, FACS, practices with Retina Consultants of Michigan.