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Vision vs. Sight - What Parents Need to Know

Melissa Taylor

If your child has passed a vision screening, that's not enough. You still need a comprehensive vision checkup. Here's why.

“Your child’s brain is like a computer,” says Dr. Hellerstein, author of See It. Say It. Do It! The Parents & Teacher's Action Guide to Creating Successful Students & Confident Kids and developmental optometrist O.D. FCOVD, FAAO. “The better the quality of the information that his eyes take in, the better his brain will be able to process that information.”

Vision is the brain activity; sight is the eye's work. Two different things. just like your dental checks, your child needs a comprehensive vision check early -- two years old and up. Even if a child's vision is fine, sight might be a problem. Find out early so you can prevent learning problems down the road.

Dr. Lynn F. Hellerstein explained vision to me this way: the keyboard is the input, the hard drive is the processing, and the printer is the output. Vision checks can evaluate all of these brain processes.  Academic success, says Hellerstein, requires 17 different visual skills and seeing 20/20 is just one of them. If there's an issue -- like dyslexia, double vision, focusing problems, visual processing problems, messy handwriting, poor sequencing skills, or poor visual memory -- a qualified developmental optometrist like Dr. Hellerstein will be able to find out with a comprehensive exam. 

What can you expect in a comprehensive exam? Dr. Jina Schaff, O.D. shares what to expect:

  1. Case history: including school performance, reading, spelling, and math, and medical.
  2. Pursuits/Saccades: How a child smoothly follows a target (pursuits), and how they can jump from one target to the next (saccades).  This represents tracking from left to right and the return sweep from right to left.
  3. Near point of Convergence: Can a child follow a target in to their nose and keep the target single. (When we look at our book or any near target we converge.)
  4. Stereopsis (depth perception): This tells me if the child is using both eyes at the same time (this assesses strabismus and amblyopia).
  5. Color Vision: I check this on all children, but color vision primarily affects boys. 
  6. Refractive Exam: Prescription: I can use a retinoscope and lenses to determine a child's prescription without the child saying a word.  I use that measurement and compare it to what the child subjectively picks (if they are old enough to understand the test). [This exam includes phorias, ranges, focusing skills and results in a treatment plan.]

Schaff wants parents to understand how vision affects reading saying, "When we read, we have three motor movements before we can process what we are reading. We have to 1) converge-aim our eyes at the target, 2) focus-make the print on the page clear, and then 3) track along the page. If any of those motor movements are deficient, you will work twice as hard to read. If your brain is focused on the motor movements there is little left for comprehension. This will impact the child's performance in school."

August is National Children’s Vision & Learning Month. Make sure your child is visually ready to go back to school. Get more than a vision screening, get a vision check that tests all of the essential visual skills mentioned above. To find a developmental optometrist in your area visit

I just learned this and my kids are seven and ten. Did you know this information? Have you ever taken your child for a comprehensive sight exam?