Common Eye Conditions

ALBINISM
ANIRIDIA
CATARACTS
MACULAR DEGENERATION
NYSTAGMUS DEGENERATION
RETINITIS PIGMENTOSA (RP)
RETINOPATHY OF PREMATURITY (ROP) and
RETROLENTAL FIBROPLASIA (RLF)
IMPLICATIONS OF VISION IN ONE EYE ONLY

What is Visual Acuity? 
Parts of the Eye 
Environmental Considerations 
Other Considerations 
World Health Organisation Classification of Vision Impairment 

Albinism

Description:

• congenital (ie present at birth) and hereditary (ie inherited)
• lack in the formation of pigment which can affect all the body’s pigmented structures (hair, skin and eyes) or just one
  ocular albinism - eyes involvement only
  oculocutaneous albinism - eyes, hair and skin involvement
• the student with albinism usually has pale skin, pale eyes (blue or pink) and sandy or fair to white hair. Sometimes the student can have freckles
• the lack of pigment and vision impairment varies from individual to individual
• often associated with other vision impairments (eg nystagmus - a rhythmic oscillation of the eyes which is always present in infants with albinism; myopia - short sightedness).

Implications:

• with little or no pigment in the retina and iris, the eye is extremely photophobic (sensitive to light)
• lack of pigment in the skin means that the skin, too, is sensitive to light and will burn easily
• the macula of the eye is often poorly formed therefore central vision is impaired
• with poor central vision, acuities can be low so visual information may need to be enlarged
• nystagmus may be present to varying degrees
• a squint (a turned eye/strabismus) may be present
• most people with albinism also have refractive errors (ie the shape of the eye causes the image not to focus correctly on the retina).

Suggested teaching strategies:

• ensure that all staff working with the student, including replacement teachers and volunteers, are aware of the vision impairment and its educational implications.

Outdoors:

• the teacher should keep the sun behind the student when addressing him/her
• dark or tinted glasses may be necessary to shield eyes from the light
• sun hats can be useful both to shield the eyes from glare and the skin from the sun
• students may be more comfortable wearing darker colours, especially on their upper body. Light coloured clothing may cause glare and discomfort especially when outside
• the student should carry sun screen and be encouraged to use it. Sun screen can be put in a roll-on dispenser (such as that used for deodorants) for easy application
• a pouch or shoulder bag may be required so that the student can carry their sun screen and other aids at all times
• reading environmental signs eg street signs may cause difficulties.

In the Classroom:

• teachers should be very careful that the student with albinism is never seated facing into light and that his/her nystagmus (where present) is taken into account
• control of light, or more particularly glare, is important in the classroom during school hours. If too much light enters the room, blinds or artwork can be placed over windows. If light cannot be conveniently controlled, a ‘dark corner’ set up for the student to go if s/he chooses may be beneficial. Remember though that eyes need a certain level of light to function. A large umbrella can offer shade over a student’s desk, as required. A beach or golf umbrella could form part of a classroom theme.
• the use of shiny surfaces (eg white boards, shiny paper for flashcards or worksheets, shiny table tops) should be avoided as they can reflect light toward the student’s eyes
• reading material may need to be modified eg tactual diagrams, audio format, braille, enlargement. For young students it may be sufficient to bring reading material close to the eyes
• utilise high contrast materials eg black texta for writing, textas for drawing, coloured paste, using clear bold illustrations to cut around
• bold lined paper may assist
• always use a clean chalk board with white or yellow chalk or white board with black marker. Use a consistent layout when presenting information on a board eg homework is always found on the far right hand side of the board
• a reading/writing stand can often assist, especially in primary school or for prolonged visual tasks. The use of a reading/writing stand will also help to occlude light from the eyes
• for writing sheets or exercise books, recycled paper (creamy or grey coloured) may be better than pure white paper, but remember that contrast is also important
• for older students, a magnifier or CCTV may need to be prescribed for near work. If using a CCTV, students with albinism will usually prefer to read white print on a black background
• paper colour, print size and type of magnification (hand held or stand magnifier, photo-enlargement or CCTV) will need to be assessed on an individual basis
• students will benefit from desktop demonstrations ensuring visual access eg correct handwriting formation of a new letter, science experiment etc
• organisational skills may require development. Developing efficient organisational skills will assist a student with a vision impairment eg having a large pencil case to store pens, calculator and visual aids; setting aside extra time to collect any equipment required; allowing extra time to complete visual tasks etc
• additional verbal description and verification may be required to ensure the student has access to his/her environment eg describe a new classroom or excursion venue, provide verbal praise etc. The student with a vision impairment may miss a smile of encouragement
• the use of a personal computer (eg laptop) may be of great assistance to a student with a vision impairment as an alternative to handwriting and to reduce visual fatigue. Software is available for enlarging text and graphics, including icons, menus etc. Voice output is available for both IBM and Macintosh computers. Individual assessment of the needs of each student is essential. Keyboarding skills should be taught in primary school
• strategies to reduce vision fatigue should be considered eg appropriate visual rests may include listening to audio tapes both for information and relaxation
• students with a vision impairment often need to be taught social skills using a direct teaching approach. Modeling appropriate social behaviors can be difficult when you cannot see them accurately
• students with a vision impairment may need additional orientation and mobility training
• understanding and acceptance of the student’s vision impairment, individual learning modes and work production methods (eg braille, computer etc) may be facilitated through carefully planned simulation activities and class education programs
• older students with albinism may benefit from genetic counseling. They may need advice on the likelihood of having children with albinism. This advice is available through the Royal Children’s Hospital which also conduct clinics at the Royal Women’s Hospital, Monash Medical Centre and in some country centres. Telephone (03) 9345 5157.

