Long-term evaluation of eccentric viewing spectacles in patients with bilateral central scotomas

Yoked prism spectacles (eccentric viewing spectacles [EVS]) facilitate eccentric viewing in patients with bilateral central scotomas. This study was conducted to evaluate the long-term success and patient satisfaction of this type of low-vision aid. METHODS. In this retrospective cross-sectional study, we reviewed the low-vision rehabilitation records of all patients who received EVS since 1993. With an 18-item survey, 191 patients were questioned about the wearing characteristics, advantages, and disadvantages of the EVS. Descriptive and nonparametric statistics were applied to compare regular users with those persons who no longer use the EVS.

The response rate was 83.2% and the average follow-up time was 4.5 years. Forty percent of all patients still used the EVS. The main disadvantages of these spectacles, mentioned mainly by the nonusers, included the heavy weight (41%), perception of curved lines (46%), dizziness during walking (46%), and poor cosmetic appearance (25%). Many successful long-term users considered the EVS suitable for home activities (86%) and walking in the street (70%) and reported that this device reduced eccentric viewing (77%), created better vision in the center of their visual field (67%), and helped with recognition of objects and faces (64%).

The prescription of EVS aids eccentric viewing in patients with dense central scotomas. Although associated with a number of disadvantages and side effects, 40% of the patients continued to use EVS. The results of this study indicate that patients who experience difficulties with eccentric fixation are most likely to benefit from these low-vision aids. A thorough explanation of the advantages and disadvantages of the EVS is important to prevent unnecessary disappointments.