Interventions for Visual Field Defects in Patients With Stroke
An estimated 20% to 57% of people have visual field defects after stroke, affecting function, quality of life, ability to participate in rehabilitation, depression, anxiety, and social isolation. There are many interventions for visual field defects, which are proposed to work by either restoring the visual field (restitution); compensating for the visual field defect by changing behavior or activity (compensation); or substituting for the visual field defect by using a device or extraneous modification (substitution).
The objective of this review was 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 9 electronic bibliographic databases including: CENTRAL (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, hand-searched journals and conference proceedings, and contacted experts.
Randomized trials in adults after stroke, in which 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. Primary outcome was functional ability in activities of daily living and secondary outcomes included visual scanning, reading ability, and visual field measures.
Data Collection and Analysis
Two authors independently screened abstracts, extracted data, and appraised trials. Assessment of methodological quality was undertaken for allocation concealment, blinding of outcome assessor, method of dealing with missing data, and other potential sources of bias. For continuous data, we calculated the treatment effect using standardized mean differences and 95% CI when different studies used different scales for the assessment of the same outcome and using mean differences and 95% CI when studies all used the same method of measuring outcome. We used a random-effect model for all analyses.
Thirteen studies (344 randomized participants, 285 of whom were participants with stroke) met the inclusion criteria for this review. However, only 6 of these studies compared the effect of an intervention with a placebo, control, or no treatment group and were included in comparison 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 (3 studies, n=129; mean difference 3.24 [0.84–5.59]) and visual scanning (3 studies, n=129; mean difference 18.84 [12.01–25.66]) but that scanning did not improve visual field outcomes (2 studies, n=110; mean difference −0.70 [−2.28 to 0.88]). There were insufficient data to enable generalized conclusions to be made about the effectiveness of scanning training relative to control or placebo for the primary outcome of activities of daily living (1 study, n=33). Only 1 study (n=19) compared the effect of a restitutive intervention (“visual restoration therapy” [VRT™]) with a control or placebo intervention and only 1 study (n=39) compared the effect of a substitutive intervention (prisms) with a control or placebo intervention.
There is limited evidence that supports the use of compensatory scanning training for patients with visual field defects (and possibly coexisting visual neglect) to improve visual field, 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 generalized conclusions about the benefits of restitutive or substitutive interventions or for patients with visual field defects after stroke.
Note: This review is published as a Cochrane Review in the Cochrane Database of Systematic Reviews 2011, Issue 10. Cochrane Reviews are regularly updated as new evidence emerges and in response to comments and criticisms, and the Cochrane Database of Systematic Reviews should be consulted for the most recent version of the review. Pollock A, Hazelton C, Henderson CA, Angilley J, Dhillon B, Langhorne P, Livingstone K, Munro FA, Orr H, Rowe FJ, Shahani U. Interventions for visual field defects in patients with stroke. Cochrane Database Syst Rev. 2011;10:CD008388.
Sources of Funding
This study was funded by the Royal National Institute of Blind People (RNIB), Scotland. The Nursing, Midwifery and Allied Health Professions Research Unit is supported by the Scottish Government Health Directorate's Chief Scientist Office.
Ms Henderson works for Royal National Institute of Blind People, which is the leading organization in the United Kingdom supporting blind and partially sighted people. Drs Rowe and Pollock are grant holders on an ongoing trial, which will be relevant for inclusion in updates of this review.
The work presented here represents the view of the authors and not necessarily those of the funding bodies.
- Received November 2, 2011.
- Revision received December 2, 2011.
- Accepted December 5, 2011.
- © 2012 American Heart Association, Inc.