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3D Vision Vocabulary

VISION:The act of perceiving and interpreting visual information with the eyes, mind, and body.

BINOCULAR:Of or involving both eyes at once

BINOCULAR VISION:vision as a result of both eyes working as a team; when both eyes work together smoothly, accurately, equally and simultaneously.

STEREO VISION: (stereopsis or stereoscopic vision): a byproduct of good binocular vision; vision wherein the separate images from two eyes are successfully combined into one three-dimensional image in the brain. For the complete scoop, see the illustrated page on Stereo Vision!

BINOCULAR DEPTH PERCEPTION:a result of successful stereo vision; the ability to visually perceive three dimensional space; the ability to visually judge relative distances between objects; a visual skill that aids accurate movement in three-dimensional space.

BINOCULAR VISION DISABILITY:A visual defect in which the two eyes fail to work together as a coordinated team resulting in a partial or total loss of binocular depth perception and stereoscopic vision. At least 12% of the population has some type of binocular vision disability. Amblyopia and strabismus are the most commonly known types of binocular vision disabilities. To find out more about these visual conditions, see What is a binocular vision impairment?.

AMBLYOPIA ("lazy eye"):   a visual defect that affects approximately 2 or 3 out of every 100 children in the United States. Amblyopia involves lowered visual acuity (clarity) and/or poor muscle control in one eye. The result is often a loss of stereoscopic vision and binocular depth perception. Vision therapy can benefit this condition, but early detection is very important. For many years, it was thought that amblyopia (lazy eye) was only amenable to treatment during the "critical period". This is the period up to age seven or eight years. Current research has conclusively demonstrated that effective treatment can take place at any age, but the length of the treatment period increases dramatically the longer the condition has existed prior to treatment. Research has also demonstrated that patients with amblyopia are more likely to sustain injuries resulting in the loss of their good eye than individuals with two good eyes. There are many reasons that early childhood eye examinations are essential. See the Directory of Vision Care Providers for a free referral to an eye doctor who offers comprehensive eye examinations.

STRABISMUS ("crossed eye", "wall eye", "wandering eye", esotropia, exotropia, hyperphoria): affects approximately 4 out of every 100 children in the United States. It is a visual defect in which the two eyes point in different directions. One eye may turn either in, out, up, or down while the other eye aims straight ahead. Due to this condition, both eyes do not always aim simultaneously at the same object. This results in a partial or total loss of stereo vision and binocular depth perception. The eye turns may be visible at all times or may come and go. In some cases, the eye misalignments are not obvious to the untrained observer. To learn more about the treatment of strabismus, go to

VISION THERAPY: (also known as vision training): therapy involving exercises which are aimed at improving visual skills such as, eye teaming, binocular coordination and depth perception, focusing, acuity (clarity of sight), and "hand-eye" or "vision-body" coordination. Vision therapy can involve a variety of procedures to correct neurophysiological or neurosensory visual dysfunctions. Practiced by optometrists. See What is Vision Therapy? for more information.

ORTHOPTICS:The eye muscle training techniques of orthoptics are included within vision therapy. Orthoptics specifically treat eye teaming skills and visual acuity and do not treat other visual dysfunctions which are addressed by vision therapy procedures. Orthoptics first became popular in Europe in the 1900s. David Wells, M.D., an ophthalmologist at Boston University, is credited with introducing orthoptics to the U.S. in 1912. Orthoptics are still practiced by a small percentage of optometrists, ophthalmologists and orthoptic therapists. Learn more about orthoptics at Frequently Asked Questions for more information.

BEHAVIORAL OPTOMETRY:an international branch of optometry which specializes in the practice of vision therapy. Behavioral optometrists (also called developmental optometrists) will sometimes consider how environmental, nutritional and/or behavioral factors affect visual health.

OPTOMETRIST:a doctor of optometry who diagnoses and treats visual health problems as dictated by state law. In most states, optometrists are licensed to examine visual health, prescribe glasses and contact lenses, fit special devices for vision-impaired individuals, treat some eye diseases, prescribe some drugs and perform vision therapy. See FAQs for more information.

OPHTHALMOLOGIST:A doctor of medicine (M.D.) specializing in diseases of the eye and surgery. See FAQs for more information.

Frequently: misspelled words: developmental ophthalmologists, opthamology, opthamologists, opthalmologists, pediatric opthalmologist, pediatric ophthalmologists, pediatric ophthalmology, pediatric optometrist.

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Magic Eye How to See 3D copyright © 1995; Out-of-Print
by Magic Eye, Inc. and Rachel Cooper, Advocate of Vision Therapy Eye Exercises for Lazy Eye.
All other images and text: copyright © 1996- by Rachel Cooper. All rights reserved.