Endophthalmitis After Intravitreous Anti-VEGF Injections in Patients Receiving vs. Not Receiving Topical Antibiotics

This is a prospective case series which aims to determine the incidence of endophthalmitis following intravitreous anti-vascular endothelial growth factor (VEGF) injection comparing between eyes receiving post-injection antibiotics drops and those not receiving antibiotics drops treated at Chiang Mai University Hospital between May 2015 and April 2017 (2-year period).

Intravitreous anti-VEGF injection has been the most common procedure performed at eye clinics worldwide. It becomes the gold standard treatment for many macular diseases, such as diabetic macular edema and neovascular age-related macular degeneration (AMD). One of the most serious complication after intravitreous injection is post-injection endophthalmitis. There is no proven preventive strategy of post-injection endophthalmitis except the use of povidone iodine. However, a number of physicians around the world prescribe topical antibiotics after the injection, despite the lack of evidence to support the benefit of topical antibiotics to prevent the occurence of endophthalmitis. Recently, many large trials from the US including the Diabetic Retinopathy Clinical Research Network (DRCR.net), the Comparison of AMD Treatment Trials (CATT) study have reported the incidence of post-injection endophthalmitis comparing between eyes receiving versus not receiving post-injection antibiotics, and the results of all studies suggested that topical antibiotics does not help reduce the incidence of post-injection endophthalmitis. In addition, the results suggested that eyes receiving antibiotics had higher rate of endophthalmitis comparing to those not receiving antibiotics. Therefore, a majority of physicians in the United States have stopped prescribing antibiotics drops following the injection. However, a majority of physicians in Asia-Pacific region still prescribe antibiotics drops following the injection (according to the Preferences and Trends (PAT) survey by the American Society of Retina Specialists in 2014).

Due to the limited evidence from Asian literature whether there is difference between incidence of endophthalmitis following intravitreous anti-VEGF injection between eyes receiving antibiotics drops versus not receiving antibiotics drops in the Asian setting, the investigators conducted this study to determine the incidence of endophthalmitis after intravitreous anti-VEGF injection, comparing between eyes receiving post-injection antibiotics versus not receiving. Results from this study would be beneficial to guide an appropriate practice for physicians in the Asian region.

Eligibility Criteria:
Inclusion Criteria:

1. More than 18 years of age
2. Have an eye conditions requiring intravitreous anti-VEGF injections, including neovascular age-related macular degeneration, diabetic macular edema, macular edema due to retinal vein occlusions in one or both eyes
3. Able to revisit for an eye evaluation at a recommended period (at least 3 weeks following the injection)
4. No history of uveitis or endophthalmitis in the study eye

Exclusion Criteria:

* Presence of blepharitis or conjunctivitis in the study at the time of intravitreous injection