Amblyopia is when 1 eye has poorer vision than the other perhaps due to anisometropia (asymmetrical prescription), uncorrected prescription, or strabismus (eye turn) causing the connection between the eye and the brain to deteriorate.  To prevent permanent vision loss it is imperative to give vision correction, vision therapy, patch treatment, or surgery before the age of 7/8 years of age as it is difficult to retrieve vision after this age even with glasses.