W3C home > Mailing lists > Public > public-low-vision-a11y-tf@w3.org > October 2015

correlation between eye conditions and functional needs

From: Jim Allan <jimallan@tsbvi.edu>
Date: Tue, 6 Oct 2015 10:01:30 -0500
Message-ID: <CA+=z1WmjPkcj3+MrN7yJoGmDsCGY6RmVTe1qeZAyibP-UF02ew@mail.gmail.com>
To: public-low-vision-a11y-tf <public-low-vision-a11y-tf@w3.org>
The school created this
http://www.tsbvi.edu/eye-conditions
it seems to meet our needs very well, if we change the heading on the last
column to "functional considerations" rather than "educational
considerations" ...though the list is a bit long. we can shorten this list
to around 15.
most common are usually
1 macular degeneration
2 glaucoma
3 detatched retina
4 cataracts
5 diabetic retinopathy
6 retinitis pigmentosa
7 stroke
8 Albinism
9 Optic atrophy



Specific Eye Conditions, Corresponding Impact on Vision, And Related
Educational Considerations
<http://www.tsbvi.edu/eye-conditions#>
Eye ConditionEffects On VisionEducational Considerations

*Achromotopsia *(color deficiency, colorblindness, achromacy, or rod
achromacy)

Cone malformation, macular deficiency, and partial or total absence of
cones.

   - Limited or no color vision
   - Colors may be seen as shades of gray
   - Loss of detail
   - Decreased acuity
   - Central field scotomas
   - Normal peripheral fields
   - Associated with  nystagmus  and Photophobia


   - Adapted color-dependent activities
   - Alternate methods for matching clothing
   - Support of eccentric viewing
   - High contrast materials
   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Reduced or diffused lighting
   - Supplement vision with auditory and tactile information

*Albinism*

Total or partial absence of pigment, causing abnormal optic nerve
development

Lenses and tinted lenses may be prescribed.

   - Decreased acuity
   - Photophobia
   - Increased sensitivity to glare
   - High refractive error
   - Astigmatism
   - Central scotomas
   - Nystagmus
   - Muscle imbalance
   - Eye fatigue with close or detailed work
   - Reduced depth perception


   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Close viewing
   - High contrast materials
   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Lighting from behind
   - Reduced glare
   - Line markers and templates - placeholders
   - Frequent breaks

*Amblyopia* (was Anopsia, called “lazy eye”) *See strabismus
<http://www.tsbvi.edu/eye-conditions#strabismus>*

Reduced visual functioning in one eye, which causes the person to use one
eye instead of both.

With young children, eye exercises, oclusion or patching of one eye or
surgery may help.

   - Monocular vision
   - Reduced visual field
   - Reduced depth perception
   - May develop blindness in one eye
   - Reduced visual-motor abilities
   - Eye fatigue with close or detailed work


   - Frequent breaks
   - Seating should favor functional eye.
   - Familiarization with new environments
   - Time to adjust in new situations
   - May need adaptations for activities requiring visual-motor coordination

*Aniridia *

A rare genetic disorder that causes absence of all or part of the iris,
usually affecting both eyes

It also causes the cornea to lose clarity over time by inhibiting the stem
cells that “refresh” it with new, clear epithelial cells. Aniridia is often
associated with amblyopia, cataracts, the development of closed angle
glaucoma, and sometimes, displaced lens, under-developed retina, and
nystagmus. Contact lenses with an artificial iris, tinted spectacles, or
bioptic glasses may be prescribed. iris and stem cell implant surgeries are
now possible.

Hereditary aniridia is associated with Gillespie syndrome. Sporatic
Aniridia may cause nephroblastoma (Wilm’s tumor), and it is associated with
WAGR syndrome

   - Decreased acuity
   - Photophobia
   - Large pupil that may be misshapen
   - Generally, respond very well to use of low vision devices
   - Corneal involvement: Scattered light, increased glare, blurred vision,
   and further reduction of  acuity
   - If cataracts develop: further reduction of visual acuity, blurred
   vision, and decreased color vision
   - Fovial involvement: loss of detailed (fine) vision
   - If glaucoma develops: fluctuating visual functioning, field loss, poor
   night vision, and decreased sensitivity to contrast



   - Vision stimulation for infants to maximally develop the visual cortex
   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Allow time for adjustment to lighting changes
   - Provide seating in the front of the classroom with back to windows
   - Reduced glare
   - Provide lighting from behind
   - Reduced or diffused lighting
   - Lamps with rheostats and adjustable arms
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Use of a black chalkboard and bold chalk
   - If white board is used, bold black markers are recommended over other
   colors
   - Felt-tipped pens and tinted paper with bold lines
   - Place paper/worksheets on a dark/black background (e.g., blotter,
   construction or butcher paper, posterboard, etc.)
   - Provide copies of materials presented on the board.
   - Use black backgrounds and white san serif fonts in slide presentations

*Anophthalmia*

Absence of one or both eyeballs

Causes can be heredity, injury, or secondary to disease. Prosthetic eyes
are prescribed to preserve the health of the eyelids and surrounding
tissues.

   - Monocular vision:
   - Reduced fields
   - Reduced depth perception
   - Blindness


   - May need visual efficiency training to develop scanning skills
   - Seating and presentation of materials should favor functional eye
   - May need tactile and auditory learning media

*Aphakia*

Absence of the lens

Although it can be caused by injury, aphakia is usually a result of
cataract surgery. Treatments include lens implants, contact lenses, and/or
glasses.

   - Inability to accommodate to varying focal distance
   - Inability to accommodate to lighting changes
   - Reduced depth perception
   - May have peripheral field distortions


   - Support wearing of any prescribed lenses
   - High contrast materials
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Enlarged printed materials
   - Close viewing
   - Adequate lighting (e.g., lights with rheostats and adjustable arms)
   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Allow time for adjustment to lighting changes

*Astigmatism*

Irregularity in the curvature of the cornea and/or lens, which prevents
light rays from being properly focused on a single point on the retina

Astigmatism commonly occurs with myopia and hyperopia. It also can be
associated with albinism and keratoconus. Corrective lenses may be
prescribed.

   - Blurred vision at any distance (uncorrected)
   - Distorted vision
   - Tendency to squint to create a pinhole effect
   - Visual fatigue associated with close work


   - High contrast materials
   - Adequate lighting (e.g., lamps with rheostats and adjustable arms)
   - Frequent breaks from close/detailed work

*Buphthalmos* (Infantile glaucoma)

Enlarged eyeballs

Caused by congenital glaucoma; hereditary; onset from birth to three years;
can cause enlargement and increased depth of the anterior chamber, damage
to the optic disc, and/or increased diameter and thinning of the cornea;
requires surgery, and blindness occurs if left untreated.

