Mention a visual processing disorder (VPD) and the first thing a parent will say is, “But the eye doctor said he has 20/20 vision!” A person can have perfect focus but still have a visual processing disorder. This is because the problem with a visual processing problem is not in the lens of the eye or the retina. The problem lies in the brain and how it processes the information that is seen.

How is a visual processing disorder diagnosed?

Optometrists and ophthalmologist generally do not assess for visual processing issues, and this is the reason you can take your child over and over and still get a clean bill of health. I’ve talked to children who insist the words are blurry when they read, but will still have 20/20 vision in an eye exam.

Behavioral optometrist are the ones who can assess and diagnose visual processing issues. They have specialized training to add this diagnostic process to their repertoire. Once diagnosed, they can then suggest vision therapy or special glasses to help the problem.

It’s important to note that while the child may be struggling, they may never bring it to your attention. For them it is how things have always been so they don’t know it can be different. So even though the struggle is great, the child will simply persevere instead of asking for help.

Types of visual processing disorders

Eye-tracking difficulties
When you read, the left-to-right movement of your eyes is called a saccade. This is one of the most complicated muscle movement the body makes, and eye tracking problems occur when one or both eyes have a problem moving smoothly or in synch in this side-to-side motion. When an eye tracking issue occurs while reading, the eyes often jump back and forward, moving sometimes two or three times as much as necessary.

Symptoms of eye tracking difficulties in school include:

• Fatigues quickly when reading
• Uses finger to try and keep place on a line
• Loses place in the text
• Strong resistance to reading
• Skipping words when reading
• Skipping lines when reading
• Guessing words
• Easier to read when the font is large
• Slow, halting reading pattern
• Rubs eyes, squints a lot or eyes water
• Keeps looking away when trying to read
• Headaches
• Fidgety when reading
• Tilts head when reading

Symptoms of eye tracking difficulties outside of school:

• Avoids activities that require good depth perception
• Avoids eye contact
• Difficulty catching or hitting a ball
• Fear of riding a bike without training wheels
• Clumsiness
• Frequent spills or bumping into objects
• May have difficulty with handwriting

Convergence Issues
Convergence describes a condition when the eyes focus either in front or beyond an object. This is not a problem with the physical eye but a neurological problem. An eye chart test does not screen for this effectively. In short periods of time, the eye and brain can adjust for this and recognize shapes of letters. This allows a patient to pass the test.

Symptoms of convergence in school:

• Complain that reading is tiring or that the letters look blurry.
• Procrastinate in reading or read slowly but never complain.
• Confuse letters that look similar because the focus is poor e.g. lower case w vs. lower case v.
• Have issues writing letters correctly or writing letters at the appropriate size.
• Tire easily when reading or writing.
• Squint or shift their heads when trying to focus.

Symptoms of convergence outside of school:

• Avoid doing activities that require comprehending written instruction or reading.
• Avoid or struggle with issues that require hand-eye coordination such as throwing a ball or riding a bike.
• Stumble or hesitate when the terrain is uneven or when they climb stairs.
• Have headaches, dizziness or abnormal fatigue after activities that require focusing for a moderate amount of time.

Strabismus
Strabismus is a condition often described as wandering eye. It results from imbalances in the muscles that control eye movement. Over time, a child with strabismus will develop neurological vision issues that severely affect depth perception. Sometimes the strabismus is intermittent, meaning it comes and goes. It’s easy to think you were seeing things or the child is just tired and that is why the eye turned in temporarily. Strabismus is not transitory. It is a medical condition that needs treatment.

Symptoms of strabismus in school:

• The obvious sign is when one eye turns a different direction than the other.
• Turn their heads when trying to focus or read.
• Complain that the letters are not clear when reading.
• Complain of double vision.
• Tire easily when doing work requiring visual concentration.
• Dysgraphia
• Respond better when images or text is larger

Symptoms of strabismus outside of school:

• Avoid or struggle with issues that require hand-eye coordination such as throwing a ball
• Avoid activities that require quick visual perception, such as riding a bike.
• Stumble or hesitate when the terrain is uneven or when they climb stairs.
• Have headaches, dizziness or abnormal fatigue after activities that require focusing for a moderate amount of time.
• Appear clumsy or accident prone due to poor depth perception.

Double vision
Double vision is an indicator of many possible issues. It can indicate convergence issues and strabismus as well as physiological issues.

Symptoms of double vision in school:

• Turn his or her head when trying to focus or read.
• Complain that the letters are not clear when reading.
• Tire easily when doing work requiring visual concentration.
• Shows signs of dysgraphia especially the inability to write words that he understands well in a verbal context.
• Shows signs of dyslexia, reversing letters and numbers.

Symptoms of double vision outside of school:

• Similar to symptoms of strabismus

Vision therapy can help VPD

The good news is that there are ways to help visual processing issues and in many cases they will disappear all together. The behavioral optometrist can provide a series of vision therapy sessions that will include exercises to improve the specific visual processing problem. According to the American Optometric Association, doctors find an 86% success rate with vision therapy. In cases where the correction is not 100%, the behavioral optometrist can prescribe special glasses that will often help the remaining issues.

To find a local behavioral optometrist, visit www.covd.org.

Recommended Reading:

• Fixing My Gaze: A Scientist’s Journey to Seeing in Three Dimensions by Susan R. Barry
• How Behavioral Optometry Can Unlock Your Child’s Potential by Joel H. Warshowsky
• Eyegames: Easy and Fun Visual Exercises by Lois Hickman and Rebecca Hutchins

Bonnie Landau

Bonnie Landau is a licensed professional clinical counselor and educational consultant in Ventura County, California. Her goal is to help parents of neurodivergent individuals find strategies and solutions to help their children succeed in school and in life. Bonnie is also the author of Special Ed Mom Survival Guide: How to Prevail in the Special Education Process and Find Life-long Strategies for You and Your Child.