Eyeworld

EW CORNEA 58 byline plus fade March 2016 with corneal opacification, several points of caution were raised in this review." These points included that the overall outcome and complications were worse over longer follow-up periods and that patients with autoimmune conditions were more susceptible to "severe, devastating complications." Improvements to the KPro design—holes in the back plate to allow for nutrient diffusion, a threadless design to reduce inci- dents of tissue melt, and a titanium locking ring to hold all the pieces of the device together—might improve outcomes and reduce complications, but Lee et al. suggested that future research include randomized trials that compare different and newer designs to assess efficacy. "In the right situation, KPro is a great alternative to provide improved vision for patients who do not do well with cadaveric corneal transplants," said co-author Roni Shtein, MD, associate professor of ophthalmology and visual science, Kellogg Eye Center, University of Michigan, Ann Arbor, Mich. "There are risks associated, and it's difficult to draw conclusions regarding long- term outcomes given the current data in the peer-reviewed literature." Other areas of future research could include longer-term studies to better understand possible complica- tions that could occur well after the procedure and also development of a better measure for assessing glau- coma risk in these patients. "We would encourage more studies that continue to follow long-term outcomes of patients with KPro, as well as studies that help us to better understand and combat the complications of KPro," Dr. Shtein said. "And we recommend future research to continue the quest for a truly biocompatible prosthetic cornea that could integrate with the patient's existing tissues and reduce the risks of extrusion, infection, inflammation, glaucoma, etc." EW Reference 1. Lee WB, et al. Boston keratoprosthesis: Outcomes and complications: A report by the American Academy of Ophthalmology. Ophthalmology. 2015;122:1504–1511. Editors' note: The physicians have no financial interests related to their comments. Contact information Lee: wblee@mac.com Shtein: ronim@med.umich.edu of patients reached this target," the study authors wrote. "Five articles reported visual acuities of 20/40 or better in 11% to 39% of eyes. Four articles reported visual acuities of 20/40 or better in 43% to 69% of eyes. Three of the 16 articles report- ed best Snellen visual acuities of 20/100 or better in 69% to 81% of patients." Dr. Lee called this "amazing vision improvement in the vast majority of cases." The report authors did note that visual acuity was "skewed toward vision improvement because reports of patients with worsened visual acuity at the study end point were excluded." Retention In the past, retention of corneal transplant devices has been quite an issue—less than 10% were success- fully retained in early KPro trials, Dr. Lee said. This literature review revealed that retention rates have increased to 65% on the low end of the range and 100% on the high end, as reported in 14 of the 22 articles reviewed, which included a follow- up range of 2 to 47 months. "The challenge remains preven- tion of infection and thinning at the graft-host junction," Dr. Lee said. Complications The most common complication re- ported in the studies was retropros- thetic membrane formation, which occurred in 1% to 65% of patients in the 13 articles reporting this issue over a follow-up range from 6 to 47 months. Glaucoma was the second most common, occurring in 2.4% to 64.0% of eyes in the 12 articles reviewing this complication during a 6- to 47-month follow-up period. Other postoperative complica- tions, to a lesser extent, included corneal melt, infectious keratitis, and scleritis. Lee et al. noted posterior seg- ment complications reported in 16 of the 22 articles reviewed. The most common was endophthalmitis, with 15 of the 22 articles reporting this complication in a range of 0% to 12.5% of patients during a follow- up period ranging from 8.5 to 47 months. Overall takeaway Lee et al. concluded that even though the literature review revealed "reasonable rates of visual recovery after KPro surgery in select patients Report continued from page 56

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