When reading with a stand magnifier (SM), navigation along each line of text and retracing back to the correct position at the beginning of the next line has been suggested as a major difficulty for people with low vision. In this study, we evaluated the immediate impact of using a simple and inexpensive line guide on navigation performance.
Twenty-nine participants with age-related macular degeneration read short passages of text using their habitual SM with and without a temporary line guide attached. Magnifier movements were recorded using a 3 SPACE Isotrak system. Reading time, magnifier movement strategies, navigation times, and navigation errors were determined. A short questionnaire was used to quantify participants' perceived difficulties with page navigation and their preference for reading with or without the line guide.
For some participants, the line guide improved the control of the vertical positioning of the SM when reading along a line (p = 0.01), but it increased the number of corrective vertical movements at the end of the retrace (p = 0.001). There was a small but significant decrease (about 6 wpm) in reading speed and increase in navigation times (p < 0.05) when using the line guide; however, 48% participants indicated a preference for reading with it attached to their SM. There was a trend (p = 0.08) for those who preferred the line guide to report greater habitual difficulties with SM manipulation.
After only minimal instruction in how to use the line guide, forward navigation control improved, but the design of the guide made retracing the SM to the start of the next line more difficult resulting in slower reading speeds. Nevertheless, 48% of participants expressed a preference for having the line guide attached to their SM. Improvements to the design of the line guide and strategies that may improve retrace navigation performance are suggested.