These notes were made by the staff of the Statewide Vision Resource Centre. They are general statements and may not apply to all students with this condition.

Aniridia

Description:

• congenital (ie present at birth) and hereditary (ie inherited)
• aniridia means ‘the absence of the iris’ (‘an’ - without, ‘ iridia’ - iris). In actual fact there is usually a thick collar of tissue around the outer edge of the iris but the muscles which open and close the normal pupil are entirely missing. This muscle normally controls the amount of light entering the eye, by opening and closing the pupil (the hole in the iris), as a reflex reaction to light levels. Without this muscle, the eye cannot control the amount of light entering it and hence will be photophobic (sensitive to light)
• the student with aniridia will appear to have no iris or a very large black pupil. Some may have small stubs of iris visible
• except in a few cases, aniridia affects both eyes
• often associated with other eye defects including nystagmus, cataract, glaucoma, or under-development of the fovea
• some students develop an induced ptosis (drooping of the eyelids) as a means of controlling the amount of light entering the eye.

Implications:

• the eye is extremely photophobic (sensitive to light)
• the macula of the eye is often poorly formed therefore central vision is greatly impaired. With poor central vision, acuities can be low so that visual information may need to be enlarged
• nystagmus (a rhythmic oscillation of the eyes which is almost always present in infants with aniridia) will cause a decrease in acuity
• glaucoma (elevated pressure within the eye), if present, may cause peripheral field loss
• contact lenses with an artificial iris may be prescribed. This will improve the appearance of the eye but will also reduce the amount of light entering the eye. The contact lens will not, however, make automatic changes to adjust to different lighting levels as occurs in the normal eye
• some students are prone to headaches.

Suggested teaching strategies:

• ensure that all staff working with the student, including replacement teachers and volunteers, are aware of the vision impairment and its educational implications.

Outdoors:

• teachers will need to be aware of the affects of various light conditions
• the teacher should keep the sun behind the student when addressing him/her
• the student should also be made aware of which lighting conditions are best for him/her. If the student is aware s/he can ask for variations which are favourable or control lighting and shading him/herself
• to reduce photophobia, the student with aniridia may be prescribed tinted spectacles or contact lenses - student and/or teacher may need to be aware of methods of care and cleaning if appropriate
• dark or tinted glasses may be necessary to shield eyes from the light
• sun hats, preferably with a dark coloured brim, can be useful to shield the eyes from light and glare
• students with aniridia may be more comfortable wearing darker colours, especially on their upper body. Light coloured clothing may cause glare and discomfort especially when outside
• reading environmental signs eg street signs may cause difficulties.

In the Classroom:

• seating position within the classroom is critical. The student should be seated taking into account her/his nystagmus (where present), and the light and glare during school hours
• control of light, or more particularly glare, is important in the classroom. If too much light enters the room, blinds or artwork can be placed over windows
• students often prefer artificial room lighting to be turned off
• students with aniridia are extremely sensitive to reflected glare from chalkboards although chalkboards tend to be preferred to whiteboards
• the use of shiny surfaces (eg white boards, shiny paper for flashcards or worksheets, shiny table tops) should be avoided as they can reflect light toward the student’s eyes
• reading material may need to be modified eg tactual diagrams, audio format, enlargement. For young students it may be sufficient to bring reading material close to the eyes
• utilise high contrast materials eg black texta for writing, textas for drawing, coloured paste, using clear bold illustrations to cut around
• for writing sheets or exercise books, recycled paper (creamy or grey coloured) may be better than pure white paper, but remember that contrast is also important
• for older students, a magnifier or CCTV may need to be prescribed for near work. If using a CCTV, students with aniridia will usually prefer to read white print on a black background
• paper colour, print size and type of magnification (hand held or stand magnifier, photo-enlargement or CCTV) will need to be assessed on an individual basis
• bold lined paper may assist
• always use a clean chalk board with white or yellow chalk or white board with black marker. Use a consistent layout when presenting information on a board eg homework is always found on the far right hand side of the board
• a reading/writing stand can often assist, especially in primary school or for prolonged visual tasks. The use of a reading/writing stand will also help to occlude light from the eyes
• many students will benefit from a telescopic distance aid (eg a monocular) for chalkboard work
• students will benefit from desktop demonstrations ensuring visual access eg correct handwriting formation of a new letter, science experiment etc
• organisational skills may require development. Developing efficient organisational skills will assist a student with a vision impairment eg having a large pencil case to store pens, calculator and visual aids; setting aside extra time to collect any equipment required; allowing extra time to complete visual tasks etc
• additional verbal description and verification may be required to ensure the student has access to his/her environment eg describe a new classroom or excursion venue, provide verbal praise etc. The student with a vision impairment may miss a smile of encouragement
• the use of a personal computer (eg laptop) may be of great assistance to a student with a vision impairment as an alternative to handwriting and to reduce visual fatigue. Software is available for enlarging text and graphics, including icons, menus etc. Voice output is available for both IBM and Macintosh computers. Individual assessment of the needs of each student is essential. Keyboarding skills should be taught in primary school
• strategies to reduce vision fatigue should be considered eg appropriate visual rests may include listening to audio tapes both for information and relaxation
• students with a vision impairment often need to be taught social skills using a direct teaching approach. Modeling appropriate social behaviors can be difficult when you cannot see them accurately
• students with a vision impairment may need additional orientation and mobility training
• understanding and acceptance of the student’s vision impairment, individual learning modes and work production methods (eg braille, computer etc) may be facilitated through carefully planned simulation activities and class education programs.

