A Randomized Controlled Trial to Determine the Effectiveness of Prism Spectacles for Patients With Age-Related Macular Degeneration

Abstract

To determine the effectiveness of prism spectacles in people with age-related macular degeneration by relocating the retinal image. Methods: We implemented a randomized, placebocontrolled, double-masked trial. Participants with agerelated macular degeneration received a standard lowvision assessment and the prescription of conventional low-vision aids 6 weeks before the study intervention. Participants were randomized to receive 1 of the following, including the optimal refractive correction: (1) custom, incorporating bilateral prisms to match participants' preferred power and base direction; (2) standard, incorporating standard bilateral prisms (6 prism diopters [⌬] base up for logMAR [logarithm of the minimum angle of resolution] visual acuity (VA) of 0.48-1.00 and 10⌬ base up for logMAR VA of 1.02-1.68); or (3) placebo, consisting of spectacles matched in weight and thickness to prism spectacles but without prism. Main Outcome Measures: Outcomes measured binocularly at baseline and 3-month follow-up included distance logMAR VA, reading speed, critical print size, visual functioning questionnaires, and observed visual task performance. Scores on the 25-item National Eye Institute Visual Functioning Questionnaire and the Melbourne Low-Vision ADL (Activities of Daily Living) Index were converted to linear estimates using Rasch analysis. The Manchester Low Vision Questionnaire was used to collect descriptive data. Results: A total of 225 participants completed the trial (median age, 81 years). We found no significant effect of treatment group on any of the outcome measures, including VA, the primary outcome (adjusted for baseline) (P = .63). Participants' responses to the Manchester Low Vision Questionnaire suggested that the prism spectacles added to their problems. Conclusions: Prism spectacles are no more effective than conventional spectacles for people with age-related macular degeneration.

Nonlinear Mixed-Effects Modeling of MNREAD Data

“…8 Precise measurements of reading performance provide valuable information for assessment 9 -12 and rehabilitation evaluation. [13][14][15] Reading speed is measured as a function of print size in the MNREAD test. 16 -20 Research has shown that reading speed increases sharply with print size at small print, plateaus at mid-range print, and decreases gradually at large print (Ͼ1.4 logMAR or 2°of visual angle; see Mansfield and Legge 21 for details on print size definitions and conversions).…”

Reading aids for adults with low vision

“…Nonetheless, they were scored as being at low risk of bias for reasons given in the Data collection and analysis section of this review. One study (Smith 2005) used a three parallel-arm randomised design.…”

“…Smith 2005 compared custom or standard bilateral prism spectacles with conventional spectacles, which included the near prescription. Differences in field of view among these devices should be small.…”

Randomized Controlled Trial on the Effects of CCTV Training on Quality of Life, Depression, and Adaptation to Vision Loss

“…In general, there is little evidence for the effect of low-vision rehabilitation or specific skills training (such as learning how to use a CCTV) on these outcome measures. [16][17][18][19][20] Furthermore, better scores on these types of outcomes may indirectly be the result of improved ability to perform certain skills (i.e., reading). Being able to read again may give a visually impaired person, who lost this skill, a sense of retrieved self-supportiveness, and may actually contribute to prolonged independent living.…”