Reduced vision in one eye may occur due to several factors. Amblyopia or lazy eye is the most common cause. It’s an early childhood condition in which vision in one eye is impaired because the eye is not receiving adequate visual stimulation. It usually happens because the brain favors the other eye. Both eyes can also be affected. Often, amblyopia is avoided if the underlying problem is treated before the child reaches six years. It’s essential to see an ophthalmologist for proper diagnosis and treatment.