Although perception may be significantly impaired in glaucomatous patients when using monocular vision, their motor performance did not differ from controls when using binocular vision, according to French researchers from the University of Lille. Individuals with glaucoma were able to perform with high accuracy a context-association task on a touch screen.

The study investigated the ability of patients with glaucoma to use a touch screen to find, recognize and associate an object to a congruent scene. It recruited 84 volunteeer that were divided into three groups: 28 patients with binocular glaucoma, a visual acuity of 0.4 log MAR or better in each eye and visual field defects (mean age=68.5), 28 age-matched controls (mean age=68.8) and 28 young controls (mean age=22.1). Researchers tested participants monocularly as well as binocularly, the habitual situation for visuomotor tasks in daily life. The participants had to associate, by moving their index on a 22-inch touch screen, a target on a unique scene that was surrounded by three other distractor images with a consistent background related to the target, such as matching a fish with the sea.

With monocular vision, exploration duration, accuracy and peak speed of the glaucomatous patients were significantly impaired, with longer durations and slower peak speeds. With binocular vision, exploration duration, deviation and movement duration were not affected by glaucoma when compared with the age-matched group. This cohort performed the task more slowly than controls but with 99% accuracy.

Researchers believe that movement parameters are not systematically impaired at a moderate stage of glaucoma, as there was no difference between glaucoma patients and the older control group in deviation, movement duration or peak speed when using binocular vision. They proposed that further testing could explore whether patients could benefit from new touch screen applications with equipment adapted to their impairment, such as larger screens, bigger icons and time to explore the screen without a screen saver, when trying to find relevant information and achieve a task, compared to a task in which reading ability is required.

Lenoble Q, Rouland JF. Context association in glaucoma patients using a touch screen. Glaucoma. May 31, 2019. [Epub ahead of print].