Reading into Central Vision Loss

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New measures provide more informative assessment of reading performance in central vision loss.
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Reading is an essential skill for performing daily activities. It also provides myriad benefits such as improving communication skills, increasing empathy levels and expanding vocabulary.

Reading is a gift that keeps on giving. As soon as we learn how to read, we keep reading every day for the rest of our lives. We use this skill to learn, relax and communicate with others.  And when we lose the ability to read, it negatively impacts our emotional wellbeing and quality of life.

“Central vision loss can impair a person’s ability to read. It is characterized by the appearance of a blurred or distorted area in the center of a person’s field of vision. This area can become so blurred that a person’s central vision is completely eliminated,” explains Dr. Tarita-Nistor, a Scientific Associate at the Krembil Research Institute.

Recently, a team led by Drs. Tarita-Nistor and Esther González (Affiliate Scientist at Krembil) evaluated the effectiveness of two new measures of reading performance—the reading accessibility index (ACC) and a quality of reading grid—in patients with central vision loss. The ACC assesses a person’s ability to read text sizes found in everyday life, such as those in newspapers and books, whereas the quality of reading grid classifies the speed at which a person reads different sizes of text.

The study included 24 participants with normal vision and 61 patients with central vision loss. The researchers used a variety of reading parameters, such as the maximum reading speed and the smallest print size that can be read, to calculate each participant’s ACC score and assess their reading ability using the quality of reading grid.

The researchers found that the ACC scores of people with normal vision were consistently high and strongly associated with indicators of good reading performance. Whereas, the scores were significantly lower in patients with central vision loss and strongly associated with indicators of poor reading performance. They also showed that the quality of reading grid provided a better understanding of the type of reading impairment affecting each patient, suggesting that it may be a good tool to evaluate improvement after reading rehabilitation.

These findings show that the ACC is a good measure of overall reading performance in patients with central vision loss and, when combined with the quality of reading grid, provides detailed information about a patient’s reading impairments. These new measures could not only improve the diagnosis of reading impairments in patients with central vision loss, but also help researchers develop more effective rehabilitation strategies for it.

This work was supported by an anonymous donor, the Vision Sciences Research Program and the Toronto General & Western Hospital Foundation.

Tarita-Nistor L, González EG, Mandelcorn MS, Brent MH, Markowitz SN, Steinbach MJ. The reading accessibility index and quality of reading grid of patients with central vision loss. Ophthalmic Physiol Opt. 2018 Jan. doi: 10.1111/opo.12429.