With normal vision, both eyes aim at the same spot. The brain then fuses the two pictures into a single three-dimensional image. This three-dimensional image gives us depth perception.
When one eye turns, two different pictures are sent to the brain. In a young child, the brain learns to ignore the image of the misaligned eye and sees only the image from the straight or better-seeing eye. The child then loses depth perception. Adults who develop strabismus often have double vision because the brain cannot ignore the image from the turned eye.
Good vision develops during childhood when both eyes have normal alignment. Strabismus may cause reduced vision, or amblyopia, in the weaker eye. The brain will recognise the image of the better-seeing eye and ignore the image of the weaker or amblyopic eye.
Amblyopia can be treated by patching the "good" eye to strengthen and improve vision in the weaker eye. If treatment is delayed until later, amblyopia usually becomes permanent. As a rule, the earlier amblyopia is treated, the better the eventual vision.
South African Optometric Association
Tel: 011 805 4517
South African National Council for the Blind
Tel: 012 452 3811
Retina South Africa
Tel: 011 622 4904