Achromotopsia - cone malformation, macular deficiency, partial or total absence of cones;

Impact: difficulty or inability to see color, decrease detail vision, decreased visual acuities, photophobia, nystagmus, macular deficiencies

 

Albinism - total or partial lack of pigment abnormal optic nerve development and lack of pigment in skin and hair;

Impact: causes decrease visual acuity, photophobia, high refractive error, astigmatism, nystagmus

 

Amblyopia - reduced visual functioning in one eye with no definitive cause for the loss;

Impact: monocularity, visual field deficits, poor depth perception

 

Aniridia - total or partial absence of the iris (related to Wilm’s Tumor);

Impact: decreased visual acuity, photophobia, visual field loss, cataracts and glaucoma are common

 

Anophthalmia - absence of one or both eyeballs;

Impact: total blindness if both eyes are affected

 

Aphakia - absence of the lens, usually caused from surgical removal of cataract;
Impact: depth perception, visual acuity loss, visual field deficits

 

Astigmatism - defect in the curvature of the cornea;

Impact: blurred vision

 

Cataracts - opacity or cloudiness of the lens which restricts light entering the back of the eye;

Impact: reduced visual acuity, blurred vision, poor color vision, photophobia

 

Coloboma - a notch or cleft in the pupil, iris, ciliary body, lens, retina, choroid or optic nerve - a keyhole pupil can occur;

Impact: decreased acuity, photophobia, nystagmus, strabismus, field loss

 

Cortical Visual Impairment - damage to the visual cortex or the posterior visual pathways, typically is in combination with other brain injury;

Impact: fluctuation in vision, inattention to visual stimuli, difficulty deciphering visual information; vision may improve over time

 

Enucleation - surgical removal of the eye;

Impact: loss of one eye causes depth perception issues

 

Glaucoma - increased pressure in the eye because of blockage in the normal flow of fluid;

Impact: fluctuating visual functioning, peripheral field loss, poor night vision, photophobia

 

Hyperopia (Farsighted) - refractive error when the focal point for light rays fall behind the retina; the eyeball shape is shorter than typical;

Impact: difficulty seeing at close distances

 

Keratoconus - cornea becomes cone shaped;

Impact: decreased distance vision, astigmatism, sensitive to glare, visual field deficits, cornea can rupture

 

Leber’s Congenital Amaurosis - form of retinitis pigmentosa causing macular degeneration, progressive central field loss;

Impact: central and peripheral field loss, color vision loss, nystagmus, rubbing of eyes is typical

 

Macular Degeneration - degeneration to the central part of the retina;

Impact: central vision loss, photophobia, color vision loss

 

Microphthalmia - birth defect causing one or both eyes to be abnormally small;

Impact: decreased visual acuity/no vision photophobia

 

Myopia (Nearsighted) - refractive error when the focal point falls in front of the retina; the eyeball shape is longer than typical;

Impact: difficult seeing at distances; can be degenerative, high myopia is high risk for retinal detachment

 

Nystagmus - involuntary eye movements which may be horizontal, vertical, circular or mixed;

 

Impact: inability to maintain fixation, reduced acuity, eye fatigue

 

Optic Atrophy/Optic Nerve Atrophy - inability to conduct electrical impulses to the brain which causes vision loss, pale optic disc causing loss in pupil reaction;
Impact: fluctuating vision, color and night vision decrease, photophobia

 

Optic Nerve Hypoplasia - optic nerve head appears small and pale;

Impact: decreased visual acuity varying from light perception to normal vision, possible visual field deficits, nystagmus

 

Ptosis - drooping of the eyelid;

Impact: reduced visual field, may cause amblyopia

 

Retinal Detachment - parts of the retina detach from the blood supply in the eye;
Impact: field loss, decreased acuity, blind spots, maybe central, peripheral or both

 

Retinitis Pigmentosa - degenerative disorder causing increased vision loss starting in the periphery;

Impact: peripheral field loss, tunnel vision, night blindness, reduced visual acuity, photophobia

 

Retinoblastoma - cancer of the eye occurring in early childhood which may require enucleation (removal) of the eye;

Impact: varying vision depending on treatment

 

Retinopathy of Prematurity - atypical retinal blood vessel development in premature infants which can cause bleeding, scarring and retinal detachment, can range from minimal to total blindness;

Impact: decreased visual acuity, blind spots, severe myopia, possible field loss, possible glaucoma

 

Septo-Optic Dysplasia Syndrome (DeMosier Syndrome) - optic nerve hypoplasia with midline brain structural deficits including partial or complete absence of the corpus callosum and additional endocrine anomalies;

Impact: varying level of decreased visual acuity, decrease night vision, photophobia; medications needed for endocrine anomalies

 

Strabismus - muscle imbalance of the eye (inward, outward, upward, downward);
Impact: binocular vision affected, may have normal acuities

 

Uveitis - inflammation which can affect the choroid, ciliary body and/or the iris;

Impact: field loss, blind spots, possible visual acuity decrease

 

Resources: TN Department of Education website www.tn.gov/education

Levack, Nancy (2007). Low Vision: A Resource Guide with Adaptations for Students with Visual Impairments. Texas School for the Blind and Visually Impaired

 

Visual Impairment

The State of Tennessee uses the following definitions for use as guidelines in it's school systems:

VISUAL IMPAIRMENT

I. Definition Visual Impairment, including blindness, means impairment in vision that, even with correction, adversely affects a child’s educational performance. The term includes both partial sight and blindness.

