Public Release: 

New eye-tracker method shows 'preferred retinal location' in both eyes

Wolters Kluwer Health

July 28, 2015 - Eyes with central vision loss adapt by developing a new fixation point in a different part of the retina, called the preferred retinal location (PRL). Now for the first time, a new method makes it possible to identify PRLs in both eyes simultaneously, reports a study in the August issue of Optometry and Vision Science, official journal of the American Academy of Optometry. The journal is published by Wolters Kluwer.

The new eye-tracker technique may help in developing visual rehabilitation approaches to improve binocular vision for the many older adults with central vision loss affecting both eyes, according to the new research led by Esther G. González, PhD, of the Vision Science Research Program at Toronto Western Research Institute.

Technique Identifies PRLs in Both Eyes of Patients with Central Vision Loss

Central vision loss results from degeneration of the fovea--the central pit of the retina, where visual acuity is sharpest. The most common cause is age-related macular degeneration, which is also the leading cause of blindness in older adults. "Especially when present in both eyes, loss of central (reading) vision is a major intrusion on quality of life and everyday functioning," explains Anthony Adams, OD, PhD, Editor-in-Chief of Optometry and Vision Science.

Taking advantage of visual plasticity that persists even in old age, the brain and eye can partly compensate for loss of the fovea by developing a PRL--shifting fixation to another nearby spot in the retina. Patients learn to use an area of their peripheral vision to substitute for their lost central vision.

A technique called microperimetry with eye-tracking can precisely identify the PRL, but only in one eye at a time. This may not adequately represent binocular function--vision with both eyes working together. "Understanding binocular vision is important for designing optimal rehabilitation methods for patients with central vision loss," Dr. González and coauthors write.

They developed a method to establish the PRLs in both eyes, based on the relationship between microperimetry and eye-tracking measurements in healthy eyes. Predicted PRLs in nine older adults with central vision loss were compared with the findings of standard PRL assessments in the two eyes individually.

All patients had at least one PRL fall onto a functional area of retina during binocular viewing. In most cases, the PRLs were found in corresponding locations in the two eyes--that is, in about the same position relative to the center of the retina. The one patient whose PRLs were not in corresponding locations had problems with double vision (diplopia).

Dr. González and colleagues note some important limitations of their "proof-of-principle" study. Further studies will be needed to evaluate the new eye-tracker method in a broader sample of patients with central vision loss.

By enabling simultaneous identification of the PRLs in both eyes, the technique provides important information on binocular function in eyes with low central vision. At least for some patients, the results may help to guide approaches to maximizing binocular vision--for example, through relocation training to help move the PRL to the corresponding location in both eyes.

The eye-tracker method may be especially valuable for managing the large number of patients with age-related macular degeneration affecting both eyes. Dr Adams comments, "Such an approach not only allows a better understanding of how the eyes and brain deal with binocular central vision loss, but also opens up exploration of new approaches to visual rehabilitation for these individuals."

###

Click here to read "Identifying Absolute Preferred Retinal Locations during Binocular Viewing."

Article: "Identifying Absolute Preferred Retinal Locations during Binocular Viewing" (doi: 10.1097/OPX.0000000000000641)

About Optometry and Vision Science

Optometry and Vision Science, official journal of the American Academy of Optometry, is the most authoritative source for current developments in optometry, physiological optics, and vision science. This frequently cited monthly scientific journal has served primary eye care practitioners for more than 75 years, promoting vital interdisciplinary exchange among optometrists and vision scientists worldwide.

About the American Academy of Optometry

Founded in 1922, the American Academy of Optometry is committed to promoting the art and science of vision care through lifelong learning. All members of the Academy are dedicated to the highest standards of optometric practice through clinical care, education or research.

About Wolters Kluwer

Wolters Kluwer is a global leader in professional information services. Professionals in the areas of legal, business, tax, accounting, finance, audit, risk, compliance and healthcare rely on Wolters Kluwer's market leading information-enabled tools and software solutions to manage their business efficiently, deliver results to their clients, and succeed in an ever more dynamic world.

Wolters Kluwer reported 2014 annual revenues of €3.7 billion. The group serves customers in over 170 countries, and employs over 19,000 people worldwide. The company is headquartered in Alphen aan den Rijn, the Netherlands. Wolters Kluwer shares are listed on NYSE Euronext Amsterdam (WKL) and are included in the AEX and Euronext 100 indices. Wolters Kluwer has a sponsored Level 1 American Depositary Receipt program. The ADRs are traded on the over-the-counter market in the U.S. (WTKWY).

Wolters Kluwer Health is a leading global provider of information and point of care solutions for the healthcare industry. For more information about our products and organization, visit http://www.wolterskluwerhealth.com, follow @WKHealth or @Wolters_Kluwer on Twitter, like us on Facebook, follow us on LinkedIn, or follow WoltersKluwerComms on YouTube.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.