Amplify EyeCare Chattanooga Logo
Authors
Granquist, Christina BS; Wu, Yueh-Hsun MS; Gage, Rachel BA; Crossland, Michael D. PhD, MCOptom; Legge, Gordon E. PhD

How People with Low Vision Achieve Magnification in Digital Reading

publication date
June 19, 2018
Category
see more

Abstract/Introduction

SIGNIFICANCE 

Digital reading displays provide opportunities for enhancing accessibility of text for low vision. How are these displays used by people in their daily lives?

 

PURPOSE 

Subjects responded to an online survey concerning their vision history, reading technology, display preferences, and reading habits. Here, we report on findings concerning acuity and magnification.

 

METHODS 

The survey asked subjects to arrange a text passage for typical reading and to report viewing distance, screen dimensions, and the number of characters per line. Seventy-five adult subjects (most with early-onset low vision, few with central field loss) completed all survey questions relevant to the analysis of acuity and magnification. Mean acuity was .92 logMAR (range, 0.1 to 1.6), and mean age was 44.8 years (range, 18 to 71 years). Twelve normally sighted controls reported the same information while viewing the passage on cell phones, tablets, and computers.


Conclusion/Results

RESULTS 

The controls had a mean viewing distance of 38.7 cm and a mean x-height of 1.38 mm. For all three types of devices, angular x-height was 0.21° (close to laboratory estimates of the critical print size for reading). Low vision subjects showed decreasing viewing distance and increasing print size with larger values of logMAR acuity. Most of the low vision subjects achieved their desirable magnification by a combination of reduced viewing distance and increased physical letter size. The majority (54 of 75) relied more on letter-size magnification. Relative to the controls, regression analysis revealed that a typical low vision subject with logMAR acuity of 1.0 reduced viewing distance by a factor of 2.8 and enlarged physical print size by a factor of 6.

 

CONCLUSIONS 

Our survey shows that people with a wide range of acuities are engaged in digital reading. Our subjects achieved desirable magnification primarily by enlarging physical character size and to a lesser extent by reducing viewing distance.


Contact Us To Amplify Your EyeCare

Working Hours

Monday - Thursday
8:00 am - 5:15pm
friday-sunday
Closed
Location
1043 Executive Drive Suite #101 Hixson, TN 37343
Website Accessibility Policy
Safety protocols page
phone-handsetarrow-uparrow-right linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram