The lack of development of clear vision, usually in just one eye. Because this condition is not due to an actual physical problem with the eye, glasses or contacts may not fully correct the vision in that eye. Amblyopia is best treated very early in life, as the prognosis for recovery of clear vision decreases with age. Signs to watch for in children include squinting or closing one eye to see, poor depth perception, an eye turning inward or outward, poor vision in one eye, or headaches. The condition is common; approximately two or three out of every 100 people has Amblyopia.