Retraining the eyes after a stroke

Brief lay background

Homonymous hemianopia – sudden loss of the right or left field of vision in both eyes – occurs in around 1 in 3 people who survive a stroke.

Around half of people who lose their sight in this way will not recover their vision, and around 180,000 stroke survivors live with partial sight loss.

Their reduced ability to work and to perform everyday tasks such as driving, reading and move around safely significantly impacts on quality of life, and is linked to poor mood and reduced self-confidence.

It also influences people’s survival from stroke: those with hemianopia have a higher risk of falls and are likely to stay in hospital for longer.

What problem/knowledge gap does it help address

There is a lack of effective treatments for hemianopia. One option showing potential benefit is a rehabilitation approach called visual scanning training. People with hemianopia make smaller, more repetitive and less efficient eye movements. The visual scanning technique aims to address this by teaching larger, quicker movements. This has been shown to improve eye movements by increasing the ability to scan to the affected field of vision.

This study will test whether visual scanning can improve hemianopia after stroke. It is the first large-scale clinical trial of a treatment for this condition.

Aim of the research project

To determine whether visual scanning training can improve vision-related quality of life in people with partial sight loss after stroke.

Key procedures/objectives

People with hemianopia will be split randomly into two groups – a treatment group and a control group.  

Those having the treatment will receive a landscape card printed with peripheral targets surrounding a central target. For 30 minutes every day, they will need to systematically scan the card for targets on their affected field of vision to speed up detection. The exercise should be carried out for six weeks. These patients will be compared to a control group given a sham version of training that does not engage visual scanning eye movements.  

The clinical trial will address three research questions: 

1. Does visual scanning training for hemianopia improve quality of life and ability to do everyday activities?
2. Is visual scanning training an acceptable treatment for patients? 
3. Does this treatment lead to earlier improvement in compensation for visual field loss? 

Potential impact on people with sight loss

If successful, the trial will provide a new rehabilitation option that could improve everyday life for thousands of people who suddenly lose their sight after stroke.