Stroke can cause some people (20% to 57% of people with stroke) to lose the ability to see the entire space in front of them - often one complete half of the normal field of vision is lost. These problems with seeing are called visual field defects. Visual field defects can make it difficult for people to function normally - especially moving about freely, avoiding obstacles, reading, driving and taking part in rehabilitation for other stroke-related problems. This review investigated if there are effective treatments for these visual field defects. We identified 13 studies (involving 285 stroke participants) that investigated the effect of treatments for visual field defects. However, only six of these studies compared the effect of treatment against no treatment or a control or placebo treatment. Four studies investigated the effect of scanning training, which involves training people to 'scan' across the space in front of them and into the 'lost' visual field. We found a small amount of evidence showing that scanning training was successful at improving people's ability to scan and also improved people's ability to read, although it did not reduce the size of the visual field defect. We did not find enough evidence to reach conclusions about the effect of scanning training on other activities of daily living. We found insufficient evidence to make conclusions about the effects of other forms of treatment, including using glasses with prisms or training to increase the size of the remaining visible area (visual restitution training (VRT)). In conclusion, scanning training is a promising treatment, but more high-quality research is needed into treatments for visual field defects.
There is limited evidence which supports the use of compensatory scanning training for patients with visual field defects (and possibly co-existing visual neglect) to improve scanning and reading outcomes. There is insufficient evidence to reach a conclusion about the impact of compensatory scanning training on functional activities of daily living. There is insufficient evidence to reach generalised conclusions about the benefits of visual restitution training (VRT) (restitutive intervention) or prisms (substitutive intervention) for patients with visual field defects after stroke.
Visual field defects are estimated to affect 20% to 57% of people who have had a stroke. Visual field defects can affect functional ability in activities of daily living (commonly affecting mobility, reading and driving), quality of life, ability to participate in rehabilitation, and depression, anxiety and social isolation following stroke. There are many interventions for visual field defects, which are proposed to work by restoring the visual field (restitution); compensating for the visual field defect by changing behaviour or activity (compensation); substituting for the visual field defect by using a device or extraneous modification (substitution); or ensuring appropriate diagnosis, referral and treatment prescription through standardised assessment or screening, or both.
To determine the effects of interventions for people with visual field defects after stroke.
We searched the Cochrane Stroke Group Trials Register (February 2011), the Cochrane Eyes and Vision Group Trials Register (December 2009) and nine electronic bibliographic databases including CENTRAL (The Cochrane Library 2009, Issue 4), MEDLINE (1950 to December 2009), EMBASE (1980 to December 2009), CINAHL (1982 to December 2009), AMED (1985 to December 2009), and PsycINFO (1967 to December 2009). We also searched reference lists and trials registers, handsearched journals and conference proceedings and contacted experts.
Randomised trials in adults after stroke, where the intervention was specifically targeted at improving the visual field defect or improving the ability of the participant to cope with the visual field loss. The primary outcome was functional ability in activities of daily living and secondary outcomes included functional ability in extended activities of daily living, reading ability, visual field measures, balance, falls, depression and anxiety, discharge destination or residence after stroke, quality of life and social isolation, visual scanning, adverse events and death.
Two review authors independently screened abstracts, extracted data and appraised trials. We undertook an assessment of methodological quality for allocation concealment, blinding of outcome assessors, method of dealing with missing data, and other potential sources of bias.
Thirteen studies (344 randomised participants, 285 of whom were participants with stroke) met the inclusion criteria for this review. However, only six of these studies compared the effect of an intervention with a placebo, control or no treatment group and were included in comparisons within this review. Four studies compared the effect of scanning (compensatory) training with a control or placebo intervention. Meta-analysis demonstrated that scanning training is more effective than control or placebo at improving reading ability (three studies, 129 participants; standardised mean difference (SMD) 0.79, 95% confidence interval (CI) 0.29 to 1.29) and visual scanning (three studies, 129 participants; SMD 1.14, 95% CI 0.29 to 2.00) but that scanning may not improve visual field outcomes (two studies, 110 participants; MD -0.73, 95% CI -3.18 to 1.72). There were insufficient data to enable generalised conclusions to be made about the effectiveness of scanning training relative to control or placebo for the primary outcome of activities of daily living (one study, 33 participants). Only one study (19 participants) compared the effect of a restitutive intervention with a control or placebo intervention and only one study (39 participants) compared the effect of a substitutive intervention with a control or placebo intervention.