Dear Editor

Intracameral antibiotics have become popular in Europe. According to a 2014 American Society of Cataract and Refractive Surgery (ASCRS) antibiotic endophthalmitis prophylaxis survey, the number of surgeons who employ intracameral antibiotics is increasing. While the number using moxifloxacin (MFLX) is fairly small in Europe, 33 % of surgeons use it in the U.S.

Previous reports on intracameral MFLX have focused on its safety up to several weeks following surgery. Therefore, the aim of the current study was to assess the long-term safety of intracameral MFLX.

Our study comprised 155 eyes of 95 patients who underwent ordinary cataract surgery from June 2011 to December 2011 at Nojima Hospital, where intracameral MFLX was introduced in September 2011. The control group (46 patients, 76 eyes), prior to introduction of intracameral MFLX, was compared with the study group (45 patients, 79 eyes) in which an intracameral injection was administered at the end of surgery using the flush technique [1] with diluted MFLX (200 μg/ml). The records of all patients were reviewed 3 years following surgery. Corrected visual acuity, intraocular pressure, corneal endothelial cell density, and foveal thickness were compared between the study group and the control group. Due to the limitation of study size, we do not perform a statistical analysis of occurrence rate of endophthalmitis and cystoid macular edema, but focus on the comparison of ocular parameters between the groups.

Patients with a history of trauma, ophthalmic surgery, or retinal disease were excluded.

The study was approved by the Nojima Hospital Review Board. Written informed consent was obtained from each patient.

A comparison between the two groups did not show any statistically significant differences in ocular parameters 3 years after surgery (Table 1). We found no case in which macular thickness increased throughout the 3 years (data not shown). No adverse events, such as severe corneal damage or toxic anterior segment syndrome (TASS), were observed in either group. Endophthalmitis did not occur in any case.

Table 1 Demographic and clinical data of patients without or with intracameral MFLX
Full size table

Lane and colleagues reported no significant differences in foveal thickness 3 months after intracameral MFLX (250 mμg/ 0.05 ml) [2]. In addition, we previously reported that intracameral MFLX did not affect the ocular parameters of visual acuity, intraocular pressure, corneal endothelial cell count, or foveal thickness 3 months after surgery [3].

MFLX has some advantages because of its broad spectrum coverage and concentration-dependent efficacy. Arshinoff reported that that the infection rate following intracameral MFLX was only one in 35,194 cases while their study included experienced surgeons [4]. We previously reported only three cases of endophthalmitis out of 18,794 following intracameral MFLX using the flush technique [5]. Moreover, there is less risk of allergic reactions compared with cefuroxime and vancomycin when MFLX is used intracamerally. Moxeza eye drops contain additives associated with severe toxic anterior segment syndrome (TASS) when injected intracamerally. Commercial Vigamox eye drops, being preservative free and isotonic, allow direct injection (diluted if necessary) into the eyes, and there have been no reports regarding serious complications.

With cefuroxime, vancomycin, or MFLX, antibiotic concentration exceeds minimum inhibitory concentration for inhibiting 90 % growth of typical pathogens by the hundreds, and estimated infection rates are so low that it is difficult to prospectively determine which antibiotic is the most effective. Cefuroxime is time dependent, and cases of allergic reaction or toxicity in which dilution was erroneous have been reported. The routine usage of vancomycin for prophylaxis is problematic. Intracameral MFLX remains controversial because it is not as widely studied as cefuroxime, and its use is considered off-label. If a safety protocol is established and a commercial product becomes available, we believe that MFLX has strong potential as an intracameral antibiotic.