Benefits of low vision aids to reading accessibility

Abstract

The Reading Accessibility Index (ACC) has been proposed as a single-value reading parameter that can capture information on both reading speed and print sizes that can be read. It is defined as the average reading speed across a relevant range of print sizes (1.3-0.4logMAR), normalised by typical young-adult reading speed of 200wpm, and with values typically in the range of 0-1. This study determines the impact of low vision aids (LVAs) on reading by evaluating ACC values for visually impaired observers reading both without and with an optical LVA. A secondary analysis of previously published data obtained from 100 visually impaired observers attending low vision assessments was undertaken. Observers had mixed causes of visual impairment but predominantly macular degeneration (n=55). All used an LVA for reading, with 88% using it 'often' or 'very often'. MNREAD reading parameters, including ACC, were determined both for reading without an LVA (clinical function) and with the LVA habitually used for reading (aided function). There was a significant (p<.001) improvement in ACC from clinical (0.31 (95% CI 0.25, 0.36)) to aided conditions (0.47 (0.41, 0.52)). Average improvement in ACC with an LVA was 0.16 (0.13, 0.18), but the benefits of LVAs in terms of improvement in ACC could not be predicted from clinical visual function. Even with an LVA reading accessibility is, on average, markedly reduced from normal levels. The ACC is a potentially valuable outcome measure for reading rehabilitation interventions.

Can listening provide a useful clinical estimate of low vision reading parameters?

“…A disadvantage of the sample is that the causes of visual loss are not necessarily ‘typical’ of a group of low vision patients and does not include a large number of participants with central field loss (e.g., those with macular degeneration). However, in previous studies considering reading, 16,18,21 we have not found differences between individuals with specifically central visual loss and those with other conditions. The level of visual function has been the important discriminating factor for performance, rather than the cause of visual loss.…”

“…36,37 A disadvantage of the sample is that the causes of visual loss are not necessarily 'typical' of group of low vision patients and does not include a large number of participants with central field loss (e.g., those with macular degeneration). However, in previous studies considering reading, 16,18,21 we have not found differences between individuals with specifically central visual loss and those with F I G U R E 4 Maximum reading speed (MRS) in words per minute (wpm) derived by inspection compared to the first judgments of reading speed by rater 1 (blue symbols) and rater 2 (orange symbols). The solid horizontal line represents a measured MRS of 80 wpm, and the dashed line a measured MRS of 120 wpm T A B L E 2 Summary of the ability of each rater to judge whether the maximum reading speed (MRS) was 'functional' (>80 wpm) or 'nonfunctional' (<80 wpm) Note: Category options as for Table 3.…”

“…Maximum reading speed tends not to change markedly with use of magnification, 19,20 and the ability to read large print fluently is the best predictor of being able to read small print fluently with a magnifier. 14,16,19 If anything, reading speed can decrease slightly with magnification 21 due to the additional constraints imposed by handling the magnifier 22,23 and reduced field of view. 24,25 As well as being time-consuming, reading speed can be challenging to measure accurately in a clinical setting: using a stopwatch to time individual sentences in real-time may be less accurate than audiorecording reading of a chart with the parameters derived later, 26 as could be done in a research study.…”

U.S. Optometrists' Reported Practices and Perceived Barriers for Low Vision Care for Mild Visual Loss

“…9 Low vision rehabilitation can help patients with moderate to severe low vision improve in their clinical reading ability, as well as overall reading speed. 10 The LOVIT-II study 11 demonstrated that basic low vision services (i.e., visual assistive device dispensed at a single in-office training session without ongoing rehabilitation therapy or homework) are effective in patients with mild vision impairment. Although randomized clinical trials are needed to better understand low vision rehabilitation outcomes in patients with mild vision impairment outside of the Veteran's Affairs system, these initial results indicate that basic low vision services can be effectively integrated into a primary care optometric practice.…”

Towards accessible news reading design in virtual reality for low vision

“…Overall, these magnification tools have been shown to increase reading ability of low-vision patients for standard news print [10,11]. However, there is a strong trade-off between portability (i.e., whether the user is required to sit at a desk) and screen space (i.e., how much content can be seen through the magnifier).…”