Amblyopia or lazy eye is the most common cause of poor sight in children. This occurs when the part of the brain the deals with the vision in that eye fails to develop normally, particularly in the first eight years of life. This decreased development is generally caused by the reduced quality of vision in the affected eye. The main cause of amblyopia is one eye being significantly more blurred, due to large differences in prescription. Cataracts can also be present at birth causing a permanent reduction in vision unless operated on very quickly. A squint or turning eye can also cause amblyopia if it is always the same eye that turns. Amblyopia can be treated by a number of measures including wearing spectacles, patching one eye part time, eye drops and treatments to correct squints. If it is detected and treated prior to the age of eight vision can be generally improved.
Strabismus is also known as a squint. This is when the two eyes do not point in the same direction when looking at objects. It can be caused by large hyperopic prescriptions, or by the eye muscles not coordinating well together.
Depending on the cause of the strabismus it can be corrected by glasses, contact lenses or surgery. If the strabismus is developed as a child often there are no symptoms, but adults who develop a strabismus can often experience double vision. If it is not treated a strabismus can lead to amblyopia and reduced binocular vision function.