Title: Assessment and Treatment of patients with Amblyopia using interactive binocular computer games
Funder: Department of Health and Social Care

Abstract: Stage 1: Development. There are five development goals: 1/ Incorporation of eye-tracking into the I-BiT&trade; system. SMI have already developed an eye-tracking system that is both compatible with shutter glasses and normal wearing of spectacles and will track each eye independently. At the moment the two systems are separate and need to be combined into a single system. The third component is the use of a large HD screen. 2/ Adapt the system for home use. Currently neither the eye-tracking, due to the complexity of the calibration system, nor the I-BiT&trade; system (which currently is also a complex arrangement of two separate computers) is suitable for home use. These systems can be combined onto one computer and screen (like most modern gaming systems for home use). Software will need to be developed to ensure ease of set-up. Patient/parent focus groups will be involved in the design to ensure acceptability and usability of the developed system. 3/ Development of an assessment tool. An automated assessment of visual acuity (using a computer version of the Keeler crowded logMAR), the presence and density of suppression (based on the Bagolini suppression test and Sbisa bar test) and the angle of deviation will be designed and incorporated into the home based system. The size of the suppression scotoma will be estimated by creating a central blurred patch of variable size to the normal eye and monitoring the size of this patch when the amblyopic eye takes up fixation. This will enhance safety by monitoring for side-effects of treatment such as detrimental effect on vision or the development of double vision allowing the gaming capacity to be disabled until the child has been reassessed in clinic. We have these tests encoded for use in a research setting which will be adapted for this purpose. 4/ Dichoptic stimulation with normal retinal correspondence. The eye tracking capability will be allow normal (harmonious) retinal correspondence in image presentation to the two eyes and allow presentation of a blurred central patch to the normal eye and that this patch remains centrally located despite eye movement. 5/ Game development. The aim is to make treatment enjoyable as a way of ensuring good compliance. This will require development of a suite of games adapted for I-BiT&trade; use. The current game is based on dichoptic stimulation and we need to develop games that require simultaneous perception in order to play. This will encourage development of binocular vision and increase the therapeutic potential of the system. Patient/Parent focus groups will help guide game development. STAGE 2: Obtaining regulatory approval. Regulatory approval will be needed for the modified I-BiT&trade; system in order to perform clinical studies. STAGE 3: Validation of assessment tool. The validation of the incorporated assessment tool will be performed at the Queen s Medical Centre. Direct comparison between the assessment tool and a masked clinical orthoptic and test-retest variability will be performed. STAGE 4: Pilot Clinical Study. A pilot study for 80 patients. This would be a randomised control trial comparing standard treatment versus the I-BiT&trade; system. The trial will be designed in conjunction with Research and Innovation and Research Design Services. The aims of the trial are to ensure that the developed system is useable and acceptable and to assess clinical efficacy (the equivalent of a Phase II study) At the end of this study, we will have a home based clinically validated assessment and treatment device for the management of amblyopia with trial data giving an indication of its utility.

Lay abstract: Around one child in fifty has a lazy eye where the eye is structurally normal but the vision fails to develop correctly. Around half of these children also have a squint (strabismus) where each eye has a different direction of gaze. This condition is most often detected at age 2 &ndash; 4 years of age and the standard treatment is to cover the good eye (patching) so as to encourage use of the lazy eye and then to consider corrective surgery for any squint that may be present. It requires up to 400 hours of patching to get maximum visual improvement but many are still left with some impairment and, in particular, poor depth perception. In addition wearing a patch is uncomfortable, impairs the child s vision and may make him/her a target for bullying. We have developed a treatment for amblyopia which has shown improvements in vision with only three hours of treatment and which is fun to undertake (The I-BiT&trade; system). The current system is hospital based and we wish to modify it for home use while including three further improvements. First, many patients with a lazy eye also have a squint and, in this group, the treatment has a risk of causing double vision. We wish to incorporate eye-tracking technology to be able to correct for the presence of squint during treatment. Secondly, this system would allow the treatment to be modified according to the response. Third, we wish to adapt more games for the I-BiT&trade; system both to avoid the patient/player becoming bored and also to increase the therapeutic potential by adding games that require simultaneous perception in order to play so as not only to improve visual acuity but also to stimulate the development of true binocular vision with depth perception.

Research activity codes: 5.7 PHYSICAL
Health categories: EYE