Glossary | Envision


Accessibility Conformance

When a resource satisfies all the requirements of a given standard, guideline or specification.


The design of products and environments for people with disabilities. This is about making things accessible to all people (whether they have a disability or not). Examples include wheelchairs, entryway ramps, hearing aids, and braille signs, text, font, building design and much more. In the IT world, accessibility often describes hardware and software designed to help those who experience disabilities. Ensuring that your resources (devices, products, website, and software) are designed such that individuals with disabilities or sensory impairments can successfully use the resource.

Accessibility Conformance

When a resource satisfies all the requirements of a given standard, guideline or specification.

Accessibility  Monitoring

Process that ensures that a resource maintains compliance as new versions or content is released.

Accessibility Testing

Process that systematically evaluates the level of accessibility and usability of a digital resource.

Accommodative Estropia

Most common form of Strabizmus. Turning of an eye caused by overactive convergence response to the accommodative effort necessary to keep vision clear. More common in farsighted (hyperopic) children. Eyeglass correction for the hyperopia (farsightedness) relaxes accommodation, sometimes allowing the eyes to align. Basically the eyes are trying to accommodate to focus vision causing one or both to turn away from proper alignment. Some complications include eye fatigue, issues with depth perception, loss of 3-D vision, and possible amblyopia (loss of vision in effected eye).


A congenital anomaly. It presents as an incomplete formation of the iris. It is associated with glaucoma, nystagmus, sensitivity to light, and poor vision.

Age-related Macular Degeneration

An eye disease that affects central vision. It is caused by deterioration of the macula, the central part of the retina that is essential for sharp, central vision.

Americans with Disabilities Act (ADA)

Prohibits discrimination against people with disabilities in several areas, including employment, transportation, public accommodations, communications and access to state and local government’ programs and services.

Anti-Vascular Endothelial Growth Factor Treatments  (Anti-VEGF)

The use of pharmaceuticals that block vascular endothelial growth factor in eye diseases such as Age-Related Macular Degeneration and Diabetic Macular Edema.

Assistive Technology

Assistive Technology is any item, piece of equipment, or product system, whether acquired commercially off the shelf, modified, or customized, that is used to increase, maintain, or improve functional capabilities of individuals with disabilities. It can be as simple as a pencil grip or as complex as an adapted computer system.

Assistive Technology

Hardware and/or software that acts as a user agent, or along with a mainstream user agent, to provide functionality to meet the requirements of users with disabilities that go beyond those offered by mainstream user agents. Some examples include screen magnifiers, screen readers, speech recognition software, or alternative keyboards.


Pertaining to people who are Blind or Visually Impaired

Bilateral Coloboma

Coloboma describes a condition where normal tissue in or around the eye is missing at the time of birth. Can affect one or both eyes, (bilateral means both sides). This basically translates into a hole in one or more of the structures of the eye. Because it is bilateral does not mean both eyes are affected the same way. In the student’s case in the ECDC the coloboma effects both eyes and includes the iris, retina, and optic nerve, according to her paperwork.

Central vision

Central vision is when our eyes focus straight ahead, allowing us to drive, read, and see details sharply. Central vision only covers about three degrees of our visual field, but it allows us to make very important judgments like estimating distance and understanding details in the path ahead.


The Orientation & Mobility Specialist (COMS) is a certified instructor who has received specialized training in teaching people who are blind or visually impaired to travel safely, gracefully and efficiently throughout their environments including indoor and outdoor, familiar and unfamiliar. An Orientation and Mobility Specialist teaches people who are blind and visually impaired specific skills they need to know where they are and how to move independently, safely, efficiently to where they want to be. Usually the O&M Specialist works with students individually.

Contrast sensitivity

The ability to distinguish between subtle gradations of light and dark. For example, seeing a white plate on a white tablecloth.