These notes were made by the staff of the Statewide Vision Resource Centre. They are general statements and may not apply to all students with this condition.

Cataracts

Description:

• opacification of the normally clear lens due to a variety of causes
• often associated with aging
• most cataracts are bilateral, but usually progress at different rates in each eye
• cataracts may be:
  congenital - present at birth or developed shortly after birth existing without other impairments; or associated with conditions such as Rubella syndrome, Down syndrome etc.
  acquired - caused by the aging process, trauma or associated with the development of another eye disease (eg glaucoma, diabetes etc).

Implications:

• with cataracts, vision is usually blurred or indistinct, but this depends on the size, position and density of the opacity
• cataracts cause reduced visual acuities - generally the decrease in visual acuity is directly proportional to the size, position and/or density of the cataract
• cataracts cause light to be scattered over the retina meaning that bright light and glare will usually cause problems for the student
• night vision is not usually affected
• as the cataract progresses, near vision is affected first
• colour vision may be affected, especially the perception of blue.

Treatment:

• where cataracts are small or centrally located, acuities may be improved significantly by the regular use of dilating agents (drops or ointment). Dilation of the pupil allows the student to see around the cataract
• where vision is markedly affected, surgery may be recommended. The procedure usually involves removing the entire lens - the eye is then known as aphakic. Aphakia or loss of the lens means that the eye has lost the ability to accommodate (ability to focus the image clearly on the retina)
• an artificial lens may be implanted
• the aphakic student must wear thick spectacles or contact lenses to compensate for the loss of the lens. For reading tasks, reading glasses or bifocals will be prescribed
• for congenital cataracts, surgery is usually undertaken soon after birth. If not, the macula will remain poorly developed.

Suggested teaching strategies:

• ensure that all staff working with the student, including replacement teachers and volunteers, are aware of the vision impairment and its educational implications.

In the Classroom:

• seating position within the classroom is critical. Glare must be minimized - the student usually needs to be seated close to the front of the class with the source of glare behind. If too much light enters the room, blinds or artwork can be placed over windows
• the use of shiny surfaces (eg white boards, shiny paper for flashcards or worksheets, shiny table tops) should be avoided as they can reflect light toward the student’s eyes
• reading material often needs to be modified eg tactual diagrams, audio format, braille, enlargement. For young students it may be sufficient to bring reading material close to the eyes
• utilise high contrast materials eg black texta for writing, textas for drawing, coloured paste, using clear bold illustrations to cut around
• for writing sheets or exercise books, recycled paper (creamy or grey coloured) may be better than pure white paper, but remember that contrast is also important
• always use a clean chalk board with white or yellow chalk or white board with black marker. Use a consistent layout when presenting information on a board eg homework is always found on the far right hand side of the board
• a reading/writing stand can often assist, especially in primary school or for prolonged visual tasks. The use of a reading/writing stand will also help to occlude light from the eyes
• for older students, a magnifier or CCTV may need to be prescribed for near work. If using a CCTV, students with cataracts may prefer to read white print on a black background
• paper colour, print size and type of magnification (hand held or stand magnifier, photo-enlargement or CCTV) will need to be assessed on an individual basis
• bold lined paper may assist
• students will benefit from desktop demonstrations ensuring visual access eg correct handwriting formation of a new letter, science experiment etc
• organisational skills may require development. Developing efficient organisational skills will assist a student with a vision impairment eg having a large pencil case to store pens, calculator and visual aids; setting aside extra time to collect any equipment required; allowing extra time to complete visual tasks etc
• additional verbal description and verification may be required to ensure the student has access to his/her environment eg describe a new classroom or excursion venue, provide verbal praise etc. The student with a vision impairment may miss a smile of encouragement
• the use of a personal computer (eg laptop) may be of great assistance to a student with a vision impairment as an alternative to handwriting and to reduce visual fatigue. Software is available for enlarging text and graphics, including icons, menus etc. Voice output is available for both IBM and Macintosh computers. Individual assessment of the needs of each student is essential. Keyboarding skills should be taught in primary school
• strategies to reduce vision fatigue should be considered eg appropriate visual rests may include listening to audio tapes both for information and relaxation
• students with a vision impairment often need to be taught social skills using a direct teaching approach. Modeling appropriate social behaviors can be difficult when you cannot see them accurately
• students with a vision impairment may need additional orientation and mobility training
• thick glasses can attract unpleasant attention from other students - understanding and acceptance of the student’s vision impairment, individual learning modes and work production methods (eg braille, computer etc) may be facilitated through carefully planned simulation activities and class education programs.

Outdoors:

• glare will cause problems - the teacher should keep the sun behind the student when addressing him/her
• students may be more comfortable wearing darker colours, especially on their upper body. Light coloured clothing may cause glare and discomfort especially when outside
• sun hats can be useful to shield the eyes from glare
• reading environmental signs eg street signs may cause difficulties.

These notes were made by the staff of the Statewide Vision Resource Centre. They are general statements and may not apply to all students with this condition.

