Eyeworld

A zithromycin oil-based eyedrops are shaping up to be a potential prophy- laxis in corneal refractive surgery as well as treat- ment for purulent bacterial conjunc- tivitis. Two studies—one published in June 2010 in the European Journal of Ophthalmology (EJO) and the other published in April 2010 in the Jour- nal of French Ophthalmology—found positive results in terms of refractive surgery prophylaxis and conjunctivi- tis management. In terms of treatment, Azyter (azithromycin 1.5%, Laboratoires THEA, Clermont-Ferrand, France) provided a quicker cure than to- bramycin. It also demonstrated a "potent antibiotic effect" after LASIK surgery in hens, according to the EJO lead study author Jesus M. Merayo-Lloves, M.D., Ph.D., Insti- tuto Universitario de Oftalmobilogia Aplicada, Valladolid, Spain. Azyter vs. tobramycin Pierre-Yves Robert, M.D., Service d'Ophtalmologie, Limoges Cedex, France, analyzed 1,043 patients with purulent bacterial conjunctivitis. They received Azyter twice daily for 3 days or tobramycin (one drop every 2 hours for 2 days, then four times daily for 5 days). The primary variable was clini- cal cure at the test-of-cure visit on day 9 of treatment on the worst eye. Dr. Robert defined cure as bulbar conjunctival injection and discharge scores of 0. "In the azithromycin group 87.8% of patients and in the to- bramycin group 89.4% were clini- cally cured at D9 [day 9]," Dr. Robert reported. "Clinical cure with azithromycin was not inferior to to- bramycin at D9: discharge was ab- sent in 96.3% of patients treated with azithromycin and 95.1% with tobramycin." This is notable since the Azyter treatment course was, in total, only six drops compared to the to- bramycin regimen, which was 36 drops. "Furthermore, patients on azithromycin presented earlier clini- cal cure on Day 3 than patients on tobramycin," Dr. Robert reported. "Azyter, with its convenient dosing (bid for 3 days), is a step forward in the management of purulent bacter- ial conjunctivitis." Azyter was also well-tolerated, Dr. Robert reported. "Azithromycin is famous as an agent that has high concentrations in the tissues," said Francis S. Mah, M.D., co-medical director, Charles T. Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh School of Medicine, explaining why Azyter works with just six drops. The use of Azyter in LASIK Dr. Merayo-Lloves analyzed 90 adult Lohmann Brown hens. The animals were divided into nine groups of 10 hens. Groups 1, 2, and 3 were PRK groups; 4, 5, and 6 were LASIK groups; 7, 8, and 9 did not have sur- gery. Groups 1, 4, and 7 were treated twice a day with Azyter 3 days pre- op and 3 days post-op. Balanced salt solution (BSS, Alcon, Fort Worth, Texas) was applied to groups 2, 5, and 8 in the same fashion. Groups 3, 6, and 9 were untreated. "Infections were present in the following proportions of corneas op- erated on by LASIK: 0% treated with azithromycin, 60% treated with BSS, and 30% untreated," Dr. Merayo- Lloves reported. "Conjunctival edema and redness were less preva- lent in LASIK-operated eyes treated with azithromycin than in BSS- treated or untreated eyes." Further, Dr. Merayo-Lloves noted, LASIK eyes treated with Azyter did not develop any ab- scesses, although other complica- tions such as epithelial ingrowth (in 15% of these eyes) were observed. Another potential advantage of Azyter use was the fact that the in- crease in epithelial thickness was slightly higher with that drug after PRK. "In PRK-operated eyes treated with azithromycin, a decrease was observed in the apoptosis and an in- crease in the stromal proliferation," Dr. Merayo-Lloves reported. "There were no differences in these parame- ters for LASIK and unmanipulated eyes." Haze was also less intensive in the Azyter group. "Regarding clinical signs, topical administration of azithromycin on the ocular surface dramatically reduced corneal infec- tion after corneal refractive surgery (LASIK) and seems to modulate the wound-healing response with less grade of haze in the PRK model," Dr. Merayo-Lloves reported. Surprisingly, BSS had a deleteri- ous effect. "The use of topically ad- ministered BSS may dilute the survival signals released in the tear film during the wound-healing process with the result of more cell death," Dr. Merayo-Lloves reported. "This finding could justify further research on the role of BSS-like eye- drops (tears substitute) after corneal surgery or injury. Further work will be necessary to elucidate the poten- tial damage of BSS (and similar for- mulations) at the ocular surface and the beneficial effect of the T1225 formulation (azithromycin or the oil-based vehicle) in the corneal wound-healing process." Dr. Mah has reservations about using an azithromycin agent as pro- phylaxis before LASIK. "I personally would not choose that as my pri- mary agent," Dr. Mah said. "It's true the medications have extremely high concentrations in tissues like the cornea, but I don't know if I'd want to put an oil-based product on a freshly made LASIK flap." Dr. Mah said potentially the oil could get under the flap and cause it to move. Further, azithromycin has no efficacy against certain bacteria, like pseudomonas. He prefers fourth- generation fluoroquinolones as pro- phylaxis instead. Azyter currently is not approved by the Food and Drug Administra- tion. However, it is undergoing Phase II clinical trials to assess effi- cacy and safety for patients with ble- pharitis. Azithromycin has some anti-in- flammatory effects, which is good for blepharitis, Dr. Mah said. EW Editors' note: Dr. Mah has no financial interests related to his comments. Drs. Merayo-Lloves and Robert have no fi- nancial interests related to the studies. Contact information Mah: 412-647-2211, mahfs@upmc.edu Merayo-Lloves: merayo@telefonica.net Robert: pierre-yves.robert@unilim.fr EW REFRACTIVE SURGERY February 2011 81 by Matt Young EyeWorld Contributing Editor Study finds azithromycin potential LASIK prophylaxis Anterior blepharitis Source: Katherine Mastrota, O.D. March 2011 ever small, so that they can deter- mine if they are willing to take the risk. "There are some patients who say, 'Even if it's rare, it's still there and I don't want to have the LASIK,'" she said. Overall, Dr. Bass stressed that LASIK has proven to be an extremely safe procedure. "I know there are in- dividual reports of people having some issues, but there are millions of these procedures being done and a very small number of patients have problems," she said. "But it's important to still be aware of the occasional patient who can have problems to avoid getting into trouble legally." EW Editors' note: Dr. Bass has no financial interests related to her comments. Contact information Bass: 212-938-5865, sbass@sunnyopt.edu On the lookout continued from page 80

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