Cortical Vision Impairment

CVI is caused by neurological (brain) damage. This condition is difficult for educators because the eye itself shows no damage (in some cases). It can be caused by hypoxia (lack of oxygen to the brain), head injuries, abnormalities in brain formation, hydrocephalus (increased fluid and pressure in the brain), seizures, metabolic diseases, infection, and neurological disorders. For students with CVI implications are very individualized. Clutter or loud busy patterns disrupt usable vision if present. Something to keep in mind when working with CVI students is to wear solid colored clothing and keep jewelry to a minimum the more clutter on you the worse it is for the student.

Diabetic Retinopathy

An eye disease that results from diabetes. Because of excess blood sugar, diabetic retinopathy damages small blood vessels lining the retina, the light sensitive tissue at the back of the eye, impairing vision.


Any condition that makes it more difficult for a person to do certain activities or interact with the world around them. These conditions, or impairments, may be cognitive, developmental, intellectual, mental, physical, sensory, or a combination of multiple factors.


The condition of having or being composed of differing elements, especially, the inclusion of different types of people (such as people of different races or cultures, abilities) in a group or organization

Eccentric Fixation

A monocular phenomenon in which the eye utilizes a portion of the retina other than the fovea for fixation.

Expressive arts

Is a discipline of helping and healing that uses the arts as its basis for discovery and change


A group of diseases characterized by an increase in the pressure inside the eye that can damage the optic nerve and retinal nerve fibers. The effects can include visual field defects, hazy appearance to eyes, large eyes, as well as other anatomical effects.

Guide Techniques

These techniques are used to assist a visually impaired or blind person reach a destination while walking. The individual being assisted will generally grasp the guide above the elbow and travel together.

Homonymous Hemianopsia

A condition in which a person sees only one side―right or left―of the visual world of each eye. Typically caused by a stroke or brain injury.

Inclusive Workplace

A deliberate effort to create an environment where everyone is respected and empowered to contribute equally and supported with access to the same resources and opportunities.


The quality or state of being inclusive


Serving or intending to unify separate things.


Influencing or having an effect on each other.


Colored portion of the eye that controls the amount of light that enters the eye by controlling the size of the papillary opening.

Joubert Syndrome

Characterized by central nervous system defects, retinal dystrophy, severe psychomotor problems, and breathing problems. The visual effects are like Leber’s congenital amaurosis which is characterized by blindness or near-blindness in both eyes; may also experience nystagmus, sensitivity to light, and sunken eyes.

Kinetic Art

Art from any medium that contains movement perceivable by the viewer or depends on motion for its effect. Of or relating to the motion of material bodies or any form of art from any medium that contains movement perceivable, and the forces and energy associated therewith

Leber’s Congenital Amaurosis

An eye disorder that primarily affects the retina, which is the specialized tissue at the back of the eye that detects light and color. People with this disorder typically have severe visual impairment beginning in infancy.

Legal Blindness

Legal blindness in the USA means visual acuity of 20/200 or worse with the best possible correction, or a visual field of 20 degrees or less.

Long Cane Travel

A visually impaired or blind person will utilize a long thin cane to travel safely and efficiently. The long cane gives the person tactile feedback as they walk to destinations.

Low Vision

Low vision is a condition caused by eye disease, in which visual acuity is 20/70 or poorer in the better-seeing eye and cannot be corrected or improved with regular eyeglasses.


Relating to or involving several physiological senses


Nearsightedness; objects close up may be clear but objects in the distance are blurry. This is a refractive error and is often correctable with glasses or contacts.

Neuro-Optometric Rehabilitation

An individualized treatment regimen for patients with visual deficits as a direct result of physical disabilities, traumatic brain injuries, and other neurological insults. Neuro-optometric therapy is a process for the rehabilitation of visual / perceptual / motor disorders. It includes, but is not limited to, acquired strabismus, diplopia, binocular dysfunction, convergence and/or accommodation paresis/paralysis, oculomotor dysfunction, visual-spatial dysfunction, visual perceptual and cognitive deficits, and traumatic visual acuity loss.


Involuntary rhythmic movement of the eye that are generally faster in one direction than they are in the other. They are typically up and down OR side to side.

