Preventing falls in older multifocal glasses wearers by providing single-lens distance glasses: the protocol for the VISIBLE randomised controlled trial

Abstract

Background: Recent research has shown that wearing multifocal glasses increases the risk of trips and falls in older people. The aim of this study is to determine whether the provision of single-lens distance glasses to older multifocal glasses wearers, with recommendations for wearing them for walking and outdoor activities, can prevent falls. We will also measure the effect of the intervention on health status, lifestyle activities and fear of falling, as well as the extent of adherence to the program.

Methods/design: Approximately 580 older people who are regular wearers of multifocal glasses people will be recruited. Participants will be randomly allocated to either an intervention group (provision of single lens glasses, with counselling and advice about appropriate use) or a control group (usual care). The primary outcome measure will be falls (measured with 13 monthly calendars). Secondary measures will be quality of life, falls efficacy, physical activity levels and adverse events.

Discussions: The study will determine the impact of providing single-lens glasses, with advice about appropriate use, on preventing falls in older regular wearers of multifocal glasses. This pragmatic intervention, if found to be effective, will guide practitioners with regard to recommending appropriate glasses for minimising the risk of falls in older people.

Trial registration: The protocol for this study was registered with the Clinical Trials.gov Protocol Registration System on June 7th 2006 (#350855).

Trial registration: ClinicalTrials.gov NCT00350389.

Figure 1

Flow of participants through the trial.

Figure 2

The distance contrast sensitivity tests. Panel A shows a participant (with his chin placed on a comfortable chinrest to prevent head movement) viewing the test plate through the lower (reading) segments of his glasses. Panel B shows the participant looking directly at the test stimulus through the upper (distance) segments of his glasses. Any difference in contrast vision between the two conditions is then shown to the participant as part of the counselling session.

Figure 3

Simulated view of street scene as viewed through single-lens distance (panel A) and bifocal glasses (panel B). The footpath misalignment (a commonly reported environmental factor involved in outdoor falls) is clearly seen in panel A, but blurred in panel B.