Macular Degeneration

Description and implications:

• macular degeneration can be a hereditary disease which causes a disturbance in the part of the retina used for fine discrimination tasks and central vision. It causes a progressive deterioration of the macula (the central part of the retina). The degeneration begins with some disturbance to central vision or maybe a small central scotoma (blind spot) which gradually increases in size
• the ‘blind spot’ is not necessarily a black spot in the field of vision, it may be a greyed area or, a blurred area, or simply an absence of vision
• macular degeneration is more common in the aged (referred to as senile macular degeneration)
• the juvenile form is called Stargardt’s Disease. It may sometimes be referred to as Bull’s Eye maculopathy
• it is necessary for the student with macular degeneration to use eccentric vision (use the parts of the retina outside the central macula area). The discrimination of fine detail will be more difficult using eccentric or peripheral vision
• as the disease progresses, discrimination of detail becomes more and more difficult
• colour vision can also be affected by the loss of central vision. The student may have difficulty discriminating or recognising some hues and shades more than others
• the effects of macular degeneration are difficult to see on the retina (through an ophthalmoscope) in the early stages. For this reason, students have sometimes been mis-diagnosed or diagnosed as ‘hysterically blind’ or functionally amblyopic (temporary blindness caused by psychological trauma)
• electroretinogram testing does not always provide conclusive results until the disease has reached a certain stage of manifestation
• macular degeneration is not treatable. It cannot be prevented or reversed.

Suggested teaching strategies:

• ensure that all staff working with the student, including replacement teachers and volunteers, are aware of the vision impairment and its educational implications
• students with macular degeneration will need to look using the area of their retina outside the affected region. This is called using their ‘eccentric vision’. The best part of the field to be used will depend on the shape and extent of the scotoma. For example, if the scotoma is small, the student may still be able to use the unaffected part of the macula to view close objects. If the scotoma is wide, the student may benefit from using the part of their vision above or below the scotoma. In this case they will need to fixate just above or just below the print. On the other hand, if the scotoma is irregular the student might need to fixate slightly to the left or right of the viewing target
• tracking and scanning techniques will require training and practice
• if there is a refractive error as well, glasses sometimes help. Reading glasses may be prescribed to magnify print materials.
• students with macular degeneration will usually require magnification of reading material. The degree of magnification will depend on the extent of the central scotoma
• for young students, the best form of magnification is simply bringing the print closer to the eyes
• for older students, enlargement may be required or optical magnification aids may be prescribed
• a telescopic aid (eg monocular) may also be helpful to enlarge distant objects
• the use of shiny surfaces (eg white boards, shiny paper for flashcards or worksheets, shiny table tops) should be avoided as they can reflect light toward the student’s eyes
• the utilisation of materials produced in alternative format eg tactual diagrams, large print, audio tapes and braille may assist the student. The use of audio tapes reduces visual fatigue. Braille may be used for labeling and/or general reading
• utilise high contrast materials eg black texta for writing, textas for drawing, coloured paste, using clear bold illustrations to cut around
• bold lined paper may assist
• always use a clean chalk board with white or yellow chalk or white board with black marker. Use a consistent layout when presenting information on a board eg homework is always found on the far right hand side of the board
• a reading/writing stand can often assist, especially in primary school or for prolonged visual tasks
• seating position within the classroom is critical. Students will normally need to be seated in the front row
• students with macular degeneration should be made aware of which lighting conditions are best for him/her. If the student is aware s/he can ask for variations which are favourable or control lighting accordingly. S/he may need additional lighting. This may be provided by a desk lamp at school and at home. Individual assessment as to the most appropriate lamp and globe should be conducted
• students will benefit from desktop demonstrations ensuring visual access eg correct handwriting formation of a new letter, science experiment etc
• organisational skills may require development. Developing efficient organisational skills will assist a student with a vision impairment eg having a large pencil case to store pens, calculator and visual aids; setting aside extra time to collect any equipment required; allowing extra time to complete visual tasks etc
• additional verbal description and verification may be required to ensure the student has access to his/her environment eg describe a new classroom or excursion venue, provide verbal praise etc. The student with a vision impairment may miss a smile of encouragement
• the use of a personal computer (eg laptop) may be of great assistance to a student with a vision impairment as an alternative to handwriting and to reduce visual fatigue. Software is available for enlarging text and graphics, including icons, menus etc. Voice output is available for both IBM and Macintosh computers. Individual assessment of the needs of each student is essential. Keyboarding skills should be taught in primary school
• strategies to reduce vision fatigue should be considered eg appropriate visual rests may include listening to audio tapes both for information and relaxation
• students with a vision impairment often need to be taught social skills using a direct teaching approach. Modeling appropriate social behaviors can be difficult when you cannot see them accurately
• students with a vision impairment may need additional orientation and mobility training
• reading environmental signs eg street signs may cause difficulties
• understanding and acceptance of the student’s vision impairment, individual learning modes and work production methods (eg braille, computer etc) may be facilitated through carefully planned simulation activities and class education programs
• older students with macular degeneration may benefit from genetic counseling. This advice is available through the Royal Children’s Hospital which also conduct clinics at the Royal Women’s Hospital, Monash Medical Centre and in some country centres.
  Telephone (03) 9345 5157

These notes were made by the staff of the Statewide Vision Resource Centre. They are general statements and may not apply to all students with this condition.

Nystagmus Degeneration

• the involuntary, rhythmic movement of the eyes which is independent of normal eye movement
• usually, but not always, secondary to another eye defect where central vision is affected. Conditions to which a nystagmus may be secondary include: albinism, congenital cataract, optic atrophy or hypoplasia, achromatopsia etc
• some forms are not secondary to another condition, but are present without other vision impairments (referred to as congenital nystagmus)
• there are several forms of nystagmus, their names describing the nature of the eye movement (eg jerky, pendular, rotational, undulatory, horizontal, vertical, oblique, roving).