Occupational Therapy

A profession that helps people across the lifespan to do the things they want and need to do through the therapeutic use of daily activities (occupations). Occupational therapy practitioners enable people of all ages to live life to its fullest by helping them promote health, and prevent—or live better with—injury, illness, or disability.

OD “oculus dexter”

RE—right eye


Medical doctors who specialize in the treatment of diseases and conditions of the eye and visual system that cause visual impairment.

Optic Nerve Hypoplasia

The optic disk in the eye is smaller than usual, due to underdevelopment of optic nerves that transmit impulses to the brain. Symptoms can include nystagmus and vision can range from no light perception to good functional vision or even full vision in one eye.

Optical Coherence Tomography (OCT)

OCT is an imaging method used to generate a picture of the back of the eye, called the retina. The picture is made by precisely measuring the amount of a dim red light that reflects off the retina. OCT is useful in diagnosing many eye conditions, including: macular hole, macular pucker, macular edema, age-related, macular degeneration, glaucoma, central serous retinopathy and diabetic retinopathy.


Eye professionals that provide a wide range of eye care services, including comprehensive eye health and vision examinations, diagnosis and treatment of eye diseases and conditions, prescription of eyeglasses, contact lenses and medications, low vision rehabilitation services and vision therapy.

Orientation and Mobility Training

A visually impaired or blind individual is trained to utilize a long cane for tactile feedback, and to combine this information with auditory cues and clues, to reach destinations safely and efficiently.

OS “oculus sinister”

LE—left eye

OU “oculus uterque”

Both eyes

Peripheral vision

The peripheral vision or indirect vision is the side vision of the eye that allows an individual to view the objects around them, without the need to turn their head or move their eyes. Peripheral vision helps view objects and scenes that lie outside of the central vision.

POUR Principles

Accessibility principles that help put people at the center of the process. The acronym POUR which guides the Principles stands for: Perceivable (can people input the information into their brain so they can process it), Operable (can people navigate using various input methods), Understandable (can people process and create predictable patterns with the information provided), and Robust (can people access the content on their device of choice).


Involving both psychological and social aspects as it relates to social conditions to mental health

Refractive Amblyopia Hyperemia

Was previously referred to as “lazy eye”; it is a functional defect characterized by decreased vision in one or both eyes without detectable anatomic damage to the retina or visual pathways. It is usually uncorrectable by optical means.

Retinitis Pigmentosa

A group of inherited eye diseases that cause degeneration of the retina and progressive vision loss. It is variable in severity but can cause total loss of vision in some individuals. It often starts with night blindness and causes tunnel vision.


Malignant intraocular tumor that develops from the retinal visual cells. When left untreated, seedling nodules produce secondary tumors that gradually fill the eye and extend along the optic nerve to the brain, ending in death. This is the most common childhood malignancy. It is most commonly treated by removal of the affected eye, followed by chemotherapy.

Retinopathy of prematurity

Series of destructive retinal changes that may develop after prolonged life-sustaining oxygen therapy is given to premature infants. When in active stages can include dilated twisted peripheral blood vessels, retinal hemorrhages, and abnormal newly formed blood vessels. This condition can regress, or form a fibrous scar that detaches the retina, which will result in vision loss. Other complications associated with ROP include glaucoma, cataracts, myopia, sunken eyes, or eye misalignment.


Often referred as a central “blind spot”-an area on the retina that does not “see” light as well as a normal, healthy retina does. Common with macular degeneration and diabetic retinopathy.

Screen reader

A software program that allows people who are blind or visually impaired to read the text that is displayed on the computer screen with a speech synthesizer or braille display.


Is the branch of the visual arts that operates in three dimensions and of all materials and processes.


The Envision Mission is to improve the quality of life and provide inspiration and opportunity for people who are blind or visually impaired through the following SERVICES – Employment, Outreach, Rehabilitation, Education, Education and Research.


Eye misalignment or eyes that do not move normally, caused by extraocular muscle imbalance. One fovea (central pit in the macula that produces sharpest vision) is not directed at the same object as the other.