   - Photophobia
   - Reduced central acuity
   - Corneal opacity
   - Excessive tearing
   - Refractive error
   - Eye pain



   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Reduced or diffused lighting from behind
   - Sunglasses, visors or hats may be worn indoors
   - Allow time for adjustment to lighting changes
   - High contrast materials
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Enlarged printed materials
   - Close viewing

*Cataracts*

Opacity or cloudiness of the lens, which restricts passage of light to the
retina; usually bilateral

Opacity increases over time until “mature” cataracts can obscure the fundus
and the pupil may appear white. Mature cataracts are usually removed
surgically, requiring lens implants or contact lenses.

   - Reduced visual acuity
   - Blurred vision
   - Reduced color discrimination
   - Photophobia
   - Associated with nystagmus
   - Visual ability fluctuates according to light
   - If cataracts are centrally located, near vision will be reduced
   - Increased sensitivity to glare



   - Support of the wearing of any prescribed lenses
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Enlarged printed materials
   - Close viewing
   - Support of eccentric viewing
   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - May need reduced or diffused lighting
   - Lighting from behind
   - May need lamps with rheostats and adjustable arms
   - Reduced glare

*Chorioretinitis*

Posterior uveitis, or an inflamation of the choroid that spreads to the
retina

This can be caused by tuberculosis, histoplasmosis, or toxoplasmosis.

   - Blurred vision
   - Photophobia
   - Distorted images
   - Central scotomas


   - Support of eccentric viewing
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Enlarged printed materials
   - Close viewing
   - Diffused, less intense light to enlarge the pupil
   - Telescope
   - May need to use tinted lenses, sunglasses, visors, or hats outdoors
   and indoors as well
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information

*Coats’ Disease*  (Exudative Retinitis or retinitis telangiectasia)

A congenital, nonhereditary, and progressive disorder that is characterized
by abnormal development of the blood vessels behind the retina

Coats’ occurs mostly in males. Symptoms typically appear in children around
six to eight years old but they can appear in infancy. Coats' usually
affects only one eye. Severity depends on the size and number of affected
blood vessels. Leakage of blood and fluids cause retinal swelling and
detachment. Cryotherapy and laser photo-coagulation sometimes are used to
stop the progression of blood vessel growth and leakage.

   - Decreased central acuity
   - Loss of detail
   - Progressive central field loss
   - Reduced night vision
   - Loss of color vision
   - May develop strabysmus
   - May have iritis
   - May have glaucoma
   - May develop cataracts
   - May be blind in one eye
   - Peripheral fields can be affected


   - Avoid contact sports and other high risk activities to prevent retinal
   detachment
   - Seating and presentation of work should favor more functional eye
   - Visual efficiency training to develop scanning skills



*Coloboma*

Hereditary birth defect that causes a notch or cleft in the pupil, iris,
ciliary body, lens, retina, choroid, or optic nerve

A “Keyhole” pupil often occurs. It can be associated with refractive error,
cataracts, nystagmus, strabismus, and glaucoma (later in life).

   - Decreased acuity
   - Photophobia
   - Muscle imbalance
   - Restricted fields (if retina is affected)
   - Reduced depth perception



   - High contrast materials
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Average to bright light
   - Reduced glare
   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well (if iris is affected)
   - High contrast line markers and templates may be helpful for reading,
   finding math problems, or locating other information

*Color deficiency *(colorblindness)

*See Achromotopsia*





*Cone Monochromacy *

*See Achromotopsia*





*Corneal Ulcers, Corneal Opacities, Corneal Scarring, Keratitis, and
Interstitial Keratitis*

An open sore or scarring on any part of the cornea

It can be caused by bacteria, viruses (herpes), fungi, vitamin deficiency,
injury, a hypersensitive reaction, diabetes, or severe dry eye. Superficial
ulcers (called abrasions) usually heal quickly and completely, but deep
ulcers cause growth of scar tissue or new blood vessels that impair vision.
Corneal ulcers are usually quite painful, and other symptoms may include
vision loss, squinting, and tearing (watering). Early diagnosis and
treatment are crucial. With extensive scarring, a corneal transplant may be
necessary. There are promising results with use of artificial corneas,
which seem to be less likely to be rejected.

   - Photophobia
   - Fracturing of light (like looking through broken glass)
   - Increased glare
   - Blurred vision
   - Reduced acuity
   - Blindness



   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Reduced or diffused lighting
   - Sunglasses, visors or hats may be worn indoors
   - Seating in front of room with back toward windows
   - Reduced glare
   - High contrast materials
   - Diffused lighting from behind
   - Lights with rheostats and adjustable arms are helpful for close work.
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Enlarged printed materials
   - Frequent breaks from visual tasks
   - Support of eccentric viewing
   - May need auditory materials for longer reading assignments

*Cortical Visual Impairment (CVI)*

A neurological visual disorder resulting from damage to the optic nerve
and/or parts of the brain that process and interpret visual information
(i.e., visual cortex)

CVI is characterized by:

   - Specific color preference, especially for red and/or yellow
   - Attraction to movement
   - Visual field preference, especially for peripheral fields
   - Visual latency: delayed visual processing - in directing gaze,
   identification, recognition, and/or discrimination
   - Difficulties with discrimination and interpretation of complex visual
   information
   - Poor visual attention
   - Atypical visual responses (e.g., looking at something while appearing
   not to look)
   - May not look at an object and reach for it simultaneously (look first,
   then look away while reaching)
   - Better visual performance with familiar objects/settings
   - Unique visual features (i.e., light gazing and non-purposeful gaze)


   - Fluctuation in visual functioning
   - Reduced visual fields
   - Photophobia
   - Fatigue has a negative impact on visual performance


   - Use of movement to increase visual attention
   - Use of preferred color to increase visual attention
   - Present visual information in preferred visual field
   - Present visual information on a solid background (e.g., black or white
   cloth)
   - Use of bright, high contrast materials
   - Increase line spacing and white space on a page of text and/or images
   to reduce visual clutter and complexity
   - Use high contrast templates to reduce the amount of information seen
   at one time
   - Close viewing
   - Vision efficiency training
   - Frequent breaks from visual tasks
   - High illumination from behind
   - Sunglasses, visors or hats may be worn indoors
   - Support use of one sense at a time
   - Reduce visual, auditory, and tactile distractions
   - Extra time to respond
   - Extra time to adjust to new environments
   - Use of consistent language
   - Use of color coding as visual cues for recognition
   - Use of consistent visual cues across settings

*Diabetic Retinopathy*

Changes in the blood vessels of the retina, causing hemorrhaging in the
retina and vitreous

It is caused by juvenile or type 2 diabetes. It may lead to retinal
detachment and blindness.

