Centre for Eye Research Australia (CERA) has called on people with amblyopia to participate in a study that will assess a treatment for the eye condition using iPod games. The treatment aims to help both eyes work together as a team.
Amblyopia is a common visual disorder that affects approximately 5 per cent of the population and is associated with decreased vision, poor or absent 3D vision and suppression (ignoring) of information from one eye. It is the most common cause of childhood visual impairment in the developed world, reducing quality of life and almost doubling the lifetime risk of serious visual impairment.
Current treatment for amblyopia includes patching of the non-amblyopic eye in childhood. According to a statement from CERA, although usually effective, this treatment can be poorly tolerated, has high relapse rates and is generally not used after the age of seven, leaving older patients with no widely accepted treatment options. The CERA researchers believe alternative therapies are required.
Previous experience has shown that a new video-game based treatment for amblyopia treatment using an iPod is effective in children and adults and can improve both visual acuity and 3D vision.
The Centre for Eye Research Australia will enrol a total of 108 people… to participate in the randomised clinical trial
Researchers of one study, published in Current Biology, wrote “it is now clear that the adult human visual cortex has a significant degree of plasticity, suggesting that something must be actively preventing the adult brain from learning to see through the amblyopic eye. One possibility is an inhibitory signal from the contralateral eye that suppresses cortical inputs from the amblyopic eye.”
Eighteen adults played the video game (Tetris) on head mounted video goggles for one hour per day over two weeks, nine of them playing the game monocularly with the fellow eye patched and the remaining nine patients playing dichoptically, “whereby stimulus elements were presented separately to each eye and lower contrast stimuli were presented to the fixing eye to counteract suppression and allow for binocular combination”. Those who played monocularly were crossed over to the dichoptic condition after two weeks.
The researchers found that dichoptic training resulted in significantly greater learning effects than monocular training. “This indicates that suppression is a key gating mechanism that prevents the amblyopic brain from learning to see,” they wrote.
In another study, children (four to12 years old) wore anaglyphic glasses to play binocular games on an iPad platform for four hours per week over four weeks. Fifty children played binocular games while 25 children were assigned to sham games.
Children in the binocular group had the option of participating for an additional four weeks and approximately half of the children were also treated with patching at a different time of day. The researchers measured best corrected visual acuity, suppression, and stereoacuity at baseline, at the four- and eight week outcome visits, and three months after the treatment concluded. They found that “binocular iPad treatment rapidly improved visual acuity, and visual acuity was stable for at least three months following the cessation of treatment”. This month’s miophthalmology insights column (page 33) edited by Assoc. Professor John Grigg, looks into this study in greater detail.
The Centre for Eye Research Australia will enrol a total of 108 people (adults and children over the age of seven years) to participate in the randomised clinical trial titled the ‘Binocular treatment for amblyopia with videogame (BRAVO) study’. It will involve six weeks of home-based use of a modified Tetris video game that runs on an iPod touch device.
Participants will be asked to play the game for one to two hours every day with play able to be split into smaller periods throughout the day.
Led by principal study doctor Dr. Lionel Kowal, the study will take place at Dr. Kowal’s Private Eye Clinic, the Ocular Motility Clinic, Royal Victorian Eye and Ear Hospital, and the Centre for Eye Research Australia.