Implications:

• the movement of the eye will cause the image to appear blurred
• measured acuity will be reduced because of the student’s inability to maintain steady fixation. The more the eyes move and the faster they move, the lower the acuity
• the student may adopt an unusual head position or head wobble to decrease the nystagmus
• many students with nystagmus have a ‘null point’ or ‘null zone’ (ie a position of the eyes at which the nystagmus slows or ceases completely). For some students, the null point is reached when the eyes look straight ahead (ie primary position). For these students, the eye movements will increase when they look to either side, up or down. For other students, the null point may be when the eyes point up or down or to one side
• nystagmus will decrease as the eyes converge to look at a close object
• nystagmus will increase when one eye is covered, so that no light enters the covered eye
• nystagmus will increase when the student is tired, nervous, unwell or stressed (eg when reading aloud, sitting tests or exams, after late nights etc)
• the student’s visual functioning will vary according to the changes in the nystagmus ie the vision will worsen with any increase in nystagmus.

Suggested teaching strategies:

• ensure that all staff working with the student, including replacement teachers and volunteers, are aware of the vision impairment and its educational implications
• be aware that stress or tiredness will cause the student’s vision functioning to decrease
• students may not automatically discover their null point. If they have one, they may need to be helped to identify the best eye position and encouraged to use it. To locate the null point, hold a pen or small bright object in front of the eyes. Ask the student to hold his/her head still, and follow the object as it is moved from side to side, and up and down. Watch for any increase or decrease in the nystagmus.

In the Classroom:

• once the null point has been identified, placement of the student in the classroom should take this into account.
• if the null point is when the student looks straight ahead, then s/he should sit so that work is directly in front of him/her (ie centrally in the classroom)
• if the null point is when the student looks down, then chalkboard work, which requires him/her to look up, will be difficult. Worksheets may be preferable in this case
• the student should be encouraged to place their reading material in the most beneficial position in relation to their eyes and their null point
• the student with nystagmus may experience reading problems such as skipping letters or lines. Tracking and scanning skills, which will be difficult for the student with nystagmus, can be developed and practiced. Initially, the use of a ‘reading window’ (a cardboard cut out which only allows the student to see one line of print at a time) may help the student to keep his/her place
• enlargement of reading material is often necessary. This is due to the nystagmus lowering visual acuity and also because the nystagmus is often secondary to a central field loss or other impairment
• reading material often needs to be modified eg tactual diagrams, audio format, braille, enlargement. For young students it may be sufficient to bring reading material close to the eyes
• utilise high contrast materials eg black texta for writing, textas for drawing, coloured paste, using clear bold illustrations to cut around
• bold lined paper may assist
• always use a clean chalk board with white or yellow chalk or white board with black marker. Use a consistent layout when presenting information on a board eg homework is always found on the far right hand side of the board
• students will benefit from desktop demonstrations ensuring visual access eg correct handwriting formation of a new letter, science experiment etc
• organisational skills may require development. Developing efficient organisational skills will assist a student with a vision impairment eg having a large pencil case to store pens, calculator and visual aids; setting aside extra time to collect any equipment required; allowing extra time to complete visual tasks etc
• additional verbal description and verification may be required to ensure the student has access to his/her environment eg describe a new classroom or excursion venue, provide verbal praise etc The student with a vision impairment may miss a smile of encouragement
• the use of a personal computer (eg laptop) may be of great assistance to a student with a vision impairment as an alternative to handwriting and to reduce visual fatigue. Software is available for enlarging text and graphics, including icons, menus etc. Voice output is available for both IBM and Macintosh computers. Individual assessment of the needs of each student is essential. Keyboarding skills should be taught in primary school
• strategies to reduce vision fatigue should be considered eg appropriate visual rests may include listening to audio tapes both for information and relaxation
• students with a vision impairment often need to be taught social skills using a direct teaching approach. Modeling appropriate social behaviors can be difficult when you cannot see them accurately
• understanding and acceptance of the student’s vision impairment, individual learning modes and work production methods (eg braille, computer etc) may be facilitated through carefully planned simulation activities and class education programs.

Outdoors:

• depth perception may be poor therefore the student may have problems with stairs, judging distance, ball skills etc
• students may have trouble using a monocular for distance viewing, as occluding one eye usually causes the eye movements to increase. The student may, instead, be prescribed a set of binoculars
• students with a vision impairment may need additional orientation and mobility training
• reading environmental signs eg street signs may cause difficulties.

These notes were made by the staff of the Statewide Vision Resource Centre. They are general statements and may not apply to all students with this condition.

Retinitis Pigmentosa (RP)

Description:

• retinitis pigmentosa (PR) is a hereditary eye disease which causes degeneration of the retina. The retina slowly degenerates and loses its ability to transmit images to the brain. Characteristic clumps of pigment appear on the retina in later stages of RP (this is seen through an ophthalmoscope)
• there are different genetic forms of RP
• the student with RP often loses peripheral vision first, often described as ‘tunnel vision’. In some cases there is a central vision disturbance at the same time as the peripheral vision is degenerating. In many cases central vision retains relatively high acuity, whilst there is an absence of receptors in the periphery (ie cone cells)
• one symptom of RP is ‘night blindness’. Night blindness occurs because central vision does not function with low illumination
• RP can eventually lead to total blindness, though most people retain limited vision for years after diagnosis. Statistics suggest that the earlier the onset of the RP, the more the vision will degenerate. Degeneration rates differ from individual to individual. For some, vision loss is slow, whilst for others vision loss may occur rapidly, or in bursts and plateaus
• a person with less than 10° of visual field remaining is classified as ‘legally blind’, and is eligible for the blind pension at 16 years of age. The handicapped child allowance is available to a legally blind child under the age of I6 years.