   - Increased sensitivity to glare
   - Lack of accommodation
   - Floating obstructions in the vitreous
   - Fluctuating acuity
   - Diminished color vision
   - Reduced visual fields
   - Double vision
   - Blindness


   - Adequate high quality lighting (e.g., lamps with rheostats and
   adjustable arms)
   - High contrast materials
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Large button/key technology may be helpful
   - Training in use of auditory materials may be needed due to loss of
   vision and tactile sensitivity
   - Training in use of speech recognition input software may be helpful
   - Precautions related to decreased sensitivity in hands and feet (e.g.,
   burns, cuts, falls)

*Diplopia*

Muscular defect that restricts the ability of the eyes to work together

It causes double vision, as the image from one eye is imposed on the image
from the other eye. Left untreated, this condition can develop into
amblyopia. Corrective lenses may be prescribed.

   - Visual confusion
   - Double vision
   - Dizziness
   - Suppression of the image from one eye, causing monocular vision
   - Eye fatigue
   - Blurring of print
   - Headache
   - Loss of place in visual tasks


   - High contrast materials
   - Reduced glare
   - Extended time to adjust to new situations
   - Frequent breaks from visual tasks
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - Familiarization with new environments

*Dislocated Lens*

The lens is not in its natural position.

It is sometimes associated with coloboma, Marfan’s syndrome, or
Marchesani’s syndrome. Also, it may be associated with diplopia or
cataracts.

   - Blurred vision
   - Double Vision
   - Visual fatigue during close or detailed visual tasks



   - Frequent breaks from visual tasks
   - High contrast materials
   - Adequate lighting (e.g., lamps with rheostats and adjustable arms)
   - Reduced or diffused lighting
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information

*Enucleation*

The anterior chamber or the entire eyeball is surgically removed from the
orbit (eye socket).

Prosthetic eyes or scleral shells are usually recommended.

   - If one eye is removed, there is no depth perception.
   - Monocular vision
   - Reduced visual field
   - Effects of any eye condition(s) of the remaining eye
   - Blindness
   - Effects visual-motor skills, especially reach and negotiation of steps
   and drop-offs


   - Training in care of prostheses
   - Vision efficiency training (i.e., scanning)
   - Considerations related to the visual impairment of the remaining eye
   - Considerations related to possible changes in learning media

*Esophoria, Esotropia, Exophoria, *and *Exotropia*   *See strabismus
<http://www.tsbvi.edu/eye-conditions#strabismus>*





*Glaucoma*

An eye disease which causes increased pressure in the eye because of
blockage in the normal flow of the fluid in the aqueous humor

Causes include changes in the lens or uveal tract, trauma, reaction to a
medication, surgical procedures, and heredity. Eye pain and headaches are
associated with glaucoma. Prescription eye drops to reduce pressure must be
used regularly, and surgery may be necessary. Untreated, glaucoma can lead
to degeneration of the optic disk and blindness.

   - Fluctuating visual functioning
   - Field loss
   - Poor night vision
   - Photophobia
   - Difficulty reading
   - Difficulty seeing large objects presented at close range
   - Decreased sensitivity to contrast
   - Eye redness
   - Hazy cornea
   - Wide open pupil
   - Stress and fatigue have a negative affect on visual performance



   - Support use of sunglasses, visors, or hats in bright sunlight and
   bright lighting indoors
   - Allow time for adjustment to lighting changes
   - Reduced glare
   - Adequate lighting (e.g., lamps with rheostats and adjustable arms)
   - High contrast materials
   - May benefit from magnification (e.g., hand-held magnifier, electronic
   magnifier, screen enlargement software, telescope, etc.)
   - May need visual efficiency training to develop scanning skills
   - Frequent breaks from visual tasks
   - May need instruction in tactile learning and braille
   - Teachers must be alert to signs of pain and increased ocular pressure.

*Hemianopia *(hemianopsia)

Blindness or impaired vision in one half of the visual field in one or both
eyes

If both eyes are affected, vision loss may occur on the same side in both
nasal fields, or in both temporal fields. Visual acuity in the unaffected
field(s) remains unchanged. Hemianopia can be caused by stroke, other brain
trauma, tumors, infection, or surgery.

   - Field loss
   - May be unaware of missing visual information


   - Visual efficiency training to develop scanning skills
   - Use markers at the beginning and/or ending of each line of text to
   facilitate reading the entire line

*Histoplasmosis* (Presumed Histoplasmosis Syndrome - POHS)

This is a syndrome affecting the choroid and retina, which is characterized
by peripheral atrophic chorioretinal scars, maculopathy, and atrophy or
scarring adjacent to the optic disc. Vision loss is secondary to macular
and choroidal neovascularization (CNV).

POHS is most likely caused by a fungal infection acquired through exposure
to spores in bird droppings and bat guano. Treatments include steroids to
treat the initial infection, laser, anti-vascular endothelial growth
factors, and photodynamic therapy. Prism lenses may be prescribed.

   - Distorted vision
   - Blind spots
   - Macular damage or central scotomas cause “patchy” fields, central
   vision loss, and reduced color vision.
   - Peripheral damage causes loss of night vision


   - Lamps with rheostats and adjustable arms
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information.

*Central damage:*

   - Eccentric viewing
   - Magnification to enlarge an image beyond the scotoma
   - Enlarged printed materials
   - Close viewing
   - Adapted color-dependent activities
   - Alternate methods for matching clothing
   - Diffused, less intense light to enlarge the pupil so that more area
   can be viewed
   - CCTV with reversable foreground and background (white on black)

*Peripheral damage:*

   - High illumnation
   - NOIR lenses or overlay filters may be helpful
   - CCTV for maximum contrast
   -  Night vision devices (e.g., Streamlight flashlights, Third
   Generation® Night Vision Devices, etc)
   - Visual efficiency training in organized search (grid) patterns
   - May need to be seated farther away from the front to see more of the
   viewing area (e.g., board, screen, chart, etc)

*Hyperopia* (Farsightedness)

A refractive error in which the focal point for light rays is behind the
retina

It is caused by the eyeball being too short from front to back. Corrective
lenses are usually prescribed.

