Study demonstrates safety of intracameral moxifloxacin

Moxifloxacin hydrochloride ophthalmic solution 0.5% (Vigamox, Alcon) seems to be a safe antimicrobial agent when injected intracamerally following cataract surgery. The eyes that received moxifloxacin had a significantly lower mean intraocular pressure value three months postoperatively compared with the control eyes that received balanced saline solution.

Key Points

Los Angeles-Moxifloxacin HCl ophthalmic solution 0.5% (Vigamox, Alcon Laboratories) seems to be a safe antimicrobial agent when injected intracamerally following cataract surgery. The eyes that received moxifloxacin had a very small but statistically significant lower mean IOP value 3 months postoperatively compared with the control eyes. All other measured parameters were similar in the two groups, according to Samuel Masket, MD. He is clinical professor of ophthalmology, Jules Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, and in private clinical practice in Los Angeles.

Preventing postoperative infection begins by limiting the opportunity for contamination. Specifically, this is accomplished by eliminating the microbes on the ocular surface, preventing intraoperative intraocular bacterial contamination, preventing postoperative contamination of the anterior chamber, and especially by killing microbes that enter the eye intraoperatively or postoperatively, Dr. Masket said.

When faced with the task of preventing intraoperative and postoperative ocular contamination, the question arises: which agent or agents are the most effective? Dr. Masket pointed out that a study carried out by the European Society of Cataract and Refractive Surgeons (ESCRS) reported a five-fold reduction in the incidence of endophthalmitis that was associated with the use of cefuroxime.

"Off-the-shelf moxifloxacin 0.5% offers potential advantages. The drug has a broad spectrum of bactericidal activity. It is a sterile, self-preserved formulation without benzalkonium chloride, is easy to administer because there is no dilution or mixing required, which may reduce the risk of toxic anterior segment syndrome," Dr. Masket explained. In addition, the drug is formulated at a pH of 6.8 and osmolality of 290 mOsm/kg, which is compatible with the human anterior chamber fluid, which has a pH of 7.4 and an osmolality of 305 mOsm/kg.

Safety study

To test the safety of intracameral moxifloxacin, Dr. Masket and colleagues conducted a randomized, multicenter, prospective study that included two groups of eyes that were similar. A total of 29 eyes were randomly assigned to receive 50 µl of undiluted moxifloxacin 0.5%, and 30 control eyes received 50 µl of undiluted balanced salt solution (BSS). Moxifloxacin was injected into the 29 eyes at the end of the cataract surgery.

The study protocol required that patients be aged at least 18 years and have no other ocular pathology other than cataract with no other ocular pathology that would prevent them from attaining a visual acuity of at least 20/30. Patients were excluded if they had glaucoma, retinopathy, maculopathy, media opacities other than cataracts, visual pathway problems, diabetes, uveitis, corneal endothelial disease, or pseudoexfoliation. Patients also were excluded if the cataract surgery was complicated and if they had a history of a previous ocular trauma or an allergy to fluoroquinolones.

Patients underwent follow-up examinations on week 1 and months 1 and 3 postoperatively when the following measurements were performed: visual acuity, endothelial cell count, corneal pachymetry, anterior chamber cell and flare, and IOP. In addition, patients were evaluated for corneal clarity and edema, fundus findings during an examination in which the eyes were dilated, and macular optical coherence tomography findings.

"At month 3, we observed a statistically significant difference in the IOP values between the two study groups," Dr. Masket reported. The patients who received moxifloxacin had a mean IOP of 12.65 mm Hg, and those who received BSS had a mean IOP of 14.22 mm Hg (p = 0.02). No significant differences were noted in the mean uncorrected visual acuity values, the mean endothelial cell counts, and the mean corneal thicknesses between the two groups.

The investigators observed trace corneal edema in only one eye that received moxifloxacin and in no eyes that received BSS. Aqueous flare was not seen in either study group. All eyes exhibited either no or trace aqueous cells (moxifloxacin group: 61% no cells, 39% trace cells; BSS group: 48% no cells, 52% trace cells).

"We found no increased safety risk associated with the use of intracameral moxifloxacin 0.5% compared with BSS within 3 months after cataract surgery. Intracameral moxifloxacin 0.5% appears safe for use during cataract surgery to prevent endophthalmitis. Intracameral moxifloxacin 0.5% in conjunction with topical postoperative therapy may further reduce the risk of endophthalmitis after cataract surgery. An efficacy study similar to the ESCRS investigation is needed to determine the prophylactic value of intraocular moxifloxacin," Dr. Masket concluded.