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72 EW CORNEA September 2012 Cornea editor's corner of the world Tackling infectious keratitis by Vanessa Caceres EyeWorld Contributing Writer Crosslinking explored as a new treatment orneal infections continue to be a leading cause of corneal blindness worldwide. Treatment failures can result from a variety of reasons including delay in treatment, patient compliance, ineffective antimicrobials, and scarring from prolonged inflammation. Clinical trials are under way to evaluate a new treatment that would provide an immediate therapy resulting in rapid eradication of the infect- ing pathogen and reduction in the patient's inflammatory response to the infection. Collagen crosslinking (CXL) may just be that treatment. C Significant corneal infections often result in the clinician eventually winning the battle to achieve corneal sterility but losing the battle to retain excellent vision. Therefore, a subsequent keratoplasty is necessary for visual recovery. CXL offers the potential for immediate sterilization of the cornea, thus avoiding the prolonged inflammatory reaction that can result in stromal scarring. I am especially interested in CXL for the most challenging corneal pathogens that don't have effective topical treatments: fungal and Acanthamoeba keratitis. Corneal specialist around the world will be evaluating this new modality, and we look forward to studies that report efficacy, dosing, and duration of CXL treat- ments for a variety of corneal pathogens. Edward J. Holland, M.D., cornea editor I t's not yet an everyday reality in the U.S., but the possible use of collagen crosslinking to treat infectious keratitis is attracting attention. Collagen crosslinking is already being used for keratoconus, ectasia, and other ophthalmological condi- tions. It also has uses outside of oph- thalmology and is being studied for applications such as the sterilization of blood supplies, said Peter S. Hersh, M.D., The Cornea & Laser Eye Institute, Teaneck, N.J. Clinicians such as Jes Mortensen, M.D., consultant ophthalmologist, Department of Ophthalmology, Örebro University Hospital, and Ryhov County Hospi- tal, Sweden, broached the possibility of using collagen crosslinking to treat infectious keratitis a few years ago. "Besides the eradication of pathogens, photo-oxidative stress generated by riboflavin illumination has the capacity to inactivate white blood cells," Dr. Mortensen said. "The improvement in associated symptoms, inflammation, and stromal melting may, at least in part, be a result from inhibition of the host immune reaction on cells such as corneal antigen-presenting cells, dendritic cells, and Langerhans cells." Implications beyond the science Clinicians believe this kind of treat- ment has real potential for several reasons. First, as keratitis is a fre- quent cause of blindness in develop- ing countries, this could provide physicians with an easy treatment alternative when antibiotics are not available, Dr. Hersh said. "This could be a one-time treatment in the office, and it could have enormous implications on the treatment of keratitis worldwide," he said. "Collagen crosslinking could be considered a treatment in refractive cases with antibiotic-resistant corneal melting and as an adjuvant therapy in severe cases," Dr. Mortensen said. "As antibiotic resistance is a growing concern, it could prove to be a valuable treatment tool." "It offers an alternative for the treatment of infectious keratitis that is resistant to traditional methods and existing antibiotics," said R. Doyle Stulting, M.D., professor of ophthalmology, emeritus, Emory University, Atlanta; adjunct profes- sor of ophthalmology, Moran Eye Center, Salt Lake City; and director, Stulting Research Center, Atlanta. If proven successful on a wide- spread basis, collagen crosslinking could also provide a treatment for common contact lens infections without the worry of medication compliance issues, said Francis W. Price Jr., M.D., Price Vision Group, Indianapolis. However, although these impli- cations are important, the patient needs to be present for treatment at an easily accessible location that has the right treatment equipment, said Francis S. Mah, M.D., Scripps Health, La Jolla, Calif. Additionally, research will have to show if the cost of crosslinking treatment is actually lower than the cost of prescribing medicine, he added. The images show a 40-year-old woman who had used soft contact lenses for many years. She had keratitis diagnosed. Collagen crosslinking was performed, and no antibiotics were used. The eye was subsequently fully healed Source: Jes Mortensen, M.D., and Karim Makdoumi, M.D.