"The development of corneal melt after implantation of [corneal inserts] is a known, although rare, complication . . . first reported by John Kanellopoulos, MD, in 2006," Dr. Kugler said. In his practice, four cases of corneal melt have occurred in association with implantation of the inserts.
Dr. Kugler, a surgical associate and cornea/refractive surgery fellow with Ming Wang, MD, PhD, in Nashville, TN, briefly described four cases of corneal melt that had one similarity, namely, that the complication developed in the area of the incision.
Dr. Kugler and his colleagues then looked at reports in the literature of 1,835 eyes that had undergone implantation related to keratoconus or ectasia. Investigators found 12 cases of corneal melt, for an incidence of 0.7%; seven of the cases (58%) had an incision overlying the implant, five cases did not.
Dr. Kugler suggested that corneal melt might occur because the corneal tissue is weaker or inflamed around the corneal inserts, and there is evidence of decreased keratocyte density. These findings suggest increased keratocyte apoptosis and tissue digestion.
Dr. Kugler cited a report by Sépideh Samimi, MD, and associates of histopathologic findings in corneas from eyes that required a corneal transplant following implantation of the inserts. Histopathologic study showed decreased keratocyte density and thinning of the epithelium. He cited a second study by Fabre et al., who theorized that degraded enzymes resulting from apoptosis in eyes with keratoconus may cause tissue damage.
Circumferential and radial forces caused by implantation cause wound gape, which, in turn, can increase the risk of developing corneal melt.
"Adding insult to injury in these cases, the presence of overlying wound gape may provide a conduit for inflammatory cytokines, inflammation, and tissue weakening," Dr. Kugler said.
Dr. Kugler received the Best Paper of Session award for his presentation at the American Society of Cataract and Refractive Surgery. He has no financial interest in the subject matter.