Abstract
Purpose: :
A RCT was conducted to evaluate the effectiveness of a low vision program for veterans with vision loss (VA ≤20/100 >20/500) from macular diseases. 126 patients from Chicago and Salisbury, NC VA facilities were randomized to low vision treatment or a waiting list control group. Usual low vision care was provided for the control group after 4 months.
Methods: :
Exploratory analysis was conducted to compare mean changes in VA LV VFQ-48 scores within the treatment and control groups at three time points. Subjects included 44 treated patients (who didn’t receive additional low vision services after the 4-month follow-up) and 56 control patients who received low vision services after the 4-month follow-up. Rasch analysis was performed to estimate scores from the ratings on VA LV VFQ-48 items. Paired t-tests were used for pre and post changes.
Results: :
Treatment group subjects showed significant improvement (P<.001) in visual reading ability (2.40 logits, SD 1) and overall visual ability (1.62 logits, SD .66) after low vision rehabilitation; effects decreased between 4 months and the 12 month follow-up in visual reading ability (-0.42 logits, SD 0.77) and overall visual ability (-0.26 SD .71). However, subjects were still statistically and clinically significantly better at their 1-year follow-up than before beginning treatment. Trends were noted for decreases in vitality and mental health scores on the SF-36 from baseline to one year. Control group subjects demonstrated a significant loss in visual reading ability (-0.41 logits, SD 0.51) and overall visual ability (-0.21 logits, SD 0.36) while waiting for services and a significant gain in visual reading ability (2.0 logits, SD 1.13) and visual ability (1.11 logits, SD 0.65) after low vision rehabilitation was provided.
Conclusions: :
The loss of visual ability at 4 months in patients who were waiting for low vision services calls for early intervention. The magnitude of the cross-over effect in the control group after treatment confirms the treatment effect described for the RCT.
Clinical Trial: :
www.clinicaltrials.gov NCT00223756
Keywords: clinical (human) or epidemiologic studies: outcomes/complications • low vision • reading