Abstract
Abstract: :
Purpose: To evaluate the statistical and clinically meaningful gains after 6 months of a multidisciplinary low vision rehabilitation using the Impact of Vision Impairment questionnaire (IVI). Methods: Participants with no prior low vision rehabilitation history were recruited. The eligibility criteria included BCVA <6/12, 18 years of age or over and the ability to speak English. The dependent variable was a multidisciplinary rehabilitation program provided by a low vision rehabilitation agency in Victoria (Australia). The main outcome measure was quality of life assessed by the validated 32–item IVI at baseline and follow up (6 months). Paired t–tests and the Wilcoxon sign rank tests (WSR) were used to determine statistical differences between pre– and post–rehabilitation scores. A ≥2–step improvement was determined as clinically meaningful based on the IVI test–retest variability (range 0.45–1.6). Results: One hundred and ninety two participants (64%, 123 females) with a mean age 79.3 yr ± 13.1 completed the rehabilitation. The majority had AMD (62%, 119) and were moderately to severely vision impaired (78%, 149). The median duration of vision impairment was 3 years (range <1 to 70 yr). Significant statistical improvements (t–test; p= 0.000) in the overall and domain scores were found at follow–up. There were also improvements on 31 of the 32 individual items of which 23 were statistically significant (WSR; p=0.00–0.04). The absolute gains for the overall, domain and item scores were however ≤1–step (range 0.3–1.0). The mean percentage of participants who improved meaningfully on the individual items was only 20% (range 12%–40%). Almost 18% of the subjects recorded no clinical meaningful improvement on any of the IVI items, 66% on ≤5 items and almost 90% on ≤10 items at follow up. Reading ordinary size print, traveling or using transport and shopping were among the items in which the least number of participants clinically improved. At follow–up, only 12% of the participants thought their difficulty with daily activities have improved. Conclusions: In spite of significant statistical improvements, the clinically meaningful gains were mild suggesting a limited effectiveness of the rehabilitation program. The minor improvements recorded in critical daily living activities such as reading and traveling indicate that alternative rehabilitation programs need to be considered. However, the high percentage of moderate to severe vision impaired participants may have contributed to the limited success of the program.
Keywords: clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled • low vision • aging