T W Raasch
The Ohio State University, Optometry, Columbus, OH, United States
Background: The outcome of low vision care provision is influenced by many factors, including the characteristics of the study population, the intervention, outcome measures, follow-up procedures, and study design features. The Low Vision Intervention Study (LoVIS) is directed at addressing the effectiveness of low vision care, while defining, where possible, the factors that may affect that outcome.
Methods: The study incorporates a "primary-care" level of low vision intervention. The study population consists of those age 60 years or over, with visual acuity between 6/12 and 6/120. Randomization is used, with a three-month delay in the delivery of care as a control condition. Study personnel are masked, where possible, to group assignment and clinical characteristics of patients. Outcome measures, based on visual performance, are assessed with a quality of life instrument (VFQ-25), and practical tests of visual functioning. Pilot studies of recruitment, QOL assessment, functional visual performance, and intervention, were performed to guide design of a full-scale study.
Results: Recruitment pilot studies indicate that of all new patients in participating clinics, 22% meet age and visual acuity criteria, and would be willing and able to participate in the full study. QOL pilot studies showed repeatability and effect sizes similar in magnitude to other studies. In the intervention pilot study, 23 of 27 subjects recruited into the study were successfully administered the protocol and followed through the primary outcome visit, three months post-baseline. Results of these pilot studies were used to refine study procedures and inform sample size requirements.
Conclusions: These pilot studies demonstrate it is possible to recruit and retain sufficient numbers of patients in a randomized study of this sort, and to carry out the standardized protocol and measurements of outcome. Guided by the results of these pilot studies, a full scale study is planned.
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