Support Programs

Social and personal enrichment activities for all people of all ages who are blind or visually impaired that promote creative expression, athletic opportunities, academic success and more.

Systemic/Ocular  Disease (SD)

The study of the relationship of any anomaly of normal function of the human body and the possible manifestation of such as signs and/or symptoms in the eye or visual system.


Designed to be perceived by touch, of, relating to, or being the sense of touch.

Therapeutic Arts

Helps to heal or to restore health through the arts.


Giving the illusion of depth or varying distances —used especially of an image or a pictorial representation on a two-dimensional medium when this illusion is enhanced by stereoscopic means

Treatment & Management of Ocular Disease: Posterior Segment (PS)

The study of the etiology, clinical pathophysiology, diagnosis, treatment, management, and outcomes of therapeutic regimens for anomalies of the posterior segment of the human eye. Examples: Degenerative, infective, and vascular diseases of the retina/choroid/sclera and optic nerve, inclusive of all aspects of surgical care involving the posterior segment of the eye, i.e., retinopathies, neuropathies, retinal laser surgery, retinal detachment surgery.

Treatment & Management of Ocular Disease: Anterior Segment (AS)

Anterior Segment (AS): The study of the etiology, clinical pathophysiology, diagnosis, treatment, management, and outcomes of therapeutic regimens for anomalies of the anterior segment of the human eye. Examples: Keratitis, anterior uveitis, conjunctivitis, blepharitis, lid anomalies, foreign body removal, etc.


A Teacher of Students with Visual Impairments (TSVI) (also called a Teacher of the Visually Impaired, a vision specialist, VI teacher, vision itinerant teacher, etc.) is typically a licensed special education teacher who has received certification and specialized training, in meeting the educational needs of students who are blind or have visual impairments ages birth through 21 (states vary on the criteria for certification as a Teacher of Students with Visual Impairments). This is an instructional position, as opposed to a related service or vision therapy.


Refers to the ease of use of any website or technology made possible by user-friendly and accessible design. Usability is just as important as accessibility.

Vision Impairment

Eyesight cannot be corrected to “normal” vision. Is defined as a decreased ability to see to a degree that causes problems not fixable by usual means, such as glasses or medication. It can limit a person’s ability to perform everyday tasks and can affect their quality of life and ability to interact with their world.

Vision Loss

Vision loss is an eyesight condition where you start to lose your ability to see things clearly. It can occur rapidly or over a period of time. Also commonly known as an impairment of vision, it can be caused due to various eye diseases or some form of damage to your eye. Not restricted to one eye, many individuals may experience vision loss at different rates in each eye, which may allow them to function quite normally with one eye until the second eye begins to lose function as well. Low vision can potentially handicap a person in performing day to day activities such as reading, driving, or recognizing faces.

Vision Rehabilitation

A service where specialists work with individuals to help them understand their vision and to maximize remaining vision by creating a plan that tailored to a person’s unique challenges, needs and goals.

Visual Acuity

Visual acuity is a number that indicates the sharpness or clarity of vision. A visual acuity measurement of 20/70 means that a person with 20/70 vision who is 20 feet from an eye chart sees what a person with unimpaired (or 20/20) vision can see from 70 feet away. An eye chart measures visual acuity. The top number is your distance in feet from the chart. The bottom number is the distance at which a person with normal eyesight can read the same line.

Voluntary Product Accessibility Template (VPAT)

A document that explains how information and communication technology (ICT) products such as software, hardware, electronic content, and support documentation meet (conform to) the Revised 508 Standards for IT accessibility. VPATs help Federal agency contracting officials and government buyers to assess ICT for accessibility when doing market research and evaluating proposals.

Web Content Accessibility    Guidelines (WCAG)

Covers a wide range of recommendations for making Web content more accessible. Following these guidelines will make content accessible to a wider range of people with disabilities, including blindness and low vision, deafness and hearing loss, learning disabilities, cognitive limitations, limited movement, speech disabilities, photosensitivity and combinations of these.