Reply.

Abstract

The difference in the seasonal incidence between our study and that of Nam et al. could be due to the difference in the study design or the study period.1 Our study used the national health insurance claims data that include all surgeries performed nationwide, including 9 provinces and 7 metropolitan cities from 2014 to 2017, whereas Nam et al. found endophthalmitis cases based on the medical records of 8 institutions located in 1 province and 1 metropolitan city from 2006 to 2009. As Fernández-Rubio et al. mentioned, Nam et al. included all infectious endophthalmitis cases, whereas we included only those that occurred after cataract surgery. Fernández-Rubio et al. suggested that the change in cataract surgery prophylaxis with time and the increasing use of intracameral antibiotics injection could explain the different seasonal pattern in 2 studies. It would be interesting to find out whether this had an effect; however, the investigation of prophylaxis protocols each institution incorporates is not possible using the claims data. The national health insurance claims data offer details on medical procedures and treatments, and the information is extracted using diagnostic and procedural codes. Therefore, the claims data include information on the prescribed pharmaceuticals, but it does not have procedure codes for intracameral injection. Also, we do not have a commercially available antibiotic for intracameral injection in South Korea. The surveys on the trends in cataract surgery in Korea include information on the use of topical antibiotics; however, they do not report on the use of intracameral antibiotic prophylaxis.2–4 A 2006 report showed that the most common topical antibiotic used was levofloxacin (38%), followed by ofloxacin (29%) and moxifloxacin (11%). Similar results were found in the 2007 report, which showed that levofloxacin was most commonly used (40%). The most recent report was on 2012, which showed that moxifloxacin was most frequently used (44%), followed by levofloxacin (28%) and gatifloxacin (13%). The transition to the fourth-generation fluoroquinolone from third-generation could have influenced the incidence pattern of postoperative endophthalmitis; however, further studies are required to accurately determine the effect of prophylaxis protocol on the development of postoperative infection.