   - Distance acuity is better than near acuity
   - Uncorrected, close visual tasks may cause headache, nausea, dizziness,
   and eye rubbing



   - Support use of prescription lenses for close visual tasks
   - Magnification for near tasks (e.g., hand-held magnifier, electronic
   magnifier, screen enlargement software)
   - Frequent breaks from close visual tasks
   - Alternate near and distance visual tasks

*Hyperphoria, Hypertropia, Hypophoria, Hypotropia   * *See strabismus
<http://www.tsbvi.edu/eye-conditions#strabismus>*





*Hypoplasia*  *See Optic Atrophy
<http://www.tsbvi.edu/eye-conditions#optic>*





*Keratitis **See Corneal Ulcer
<http://www.tsbvi.edu/eye-conditions#corneal>*





*Keratoconus* (KC)

Degenerative disorder in which the cornea thins and takes on a conical shape

Keratoconus is often bilateral but not symmetrical, so vision may be
significantly better in one eye than the other. Vision deteriorates at
varying rates (sometimes quite rapidly), and plateaus of stable vision can
occur. Although it seems to be hereditary, keratoconus is typically
diagnosed in adolescence. It is sometimes associated with retinitis
pigmentosa, Down’s syndrome, Marfan’s syndrome, and aniridia.  Treatments
include prescription lenses and various surgeries: intrastromal corneal
ring segments, cross-linking, mini asymmetrical radial keratotomy, and
corneal transplants. There are promising results in transplants with use of
artificial corneas, which seem to be less likely to be rejected.

   - Slightly blurred vision in early stages, increasing as KC progresses
   - Distortion of entire visual field, which worsens in low light
   - Decreased visual acuity especially distance vision
   - Irregular astigmatism (parts of the field are in focus, and parts are
   out of focus)
   - Increased sensitivity to glare
   - Decreased night vision
   - Multiple images
   - Flaring of images
   - Streaking
   - Stationary objects/lights may appear to move
   - May develop photophobia
   - Cornea can rupture
   - Can lead to blindness


   - Avoid activities that could cause corneal damage, such as  contact
   sports and swimming in heavily chlorinated water
   - Reduced glare
   - Diffused lighting
   - Lamps with rheostats and adjustable arms
   - High contrast materials
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)

*Leber’s Congenital Amaurosis *(LCA, Leber’s Congenital Amaurosis)

A rare hereditary disorder that leads to degeneration of the macula

LCA becomes evident within the first few months of life. Progressive
central field loss can occur, although vision is generally stable. LCA is a
subset of retinitis pigmentosa with at least thirteen described types that
are distinguished by genetic cause, patterns of vision loss, and associated
eye conditions. Nystagmus, keratoconus, photophobia, extreme hyperopia, and
sluggish (or absent) pupilary response to light are often present with LCA.
Excessive rubbing of eyes (also poking or pressing) is a characteristic
behavior.



   - Decreased acuity
   - Reduced night vision
   - Progressive central field loss
   - Loss of color vision
   - Loss of detail
   - Peripheral fields can be affected


   - May need visual efficiency training to develop scanning skills
   - Support of eccentric viewing
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - High contrast materials
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - Enlarged printed materials
   - Close viewing
   - Adapted color-dependent activities
   - Alternate methods for matching clothing
   - Lamps with rheostats and adjustable arms
   - Support use of sunglasses, visors, or hats in bright sunlight
   - Seat in the front of the room with windows behind back
   - May need frequent breaks from visual tasks
   - May need instruction in use of auditory materials
   - May need instruction in tactile learning and braille

*Leber’s Hereditary Optic Neuropathy* (LHON, Leber’s Optic Atrophy)

It is a rare hereditary disease caused by a mitochondrial mutation and
passed on by the mother. It is characterized by rapidly progressive and
severe optic nerve degeneration (atrophy).

It occurs in young men and, rarely, young women. Onset is usually in young
adulthood. Most often, there is acute vision loss in one eye and then, a
few weeks or months later, in the other eye, but vision loss sometimes
occurs in both eyes simultaneously. It can include other types of central
nervous system involvement.

   - Reduced central acuity
   - Vision may be blurred
   - Fluctuating visual performance
   - Color vision may be impaired
   - Visual perception may be impaired



   - High illumination
   - High contrast
   - Enlarged printed materials
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Avoid visual clutter:
   - Present visual information in isolation
   - Avoid busy backgrounds
   - Avoid wearing patterned clothing when presenting visual information

*Macular Degeneration* (Macular Disease, Congenital Macular Disease, and
Age-Related Macular Degeneration)

Progressive (degenerating) damage to the central part of the retinal cones

The dry form involves yellow deposits (celluar debris) on the macula and
eventually, thinning of cells in the macula, which leads to tissue death.
In the wet form, there is abnormal growth of blood vessels in the choroid
underneath the macula. These blood vessels leak blood and fluid into the
retina, causing distortion, blind spots, loss of central vision, retinal
scarring, and risk of retinal detachment. Macular degeneration is the
leading cause of blindness in people over sixty, but it also can occur in
children below age seven. Factors contributing to the development of the
disease include heredity, diabetes, head injury, nutritional deficits, high
cholesterol, smoking, and exposure to sunlight without eye protection.
There is no cure, but treatment can slow progress of the disease.
Treatments include nutritional supplements, laser therapy, and medication.

   - Reduced central acuity
   - Peripheral vision is not affected
   - Central scotomas
   - Distorted vision
   - Blurred vision
   - Decreased color vision
   - Slow recovery from changes in light
   - Loss of contrast sensitivity
   - Visual fatigue


   - Support of eccentric viewing
   - Support use of sunglasses, hats, or visors in bright sunlight
   - Allow time for adjustment to lighting changes
   - Adequate lighting (e.g., lamps with rheostats and adjustable arms)
   - Diffused lighting may allow the pupil to enlarge so that more area can
   be viewed
   - Close viewing
   - Magnification (e.g., hand-held magnifier, electronic magnifier with
   light text on dark background, screen enlargement software, telescope for
   distance viewing etc.)
   - Reduced glare
   - High contrast materials
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - Seating in front with back to window
   - Adapted color-dependent activities
   - Alternate methods for matching clothing
   - Frequent breaks from visual tasks
   - Avoid standing in front of a light source when speaking to the student

*Microphthalmia* (Microphthalmos, nanophthalmia, nanophthalmos)

A hereditary, developmental disorder that causes one or both eyes to be
abnormally small

It may occur with other congenital abnormalities such as club foot,
additional fingers or toes, webbed digits, polycystic kidneys, and cystic
liver. This disorder can be associated with Patau Syndrome, Triploid
Syndrome, or Wolf-Hirschhorn Syndrome. It may result in  cataracts,
glaucoma, aniridia, and coloboma.

