Research

• A significant proportion of the global population is visually impaired solely because of uncorrected refractive error (URE). Considering its potential impact, URE has become one of the priorities of the VISION 2020 programme to eradicate avoidable blindness.

• The purpose of this study was to summarise relevant literature investigating the impact of URE on adults and the impact of correcting refractive error in this population.

• A systematic search of 13 data bases and the reference lists of retrieved studies was conducted using the standard methodology for systematic reviews as described in the PRISMA statement. The Consolidated Standards of Reporting Trials (CONSORT) Guidelines and the Critical Appraisal Skills Programme (CASP) tools were used to assess the quality of the full text articles that were initially considered as meeting the systematic review inclusion criteria. Descriptive statistics was used to analyse the data.

• The initial search retrieved 663 studies and 23 met the set inclusion criteria. Of the 23 studies selected for inclusion in the review, two were randomised control trials (RCTs), one was a cohort study, two had a case-control design, and 18 studies employed a cross-sectional design.

The aim of this review is to evaluate the impact of URE in adults with respect to their visual functioning, social behaviours, socio-economic status, mental health and quality of life status, and to review the impact of correcting refractive errors, in adults aged 18 years and over. The outcome measures were visual functioning, psychosocial (behavioral, well-being, quality of life), economic outcomes (costeffectiveness; cost-benefit; cost-utility) and educational outcomes (adult education). Negative aspects regarding the emotional and psychological impact of wearing spectacles were also considered. Details on the methodology and results are available here. A total of 663 studies were retrieved and 23 met the inclusion criteria. These studies included two randomised controlled trial, one was a cohort study, two were case-control studies and 18 were cross-sectional studies. Limitations in the studies that were included are also here. The focus of most studies about visual impairment and uncorrected refractive error in adults is on quality of life and visual function, with the majority of them observing a decline in both quality of life and visual function with the occurrence of uncorrected refractive error. It is recognised that uncorrected refractive error decreases the quality of life, impairs physical functioning and difficulties with activities of daily living (self-care which comprises of personal hygiene, dressing, eating, shopping, cooking, managing finances, etc.) in adults. Of the impact outcomes investigated, quality of life, distance and near vision and psychosocial function were highlighted as the main concerns. There is evidence for significant improvement in general health, mental health and vision targeted health related quality of life, with the provision of spectacles. Uncorrected refractive error is associated with measurable reductions in utility and these reductions were similar for both distance and near vision in adults. Thus, a reduction in near and distance vision can have a psychosocial impact on an individual. The impact of uncorrected refractive error in adults manifests in measurable reductions in utility, thus quality of life. There are also psychological implications such as self-esteem and misconceptions regarding the consequences of wearing spectacles. But the impact on visual functioning and economic outcomes is limited. This review has emphasised the need for standardised quality studies for measuring the impact of uncorrected refractive errors in adults and the impact of spectacle correction on these outcomes