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UK shortage of cornea donors

Donor cornea supply in the UK is predominantly channelled through the UK Transplant Support Service (UKTSS) Authority, a central organisation located in Bristol which organises the distribution of organs for transplantation generally. In recent years the cornea transplant service (CTS), a subdivision of the UKTSS, has devolved to two main centres of distribution, at Manchester and Bristol. Supply of donor material has been excellent and the service provided is a highly efficient one, such that most anterior segment surgeons can now schedule corneal graft surgery as part of their routine surgical list. For a number of reasons, it is believed that this “cold surgery” approach has a beneficial effect on graft survival. However, over the past year, the ability of the CTS to sustain this service has been under threat owing to the shortage of corneas, especially from younger donors. The number of requests accepted for donor corneas has had to be restricted, and some users of the service are being faced with rescheduling graft surgery or returning to the old days of “ad hoc” surgery when material becomes available to them locally. The shortage of tissue is due solely to a fall in numbers of eyes being contributed to the CTS eye banks. In the first eight months of 1997, only 2392 donor eyes were received, compared with 2853 for the same period in 1996, a 16% reduction. The CTS is unsure as to the reasons for this fall off in supply and aims to encourage donations through a publicity drive. In addition, the CTS offers courses in eye retrieval techniques in Bristol and Manchester aimed at training non-medical staff, such as nurses and mortuary technicians.

Diabetes and the St Vincent Declaration

Ophthalmologists responsible for the management of diabetic eye disease need no reminder of the aims of the St Vincent Declaration, a declaration signed by the British Diabetic Association, the World Health Organisation, and several other national diabetic associations in 1989, which has set one target among several as the reduction in blindness due to diabetes by the year 2000. The British government has now joined forces in this enterprise with the publication of its guidelines for a good diabetic service (Key features of a good diabetic service. NHS Executive Health Service Guidelines HSG (97)45). Its primary aims are to support health authorities and general practitioner fundholders in their fight against diabetes by stressing the importance of the multidisciplinary approach. Much of this is involved in ensuring the dissemination of information between disciplines but especially to patients; in addition, there should be flexibility in accounting for local needs and regional differences in the population base. The publication of these guidelines coincides with the recent publication of the “Guidelines for the management of diabetic retinopathy” by the Royal College of Ophthalmologists and indicates the general drive to combat the morbidity associated with diabetes.

NHS R&D: disseminating information as part of the Health Technology Assessment Programme

The National (UK) Coordinating Centre for Health Technology Assessment has as part of its remit a responsibility for ensuring the dissemination of information regarding studies which it has sponsored or underwritten. The HTA was set up in 1996 to identify gaps about health technologies important to decision makers in the UK National Health Service and thus potentially has a significant influence on the practice and delivery of medicine. HTA activities include prioritising potential topics for research and commissioning high quality research projects from academic departments, not necessarily restricted to the UK. Once the research is completed, the HTA also reckons that it has responsibility for ensuring that the data are published and disseminated, and to achieve this the research reports are produced as monographs. In this regard the HTA became concerned that recent promulgations concerning the undesirability of authors to engage in duplicate publication was in one sense seen as running counter to its primary aims of ensuring that the information is in fact disseminated to the appropriate audience. As a result the HTA has stated that it expects authors of monographs to be explicit to journal editors regarding submission of same or overlap material and to be prepared to provide journals with monograph material for assessment. In addition it has indicated that it is willing to delay publication of its monographs until after the publication of the original data in the journal. These assurances should alleviate any concerns authors may have about duplicate publication. Similar arrangements regarding publication of proceedings of meetings and other possible occasions of redundant publication might be achievable and indeed would be highly desirable.

A centre for motion perception

There is a long history of interpreting the functions of the cerebral cortex from study of patients with specific cortical lesions. This is especially true for visual function. In a recent letter to Nature (1997;389:849) a patient, with discrete bilateral extrastriate cortical lesions, was found to have a false perception of motion when viewing the stationary world. Normally when we scan the world around us using smooth pursuit movements, the motion of the external images across the retina is not detected because in some way we “subtract the retinal motion signal from an internal reference signal” generated by the movements of the eye. This is known as the retinal slip and the patient described in the letter by Haarmeier and colleagues had lost the ability to compensate for retinal slip when the motion of the stationary world corresponded to that of his eye movements. As a result he had complaints of vertigo and nausea especially when tracking movements such as watching his children on a carousel or playing a computer game that involved tracking movements. Magnetic resonance imaging showed he had damage to the parieto-occipital region of the brain on both sides and the authors believe that while the precise area in humans which regulates this form of “ego motion” has yet to be located it must lie in close proximity to the motion processing area of cortical area V5.

Vitamin C and cataract

A recent study in the American Journal of Clinical Nutrition (1997;66:911) has addressed yet again the question of oxidation and cataract formation. This time, Jaques and colleagues performed a cross sectional study, in women over a 10–12 year period, of vitamin C use without prior assessment of lens status, thus avoiding the potential bias of knowledge of lens status influencing the observations. The study cohort comprised 247 women aged 56–71 years. Vitamin C use was associated with a 77% reduction in the incidence of early lens opacities as assessed by the LOCS II technique, after adjustment for age and other confounding factors such as smoking. However, prolonged use of vitamin C appeared to be important since there was no reduction in the incidence of cataract if the intake of vitamin C was less than 10 years. The authors probably underestimate the value of vitamin C to a degree since, by the nature of the methods inherent in questionnaire evaluation of dietary intake, they restricted themselves to supplemental vitamins C intake and excluded intake of vitamin C in foods. However, the results are interesting and support a mechanism involving oxidation of lens proteins in cataract formation.