   - Decreased visual acuity
   - Photophobia
   - May have fluctuating visual abilities



   - High contrast
   - Reduced glare
   - Average to bright light
   - May need magnification (e.g., hand-held magnifier, electronic
   magnifier, screen enlargement software, telescope, etc.)
   - Expectations may need to be adjusted due to the frustration related to
   fluctuating visual abilities
   - Frequent breaks from visual tasks
   - Instruction in strategies for stress reduction and dealing with
   frustration related to fluctuating visual abilities

*Muscle Imbalance* See *Strabismus
<http://www.tsbvi.edu/eye-conditions#strabismus> and Amblyopia
<http://www.tsbvi.edu/eye-conditions#amblyopia>*





*Myopia (*Simple and Degenerative Myopia, nearsightedness)

A refractive error in which the image of a distant object is formed in
front of the retina and cannot be seen distinctly; eyeball is elongated
from front to back

Degenerative myopia is progressive, causing increasingly severe
nearsightedness, so that visual acuity often cannot be corrected to normal
with lenses. It can lead to retinal detachment, choroidal hemorrhages,
reduced central vision, opacities in the vitreous, macular swelling, and
cataracts. Treatments include corrective lenses and LASIC surgery.

   - Reduced distance acuity
   - Near vision is better than distance vision
   - May squint and frown when trying to see at a distance



   - High illumination
   - Reduced glare
   - May need to be seated closer to the front in order to see written
   information, videos, and demonstrations
   - If myopia is progressive, take precautions to protect the retina

*Nystagmus*

Involuntary eye movements, which can be horizontal, vertical, circular, or
mixed

Causes can be heredity, neurological disorders, toxicity, pharmaceutical
drugs, alcohol, inner ear disturbance, or unknown. Nystagmus can be
increased by stress, spinning, and rhythmic movements.

   - Inability to maintain steady fixation
   - Reduced visual acuity
   - Visual fatigue
   - Vertigo (rare)
   - Stripes and other patterns may increase the rate of the nystagmus


   - Shifting gaze or tilting the head may help to find the null point at
   which the nystagmus slows.
   - Frequent breaks from close visual tasks
   - Vary visual tasks
   - Adequate lighting
   - Good contrast
   - Line markers, rulers, typoscopes, and other templates may be helpful
   for keeping the place on a page
   - Instruction in stress reduction strategies

*Optic Atrophy *(Optic Nerve Atrophy)

Hereditary or acquired damage to the optic nerve that limits or stops
transmission of visual information from the eye to the brain

It is evidenced by a pale optic disc and reduced pupilary response.
Acquired optic atrophy can be caused by disease, pressure on the optic
nerve, trauma, glaucoma, or toxicity. Type 1 optic atrophy is progressive.



   - Fluctuating visual performance
   - Color vision may be reduced
   - Night vision may be reduced
   - Visual perception may be impaired
   - May have photophobia


   - Visual stimulation in infancy and early childhood.
   - Low vision training in early childhood to help the child interpret
   visual information
   - Supplement visual information with tactile and auditory information
   - High illumination
   - If photophobia is present:
   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Provide adequate lighting through use of lamps with rheostats and
   adjustable arms)
   - High contrast
   - Enlarged print
   - May need magnification (e.g., hand-held magnifier, electronic
   magnifier, screen enlargement software, telescope, etc.)
   - Avoid visual clutter:
   - Present visual information in isolation
   - Avoid busy backgrounds
   - Avoid wearing patterned clothing when presenting visual information
   - May need adapted color dependent activities
   - May need alternate methods for matching clothing
   - May need instruction in tactile learning and braille

*Optic Nerve Hypoplasia*(ONH)

ONH and Septo-Optic Dysplasia (SOD) are related disorders of early brain
development. ONH is a congenital, nonprogressive condition in which the
optic nerve is under-developed and small.

It may affect one or both eyes, and when both are affected, side-to-side
nystagmus is frequently present. During the first few years of life, vision
may improve as the brain continues to develop. The incidence of strabismus
is increased with ONH. It is one of the three defining characteristics of
Septo-Optic Dysplasia, which is also called DeMorsier’s Syndrome. Learning
disability, autism, cerebral palsy, and intellectual developmental delays
can occur with ONH and SOD. Possible causes include young maternal age,
genetic mutation, fetal alcohol syndrome, trauma, and viral infection.

   - May have decreased visual acuity
   - May have better acuity In one eye than in the other
   - May have nystagmus
   - May have strabismus
   - May have variable field restrictions
   - Visual perception may be impaired


   - High illumination
   - High contrast
   - Enlarged printed materials
   - May need magnification (e.g., hand-held magnifier, electronic
   magnifier, screen enlargement software, telescope, etc.)
   - Avoid visual clutter:
   - Present visual information in isolation
   - Avoid busy backgrounds
   - Avoid wearing patterned clothing when presenting visual information
   - Provide opportunities to confirm or clarify visual information through
   tactile exploration
   - May benefit from verbal descriptions to help make sense of visual
   information.
   - May need adapted color dependent activities
   - May need alternate methods for matching clothing
   - May need instruction in tactile learning and braille

*Peter’s Anomaly*

A congenital, genetic disorder that involves clouding (opacity) and
thinning of the cornea

It is caused by abnormal development of the front third of the eye
(anterior segment), and central opacities are most common. The iris may or
may not be attached to the cornea (Type 1), and cataracts and other lens
abnormalities may be present (Type 2). It is very common for amblyopia and
glaucoma to develop. This condition can be associated with peters plus
syndrome.

