OSNAPAO: Should we use prophylaxis topical antibiotics after intravitreal injections?

Intravitreal delivery of medications by injection through the pars plana has become a routine ophthalmic procedure since anti-VEGF medicines became commercialized. Due to the huge number of intravitreal injections every year — and this number is assumed to be increasing continuously — the complications from intravitreal injection have received more attention, especially the serious adverse complications. One of the most feared complications is endophthalmitis. According to recent studies, the incidence of endophthalmitis after intravitreal injection of anti-VEGFs has been reported to be in the range of 0.02% to 0.085%. A current debate is whether prophylactic antibiotics should be used or not. The cover story in this issue of OSN APAO Edition discusses the revised guidelines for intravitreal injections in which antibiotic use is discouraged. Patients with post-injection endophthalmitis typically present within 5 days after intravitreal injections. The most common complaints include red eye, pain and decreased vision, and some patients also have floaters, lid swelling and discharge. The most common signs are vitritis, hypopyon, hyperemia and corneal edema, and a few patients have increased IOP.

The management of post-injection endophthalmitis is challenging. Early cases can get a good response from an injection of intravitreal antibiotics. However, in cases with dense vitritis, rapid onset of symptoms and poor visual acuity, there should be a low threshold for pars plana vitrectomy and intravitreal injection of appropriate antibiotics. Vitrectomy should also be considered when eyes fail to respond to the initial intravitreal antibiotic injection. The visual outcomes of patients with post-injection endophthalmitis are harder to assess because of the wide range of baseline visual acuities due to the primary diseases. However, recent studies indicate that visual outcomes may be dependent on the organism causing the infection, and the infections caused by Streptococcus species have the worst outcomes.

To reduce the risk of post-injection endophthalmitis, most doctors routinely use topical antibiotics during and after the procedure. Recently, some studies suggest that antibiotic use may not reduce the risk of endophthalmitis. On the contrary, it increases the incidence of post-injection culture-positive endophthalmitis. One hypothesis is that the use of topical antibiotics after intravitreal injection increases the drug resistance of bacteria on the ocular surface. Based on these studies, there are suggestions that topical antibiotics are not needed and should not be used at all before, during and after the injections. The clinical practice of intravitreal injections has variations. For instance, the duration of topical antibiotics ranges from 3 to 7 days; the concentration of povidone-iodine used as a disinfectant ranges from 5% to 10%; and the use of a lid speculum, mask and gloves and whether administered in the operating room or not varies from surgeon to surgeon. With these big practice differences, it would be difficult to interpret results of some of the studies. Large-scale multicenter randomized controlled trials using standardized methods to evaluate the role of antibiotics in post-injection endophthalmitis seem warranted.

It is likely that the debate will continue for quite a while until more compelling evidence is available. For the time being, for those who opt to use post-injection antibiotics, a halfhearted use of antibiotics for only 3 to 5 days should be discouraged because this may cause more drug resistance.

References:

Haddock LJ, et al. Semin Ophthalmol. 2014;doi:10.3109/08820538.2014.959616.

Samia-Aly E, et al. Ophthalmic Physiol Opt. 2015;doi:10.1111/opo.12217.

Sigford DK, et al. Clin Ophthalmol. 2015;doi:10.2147/OPTH.S77067.

Storey, P, et al. Ophthalmology. 2014;doi:10.1016/j.ophtha.2013.08.037.

Storey P, et al. Graefes Arch Clin Exp Ophthalmol. 2015;doi:10.1007/s00417-015-3035-x.

For more information:

Dennis S.C. Lam, MD, FRCOphth, can be reached at State Key Laboratory in Ophthalmology, Sun Yat-Yen University, 54 South Xianlie Road, Guangzhou 510060, People’s Republic of China; email: dennislam.gm@gmail.com.

Disclosure: The authors report no relevant financial disclosures.

Click here to read the commentary published in Ocular Surgery News APAO Edition, June 2015.