1. Summary of programme area and objectives

Research priorities

1.1 Epidemiological and Service Issues

1.1.1 Epidemiology of childhood visual impairment - understanding the extent and the causes of childhood visual impairment
1.1.2 Effects of childhood visual impairment : educational, emotional and social
1.1.3 Visual rehabilitation

1.2 Clinical and Laboratory Issues

1.2.1 Inherited eye disease
· identification of disease causing mutations,
· investigation of disease mechanisms,
· development of novel treatment strategies

1.2.2 Brain injury and visual impairment
· multidisciplinary research to understand the mechanism of brain injury
· investigation of visual development and visual performance in brain injured children

  2. Programme plan

2.1 Understanding amblyopia in children - Studies of the pathophysiology of amblyopia in man using psychophysical and clinical electrophysiological methods are demonstrating abnormalities affecting a range of visual functions other than acuity. These are likely to lead to a better understanding of the underlying abnormalities and are likely to lead to better ways of monitoring and treating these patients. In particular, patients with squint and amblyopia rely on their fellow eye for visual function and most suppress their amblyopic eye. Several studies, both in animals and man, have demonstrated abnormalities affecting the fellow eye. Studies are needed to define these abnormalities and to see if they are intrinsic to the condition or related to patching and to define the effects of amblyopia on the overall visual function of the patient.

2.2 Finding and treating amblyopia - A recent review identified a number of areas where research is needed. Clinical studies were recommended into the extent of disability attributable to amblyopia, the incidence of blindness or partial sight due to amblyopia with subsequent loss of the fellow eye and the prognosis for vision in the amblyopic eye under these circumstances. Although randomised control trials of the treatment of amblyopia have been recommended, reservations have been expressed with respect to denying children in an untreated control group what is generally considered to be an effective treatment. Studies comparing outcomes for non-compliant and compliant children are of value in this context. The cost-effectiveness of pre-school vision screening and treatment also needs to be examined. Outcome studies of the effectiveness of amblyopia treatment show a residual group who fail to respond even with apparently good compliance with patching. This group deserves further study to identify reasons for the poor response.

2.3 Understanding and treating squint - Most children with a squint lose binocular function and this is rarely restored following squint surgery. The ultimate aim of research in this area is to understand the mechanisms underlying this loss and to find ways of preventing it or reversing it. Studies of very early intervention either with surgery or using Botulinum toxin have produced encouraging results and this area deserves further study. A number of types of childhood squint are intermittent, with apparent partial loss of binocularity and development of a degree of suppression. Studies of the underlying pathophysiology of binocular function in such patients are likely to give important information as to why and how binocular function is lost both in these and other groups of patients. There is currently no good evidence as to whether early surgical intervention in children with intermittent squints is beneficial and studies are needed to establish the optimum management of such children.

2.4 Preventing long and short sight - Animal studies are demonstrating that visual feedback has a major effect on the development of correct focusing of the eyes and the elimination of refractive errors. Evidence is appearing which suggests that similar mechanisms operate in man. These studies are potentially of great importance, in particular studies which aim to understand why these mechanisms break down, leading to refractive errors.

2.5 Treating nystagmus (wobbly eyes) - Nystagmus remains a significant cause of visual disability in both children and adults. Studies are needed of the underlying disorders of oculomotor control and whether surgical intervention has significant benefits.

2.6 Adult Squint - In the majority of adults with a squint, the condition represents the continuing effect of a childhood onset squint. Although the benefits of adult squint surgery are well recognised by anecdotal reports from patients, a systematic study is needed to evaluate the incidence of untreated adult squint and its social impact, in particular its effects on employment prospects, self-esteem and personal relations and the benefits from surgery.

2.7 Unresolved clinical problems - Two particular conditions that pose continuing problems for clinical management are thyroid eye disease and orbital blowout fractures. i) Thyroid Eye Disease - With the rapid advances that are occurring in immunology, studies are required to apply these to the investigation of the pathophysiology of thyroid eye disease. Studies are required to determine the balance between benefit from treatment and the risk of potentially major side-effects for aggressive and conservative management strategies using steroids and other immunosupressive agents and orbital radiotherapy. ii) Orbital Blowout Fractures - These most commonly affect young men and have a major impact on employment prospects and the ability to drive. The indications for early surgical intervention remain controversial and studies are needed to determine which patients benefit from early surgical intervention. These need to be carried out in collaboration with maxillo-facial surgeons, who often see these patients at their initial presentation.

  3. Future development work in the programme during 2002/3

Research Priorities

3.1 Epidemiological and Service Issues

· Determining whether very early squint surgery gives better outcomes for binocular function.
· Determining the optimum management of intermittent squints.
· Determining optimum management for thyroid eye disease.
· Cost-benefit analysis of visual screening in children and determining the optimum age(s) for screening.
· Health-care delivery in management of strabismus and amblyopia

3.2 Clinical and Laboratory Issues

· Understanding the changes in the brain underlying amblyopia and determining why some children fail to respond to patching.
· Understanding why binocular function breaks down in some children.
· Understanding mechanisms underling development of correct focussing of the eye and why this fails in some children.
· Randomised controlled trials of treatment of amblyopia and strabismus