   - Blurred vision
   - Decreased central acuity
   - May have scotomas in peripheral fields
   - Photophobia
   - Increased sensitivity to glare
   - Reduced color discrimination
   - Visual ability fluctuates according to lighting
   - May have reduced near vision



   - Support of eccentric viewing
   - May need visual efficiency training to develop scanning skills
   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Adequate lighting from behind using lamps with rheostats and
   adjustable arms
   - Reduced glare
   - Seat with back to windows
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Enlarged printed materials
   - High contrast materials
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - Close viewing
   - May need adapted color-dependent activities
   - May need alternate methods for matching clothing
   - Frequent breaks from visual tasks

*Photophobia*

Abnormal sensitivity to light (any type)

It is usually associated with an eye disease or disorder (e.g., iritis,
ocular albinism, aphakia, aniridia, dislocated lens, cataracts, glaucoma,
etc.). However, many people experience mild photophobia that is unrelated
to another eye condition. Other causes include corneal inflammation, some
medications, and eye injuries. Severe photophobia can be quite painful,
even in relatively dim light.

   - Squinting
   - Closing the eyes
   - Eye pain
   - Headaches
   - Eye fatigue


   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Reduced or diffused lighting
   - Provide lighting from behind
   - Use of shielded lamps with rheostats and adjustable arms)
   - Reduced glare
   - May benefit from use of NOIR sunglasses and/or filters (colored
   overlays) when reading
   - May need breaks from visual tasks or rest periods in a darkened area

*Phthisis bulbi*

Abnormally low intraocular pressure, which can cause shrinkage of the eye

It may occur as a complication of eye surgery, or it can be caused by eye
diseases, serious and long-term inflammation, or injury. Low pressure
damages the macula. The tissues inside the eye deteriorate, become
disorganized, and scar tissue is formed. In some cases, the eye can become
completely nonfunctional. Sometimes a scleral shell prosthesis is
prescribed for proper lid function, eyelash direction, healthy tearing,
protection of the cornea, and aesthetics.

   - Reduced central acuity
   - Reduced color vision
   - Blindness


   - Average or bright light
   - Reduced glare
   - May need high contrast
   - May need magnification (e.g., hand-held magnifier, electronic
   magnifier, screen enlargement software, telescope, etc.)
   - May benefit from use of high contrast line markers or templates for
   reading, finding math problems, or locating other information
   - May need some materials presented auditorily
   - May need instruction in tactile learning and braille

*Presbyopia*

The gradual loss of flexibility of the lens that occurs with age

It results in inability of the eye to focus at near distance. Presbyopia
generally begins to noticeably affect visual functioning around age 40, and
people often need prescription lenses by age 45. Options for prescription
lenses include glasses for near-distance tasks, bifocals, transition
lenses, and monovision contact lenses. Vision also can be corrected by
reshaping the cornea using lasers (LASIK), radio waves (conductive
keratoplasty - CK), or gas bubbles (IntraCor). Other surgical treatments
include artificial lens implants, corneal inlays, and corneal overlays.

   - Blurred vision at normal reading distance
   - Headaches from doing close visual tasks
   - Further compromises the vision of aging adults who have existing
   visual impairments



   - Adequate lighting
   - High contrast
   - Frequent breaks from near-distance visual tasks

*Ptosis*

Drooping (sagging) of the eyelid

It may affect upper and/or lower lids and one or both eyes. Ptosis is
usually due to weakness of the muscles that control the eyelids, damage to
the nerves that control these muscles, or very loose skin of the upper
eyelids.  Commonly associated with the aging process, ptosis also can be
congenital and hereditary, or caused by injury or disease. A ptosis crutch
may be prescribed to elevate the eyelid. Medications may be prescribed for
those who have myasthenias gravis. Children with severe ptosis need eyelid
lift surgery early in life to insure normal visual development and to
prevent amblyopia.

   - Severe ptosis obscures the upper visual field
   - Long-term reduction of visual field can cause amblyopia



   - May need visual efficiency training to develop scanning skills
   - Ensure access to information that is elevated (bulletin boards,
   black/white boards, video screens, etc.)

*Retinal Detachment*

An emergency situation in which parts of the retina pull away from the
underlying tissue that nourishes it and from the supporting structure of
the eye

Detachments can be repaired if treated within 24-72 hours, but detached
parts deteriorate rapidly. Any detachment endangers the entire retina.
Detachments are caused by retinal tears, fluid under it, or shrinkage of
the vitreous. These conditions may be due to injury, inflammatory eye
disorders, advanced diabetes, degenerative myopia, and other retinal
disorders.

   - Field loss
   - Blind spots (scotomas)
   - Blurred vision
   - Possible loss of central vision
   - May develop myopia and/or strabismus


   - Avoid contact sports and other high risk physical activity to prevent
   retinal detachment
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - May need visual efficiency training to develop scanning skills
   - Support of eccentric viewing
   - High illumination
   - Reduced glare
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - Seating in front with back to window
   - Adapted color-dependent activities
   - Alternate methods for matching clothing
   - Frequent breaks from visual tasks

*Retinal* *Dysplasia*

A rare, hereditary disorder resulting in abnormal development or growth of
the retina and characterized by retinal folds, overgrowth of cells, and
rosettes of retinal tissue

It can be associated with Meckel syndrome.

   - Field loss
   - Blind spots (scotomas)
   - Blurred vision
   - Possible loss of central vision
   - Reduced visual functioning at night or in dimly lit places


   - Nighttime orientation and mobility evaluation
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Visual efficiency training to develop scanning skills
   - Support of eccentric viewing
   - Lamps with rheostats and adjustable arms
   - Reduced glare
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - Adapted color-dependent activities
   - Alternate methods for matching clothing
   - Frequent breaks from visual tasks

*Retinitis Pigmentosa (RP)*

A group of hereditary disorders causing degeneration of the retina

It is characterized by progressive loss of vision and reduction of visual
fields, usually from the periphery inward. However, in some cases, central
vision is affected first. RP may be associated with Usher’s syndrome, Leber
congenital amaurosis, Laurence-Moon Biedl, and Bassen-Kornzweig syndrome.



   - Loss of peripheral vision
   - Night blindness
   - Tunnel vision
   - Decreased acuity
   - Decreased depth perception
   - Blind spots (scotomas due to retinal scarring
   - Photophobia
   - May develop cataracts
   - May become totally blind
   - May be associated with myopia, vitreous opacities, cataracts, and
   keratoconus


   - Avoid contact sports and other high risk physical activity to prevent
   retinal detachment
   - High illumination
   - Reduced glare
   - NOIR lenses or overlay filters may be helpful
   - Video magnifier for maximum contrast
   - Night vision devices (e.g., Streamlight flashlights, Third Generation®
   Night Vision Devices, etc.)
   - Visual efficiency training in organized search (grid) patterns
   - Orientation and mobility evaluation at night and in dimly lit places
   - For central vision loss: magnification (e.g., hand-held magnifier,
   electronic magnifier, screen enlargement software, telescope, etc.)
   - For peripheral field loss: increase viewing distance to see more area.

