A Cochrane review included five trials of multi-component assessment with a total of 3 494 participants. Length of follow-up ranged from two to four years. All the trials used self-reported measures for vision impairment, both as screening tools and as outcome measures. In four of the trials people reporting visual problems were referred to either the eye services or to a physician. In one trial people reporting visual problems received information about resources in the community designed to assist those with poor vision. The proportions of participants in the intervention and control groups who reported visual problems at the time of outcome assessment were 0.26 and 0.23 respectively (RR for visual impairment 1.03, 95% CI 0.92 to 1.15).
Comment by reviewer: Results from community surveys in the over 75 age group (Wormand 1992, Klein 1991) suggest that over half the visual impairment in this age group could potentially be reduced with treatment, notably by cataract surgery or refractive correction. In light of this, the lack of improvement seen in these trials is somewhat surprising, and cannot be explained with any certainty from the data available. In the trials included in this review, information about whether participants attended referrals, diagnoses made, and interventions offered and accepted was not available.
Comment: The quality of evidence is downgraded by study limitations and indirectness of evidence (both interventions and outcomes).