Search

An active program of corneal transplantation depends upon a constant supply of high quality donor tissue. We describe an effective and inexpensive system of corneal donor retrieval in a major teaching hospital, and present an analysis of its donor population. During the five-month period studied in detail (May to October 1991), 365 deaths occurred in the hospital. The relatives of the decreased were contacted and consent for donation was requested after 323 (88.5%) of these deaths. Consent was given in 212 cases (65.5% of requests), with a mean age of the donor population of 69 years. After screening donor tissue for quality, 110 pairs of corneal buttons and 10 globes of sclera were dispatched for surgery during the study period, giving an overall procurement rate of over 30%. Further, the efficient notification and 'on-call' retrieval system led to very rapid corneal retrieval, resulting in an average death to storage medium time of less than two hours.

The first dedicated, public hospital day-case eye surgery unit opened in Melbourne in June 1987. This report details the mode of operation of this unit, and analyses the 218 procedures performed in the first 15 months of operation, and includes an assessment of the level of patient acceptance.

Thirty-five patients have had 39 consecutive epikeratoplasty procedures (12 adult aphakic, 9 pediatric aphakic, 12 myopic, and 6 keratoconic eyes) by the same surgeon, using commercially prepared lenticules. The lenticule remained totally clear in 85% of eyes. Two lenticules were removed due to infection and scarring; four lenticules had minimal scarring and did not require removal. Spectacle-corrected acuity was worse than one line from the preoperative spectacle-corrected acuity in 58% of the adult aphakic eyes; however, 75% were 20/50 or better postoperatively. Fifty percent were within 2 diopters (D) of emmetropia and 92% within 3 D. All pediatric aphakic patients showed an improvement in best-corrected acuity, and 83% of eyes at 6 months were within 2 D of emmetropia; by 1 year a 3.4-D average myopic shift had occurred. Two of the six eyes (33%) using the original myopia technique were within 2 D of emmetropia, whereas five of the six eyes (83%) with the current technique are within this range. Spectacle-corrected acuity in the entire current myopia group has either improved by one or more lines or has remained unchanged. Five of the six keratoconic eyes had 20/40 or better spectacle-corrected and 20/25 contact lens-corrected acuity postoperatively; average corneal flattening was 6 D. Persistent epithelial defect and irregular astigmatism were the principal factors in delay in visual recovery.

Changes in intracorneal and storage-medium pH values of organ-culture-stored cat corneas were monitored over a 4-week period. The intracorneal pH was determined using the phosphorus-31 magnetic resonance spectroscopy (31P MRS) chemical shift of inorganic orthophosphate in conjunction with a standard pH titration curve. We incubated 32 adult cat corneas using two similar standard organ-culture methods, one with chondroitin sulfate (method 1) and the other without (method 2). Time-course data at 0, 1, 3 and 4 weeks of storage were used to calculate the rate of pH change. The intracorneal pH was not changed significantly for either organ-culture method; however, the storage-medium pH rate of change declined significantly for both methods (method 1, 0.15 pH units/week; method 2, 0.12 pH units/week). The difference between intracorneal and storage-medium pH values over time increased at a rate of 0.12 and 0.11 pH units/week for method 1 and method 2, respectively. The declining storage-medium pH in conjunction with the maintenance of intracorneal pH contributes to an increased metabolic demand on the cornea.

Elective penetrating keratoplasty has been performed on an outpatient basis on 37 patients since July 1987. The commonest indications have been herpetic keratitis, keratoconus, and pseudophakic or aphakic corneal oedema. Local anaesthesia, with little or no sedation, was used in most cases, and only three patients had a general anaesthetic. Accompanying procedures have included anterior vitrectomy, extracapsular cataract extraction with posterior chamber lens implantation and IOL exchange. The results demonstrate that outpatient keratoplasty is a safe, effective alternative to hospitalisation, and has a very high level of patient acceptance.

Epikeratoplasty has been performed on eight eyes of seven patients by one surgeon in Melbourne since March 1988. All cases were contact lens or spectacle intolerant. Standard surgical techniques utilising donor lenticules imported from the United States and including an annular keratectomy were employed for the procedure. An eight-month follow-up is available for the first two cases, aged two and 10 years. The elder of these children has achieved corrected acuity of 6/9 in each eye. Refractive and early visual acuity results are presented for the five other cases which have at least two months of follow-up. The results indicate that in appropriately selected patients, epikeratoplasty offers a safe, effective modality for visual restoration and development in otherwise untreatable aphakic children.