Introduction
The Institute of Optometry has just completed the statistical analysis of its three year research study into the possibilities of treating congenital nystagmus with vision therapy. The researchers were Dr Bruce Evans, Dr Janyce Jordahl-Moroz, Mrs Bettine Evans, and Mr Mustafa Nabee. Dr Evans and his team would like to thank the 38 people who participated in the study. They would also like to thank the Nystagmus Network for publicising the research and for sponsoring participants' travelling expenses.

Aims of research
The goals of the research were to discover whether treatments based on visual stimulation and designed to provide feedback about eye movements could improve vision. If treatment did bring about an improvement in vision then the researchers wanted to discover whether this was a true result of the treatments, or whether it was due to other factors. In particular, the vision in congenital nystagmus is often worse when sufferers are under stress, and the researchers wanted to know whether any improvement in vision was attributable to this, or to a genuine effect of the therapies.

Methods used in the research
A survey at an Nystagmus Network Open Day showed that, overwhelmingly, the single most sought after outcome from treatment was for vision to be improved. So, the researchers developed a new, very sensitive, method of measuring visual acuity with a special design of letter chart.
Previous research has tended to measure vision once before treatment, and then each week when the patient received treatment. A problem with this is that the researchers would not know whether any improvement in vision is caused by the treatment, or by the participants becoming more practised at reading the letter chart. In their research study, Dr Evans and his colleagues measured the visual function on three separate occasions before starting treatment, so that they could discover how much improvement occurred with practice. They then applied the treatment for six sessions (usually once a week) and finally measured the visual function once again at the end.
To add another dimension to the study, the researchers divided the participants into two groups and gave each group a different form of vision therapy. One therapy was based on flashing lights and the other on rotating stripes. The researchers wanted to know whether one group did better than the other, since this would throw important light on the mechanism for any benefit.

Results of research
The results of the research were fairly conclusive, but rather disappointing. Each time a person's visual function was assessed it did tend to improve compared with the previous assessment. However, the study design and statistical analysis showed that this improvement was not because the treatments were having any direct therapeutic effect, but rather because the participants were simply getting more practised at the visual assessments.

Conclusions
If the vision is repeatedly measured then, even in a person without nystagmus, it will improve with practice. In congenital nystagmus, the vision is often worse when a person is under stress. Each time the vision is measured in a clinic a nystagmus sufferer may become a little more relaxed so that their vision improves, adding to any effect of practice. This seems to be why the vision appeared to improve in this research study.

The future of IPS therapy
Research into IPS, and other putative treatments for nystagmus, have been carried out at the Institute of Optometry for many years. Many people who have attended the Institute for IPS treatment may feel that it caused an improvement in their vision.
Congenital nystagmus is a complex condition and research studies have to look at average results in groups of people. But people are individuals, not groups, and it is impossible for any research study to ever prove that a given treatment might not help some people with a condition.
So, the researchers have been careful about the claims they make. Their results do not mean that IPS has not been helpful to people in the past. The results do, however, mean that it is statistically unlikely that a person embarking on IPS will receive a substantial therapeutic benefit that can be directly attributed to the treatment. In view of these new results it is felt that future work at the Institute should concentrate on other approaches, as described below.

Other treatments for people with congenital nystagmus
People with congenital nystagmus often have high refractive errors (long-, short-sightedness, or astigmatism) and it is very important that these are carefully corrected. Research suggests that, for many people with congenital nystagmus, contact lenses may be the preferred method of correction since the vision can be better with these than with glasses.
One rather different approach to treatment is hypnosis. The researchers at the Institute found that, for some people, the vision improved dramatically as they became more relaxed about having their vision assessed. Hypnosis can be used to relax people, particularly when their vision becomes worse under particular circumstances (e.g., in examinations or job interviews). Dr Evans at the Institute has been trained in hypnosis and he is currently investigating the effect of this on people with congenital nystagmus.