Date Published: January 23, 2017
Publisher: Public Library of Science
Author(s): Aurélie Calabrèse, Tingting Liu, Gordon E. Legge, Randi Starrfelt.
Individuals with macular degeneration often develop a Preferred Retinal Locus (PRL) used in place of the impaired fovea. It is known that many people adopt a PRL left of the scotoma, which is likely to affect reading by occluding text to the right of fixation. For such individuals, we examined the possibility that reading vertical text, in which words are rotated 90° with respect to the normal horizontal orientation, would be beneficial for reading. Vertically oriented words would be tangential to the scotoma instead of being partially occluded by it. Here we report the results of an exploratory study that aimed at investigating this hypothesis. We trained individuals with macular degeneration who had PRLs left of their scotoma to read text rotated 90° clockwise and presented using rapid serial visual presentation (RSVP). Although training resulted in improved reading of vertical text, the training did not result in reading speeds that appreciably exceeded reading speeds following training with horizontal text. These results do not support the hypothesis that people with left PRLs read faster with vertical text.
People suffering from macular degeneration (MD) often lose the ability to use central vision. Both age-related macular degeneration (AMD) and juvenile forms of macular degeneration (JMD) can lead to the development of bilateral central scotomas, seriously affecting the performance of high-resolution tasks such as reading. Difficulty with reading is often the primary complaint of people with central vision loss .
This exploratory study focused on two questions. First, would reading performance of MD subjects with left PRLs exhibit increased reading speeds when trained to read vertically oriented text? The answer is yes. We found that RSVP training with vertical text improved vertical reading performance by an average of 79% (SD = 52%). This value is higher than the average improvement of 29% (SD = 35%) measured in our participants with left PRLs who were trained to read horizontal text. By comparison, Chung (2011)  found a 53% average improvement in reading speed by a group of six MD subjects trained with horizontal RSVP text. The fact that participants continue to improve over the course of the vertical training, implies that the performance change measured after vertical training cannot simply be du to task familiarity. We conclude that individuals with MD can learn to read vertically oriented text.