Re: correlation between eye conditions and functional needs

Absolutely great information. Yes, I think we can re-use with due credits.
Thank you for sharing, Jim.
Regards,
Vasu

Best regards,

*Srinivasu Chakravarthula*
Sr. Accessibility Consultant, *Deque* <http://deque.com>
Hand phone: +91 709 380 3855

Deque University <http://dequeuniversity.com> | Follow me on Twitter
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On Tue, Oct 6, 2015 at 8:31 PM, Jim Allan <jimallan@tsbvi.edu> wrote:

> 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
>