Project 462658

Babies born with cataracts face a life-long struggle. Although the cataracts that block vision in one or both eyes are removed within the first year of life, the rapidly developing brain misses important input from the eyes that is needed to correctly wire the brain. Even decades after cataract removal, these individuals still have difficulty with many everyday vision skills including seeing small objects and recognising faces because the brain does not use information from the eyes correctly. The aim of our project is to provide information that will support the development of future treatments for patients with brain-based vision problems. Although all of these patients fail standard tests of binocular vision (the ability of the two eyes to work together), we recently discovered that some patients can use both eyes together when tested with more sensitive measures (we call this discovery hidden binocularity). Additionally, when measuring how well these patients can use their senses together, we discovered normal combination of vision and touch but problems combining vision and hearing. In this project we will investigate the effect of childhood cataracts on hand-eye coordination and how hidden binocularity relates to hand movement control. A range of tests that measure how well the brain can use vision to guide the movement of the hands will be used. We will test two unique groups of patients. The first group live in Canada and were treated in the 1990s; the second group live in China and have been treated over the past decade. Studying both groups allows us to measure the effects of early blocked vision at two stages of brain development: mid-childhood and adulthood. Our project will provide novel insights into how vision guides human brain development and the role of hidden binocularity in hand-eye coordination.