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Interferon alfa for Behçet’s disease?
Currently interferon alfa therapy in ophthalmology is receiving bad press. A recent editorial in Archives of Ophthalmology (1997;115:915–6) reviewed the evidence for the lack of effectivity of interferon alfa in the treatment of subretinal neovascular membranes which occur in some forms of macular degeneration. The authors went further and suggested that previous uncontrolled pilot studies of interferon alfa in age related macular degeneration were ill advised in view of the side effects of the drug which in the USA at least had some serious undesirable consequences. In the current climate in which evidence based medicine is setting the standard, strong views such as these on the place of pilot studies have some justification. However, does this approach mean that only the large multicentre study can be allowed? Is there not a risk that valuable uses of some drugs may be unintentionally sidelined?
Interferon alfa is a case in point. In 1994, Feron et al (Lancet 1994;344:333) reported that interferon alfa was effective in controlling the sight threatening uveoretinal inflammation that occurs as a complication of Behçet’s disease. At the Fourth International Symposium on Uveitis (Yokohama 10–14 October 1997) further support for the use of recombinant human interferon α2b in Behçet’s associated ocular inflammation was presented (Stubinger et al). Remarkably, all 15 patients in whom the drug was used experienced complete resolution of their inflammation, and in 11 of 15 patients there was recovery of vision to normal even in those with occlusive vascular disease where visual recovery appeared unlikely on the basis of retinal ischaemia. Furthermore, at the same meeting Okada et al presented evidence of an anti-inflammatory effect of interferon alfa in the experimental model of autoimmune uveoretinitis. In Behçet’s posterior uveitis and retinal vasculitis, the value of interferon alfa remains to be established but the possibility of its use in this disease would not be raised without these preliminary pilot open studies. Furthermore, the challenge of a randomised multicentre trial will be quite daunting but essential if this drug is to have a place in management of this severe blinding disorder.
Eye pathology opens up lines of communication
Pathology is fundamental to a better understanding of disease processes and in no discipline is this more true than in ophthalmology. In the UK, the Wellcome Trust has recently advertised a fellowship scheme to encourage the development of academic ophthalmic pathology (for information contact The Wellcome Trust, 183 Euston Street, London NW1 2BE). A further initiative has been taken by the newly formed ‘eyepathology’ email discussion group. The aims of the group are wide ranging and include discussion of clinical cases, techniques, research expertise, distribution of material, publication of seminars and conferences plus much more on an informal one to one level. Although the group is UK based its network is worldwide and is intended to reach all interested professionals. Eligible subscribers are professionals with an interest in any aspect of eye pathology whether they are pathologists, clinicians, or basic scientists and the object is to foster academic discussion of diagnostic work, research, or educational matters relating to eye pathology or more broadly ophthalmic science. The service is free to the user and is funded by the Joint Information Systems Committee of the Higher Education Funding Councils for England, Scotland and Wales, and the Department of Education of Northern Ireland. It is provided by the Mailbase service of the Computing Service of the University of Newcastle. Interested subscribers should contact Dr Brian Clark by email:().
Disparity detectors may subserve involuntary vergence movements required for image registration rather than depth perception
Understanding cortical responses which underlie stereopsis has intrigued ophthalmologists and vision scientists since the original observations by Wheatstone that slight differences in the position of images in our two eyes can create a perception of depth. This has led to the notion that there are specific ‘disparity detectors’ in the cortex—that is, cortical neurons whose primary function is to detect these minor differences in each image and to ‘fuse’ the two images in a single three dimensional image. However, it has been realised that neurons which can perform such functions are probably not simple detectors uninfluenced by other properties of the image such as contrast and brightness but are more likely to be complex detectors functioning at a later stage in processing.
Now, two recent studies (see Nature1997;389:280, 283 and accompanying editorial on page 236) have added further complexity to this process by showing that disparity detectors in cortical area VI do not in fact primarily detect depth but are involved more in the registration of the two retinal images achieved by involuntary vergence movements, in the process of which an impression of depth can be obtained. It would appear in fact that depth perception may occur somewhere other than VI, or at least the integration of depth perception stimuli occurs elsewhere and may be relayed to VI, and that there are complex processes involving image registration, vergence eye movements, and stereopsis. This area is undoubtedly ripe for further investigation and should yield some fascinating information in the near future.
A new horizon for European eye and vision research?
European eye and vision research is extensive and covers many areas of activity. However, unlike similar activity in North America there has been no umbrella organisation which, like the Association for Research in Vision and Ophthalmology (ARVO), accommodated the many different groups that worked within the areas of vision and ophthalmology. Now an interim group, the Joint European Meetings in Ophthalmology and Vision (JERMOV), which was set up to bring together the many different groups has handed over the responsibility for development of a single European association to a new grouping, the Association for European Vision and Eye Research (EVER). Existing groups such as the Association for Eye Research, the AER, and the European Congress of Ophthalmic Research Associations (ECORA) are likely to merge and disappear under this single grouping. As Europe heads for 1999, it might be important that there is a single European eye and vision research group that can make its voice heard in the new century.
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