Cornea
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A great deal of controversy and concern exists over potential transmission of central nervous system diseases by corneal transplant. The purpose of this study was to evaluate the available data relative to this question, pertaining especially to transmission of infectious dementia. From these data, determination of conveyance risks are possible, and rational policies for donor inclusion criteria can be constructed. ⋯ That this case represents an extremely rare event is supported by a lack of successful transmission via corneal transplant in monkeys; lower levels of infectious agent in cornea than in brain; lack of successful transmission of similar human dementias, including Alzheimer's disease to primates; the apparent requirement for homozygosity at codon 129 of chromosome 20 for transmission; lack of transmission in 5-10% of CJD cases even after brain inoculation; and low numerical risk of transmission based on population data. Only 0.5-4 CJD infected donors per year would be expected. Current Eye Bank Association of America criteria for donor exclusion based on suspicious history are adequate to protect against accidental conveyance of transmissible dementia.
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The purpose of this study was to identify new trends in the changing indications for penetrating keratoplasty. We retrospectively reviewed the clinical and pathologic diagnoses of 1,104 corneal buttons that had been submitted to the Estelle Doheny Eye Pathology Laboratory, Los Angeles, during the 5-year period 1989-1993. ⋯ The incidence of pseudophakic corneal edema remained stable over the study period and was actually surpassed by regraft in the last year of the study. Although pseudophakic corneal edema remains the predominant indication for penetrating keratoplasty, our findings suggest that its occurrence rate has begun to level off.
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Eighteen eyes with wound dehiscence after penetrating keratoplasty were studied. Keratoplasty was performed for corneal scarring (n = 8), dystrophies (n = 6), graft failure (n = 2), and corneal edema (n = 2). The mean duration between keratoplasty and wound dehiscence was 6.54 months. ⋯ Trivial trauma resulted in dehiscence in 10 of the 18 eyes. The major determinants of visual outcome were the force of trauma and status of the posterior segment. Dehiscence of the graft-host junction in all cases reflects its persistent weakness after surgery.
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Contaminated allograft donor tissue represents a potential source of infection unique to keratoplasty. We prospectively studied perilimbal cultures of drowning victims over 30 months to determine if the ocular surface flora of drowning victims was unique. Twenty-eight donor eyes were cultured from 14 drowning victims. ⋯ The incidence of gram-negative isolates was also markedly higher in drowning victims, compared to previous studies of donor globes. This prospective study has shown that the ocular surface flora of drowning victims harbors markedly increased numbers of streptococcal species as well as gram-negative organisms. These findings demand careful globe decontamination, and emphasize the need for appropriate antibiotic coverage in corneal storage media.
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Shortages in transplantable corneas are common, yet little appears in the medical literature about patterns of tissue donation and factors affecting procurement. We have analyzed data on eye donations and taken measures to improve procurement rates based on our findings. Fifty consecutive Cardiovascular Intensive Care Unit (CVICU) deaths were reviewed to compare the number of transplant-eligible donors to the amount of tissue received. ⋯ During the 12 months after this initiative, the number of transplantable corneas donated from our facility doubled, as compared with the same period in 1992. Despite required request laws and regulations, failure to request tissue donation is common in our facility and may be common elsewhere. Systematic analysis of obstacles to donor eye procurement and their solutions may help to improve our country's performance in this area.