As a result of stroke, an individual may lose half of their visual field in either the left or the right eye. This is called ‘homonymous hemianopia’ and affects up to half of all stroke survivors.
Homonymous hemianopia can have a direct impact on how someone is able to function, with an increased risk of falling, impaired ability to read and inability to judge distances. It may therefore impact upon on their ability to participate in rehabilitation, to live in their own home, and upon their levels of depression, anxiety, and social isolation, leading to a significant reduction in their quality of life.
Visual rehabilitation techniques are available to help people with homonymous hemianopia after stroke. However, they are not used consistently across stroke services within the NHS, and there is limited evidence supporting their usefulness. Furthermore, although potentially cheap to administer no study has investigated how cost-effective they are to deliver within the NHS.
The VISION trial was a pilot randomised controlled trial (RCT) to compare the use of two visual rehabilitation techniques (visual search training or ‘monocular prism’ treatment) with standard care. Its aims were to determine the effects of the two techniques on the visual field of stroke patients with homonymous hemianopia and their general quality of life. Training with visual search exercises involves training the person to make more effective eye movements into the side of their visual loss so that they compensate better for this side. This can simply involve patients transferring gaze quickly between printed targets on an A4 visual search card.
Eighty-seven participants recruited into the trial were randomised into three groups. Twenty seven participants were allocated to intervention group A (to receive monocular prisms) and 30 participants were allocated to intervention group B (visual search training). Thirty participants were allocated to the control group C (standard care, consisting of advice only).
Participants were randomised to their respective groups at approximately 11 weeks after their stroke. Most had ischaemic stroke (95%) in all three groups. The stroke affected the left side of the brain in 44%, the right side of the brain in 54% and both sides of the brain in 2% of participants. Across all three groups there were similar values for the side (right versus left) and extent (partial versus complete visual field loss) of homonymous hemianopia.
This trial showed there to be little improvement in the size of participants’ visual field between the two treatment groups and the standard care (advice only) group.
Group A (monocular prisms) had the greatest number of complications which typically included headaches and confusion of vision. Such complications could act as a barrier for patients to continue use of prism therapy. Group B (visual search training) had a significant improvement in vision-related quality of life.
Future research aims to concentrate on visual search training as a treatment option for post-stroke homonymous hemianopia.
- Rowe, F. J., Hepworth, L. R., Conroy, E. J., Rainford, N. E. A., Bedson, E., Drummond, A., Sackley, C. (2019). Visual Function Questionnaire as an outcome measure for homonymous hemianopia: subscales and supplementary questions, analysis from the VISION trial. Eye (London, England), 33(9), 1485-1493.
- Rowe, F. J., Conroy, E. J., Bedson, E., Cwiklinski, E., Drummond, A., Garcia-Finana, M., Sackley, C. (2017). Choice of outcome measures for the VISION pilot trial of interventions for hemianopia. ACTA NEUROLOGICA SCANDINAVICA, 136(5), 551-553.
- Rowe, F. J., Conroy, E. J., Barton, P. G., Bedson, E., Cwiklinski, E., Dodridge, C., Shipman, T. (2016). A Randomised Controlled Trial of Treatment for Post-Stroke Homonymous Hemianopia: Screening and Recruitment. Neuro-ophthalmology (Aeolus Press), 40(1), 1-7.
- Rowe, F. J., Conroy, E. J., Bedson, E., Cwiklinski, E., Drummond, A., Garcia-Finana, M., Sackley, C. (2017). A pilot randomized controlled trial comparing effectiveness of prism glasses, visual search training and standard care in hemianopia. ACTA NEUROLOGICA SCANDINAVICA, 136(4), 310-321.
- Rowe, F., Drummond, A., Sackley, C. M., Pollock, A., Pollock, A., Bedson, E., Shipman, T. (2015). A randomized controlled trial comparing the effectiveness of prism glasses, visual search training and standard care to improve visual field for people with hemianopia post stroke. In INTERNATIONAL JOURNAL OF STROKE Vol. 10 (pp. 12-13)
- Rowe, F. J., Barton, P. G., Bedson, E., Breen, R., Conroy, E. J., Cwiklinski, E., et al (2014). A randomised controlled trial to compare the clinical and cost-effectiveness of prism glasses, visual search training and standard care in patients with hemianopia following stroke: a protocol. BMJ OPEN, 4(7).