Some syndromes which include RP:

• Usher’s Syndrome - this syndrome includes hearing impairment. There are two types of Usher’s Syndrome - type one and type two. The students with type one are more likely to develop symptoms of RP earlier than those diagnosed with type two
• Laurence-Moon-Bardet-Beidl Syndrome - the symptoms of this syndrome can include RP, polydactyly (extra digits), obesity, intellectual impairment, congenital heart disease, scantness of body hair, shortness of stature and genital hypoplasia (underdeveloped genitals).

Suggested teaching strategies:

• ensure that all staff working with the student, including replacement teachers and volunteers, are aware of the vision impairment and its educational implications
• illumination is critical for student with RP. A student with RP will require high illumination to avoid ‘night blindness’. Some students may require additional illumination (eg a lamp), to be used at their desk. High quality torches can be useful for dark areas eg keep a torch in a locker to assist with locating books, a penlight in a pencil case can be useful, a penlight attached to a key ring is useful for negotiating a locker key and a torch beside the student’s bed when on school camp - for those middle of the night toilet trips
• orientation and mobility difficulties may occur due to peripheral vision loss. A student with RP will need to be taught to turn his/her head to see beyond his/her field of view. Students with a RP may need additional orientation and mobility training
• students with limited central visual field may benefit from a reduction in the size of print they use
• consider contrast when producing/presenting materials to a student with RP
• the use of shiny surfaces (eg white boards, shiny paper for flashcards or worksheets, shiny table tops) should be avoided as they can reflect light toward the student’s eyes
• reading material often needs to be modified eg tactual diagrams, audio format, braille, enlargement. For young students it may be sufficient to bring reading material close to the eyes
• reading strategies may need to be developed to compensate for a narrowed field of view. With a reduced field, the student will see only a few words or letters at a time. Visual memory and the ability to ‘chunk’ information can be a helpful strategy
• utilise high contrast materials eg black texta for writing, textas for drawing, coloured paste, using clear bold illustrations to cut around
• bold lined paper may assist
• consider acceptance of impairment. A student with a degenerative impairment may be going through a grieving process. Loss of peripheral vision can cause mobility difficulties which can produce anxiety and a loss of confidence in moving about in the environment
• keep the classroom layout as static as possible
• always use a clean chalk board with white or yellow chalk or white board with black marker. Use a consistent layout when presenting information on a board eg homework is always found on the far right hand side of the board
• assist student in locating where s/he is required to look eg ‘The handwriting task is on the left hand side of the chalkboard’
• the speaker should be in front of the student with RP (or best field of vision), particularly with students with an additional hearing impairment
• students will benefit from desktop demonstrations ensuring visual access eg correct handwriting formation of a new letter, science experiment etc
• organisational skills may require development. Developing efficient organisational skills will assist a student with a vision impairment eg having a large pencil case to store pens, calculator and visual aids; setting aside extra time to collect any equipment required; allowing extra time to complete visual tasks etc
• additional verbal description and verification may be required to ensure the student has access to his/her environment eg describe a new classroom or excursion venue, provide verbal praise etc. The student with a vision impairment may miss a smile of encouragement
• the use of a personal computer (eg laptop) may be of great assistance to a student with a vision impairment as an alternative to handwriting and to reduce visual fatigue. Software is available for enlarging text and graphics, including icons, menus etc. Voice output is available for both IBM and Macintosh computers. Individual assessment of the needs of each student is essential. Keyboarding skills should be taught in primary school
• strategies to reduce vision fatigue should be considered eg appropriate visual rests may include listening to audio tapes both for information and relaxation
• students with a vision impairment often need to be taught social skills using a direct teaching approach. Modeling appropriate social behaviors can be difficult when you cannot see them accurately
• understanding and acceptance of the student’s vision impairment, individual learning modes and work production methods (eg braille, computer etc) may be facilitated through carefully planned simulation activities and class education programs
• reading environmental signs eg street signs may cause difficulties.

Some useful resources:

• ‘Retina Australia’ (formerly The Retinitis Pigmentosa Society or RP Society) represents people who live with Retinitis Pigmentosa and other Retinal Dystrophies.
  Phone: 03 9650 5088.
• ‘Usher’s Syndrome - Vision and Hearing Loss’ (information kit), produced by, The Usher Committee c/o Deaf Blind Care Association, PO BOX 267, Clifton Hill 3068.
  Phone: (03) 9482 1155.

These notes were made by the staff of the Statewide Vision Resource Centre. They are general statements and may not apply to all students with this condition.

Retinopathy of Prematurity (ROP) / Retrolental Fibroplasia (RLF)

Description and implications:

