Methodological quality of the review: High confidence
Author: Virgili G, Rubin G.
Region: United States of America (USA)
Sector: Low vision
Sub-sector: Orientation, mobility, training
Equity focus: Adults with low vision
Review type: Effectiveness review
Quantitative synthesis method: Meta-analysis
Qualitative synthesis methods: Not applicable
Progressive visual impairment often affects people as they age. Training is used to help people with low vision maintain travel independence, with new orientation and mobility skills to compensate for reduced visual information. Orientation is the ability to recognize one’s position in relation to the environment, whereas mobility is the ability to move around safely and efficiently. Orientation and mobility (O&M) training teaches people to use their remaining vision and other senses to get around. Canes and optical aids may also be used.
To assess the effects of O&M training, with or without associated devices, for adults with low vision.
Two small studies satisfied the inclusion criteria, both conducted in the USA. They were consecutive phases of development of the same training curriculum and assessment tool. The intervention was administered by a volunteer on the basis of written and oral instruction. In both studies the randomization technique was inadequate, being based on alternation, and masking was not achieved. Though training had no effect in the first study it tended to be beneficial in the second but not to a statistically significant extent. Reasons for differences between studies may have been: the high scores obtained in the first study, suggestive of little need for training and small room for further improvement (a ceiling effect), and the refinement of the curriculum allowing better tailoring to patients’ specific needs and characteristics, in the second study.
The authors noted that more research is needed on O&M training for low vision adults. The complexity and diversity of patients’ needs makes it necessary to adapt any training curriculum to individual patients’ profiles, as pointed out by the authors of the studies retrieved in this review. The O&M community should develop standard, yet flexible methods to objectively test O&M performance which are valid and reliable. The complexity of the relationship between O&M training and a person’s experience suggests that instruments that capture more fully subjective perceptions of health, such as questionnaires on quality of life that are specific to these tasks, could also be useful tools for assessing the outcome of O&M training.
The authors planned to include all relevant randomized or quasi-randomized trials including participants aged 16 or over with low vision. Interventions included any type of O&M training compared to no training or control, including different types of O&M training. Primary outcome measures considered included performance in travel activities of daily life. Secondary outcome measures included performance obtained in predetermined laboratory or real world routes; ability to use guide dogs; social interaction; scored obtained in quality of life questionnaires; participants’ perceptions of the effect of O&M training.
A database search was conducted on Central, LILACS, Medline, Embase, OpenSIGLE (grey literature) and others, from inception to 2010. As part of the search strategy, authors also screened the references from retrieved trials. Reviewers contacted corresponding authors of included studies to obtain missing data and to verify data.
Two authors independently assessed the tiles and abstracts resulting from the search, extracted data and assessed risk of bias of included studies. The trials were assessed for bias according to the methods described in Chapter 8 of the Cochrane Handbook for Systematic Reviews of Interventions.
Data analysis was conducted according to Section 8 of the Cochrane Handbook for Systematic Reviews of Interventions. The mean and standard deviations were obtained. Results were summarized across studies using the difference in means (fixed effect model).
The authors noted that, given the complexity of O&M interventions and the small size of the two studies in this review, as well as the fact that they were conducted by the same study group, it cannot be assumed that findings are applicable to other settings.
Although the authors did not restrict their search to specific income settings, only studies from high income settings (USA) were included in the review. As the authors noted, findings from this review may not be applicable to other settings due to the characteristics of included studies.
Overall, there is high confidence in the conclusions about the effects of this study. The authors conducted a comprehensive search of the literature to ensure the inclusion of all relevant published and unpublished studies, avoiding risk of bias. Appropriate methods were used in terms of study selection, data extraction and risk of bias assessment of included studies. The authors clearly explained methods used to conduct analysis of findings, and explored reasons for differences between studies. Nevertheless, as they also noted, this review was published in 2010 and needs updating.