Adding access to a video magnifier to standard vision rehabilitation: initial results on reading performance and well-being from a prospective, randomized study

Abstract

Purpose: Both optical and electronic magnification are available to patients with low vision. Electronic video magnifiers are more expensive than optical magnifiers, but they offer additional benefits, including variable magnification and contrast. This study aimed to evaluate the effect of access to a video magnifier (VM) added to standard comprehensive vision rehabilitation (VR).

Methods: In this prospective study, 37 subjects with central field loss were randomized to receive standard VR (VR group, 18 subjects) or standard VR plus VM (VM group, 19 subjects). Subjects read the International Reading Speed Texts (IReST), a bank check, and a phone number at enrollment, at 1 month, and after occupational therapy (OT) as indicated to address patient goals. The Impact of Vision Impairment (IVI) questionnaire, a version of the Activity Inventory (AI), and the Depression Anxiety and Stress Scale (DASS) were administered at enrollment, 1 month, after OT, 1 month later, and 1 year after enrollment. Assessments at enrollment and 1 month later were evaluated.

Results: At 1 month, the VM group displayed significant improvement in reading continuous print as measured by the IReST (P = 0.01) but did not differ on IVI, AI, or DASS. From enrollment to 1 month all subjects improved in their ability to spot read (phone number and check; P < 0.01 for both). The VM group improved in their ability to find and read a number in a phone book more than the VR group at 1 month after initial consultation (P = 0.02). All reported better well-being (P = 0.02).

Conclusions: All subjects reported better well-being on the IVI. The VM group read faster and was better at two spot reading tasks but did not differ from the VR group in other outcome measures.

Figure 1

Study flowchart. Results presented in this study are from enrollment to 1 month after enrollment (dashed box).

Figure 2

Mean changes in reading speed (IReST) in words per minute. The most significant improvement in reading speed was observed at 1 month in the video magnifier (VM) group, adjusted for age, Geriatric Depression Scale, visual acuity, contrast sensitivity, and central visual field (interaction between time and group, P = 0.01). Error bars represent standard error of the mean (SEM).

Figure 3

Difficulty scores for reading tasks (change from enrollment to 1 month later). For ease of viewing, individual difficulty scores at enrollment were subtracted from 1 month later to give a difference in individual difficulty scores, and the averages of the difference scores are represented below. The VM group improved more than the control group in reading a phone number at 1 month (P = 0.02). Error bars represent SEM.