Title: The effectiveness of portable electronic vision enhancement systems (EVES) in comparison to optical magnifiers for near vision activities in visual impairment – the p-EVES Study
Funder: Department of Health (England)

Abstract: Over 1 million people in the UK suffer from untreatable visual impairment; many of them are elderly and numbers will inevitably rise with the aging of the population. The UK Vision Strategy (1), recognises the importance of delivering support, and achieving independence, for visually impaired people. The major complaint of these individuals is their inability to carry out simple tasks, especially those involving reading. It is known that this activity limitation is a major cause of depression in an older population (2,3): vision loss, disability and depression can be a “single syndrome, with each element amplifying and perpetuating the adverse effects of the others” (4). Low vision clinics in hospital ophthalmology departments, dispense optical magnifiers, free on permanent loan, to allow patients to carry out these tasks again. These magnifiers have limitations of reduced field of view and very short working distances and several different devices are often needed if the patient wants to perform a variety of tasks. Recent technological advances have led to the introduction of moderately-priced portable electronic aids (p-EVES), which can be used more naturally, and which incorporate many features not seen in optical aids. They are likely to be psychologically more acceptable to some patients, since they resemble other high-tech hand-held devices such as i-Pads.. Despite their advantages, they are currently not available through the NHS. There are some disadvantages compared to optical devices, and p-EVES could never be a complete replacement. The greater complexity, for example, may make them unsuitable for patients with poor cognitive abilities. Evidence is therefore needed as to whether p-EVES could offer a clinically significant benefit to particular patients. The prospective study is a two-arm randomised cross-over study to determine the effectiveness and acceptability of p-EVES and conventional optical low vision aids (LVAs) for near tasks. Participants will be randomised to either receive the two interventions in the order AB, or in the order BA: A is a 2-month period with the patient’s existing optical devices, and B is a 2-month period with the p-EVES and the optical devices. Masking of users and researchers is not possible because the p-EVES are easily distinguished by their external appearance, but possibility of bias will be reduced by different researchers collecting outcome data, and prescribing the devices. Effectiveness will be measured by comparing the number of times the aids are used, the duration, and range of tasks, reading speed, fatigue using the aid, timed performance of practical activities, and report of near vision difficulties. Interviews will be used to explore patient experiences more fully. Well-being/depression will also be measured since this may also be improved if the device allows more independence and more effective performance of important tasks (5). For supply of these devices (if successful) to be implemented within the NHS will however require positive guidance from NICE, which will require evidence of an improvement in the health-related quality of life. The EQ-5D (6) is the mandated measure in this field, but has been shown to be unresponsive to vision-related problems (7). Inadequate responsiveness is particularly likely in the proposed study which compares two interventions (rather than comparing an intervention and a no-intervention control). The study will therefore include a feasibility study to measure change following use of the aids. We will use EQ-5D for comparability with other studies of use of health care resources; ICECAP (O) (8,9), based on the capability theory and being developed as a possible alternative to EQ-5D as a basis for QALY weight (and potentially more sensitive in settings such as with patients experiencing sight loss); and a sight loss specific quality of life measure (VISQOL) (7,10).


Research activity codes: 6.3 MEDICAL DEVICES
Health categories: EYE