*Retinoblastoma*

A rare type of cancer in which malignant cells grow in the retina

It usually develops in early childhood. The majority of children who
develop this cancer have mutations only in eye cells (non-germinal). They
will not pass on the mutation, and usually, retinoblastoma develops only in
one eye. When the mutation occurs in all body cells (germinal
retinoblastoma), the disease is hereditary. These children are more likely
to develop retinoblastoma in both eyes, pineal brain tumors (trilateral
retinoblastoma), and other forms of cancer anywhere in the body. Current
treatments include surgery, radiation, and chemotherapy. Retinoblastoma can
become life threatening if the tumor extends beyond the eye, so enucleation
is frequently necessary.

   - Strabismus is one of the first signs of retinoblastoma.
   - Restricted fields due to removal of tumors
   - Blind spots (scotomas) due to removal of small tumors
   - With monocular vision, there is no depth perception and visual field
   is restricted.
   - Blindness
   - Medications can negatively affect residual vision.



   - Avoid contact sports and other high risk physical activity to prevent
   retinal detachment
   - Orientation and mobility evaluation at night and in dimly lit places
   recommended
   - May need visual efficiency training to develop scanning skills
   - Support of eccentric viewing
   - May need magnification (e.g., hand-held magnifier, electronic
   magnifier, screen enlargement software, telescope, etc.)
   - May benefit from access to auditory materials
   - May require instruction in tactile learning and braille

*Retinopathy of* *Prematurity* (ROP, retrolental Fibroplasia)

Incomplete development of the blood vessels of the retina

It occurs in premature infants. The vessels also may grow abnormally from
the retina into the back of the eye. They may bleed into the eye, scar
tissue may develop, and retinal detachment may occur. The major risk
factors are degree of prematurity and low birth weight. There are five
stages of ROP, ranging from mildly abnormal blood vessel growth in stage
one to retinal detachment in stage five. ROP may be associated with other
issues caused by incomplete development. Lasers or freezing
(photocoagulation and cryotherapy) may be used to stop the abnormal blood
vessels from continuing to grow. Also, surgery may be done to re-attach the
retina.

   - Retinal scarring
   - Decreased visual acuity
   - Severe myopia
   - Field loss
   - Partial or complete retinal detachment
   - Blind spots (scotomas)
   - Strabismus
   - Total blindness
   - May develop glaucoma



   - Early intervention and sensory stimulation
   - Avoid contact sports and other high risk physical activity to prevent
   retinal detachment
   - Nighttime orientation and mobility evaluation
   -  May need visual efficiency training to develop scanning skills
   - Visual efficiency training in organized search (grid) patterns
   - Adequate to high illumination (e.g., lamps with rheostats and
   adjustable arms)
   - Reduced glare
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - Frequent breaks from visual tasks
   - May benefit from access to auditory materials
   - May need instruction in tactile learning and braille
   - May benefit from magnification (e.g., hand-held magnifier, electronic
   magnifier, screen enlargement software, telescope, etc.)
   - Reduced glare
   - Night vision devices (e.g., Streamlight flashlights, Third Generation®
   Night Vision Devices, etc.)
   - Balance need for a larger viewing area with the need for magnification
   - Balance need for close viewing against the need for increased distance
   and a larger portion of the text/pictures
   - Adapted color-dependent activities
   - Alternate methods for matching clothing
   - Support of eccentric viewing

*Retinoschisis*

A degenerative disorder in which the retina splits into two separate
layers, resulting in progressive loss of vision, beginning in the fields
that correspond to the areas where the retina splits

The hereditary form (juvenile X-linked retinoschisis) affects mostly boys
and young men. The more common form can affect both men and women, and it
usually is acquired in middle age or older (senile retinoschisis). Both
forms may be associated with cysts (sack-like blisters) that form a
spoke-like pattern in the retina. Retinal detachments can occur, and if
detected early, they sometimes can be repaired with surgery. Prismatic
glasses may be prescribed to increase field of vision.

   - Strabismus
   - Nystagmus
   - Central field loss
   - Peripheral field loss
   - Reduced visual acuity
   - Reduced color discrimination
   - Blind spots (scotomas)
   - Blindness



   - Avoid contact sports and other high risk physical activity to prevent
   retinal detachment
   - May need visual efficiency training to develop scanning skills
   - May need visual efficiency training in organized search (grid) patterns
   - Adequate lighting (e.g., lamps with rheostats and adjustable arms)
   - Reduced glare
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - Frequent breaks from visual tasks
   - May benefit from access to auditory materials
   - May need instruction in tactile learning and braille

For central vision loss:

   - Nighttime orientation and mobility evaluation
   - Magnification (e.g., hand-held lighted magnifier, electronic
   magnifier, screen enlargement software, telescope, etc.)
   - High illumination
   - Night vision devices (e.g., Streamlight flashlights, Third Generation®
   Night Vision Devices, etc.)
   - Adapted color-dependent activities
   - Alternate methods for matching clothing

For peripheral field loss:

   - Increase viewing distance to see more area
   - Support of eccentric viewing
   - Balance need for a larger viewing area with the need for magnification

*Rod Achromacy     **See Achromotopsia
<http://www.tsbvi.edu/eye-conditions#achormotopsia>*





*Scotoma *(pl. *scotomata, scotomas)*

A portion of the visual field that is blind or partially blind and
surrounded by relatively normal vision, depending on the presence of other
eye conditions

Scotomas can occur in any part of the visual field. They can be caused by
retinal disorders, tumors, stroke, or traumatic brain injury.

