Vision Beyond Vision: Lessons Learned from Amblyopia

ABSTRACT

Amblyopia is characterized by spatiotemporal uncertainty in the visual system. In addition to its effects on vision, amblyopia also exerts a widespread impact on other systems. Many of these changes are observed not only during amblyopic eye viewing but also during fellow eye and binocular viewing. They generally correlate with the severity of visual acuity and stereo acuity loss. The affected systems include: (1) oculomotor control manifested as abnormal fixation, saccades, smooth pursuit, and saccadic adaptation; (2) motor control with altered programming, execution, and temporal dynamics of eye-hand coordination, and decreased ability of the sensorimotor system to adapt to changes in the visual environment; (3) balance control with decreased postural stability; (4) multisensory integration characterized by reduced McGurk effect and altered cross-modal interactions in audiovisual perception; and (5) auditory localization manifested as impaired spatial hearing as a result of abnormal developmental calibration of the auditory map. To detect amblyopia early, a targeted approach is required to identify children from low-income families through in-school visual screening, supplemented by follow-up care and free eyeglasses in high-needs schools.

KEYWORDS:

• Eye movements
• eye-hand coordination
• balance
• audiovisual integration
• vision screening

Acknowledgments

I would like to take this opportunity to thank my students, fellows, laboratory staff, and collaborators, without whom this research would not have been possible. I am deeply grateful for their contribution, insight, and support, which have made this work so fruitful, stimulating, and fulfilling.

I also thank the many agencies and organizations that funded this research, including grant MOP 106663 from the Canadian Institutes of Health Research (CIHR), a Collaborative Health Research Projects grant from the CIHR in partnership with the Natural Sciences and Engineering Research Council of Canada (NSERC), an operating grant from the Physicians’ Services Incorporated Foundation, the Joanne Angle Investigator Award from Prevent Blindness, the Leaders Opportunity Fund from the Canada Foundation for Innovation (CFI), the Brandan’s Eye Research Foundation, and the John and Melinda Thompson Endowment Fund in Vision Neurosciences in the Department of Ophthalmology and Vision Sciences at The Hospital for Sick Children.

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

The work was supported by the Brandan’s Eye Research Foundation, Canada Foundation for Innovation, Canadian Institutes of Health Research, John and Melinda Thompson Endowment Fund in Vision Neurosciences, Physicians’ Services Incorporated, and Foundation Prevent Blindness