Loss of Binocular Vision
Most people see the world through binocular vision, which is vision that receives input from both eyes. People with a glass eye have monocular vision; they see the world with only one eye. Binocular vision allows input from two different angles to be combined into a three-dimensional picture, according to the EyeCare Connection. Loss of binocular vision causes a flatter, non-stereoscopic view, although the brain will compensate for this in many individuals. According to the EyeCare Connection, even if there's compensation, those who have sight in only one eye will perceive things differently than people with binocular vision.
Depth Perception
The loss of visual input from the glass eye decreases depth perception. Depth perception is the ability to tell how far away objects are and how they relate to each other in terms of distance, according to the EyeCare Connection. Monocular vision can cause difficulties in determining distances and poor hand-eye coordination, according to NORA, the Neuro-Optometric Rehabilitation Association. Walking up and down the stairs and driving may also be difficult; people who lose binocular vision at a younger age may be better able to adapt and compensate.
Peripheral Vision
People who lose binocular vision also lose 10 to 20 percent of peripheral vision, according to NORA. Loss of vision at the periphery means that people with one glass eye will need to turn their head more frequently to keep objects on the edge of the visual field within sight. Those who have vision in only one eye are seven times more likely to be involved in motor vehicle accidents, according to NORA. The use of wide mirrors on either side of the vehicle helps compensate for the loss of peripheral vision.
Accommodation
Monocular vision makes close work difficult. People with only one eye have trouble seeing things closer than 3 feet away clearly, according to NORA. This is because the eyes need to work as a pair to focus, or accommodate, on near objects more than they do on objects in the distance. Reading, needle work or working at a computer all require close vision and accommodation, and the ability to carry out these activities may be impaired in people with monocular vision.
