Nancy A. Melville

April 10, 2014

PALM SPRINGS, California — An innovative binocular iPad application can help improve amblyopia in preschool children and can help prevent recurrence, according to a new study.

The results suggest that "the binocular iPad treatment can improve visual acuity, even for children who have 'maxed out' with patching," said lead author Eileen Birch, PhD, director of the Crystal Charity Ball Pediatric Vision Evaluation Center at the Retina Foundation of the Southwest in Dallas, Texas.

They also suggest that the binocular iPad games can achieve the same degree of improvement in visual acuity as patching, but with significantly fewer hours of treatment, she told Medscape Medical News.

Patients with amblyopia do not always achieve 20/20 vision with patching, and the condition recurs in up to 35% of children. The iPad treatment is designed to address a key shortcoming of patch treatment — its inability to treat binocular dysfunction, Dr. Birch explained.

What is unique about the iPad treatment is that "the contrast of the images presented to the normal eye is reduced, compared with the high-contrast images presented to the amblyopic eye," she said. "By design, this sets up the conditions needed for the amblyopic child to combine information from the 2 eyes."

The results were presented here at the American Association for Pediatric Ophthalmology and Strabismus 2014.

The study cohort involved 50 amblyopic children, 3.8 to 6.9 years of age. Three quarters had previously been treated with patching.

The children were asked to play the iPad games at home for at least 4 hours a week for 4 weeks, for a total of 16 hours of treatment. The treatment was incorporated into games such as Tetris, Pong, Labyrinth, and Balloons.

Five of the children received sham games, in which high-contrast images were presented to the normal eye and low-contrast images were presented to the amblyopic eye; the other 45 received the treatment games.

At the end of the study period, improvement was significantly better in children who had played at least 2 hours per week (8 hours over the 4 weeks) than in children in the sham group (P = .048).

"Some patients achieved 20/20 vision," Dr. Birch reported.

There was very little change in visual acuity in about one third of the children who played less than 1 hour per week; these children were considered noncompliant.

Improvement was significantly greater in the 27 children who were considered to have good compliance than in those with poor compliance (P = .008).

In follow-up assessments 3 and 6 months after the treatment period ended, none of the children who were compliant had recurrence of amblyopia (95% confidence interval, 0% - 14%).

Dr. Birch said she is not aware of any other iPad applications designed to treat amblyopia. Although many studies have shown that monocular and binocular, including dichoptic, perceptual training can be effective in improving amblyopic visual acuity later in life, none of the approaches are designed to treat binocular dysfunction in children, she noted.

The approach of degrading images seen by the normal eye to achieve balance with the amblyopic eye was developed by Robert Hess, MD, and colleagues from McGill University in Montreal. Dr. Birch and her team have worked with the McGill researchers in their research on the binocular dysfunction theory.

Lenses or diffusing filters have long been used to reduce contrast or brightness in the normal eye to treat amblyopia, but an electronic approach offers more precision, said Joseph L. Demer, MD, chief of the pediatric ophthalmology and strabismus division and professor of ophthalmology and neurology at the UCLA Stein Eye Institute in Los Angeles.

"Obviously, electronic image processing with electronic shutters or dichoptic glasses allows for more precision in controlling exactly what the normal eye sees," he told Medscape Medical News.

However, "this idea is probably not quite ready for general clinical use," said Dr. Demer. The game content needs to be sufficiently entertaining to motivate prolonged use by most kids.

Dr. Birch underscored the differences between traditional amblyopia treatment — the eye patch — and the iPad treatment. "Patching certainly has the bulk of randomized clinical trial evidence. It's simple and inexpensive, compared with the iPad," and children can do other activities, like homework, while they wear the patch, she said.

"The iPad is designed to treat binocular dysfunction, which we think is primary to amblyopia. Children have fun doing it and there is less social stigma associated with it," she explained.

A multicenter study of the iPad treatment, funded by the National Eye Institute, is being launched this summer by the Pediatric Eye Disease Investigator Group, Dr. Birch reported.

Dr. Birch and her colleagues received a grant from the National Eye Institute to study suppression and amblyopia, and start-up funds to purchase a lending library of iPads from the BB Owens Foundation and the Harold Simmons Foundation. Coauthor Simone Li, PhD, received a postdoctoral fellowship from Fight for Sight. None of the authors have a commercial interest in the iPad binocular treatment.

American Association for Pediatric Ophthalmology and Strabismus (AAPOS) 2014: Abstract 10. Presented April 3, 2014.

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