   - May affect central or peripheral fields
   - Reduced acuity
   - May cause loss of detail
   - May cause photophobia
   - May cause reduced color vision


   - Visual efficiency training to develop scanning skills
   - Support of eccentric viewing
   - Seating and presentation of work should favor more functional eye
   - May need to use sunglasses, visors, or hats outdoors and indoors as
   well
   - Reduced glare
   - May need lighting from behind using adjustable lamps with rheostats
   and adjustable arms
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - May benefit from enlarged printed materials
   - May benefit from close viewing
   - High contrast materials
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - May need adapted color-dependent activities
   - May need alternate methods for matching clothing

*Septo-Optic Dysplasia* *See Optic Nerve Hypoplasia
<http://www.tsbvi.edu/eye-conditions#onh> and "Syndromes
<http://www.tsbvi.edu/component/content/203-resources/4420-syndromes?Itemid=1164>"*





*Strabismus* (muscle imbalance

Abnormal alignment of the eyes; an inability to look at the same point in
space with both eyes at the same time

It can be caused by a defect in the extra-ocular muscles or in the part of
the brain that controls eye movement. It can be hereditary, and it may be
associated with brain tumors, cerebral palsy, Down syndrome, extreme
farsightedness, cataracts, or having much better vision in one eye than in
the other. Strabismus includes:

   - “phorias”– muscle imbalances that are controlled by the brain's
   efforts toward binocular vision. Not always present, they tend to manifest
   when the person is tired.
   - “tropias” - observable deviations that the brain cannot resolve. They
   are always present.
   - Eso – turned inward/nasal (esophoria and esotropia)
   - Exo – turned outward/temporal (exophoria and exotropia)
   - Hyper – turned upward (hyperphoria and hypertropia)
   - Hypo – turned downward (hypophoria and hypotropia)

Treatments can be effective for young children: eye exercises, occlusion of
the better eye, medications, and surgery. Prismatic glasses may be
prescribed to increase field of vision.

   - Impaired ability to achieve binocular vision
   - Decreased depth perception
   - Affects eye-hand coordination
   - Difficulty fixating
   - May have difficulty scanning, tracking, and tracing
   - Difficulty following fast-moving objects
   - Difficulty making eye contact



   - Orientation and mobility evaluation recommended, specifically for
   negotiation of drop-offs and stairs in unfamiliar places
   - Vision efficiency training in scanning, tracking, and tracing



*Toxoplasmosis*

Congenital or acquired inflammation of the retina and choroid
(retinochoroiditis), which can cause retinal scarring

Toxoplasmosis is caused by infection with the toxoplasma parasite found in
animal feces and unpasteurized milk. Unborn babies are most vulnerable to
the infection, and it can cause damage to the brain, eyes, or other organs.
Treatments include anti-inflammatory medications, photocoagulation (laser)
therapy, and cryotherapy (freezing).

   - Scotomas
   - Peripheral field loss
   - Central field loss
   - Loss of visual acuity
   - Decreased color vision
   - Photophobia
   - Increased sensitivity to glare


   - Visual efficiency training to develop scanning and eccentric viewing
   skills
   - Reduced glare
   - May need lighting from behind using adjustable lamps with rheostats
   and adjustable arms
   - Magnification (e.g., microscopic lenses, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - May benefit from enlarged printed materials
   - May benefit from close viewing
   - High contrast materials
   - High contrast line markers or templates for reading, finding math
   problems, or locating other information
   - May need adapted color-dependent activities
   - May need alternate methods for matching clothing

*Trachoma*

A contagious bacterial infection of the eyes and eyelids, causing scarring
and buckling of the eyelids

This causes the eyelashes to turn under, which leads to corneal scarring.
Repeated and prolonged infection causes permanent visual impairment and
blindness. Trachoma is spread through direct contact with secretions from
the eyes, eyelids, or nose of an infected person. It is the leading cause
of preventable blindness worldwide.

   - Photophobia
   - Fracturing or scattering of light (as in looking through a broken
   windshield
   - Increased glare
   - Blurred vision
   - Reduced acuity
   -


   - Sunglasses, visors or hats outdoors, and indoors as well
   - Reduced or diffused lighting from behind (e.g., lamps with rheostats
   and adjustable arms)
   - Front row seating with back toward windows
   - Reduced glare
   - High contrast materials
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Enlarged printed materials
   - Frequent breaks from visual tasks
   - Support of eccentric viewing
   - Auditory materials for long reading assignments
   - May need instruction in tactile learning and braille

*Uveitis*

Inflammation of the uveal tract (middle layer of the eye), which consists
of the iris, choroid, and ciliary body

The most common form affects the iris, and it may be called anterior
uveitis or iritis. The cause may be unknown. Known causes include
autoimmune disorders, infection, toxoplasmosis, tuberculosis, and
histoplasmosis. Complications can cause glaucoma and damage to the retina
or cornea, leading to permanent vision loss.

   - Photophobia
   - Blurred vision
   - Floaters
   - Decreased acuity
   - Glaucoma
   - Retinal scarring
   - Corneal damage



   - High contrast materials
   - Reduced glare
   - Allow additional time for adjustment to new visual conditions
   - Use of lamps with rheostats and adjustable arms
   - May need visual efficiency training to develop scanning and eccentric
   viewing skills

*Wilm’s Tumor *(nephroblastoma)

Rare abnormalities of the eye, especially aniridia, related to a malignancy
of the kidneys

Although the cause is sometimes unknown, this form of cancer can be caused
by genetic changes, which also can be hereditary. Pinhole contact lenses
and sunglasses may be prescribed.

See “*Syndromes
<http://www.tsbvi.edu/component/content/203-resources/4420-syndromes?Itemid=1164>*"
for associated conditions.

   - Decreased acuity, further reduced by other conditions
   - Photophobia
   - Large pupil (misshapen)
   - With corneal involvement: Fractured light, increased glare, blurred
   vision
   - With cataracts: blurred vision, and decreased color vision
   - Fovial involvement: loss of detail vision
   - With glaucoma: fluctuating visual functioning, field loss, poor night
   vision, and decreased sensitivity to contrast
   - May have nystagmus
   - May have ptosis


   - Vision stimulation for infants to develop the visual cortex
   - Sunglasses, tinted contact lenses, visors or hats in bright light
   outdoors and indoors
   - Allow time for adjustment to lighting changes
   - Front row seating with back to windows
   - Reduced glare
   - Provide reduced or diffused lighting from behind
   - Lamps with rheostats and adjustable arms
   - Magnification (e.g., hand-held magnifier, electronic magnifier, screen
   enlargement software, telescope, etc.)
   - Use a blackboard and bold chalk
   - Use of bold, black markers on a white board
   - Felt-tipped pens and tinted paper with bold lines
   - Use of dark/black background
   - Provide copies of materials presented on the board.



-- 
[image: http://www.tsbvi.edu] <http://www.tsbvi.edu>Jim Allan,
Accessibility Coordinator
Texas School for the Blind and Visually Impaired
1100 W. 45th St., Austin, Texas 78756
voice 512.206.9315    fax: 512.206.9264  http://www.tsbvi.edu/
"We shape our tools and thereafter our tools shape us." McLuhan, 1964
Received on Tuesday, 6 October 2015 15:02:08 UTC

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