EyeWorld India March 2019 Issue

28 EWAP SECONDARY FEATURE March 2019 once or twice daily. I often choose ointment form at bedtime, which besides providing the dose of steroid has a depot effect because of longer dwell time and provides barrier lubrication that is far more effective than drops or gels.” Dr. Jacobs emphasized the distinction between ointments and drops or gels. “Gels are not equivalent to ointment in this regard, as they are water-based and although they may have longer dwell time, they do not serve as a barrier against evaporation nor do they have the same protective effect against friction from the lids.” Scleral lenses “Scleral lenses and PROSE treatment can be used as therapeutic lens in NK,” Dr. Jacobs said. She explained that scleral lenses can be used for support of the surface and protection from the environment. “The disadvantage is that they are approved and are generally worn on a daily basis only and must be taken out and disinfected overnight. The advantage is that there is lower risk of infection than with overnight wear of a soft lens. “There are some instances in which the mechanical contact of a soft lens is enough to trigger a breakdown,” she added. “Some patients with NK experience less breakdown in daily wear of a scleral lens or PROSE device than extended wear of a bandage soft contact lens.” In Dr. Pflugfelder’s experience, scleral lenses do work better than soft contacts. “They can be used on an extended basis for 24–48 hours, if no corneal edema develops,” he said. Amniotic membrane transplantation (AMT) “I think that most NK corneas reepithelialize in a couple weeks if a good environment is offered,” Dr. Jacobs said. To that end, amniotic membrane transplantation offers only limited assistance. “AMT may downregulate intrinsic inflammation, but it is not as good as a BSCL or scleral lenses for improving the environment.” Dr. Pflugfelder is more optimistic about AMTs. “There are reports of AMT healing NK,” he said. “I tend to use double-layer AMT fixated with fibrin tissue glue and covered with bandage contact lens and temporary tarsorrhaphy to enhance retention.” Tarsorrhaphy “Tarsorrhaphy is an excellent option for patients who cannot or will not manage the regimens of frequent application of topical agents or application and removal of therapeutic lenses,” Dr. Jacobs said. “I bring it up immediately if there is already significant ulceration putting integrity of the globe at risk or if it is clear that adherence to regimens is going to be a problem because of medical, cognitive, or logistical challenges.” While not in disagreement, Dr. Pflugfelder spoke more circumspectly regarding the procedure. “Permanent tarsorrhaphy is considered the last resort for this condition because it reduces vision/visual field and patients don’t like the appearance of the eye.” However, Dr. Jacobs noted that “a 40% tarsorrhaphy is much less disfiguring than expected and can be very helpful in support of the surface.” Down the pipeline In terms of future options, “[b] iologics for support of the surface and regeneration of nerves hold promise,” Dr. Jacobs said. “I doubt any one of them will be a panacea for all NK. Some target nerve regeneration direction, others work by supporting the epithelium. What works for damage from multiple surgeries may not work for damage from VZV. Congenital or genetic problems may respond very specifically or not at all and may depend on the age of the patient at the time treatment is initiated.” Dr. Pflugfelder has had experience with one of the drugs coming down the pipeline: cenegermin, a recombinant form of human nerve growth factor that was approved in the European Union for the treatment of NK in adults in July 2017. “I was an investigator in the FDA Phase 3 clinical trial used for orphan drug approval,” he said. “Consequently, I don’t know whether patients received placebo or active. The clinical trial results are impressive with a significant difference in healing vs. vehicle (up to 75% healing in some studies) and lack of recurrence for an extended period after stopping the drug.” Dr. Pflugfelder is not sure there is evidence that other therapies such as thymosin beta-4 factor and synthetic neurotrophin mimetics will be effective; however, regarding cenegermin, “I plan to use it when it becomes commercially available at the end of this year or early next year,” he said. EWAP Reference 1. Sacchetti M, Lambiase A. Diagnosis and management of neurotrophic keratitis. Clin Ophthalmol . 2014;8:571–9. Editors’ note: Dr. Jacobs was a full-time employee of BostonSight in the past 12 months, but has no financial interests in any contact lens or prosthetic device. Dr. Pflugfelder has no financial interests related to his comments. Contact information Jacobs: deborah_jacobs@meei.harvard.edu Pflugfelder: stevenp@bcm.edu Managing neurotrophic – from page 27 Carl Zeiss Meditec Page: 58, 59 www.zeiss.com VSY Biotechnology Page: 49 www.vsybiotechnology.com APACRS Page: 2, 7, 10, 19, 20, 21, 42, 51, 57, 67, 70, 72 www.apacrs.org ASCRS Page: 5, 71 www.ascrs.org EyeWorld Page: 32, 38 www.eyeworld.org Index to Advertisers