• Retinopathy of Prematurity (ROP) is most often seen in premature infants who received oxygen therapy, although it does occasionally occur in full-term infants. The severity of ROP may range from minimal ocular damage with no vision impairment to complete retinal detachment and scaring that can cause total blindness. The extent of the condition depends on many factors, including the length of time the infant received oxygen and the amount of oxygen that was administered. There is no effective treatment, however careful monitoring of the blood levels of premature infants and the use of oxygen only when necessary to prevent death or brain damage significantly reduced the number of students affected by this condition. ROP was a major cause of vision impairment in the 1940s and 1950s when unlimited oxygen was given to premature babies. It is becoming an important cause of vision impairment again in the 1990s as more low-birth weight infants are surviving
• ROP almost invariably affects both eyes within a few weeks of birth, particularly when the birth weight is less than 1200 grams and where the concentrations of oxygen is in excess of 30 per cent. The oxygen causes a sequence of events in the immature retinal vessels:
  i) vasoconstriction which leads to vaso-obliteration during exposure to oxygen: in the presence of too much oxygen, the immature blood vessels in the retina spasm and close down
  ii) vasoproliferation after removal from the oxygen: when the supplemental oxygen is withdrawn, the area where the vessels have closed down becomes anoxic. To supply the anoxic tissue, new vessels quickly invade from the adjacent retinal tissue. These invading vessels are abnormal and leak, causing oedema (swelling) of the retinal tissue. Later this area becomes fibrotic which leads to scarring which may, in a small number of premature babies, cause detachment of the retina
• depending on the extent of the vascular damage to the retina, the student may have areas of normal or near-normal vision. If these areas are in or near the macula (the area of the retina responsible for fine discrimination tasks eg reading), the student will be more able to access printed material. Where visual fields are fragmented, the student will have difficulty with visual closure (eg interpreting maps and diagrams). Severe ROP can result in total blindness
• associated conditions may include microphthalmus (a small underdeveloped eye), moderate to severe myopia (near sightedness), amblyopia (lazy eye) may result if the student’s refractive errors are significantly different, glaucoma, cataracts and uveitis are common secondary problems
• a significant number of these students will have brain damage which may result in learning difficulties.

Suggested teaching strategies:

• ensure that all staff working with the student, including replacement teachers and volunteers, are aware of the vision impairment and its educational implications
• if the student has a refractive error in addition to the ROP, glasses may be prescribed
• students may require magnification of reading and graphic material. This can be achieved by bringing the material closer to the eye, or by the use of prescribed magnification aids - hand held magnifiers or reading spectacles for near work or monocular/miniscope for distance viewing. A closed circuit television (CCTV) may be found to be beneficial especially in the primary years when students tend to move around less. It may be necessary to enlarge some or all of the students work, but it is usually preferable for the student to use a hand held magnifier competently as this skill will assist the student to operate independently with other out-of-school tasks
• if the student has patchy fields, enlargement may not be of assistance. Enlargement of reading material will mean that fewer letters are seen in the restricted visual field. If lowered acuity necessitates enlargement, ensure that the optimum print size is used (ie the minimum print size which can be sustained), and implement a program to gradually decrease the print size managed
• students with ROP may need good lighting for reading tasks. A lamp may be necessary
• the use of shiny surfaces (eg white boards, shiny paper for flashcards or worksheets, shiny table tops) should be avoided as they can reflect light toward the student’s eyes
• always use a clean chalk board with white or yellow chalk or white board with black marker. Use a consistent layout when presenting information on a board eg homework is always found on the far right hand side of the board
• reading material often needs to be modified eg tactual diagrams, audio format, braille, enlargement. For young students it may be sufficient to bring reading material close to the eyes
• utilise high contrast materials eg black texta for writing, textas for drawing, coloured paste, using clear bold illustrations to cut around
• bold lined paper may assist
• reading strategies may need to be developed to compensate for a narrowed field of view. With a reduced field, the student will see only a few words or letters at a time. Visual memory and the ability to ‘chunk’ information can be a helpful strategy
• students with patchy fields may need to look using a less affected area of their retina. This is called using their ‘eccentric’ vision
• tracking and scanning techniques will require training and practice
• depending on the amount of residual vision, and the amount of remaining field of vision, the student with ROP may be very clumsy and have mobility difficulties
• field disturbances may mean that the student must turn his/her head to see beyond his/her field of view
• students will benefit from desktop demonstrations ensuring visual access eg correct handwriting formation of a new letter, science experiment etc
• organisational skills may require development. Developing efficient organisational skills will assist a student with a vision impairment eg having a large pencil case to store pens, calculator and visual aids; setting aside extra time to collect any equipment required; allowing extra time to complete visual tasks etc
• additional verbal description and verification may be required to ensure the student has access to his/her environment eg describe a new classroom or excursion venue, provide verbal praise etc. The student with a vision impairment may miss a smile of encouragement
• the use of a personal computer (eg laptop) may be of great assistance to a student with a vision impairment as an alternative to handwriting and to reduce visual fatigue. Software is available for enlarging text and graphics, including icons, menus etc. Voice output is available for both IBM and Macintosh computers. Individual assessment of the needs of each student is essential. Keyboarding skills should be taught in primary school
• strategies to reduce vision fatigue should be considered eg appropriate visual rests may include listening to audio tapes both for information and relaxation
• students with a vision impairment often need to be taught social skills using a direct teaching approach. Modeling appropriate social behaviors can be difficult when you cannot see them accurately
• students with a vision impairment may need additional orientation and mobility training
• understanding and acceptance of the student’s vision impairment, individual learning modes and work production methods (eg braille, computer etc) may be facilitated through carefully planned simulation activities and class education programs
• ball games may be difficult. Ensure that teachers are aware of this and provide as many auditory cues as possible
• reading environmental signs eg street signs may cause difficulties
• where the student cannot access printed material, braille tuition may need to be introduced, This will require careful introduction and timing
• students with ROP are sometimes small in stature and staff and students may be disposed to treat them as if they are younger than their chronological age. It is important to encourage independence and age appropriate behaviour at all times.

Note: Students with significant residual ROP changes can be at risk of further damage to the retina including retinal detachment. Some retinal specialists advocate that they be warned against undue exertion and contact sports.

References:
Jose, R. T., Understanding Low Vision, American Foundation for the Blind, 1983.
Wybar, K., Ophthalmology, Balliere, Trindall & Cassell, London, 1966.
Scott, E., Your Visually Impaired Student - A Guide for Teachers, University Park Press, USA, 1982.
Goble, I.L. Visual Disorders in the Handicapped Child, Marcel Dekker Inc., New York, 1984.
Vaughan. D., Asbury. T., General Ophthalmology, 11th Edition, Appleton-Century-Crofts, Prentice Hall, USA, 1986.

