Experts differ on the ages after which amblyopia treatment ceases to be effective, however, most studies show and most experts agree that the earlier treatment begins, the better the likely outcomes. Some studies have shown treatment after ages 6 or 7 largely ceases to be effective, while others believe treatment can be effective up to the ages of 9 or 10, by which time a child’s visual system is normally fully developed. But some studies by the National Institutes of Health (NIH) have demonstrated that even teenagers up to the age of 17 may still benefit from amblyopia treatment. Because early treatment is so important, it is best to screen a child early. If the child is being screened while they are pre-verbal and still too young to use an eye chart, then using a photoscreener such as iScreen Vision, can be an ideal way to perform pediatric vision screening or vision testing for amblyopia or lazy eye.