Eyeworld

EW CORNEA 68 March 2011 T he first case of progressive retrocorneal epithelial downgrowth of donor ori- gin after Descemet's strip- ping automated endothelial keratoplasty (DSAEK) surgery has been reported in medical literature, along with some tips on dealing with this problem when it arises. The research, published online in July 2010 in Cornea, notes that downgrowth can potentially occur after every intraocular procedure due to the fact that epithelial cells can inadvertently be implanted where they shouldn't be. The July study is unique because researchers suggest downgrowth from donor origin behaves less aggressively than that from patient origin, and treatment options, there- fore, may be modified. "The relatively benign course in our patient may be related to the im- mune rejection process," according to lead study author Mark S. Gorovoy, M.D., private practice, Fort Myers, Fla. "Avoidance of PKP [penetrating keratoplasty] and ag- gressive destructive anterior segment surgery may be recommended in this scenario." New tactics for dealing with downgrowth The patient involved was a 70-year- old woman who underwent DSAEK for pseudophakic Fuchs' dystrophy. The 9.0-mm donor cornea was cut by the surgeon using the Moria ALTK system (Moria, Antony, France). It was inserted through a 5- mm clear corneal wound with for- ceps, which was then closed with su- tures. "She was maintained on pred- nisolone acetate drops 4 times a day for the first 3 months, which were then tapered monthly and main- tained once daily," Dr. Gorovoy re- ported. Although she was 20/40 at 3 months post-op, slowly, problems began to arise. "Three years after operation, iris synechiae and ectropion uvea were noted to the donor thick edge," Dr. Gorovoy reported. "Six months later, a peripheral retrocorneal mem- brane was noted and BSCVA [best spectacle-corrected visual acuity] was unchanged. Observation over the next 15 months revealed growth of this membrane centrally with graft edema and decreased BSCVA to 20/200." A repeat DSAEK was performed 56 months after the original opera- tion. Despite the repeat procedure, DSAEK was a different treatment technique for this downgrowth situ- ation. "Retrocorneal epithelial down- growth may behave invasively and aggressive treatment is often recom- mended," Dr. Gorovoy noted. "How- ever, this treatment regime is based on the historical literature, which includes PKPs [penetrating kerato- plasties] but does not yet include DSAEK." Dr. Gorovoy described the process and findings. "The iris synechiae was separated from the donor and the surface vacuumed with the I&A hand piece, but no ex- cisions were done," he reported. "Histopathological evaluation of the removed donor, including fluores- cence in situ hybridization studies using X and Y centromeres, con- firmed the diagnosis of epithelial downgrowth with an XY pattern, in- dicating the epithelial cells were from a male donor in this female pa- tient. Six months postoperatively, BSCVA was 20/30 with no signs of downgrowth." Dr. Gorovoy explained that the implanted donor epithelial cells from a full-thickness donor edge re- sulted from a decentered trephina- tion after the anterior lamellar keratome cut. "Unique to our case is the un- usually long period of quiescence (4 years) before slit lamp revealed downgrowth," Dr. Gorovoy re- ported. "Further conservative obser- vation did not appear to jeopardize the final successful outcome of re- peat DSAEK, despite a residual iris membrane." This type of downgrowth might even be called passive in nature. "The extremely less aggressive be- havior of this downgrowth may be explained by the nonhost origin of the epithelial cells," Dr. Gorovoy re- ported. "Foreign cells should be eliminated by the immune process. Topical steroids suppress the rejec- tion process, which may allow these implanted cells to survive but not thrive and proliferate. Gradual re- duction to just 1 drop daily may then facilitate these cells' growth, more so on the avascular cornea sur- face than the vascular iris. In fact, total cessation of the steroid drops may enhance the rejection process to kill the epithelial cells and may be helpful in modulating growth of the epithelial cells." The downgrowth could have been prevented to begin with. "Eliminating the full-thickness edge of the donor at the time of surgery would have prevented this compli- cation," Dr. Gorovoy concluded. "We recommend this be done by trephining the thick edge off rather than using scissors." by Matt Young EyeWorld Contributing Editor Study examines downgrowth of donor origin after DSAEK Corneal crosslinking shows promise for keratoconus and ectasia patients V isual acuity and topographic measurements were significantly improved in patients who underwent corneal collagen crosslinking for keratoconus and ectasia after LASIK, according to 1-year results reported in the January issue of the Journal of Cataract & Refractive Surgery. In this prospective, randomized, controlled clinical trial, collagen crosslinking was performed in eyes with keratoconus or ectasia. The treat- ment group received standard CXL and the sham control group received riboflavin alone. Keratoconus patients in the treatment group had more improvement in topographic measurements than patients who had ectasia. Both CDVA and maximum K value worsened between baseline and 1 month, fol- lowed by improvement between 1, 3, and 6 months and stabilization thereafter in the same group. After one year, uncorrected distance visual acuities improved signifi- cantly from 0.84 logMAR ±0.34 (SD) (20/137) to 0.77±0.37 logMAR (20/117) (P=.04), and the corrected distance visual acuity improved from 0.35±0.24 logMAR (20/45) to 0.23±0.21 logMAR (20/34) (P<.001). The maximum K value decreased from baseline by 1.7±3.9 D (P<.001), 2.0± 4.4 D (P=.002), and 1.0±2.5 D (P=.08) in the entire cohort, keratoconus subgroup, and ectasia subgroup, respectively. The maximum K value de- creased by 2.0 D or more in 22 patients (31.0%) and increased by 2.0 D or more in three patients (4.2%). An eye post-DSAEK surgery; a new study examines epithelial downgrowth of donor origin after this procedure Source: Mark S. Gorovoy, M.D. continued on page 70

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