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Behavioral Vision

A Vision Checklist

Look for these signs and symptoms

If you check off several items on the following checklist, consider a vision exam.

Please contact us to answer any of your questions and to schedule an appointment.

You experience or observe the following behavior:

  • one eye drifts or aims in a different direction than the other (this can be subtle). This is significant even if it only occurs when tired or stressed.
  • turns or tilts head to see
  • head is frequently tilted to one side or one shoulder is noticeably higher
  • squinting or closing or covering of one eye
  • excessive blinking or squinting
  • short attention span
  • daydreaming at school/work
  • poor handwriting
  • poor visual/motor skills (often called "hand-eye coordination")
  • problems moving in space, frequently bumps into things or drops things
  • clumsiness


While reading or doing close work:

  • holds the book or object unusually close
  • closes one eye or covers eye with hand
  • twists or tilts head toward book or object so as to favor one eye
  • frequently loses place and fatigues easily
  • uses finger to read
  • rubs eyes during or after short periods of reading
  • reversals when reading (i.e., "was" for "saw", "on" for "no", etc.)
  • reversals when writing (b for d, p for q, etc.)
  • omitting small words
  • confusing small words
  • transposition of letters and numbers (12 for 21, etc.)
  • loss of place when reading, line to line and word to word.
  • child's ability to learn verbally surpasses his ability to learn visually.


Frequent complains of:

  • only being able to read for short periods of time
  • headaches or eyestrain
  • nausea or dizziness
  • motion sickness
  • DOUBLE VISION!

Frequently Asked Questions

Vision therapy -- a type of physical therapy for the eyes and brain -- is a highly effective non-surgical treatment for many common visual problems such as lazy eye, crossed eyes, double vision, convergence insufficiency and some reading and learning disabilities. Many patients who have been told, "it's too late," or "you'll have to learn to live with it" have benefited from vision therapy.


In the case of learning disabilities, vision therapy is specifically directed toward resolving visual problems which interfere with reading, learning and educational instruction. Optometrists do not claim that vision therapy is a direct treatment for learning disabilities.


The first step in any Vision Therapy program is a comprehensive vision examination. Following a thorough evaluation, a qualified vision care professional can advise the candidate as to whether Vision Therapy would be appropriate treatment.

Convergence Insufficiency (CI) is the leading cause of eyestrain, blurred vision, double vision (diplopia), and/or headaches.

  • Convergence insufficiency is a common near vision problem that -- due to recent scientific research -- is gaining public recognition.
  • Convergence insufficiency disorder interferes with a person's ability to see, read, learn, and work at near (close distances).
  • In the past, convergence insufficiency disorder has often gone undetected because testing is not included in (1) pediatrician's eye tests; (2) school screenings; or (3) basic eye exams
  • A person can pass the 20/20 eye chart test and still have convergence insufficiency.
  • Treatments range from passive (prism lenses) to active (office-based vision therapy)
  • Scientific research by the National Eye Institute has proven that office-based vision therapy is the most successful treatment.
  • Home-based pencil pushups therapy appears to be the most commonly prescribed treatment5, but scientific studies have shown that this treatment is ineffective
  • Eye surgery is rarely, if ever, recommended
  • While clinical results show that Convergence Insufficiency can be treated at any age, current scientific research has been completed on the pediatric population only

If the two eyes are misaligned and aim at different targets, two non-matching images will be sent to the viewer's brain. When the brain accepts and uses two non-matching images at the same time, double vision results.


Double vision is dangerous to survival, so, the brain naturally guards against its occurrence. In an attempt to avoid double vision, the brain will eventually disregard one of the mismatching images. That is, the brain will ignore one eye (called suppression).


Due to the brain's ability to suppress one eye, a person's double vision can appear to go away without medical evaluation or treatment. Bear in mind that the causes of the double vision are very likely still present and that loss of vision in one eye has probably occurred due to lack of treatment. When vision in one eye is lost, the person has also lost normal depth perception and stereo vision. However, the loss of vision could be temporary and treatable.


Double vision is not a minor complaint! When double vision occurs, seek a complete visual evaluation from a specialist in binocular (two-eyed) vision.


There are two possible and different causes:

  1. The most common cause of double vision is misalignment of the two eyes due to functional problems in the visual system. This web page contains complete information on this type of double vision: binocular diplopia.
  2. A structural defect in the eye's optical system is a much less common cause of double vision. Cataracts, for example, might cause such a defect. In this case, diplopia can appear in only one eye; this is called monocular diplopia.

Amblyopia, commonly known as lazy eye, is the eye condition noted by reduced vision not correctable by glasses or contact lenses and is not due to any eye disease. The brain, for some reason, does not fully acknowledge the images seen by the amblyopic eye. This almost always affects only one eye but may manifest with reduction of vision in both eyes. It is estimated that three percent of children under six have some form of amblyopia.


Anything that interferes with clear vision in either eye during the critical period (birth to 6 years of age) can cause amblyopia. The most common causes of amblyopia are constant strabismus (constant turn of one eye), anisometropia (different vision/prescriptions in each eye), and/or blockage of an eye due to cataract, trauma, lid droop, etc.


Amblyopia is a neurologically active process. In other words, the loss of vision takes place in the brain. If one eye sees clearly and the other sees a blur, the brain can inhibit (block, ignore, suppress) the eye with the blur. The brain can also suppress one eye to avoid double vision. The inhibition process (suppression) can result in a permanent decrease in the vision in the blurry eye that can not be corrected with glasses, lenses, or lasik surgery.

Strabismus, more commonly known as cross-eyed or wall-eyed, is a vision condition in which a person can not align both eyes simultaneously under normal conditions. One or both of the eyes may turn in, out, up or down. An eye turn may be constant (when the eye turns all of the time) or intermittent (turning only some of the time, such as, under stressful conditions or when ill). Whether constant or intermittent, strabismus always requires appropriate evaluation and treatment. Children do not outgrow strabismus!


It is estimated that up to 5 percent of all children have some type or degree of strabismus. Children with strabismus may initially have double vision. This occurs because of the misalignment of the two eyes in relation to one another. In an attempt to avoid double vision, the brain will eventually disregard the image of one eye (called suppression).