How Is Dyslexia Diagnosed? What Most Parents Don’t Know About Misdiagnosis and Binocular Vision Dysfunction
- Dr. Kalie McCartin
- 6 days ago
- 3 min read
When a child struggles with reading, attention, letter reversals, or school performance, the first thought many parents and teachers have is dyslexia. Naturally, the next step is to schedule a dyslexia evaluation. But there’s a critical problem:
Dyslexia tests do not evaluate for Binocular Vision Dysfunction (BVD)—a condition that causes nearly all the same symptoms as dyslexia.
Even more concerning:👉 Double vision (a hallmark symptom of BVD) is never checked in a dyslexia test.👉 Anyone with double vision would fail a dyslexia test—even if they are not dyslexic.👉 BVD is over 50% more common than dyslexia and goes undiagnosed in over 90% of children and adults who have it.
Why You Should Never Schedule a Dyslexia Evaluation Before an Eye Teaming Exam
This point cannot be emphasized enough:
BVD is more than 50% more common than dyslexia.
BVD goes undiagnosed in over 90% of cases.
And dyslexia tests never check for BVD.
This means thousands of children and adults every year are:
Labeled dyslexic
Given reading tutoring
Placed in special academic programs
Told they have a permanent disability
…when the true cause is an eye coordination issue that can be treated.
If double vision is present, the individual will
automatically fail a dyslexia test, because:
Their eyes cannot point at the same place
Letters blur or overlap
The brain suppresses one eye to cope
Tracking becomes unstable
Visual confusion disrupts comprehension
A dyslexia diagnosis made under these conditions is not reliable.
What Most People Don’t Know: Dyslexia and BVD Share Nearly Identical Symptoms
Before diving into how dyslexia is diagnosed, it’s crucial to understand why dyslexia is so often misdiagnosed, especially in children.
Typical Symptoms of Dyslexia
Difficulty reading or sounding out words
Letter reversals
Poor spelling
Slow reading speed
Avoiding reading
“Losing place” on the page
Low reading comprehension
Symptoms of Binocular Vision Dysfunction (BVD)
Double or overlapping vision
Skipping lines while reading
Headaches or eye strain
Difficulty focusing
Fatigue when reading
Poor comprehension
Words appearing to “move” or “jump”
Trouble tracking from line to line
These symptoms overlap almost perfectly.That’s why so many parents pursue dyslexia testing—and end up with a diagnosis that doesn’t address the true problem.
How Is Dyslexia Diagnosed? (And What the Tests Don’t Check)
A typical dyslexia evaluation includes:
Cognitive and phonological awareness testing
Reading fluency tests
Spelling and decoding assessments
Working memory evaluations
These tools help measure how efficiently the brain processes language.
But here’s the issue:
❌ Dyslexia tests do NOT evaluate:
Eye teaming
Eye alignment
Convergence insufficiency
Double vision
Tracking accuracy
Visual processing speed
Eye movement control (pursuits and saccades)
A child can have perfect phonological skills—yet fail every reading test simply because their eyes cannot coordinate well enough to read comfortably.
This leads to an incorrect—but common—outcome:👉 Dyslexia misdiagnosed as a learning problem rather than a binocular vision problem.
How We Identify the Real Cause: Developmental Vision + Visual Processing Exams
At the Visual Processing Institute, we do something very few clinics in California provide:
⭐ Comprehensive developmental vision exams
These include:
Eye alignment testing
Tracking and saccade analysis
Convergence and divergence evaluation
Double-vision screening
Eye teaming stability assessments
Visual processing diagnostics
Binocular vision stress tests using computerized technology
We also assess visual processing skills that directly affect learning:
Visual memory
Visual discrimination
Visual–motor integration
Spatial awareness
Visual figure–ground
Our clinics are equipped with the largest and most advanced vision therapy technology suites in California, offering far deeper diagnostics than standard eye exams or school-based assessments.
The Visual Processing Institute Advantage
We are proud to be:
🥇 The largest vision therapy provider in California
🖥️ The most technologically advanced clinics in the state
💰 The lowest-priced program in California (as low as $123.33 per session)
🚀 The fastest graduation rates and the highest success stories
Families choose us because:
We identify issues other clinics miss
Our programs are custom-built for each child or adult
Our outcomes are faster and more consistent
We provide transparent, research-based care
The Bottom Line: Don’t Get a Dyslexia Evaluation Until BVD Has Been Ruled Out
If your child—or you—are struggling with reading, attention, or comprehension:
👉 Rule out Binocular Vision Dysfunction FIRST.👉 It’s more than 50% more common than dyslexia.👉 It is missed in over 90% of cases.👉 And dyslexia tests never check for it.
A developmental vision exam can save years of frustration, misdiagnosis, and ineffective tutoring.
Schedule a Developmental Vision Exam Today
If you live near Newport Beach, Torrance/South Bay, Rolling Hills Estates, Palos Verdes, West LA, San Juan Capistrano, Laguna Niguel, Coto de Caza, Ladera Ranch, Bel Air, or Culver City, we are here to help.
Your child’s difficulties may not be dyslexia at all—they may simply need their visual system evaluated.