Corneal transplantation: how successful are we?
- Bristol Eye Hospital, Lower Maudlin Street, Bristol BS1 2LX
- Mr A Waldock awaldock{at}hotmail.com
The cornea is one of a few relatively immunologically privileged sites within the human body.1 Corneal transplant surgery is the most commonly performed allograft in the United Kingdom.2 In terms of solid tissue allografts in humans, the cornea appears to be very successful with an overall first year survival rate as high as 90%.3 Unfortunately, the long term reality is that the overall success rate diminishes to 74% at 5 years and 62% at 10 years3 (Fig 1). In those eyes considered to be “high risk”, especially those with corneal neovascularisation or ongoing ocular inflammation, the long term 10 year survival rate is less than 35%4 (Fig 1). Of greater concern is that these survival rates have not improved over the past 10 years.5
Comparison of organ transplant survival rates over the same time period 1984 to 1996.
The leading cause of corneal transplant failure is allograft rejection.5 6 Table 1 illustrates the causes of corneal graft failure using data from the Australian Corneal Graft Registry (ACGR)5 and the Corneal Transplant Follow-up Study (CTFS).6 As one third of failures are due to irreversible rejection episodes, are ophthalmologists being unduly complacent about the management of such events? Furthermore, is this disappointingly poor and non-improving long term outcome seen with other solid organ transplants?
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Causes of corneal transplant failure
A review of the United Kingdom Transplant Support Service Authority (UKTSSA) audit data for the 1985–95 time period illustrates the following survival rates. For heart transplantation, the overall survival rate at 1 year was 75%, falling to 64% at 5 years.7 The 12 month transplant survival rate has improved from 73% to 77% between the first and second 5 year periods of the 10 year audit review.7 Liver transplantation was less successful …
