Dichoptic Treatment: A virtual game in amblyopia treatment

Rupali Singh, Bachelor in Optometry

Fellow Optometrist, Paediatric & Vision Therapy Department, Dr. Shroff’s Charity Eye Hospital, Delhi, India.

Amblyopia can be defined as unilateral or bilateral reduced best corrected visual acuity, which is not due to any structural abnormality of the eye or any visual pathways system. Its primary causes are strabismus, anisometropia or bilateral high refractive errors, and stimulus deprivation. ⁽¹⁾ Early detection of amblyopia is very important to attain the best response to a treatment. Treatment modalities in amblyopia like patching, atropinisation of better eye are used for amblyopia therapy.⁽²⁾ Recently many computer-based programmes has been developed for the treatment of amblyopia. Dichoptic training and i-pad games has been seen very successful in treating dense amblyopia with anisometropia and strabismus. ^(3,4),

Amblyopia is associated with cortical dysfunction, and it is also suggested as a consequence interocular suppression.⁽⁵⁾ Therefore, binocular training strategies has become very important in amblyopia therapy. Dichoptic training is a therapeutic  in which stimuli are presented separately and independently in both eyes. In this the contrast of the image shown to the good eye is reduced to encourage binocular combination of the two inputs. ⁽⁶⁾ It is based on motion coherence strategy, in which the patient had to identify the direction of motion of signal dots which is presented in one eye from the noise dots which is presented to the other eye. ⁽⁶⁾ Binocular balancing occurs when the contrast of the image seen by the non-amblyopic eye is reduced significantly to resolve the interocular unbalancing due to suppression. These dichoptic training techniques reported to improve amblyopic eye visual acuity, and in some cases stereo acuity also. ⁽⁷⁾

Playing video games enhances broad range of visual tasks in both children and adults with normal vision, including light sensitivity, contrast sensitivity, visual crowding, and visual attention. ⁽⁸⁾  The game include an immersive and engaging game environment which is used  along with binocular dichoptic treatment, where a split screen view is used to allow independent control of image luminance and contrast to the right and left eye separately. ⁽⁹⁾  Perceptual learning task is seamlessly embedded within the game which consists of a Gabor patch embedded in a grey square and presented to the amblyopic eye only. ⁽⁹⁾ The Gabor patch task enables to check the amblyopic eye resolution limit under dichoptic conditions, while simultaneously serving as a suppression check, ensuring that the amblyopic eye is actively engaged during dichoptic game play. ⁽⁹⁾

Vedamurthy et al., (2015) reported that following dichoptic training, there were significant improvements noted in visual acuity, stereopsis, as well as contrast sensitivity and the reading speed. ⁽⁹⁾ In 2015 another study by Li et al., found that passive dichoptic movie watching benefited with improved visual acuity in children. ⁽³⁾ Both dichoptic game and movies found to improve contrast sensitivity as well. ⁽³⁾ Therefore, it is evident that dichoptic therapy in amblyopic patient improves visual acuity, stereopsis, and contrast sensitivity significantly in both children and adult’s patients.

Consent:

Consent was taken from the patients at Dr Shroff’s Charity Eye Hospital for the use of their picture for any research publication and use.

Reference:                                                                                                                                 

1. DeSantis, D. (2014). Amblyopia. Pediatric Clinics of North America, 61(3), 505-518.
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