Posted on July 17, 2017
Checking Vision in Young Children
By: Jeffrey Colburn, MD
Many a parent has wondered how we check vision on their young children. A few on patient satisfaction surveys have even commented that we must be guessing at their child’s visual performance. When we think of measuring visual performance we usually think of reading off letters or symbols on an eye chart. For adults and older children, measuring visual acuity on an eye chart is usually fairly straightforward and accurate. But for infants, toddlers, and pre-reading pre-schoolers it is definitely more challenging.
(Note that this discussion is different than how we check small children for their glasses measurements. For more information on that, see Dr. Weed’s video on retinoscopy on our Facebook page).
For newborns, vision is still fairly blurry and we mostly note whether the infant reacts to bright lights and assure that there are no structural problems with the eye. Over the first few months of life, we can start to watch for other clues of normal vision development. A newborn’s brain is programmed to fixate (look directly ) at their mother’s face and then other faces early, so observing this is a good sign. They will later start fixating on other objects of interest around them such as toys, lights, etc. We will note how well they “fix and follow” with each eye.
Most infants are seeing fairly normal by about 6 months of age, though of course we aren’t able to measure this on an eye chart yet. The most important assessment of vision during the early months and years is whether the child is developing equal vision between the eyes. This can be checked by doing a prism test in the office that makes the child see double when looking at a target toy or other object and observing whether they will choose to use the eyes equally or always favor one over the other.
As a child is getting older, often around the age of 3, but sometimes earlier or later, we can start to truly measure visual acuity by doing matching games on the eye chart with either symbols of letters. By using easily recognizable letters and doing matching, even children who do not yet know their letters can participate. If this testing is done carefully and correctly, the measured vision on the eye chart is actually quite accurate. Don’t worry if your young child does not measure 20/20 on the eye chart right away. They could still be in the normal range for their age and will continue to improve over time. Ask your eye doctor if you aren’t sure or are worried about their vision testing results. Thereafter, by early grade school, things get easier and most children are able to cooperate and help us accurately measure their vision.