Visual Impairment includes at least one (1) of the following:

(1) Visual acuity in the better eye or both eyes with best possible correction:

     (a) Legal blindness – 20/200 or less at distance and/or near; or

     (b) Low vision – 20/ 70 or less at distance and/or near.

(2) Visual field restriction with both eyes:

     (a) Legal blindness – remaining visual field of 20 degrees or less;

     (b) Low vision – remaining visual field of 60 degrees or less; or

     (c) Medical and educational documentation of progressive loss of vision, which may in the future affect the student's ability to learn visually. (3) Other Visual Impairment, not perceptual in nature, resulting from a medically documented condition (i.e., cortical visual impairment).

 

Medical

Optometrist - An eye doctor who goes to optometry school (OD) who takes care of primary eye care.  An optometrist performs eye exams, and prescribes glasses or contacts.  When there is an additional medical condition the client is referred to an ophthalmologist. 

Ophthalmologist - An eye doctor with a medical degree (MD). An ophthalmologist diagnoses and treats eye diseases, can perform eye surgery and other medical treatments as well as prescribe glasses or contacts. Some ophthalmologists specialize in areas such as retina, cornea, glaucoma, pediatric 

Neuro-Ophthalmologist - An ophthalmologist who has an additional degree in neurology.

Low Vision Specialist - An eye doctor, usually optometrist, who has additional training in low vision specific issues.  A Low Vision Specialist prescribes magnifiers, hand held telescopes and bioptics.  This specialist will help determine if the client is eligible to drive. 

 

Assessments

Functional Vision Assessment (FVA) - A Functional Vision Assessment must be completed as part of the qualification process. The purpose of the assessment is to determine how the student functions visually in the school environment with variable lighting and visually complex environments. The assessment must include specific components as outlined in the Resource Packet for Visual Impairments on the TN Education website.  

Expanded Core Curriculum (ECC) - The Expanded Core Curriculum is a specific curriculum for students with visual impairments. The curriculum covers nine areas needed to be specifically taught to compensate for vision loss due to skills typically learned incidentally through visual observation.  The areas are: compensatory access, sensory efficiency, assistive technology, orientation and mobility, independent living skills, social interaction, recreation and leisure, career education and self-determination.  These areas must be assessed and included in the Functional Vision Assessment. 

Learning Media Assessment (LMA) - The Learning Media Assessment is a mandatory component of the Functional Vision Assessment. This assess the best learning media for the student (and combinations), visual, tactual and/or auditory.  This can change as the student gets older and with visual changes. 

Orientation and Mobility (O&M) - Orientation and Mobility (O&M)  - the field dealing with systematic techniques by which blind and visually impaired persons orient themselves to their environment and move about independently (Weiner, W., Welsh, R. and Blasch, B. (Ed.) (2010) Foundations of Orientation and Mobility, (3rd ed.) AFB Press.   This area must be taught by an Orientation and Mobility Specialist - an individual with specialized training in orientation and mobility who has completed an undergraduate or graduate program in this area. (TAPS: An Orientation and Mobility Curriculum for Students with Visual Impairments. (3rd ed.) TSBVI)

      Resources: TN Department of Education website www.tn.gov/education

      Levack, Nancy (2007). Low Vision: A Resource Guide with Adaptations for Students with Visual Impairments. Texas School for the Blind and Visually Impaired

Functional Vision Assessment

The purpose of a Functional Vision Assessment (FVA) is to:

a.) Determine if, and to what degree, visual impairment interferes with learning;

b.) Determine the quantity and quality of functional vision; and

c.) To provide supporting documentation of the ophthalmologic or optometrist’s visual examination for certification or re-certification eligibility for vision services.

The functional vision report must include identifying information about the student, a data review of school history and educational records, a summary of the student’s eye condition based on information from the eye report, a summary of the student’s clinical low vision evaluation (if appropriate), a summary of interviews and general observations of the student, a summary of the student’s visual functioning, educational implications, an eligibility statement, and recommendations for services.

Low Vision Aids and Training

In 1997, TSB added a Low Vision class to the Elementary Curriculum III program. Optical devices, such as magnifiers, small telescopes, and other lenses, have been used to help children with low vision to read regular print books and chalkboards. TSB’s Low Vision class was designed to reinforce training of optical devices prescribed to our students by Vanderbilt University’s Project PAVE (Providing Access to the Visual Environment). As part of Project PAVE, students receive at no cost a clinical low vision evaluation and prescribed handheld optical devices, spectacle lenses, or therapeutic contact lenses. Project PAVE staff provides initial training of any prescribed optical device while the TSB teachers reinforce instruction through daily living skills as well as academic activities.