These notes were made by the staff of the Statewide Vision Resource Centre. They are general statements and may not apply to all students with this condition.

lmplications of Sight in One Eye Only

The student with normal vision in one eye should be able to read regular size print and to access visual information in the classroom as efficiently as students with normal two-eyed vision. S/he should have no difficulty with reading from the chalkboard, seeing a TV screen or projector screen, or discriminating objects in the distance. S/he may, however, experience some difficulties with eye- hand coordination or mobility. Use the following as a guide, or ask your Visiting Teacher for the Vision Impaired for more specific advice.

Check on prognosis for other eye:

• check with parents or specialists
• teachers need to be aware of any prognosis for vision in the remaining eye
• know what signs indicate a degeneration in vision
• know what action should be taken if these signs appear.

Restriction to field of view:

• with normal vision in both eyes, the field of view is about 175°
• with vision in only one eye, this is restricted to about 100°
• the field is absent on the side of the affected eye.

Implications:

• the student will not see objects or activity on his/her ‘blind’ side
• student may bump into objects on ‘blind’ side
• try to approach student from side of better vision
• student will need to move head into ‘blind’ side to compensate for reduced field
• student will need to be especially aware of road safety one ‘blind’ side.

Lack of depth perception:

We need two eyes to triangulate to perceive depth or distance from objects. With one-eyed vision, a student will need other strategies to compensate for this deficit.

Implications:

• student may have difficulty in sporting activities which involve judgment of distances (eg ball sports, hurdles, golf, high jump etc)
• eye-hand coordination may be affected if student cannot grasp accurately for objects or judge whether they are within reach (eg putting brush in clag bottle or paint pot, threading activities etc)
• mobility may be affected, especially when on contoured ground (eg walking up/down unfamiliar steps, negotiating contoured terrain etc).

Strategies for compensating for lack of depth perception:

Lack of depth perception can be compensated for by judging size and position of objects or by using ‘motion parallax’.

Size and Position

We learn that objects become smaller as they move further away and larger as they come closer. If we know the size of an object, we can often judge its distance by its apparent size.

Implications:

• show student the size of a ball before playing a game
• build up student’s awareness of common object sizes

Implications:

• make the student aware of this and practice using it for judging the distance between objects
• student should move his/her head when trying to judge distance between objects. This will tell student which objects are closer.

What is Visual Acuity?

Visual acuity refers to:

Visual acuity refers to the measure of ‘the eye’s ability to see at both short and long distances and to distinguish detail and shape. Each eye has its own level of visual acuity and this can vary considerably. The standard or normal visual acuity is 6 over 6 or 6/6 in each eye’. (Royal Blind Society of New South Wales - ‘A Vision to Share - a Resource for Secondary Teachers’).

Distance visual acuity:

The capacity of the eye to resolve fine detail is measured by determining the smallest size print/picture symbol that the student is able to read. The student’s visual acuity is recorded as a ‘Snellen fraction’, the numerator representing the testing distance and the denominator indicating the smallest letter/picture symbol size the student is able to read. A student who has a visual acuity of 6/24 sees at 6m what the ‘normal’ (ie 6/6 vision) eye can see at 24m.

Near visual acuity:

Determining near vision acuity involves assessing the capacity of the eye to resolve fine detail. Near vision acuity is recorded as an N point size. The N point refers to a measure of print size used by printers.

The DOE Visiting Teacher Service (VI) assess near vision acuity using Gayle Lamb’s ‘Near Vision Test for Children (NVTC)’.

The N point size indicated on the Educational Vision Assessment Clinic reports (and other ophthalmologist’s reports) refers to the minimum size print a student can resolve. A vision impaired student often requires a different size print for sustained reading. The NVTC is also used to ascertain an appropriate sustained print size.

Parts of The Eye

Eye:

• roughly spherical in shape and with a diameter or 23 mm
• contained at the back by the Sclera and at the front by the Cornea.

Cornea:

• composed of clear tough fibrous tissue
• no blood vessels
• allows light into the eye.

Aqueous Fluid:

• clear fluid manufactured and circulated within the front of the eye which escapes by the Canal of Schlemm and is finally absorbed into the blood stream
• provides nutrition to the front of the eye
• together with the Vitreous, it is the means of maintaining the pressure within the eye.

Canal of Schlemm:

• located within the front part of the eye
• circular vein which provides an outlet for a fluid known as the Aqueous.

Iris:

• coloured part of the eye which can be seen through the Cornea
• has a central hole called the pupil
• by means of two muscles, the iris can rapidly alter the size of the pupil depending on the amount of light available.

Lens:

• alters shape to focus the image on the retina.

Vitreous Fluid:

• clear liquid towards the back of the eye through which light passes.

Retina:

• delicately thin membrane covering the back part of the inside of the eyeball
• contains light sensitive cells - cones (responsible for fine discrimination and colour vision) and rods (responsible for peripheral vision and vision in dim light).

Macula:

• area of 1-3 mm in diameter
• area of the retina where cone cells are most abundant and therefore responsible for fine discrimination.

Fovea:

• situated at the centre of the Macula
• responsible for the finest of fine discrimination.

Optic Nerve:

• nerve endings from the Retina join and leave the eye at the point of the Optic Disc (Blind Spot)
• images are received by the Retina and transmitted to the brain via the Optic Nerve.

References:

Marshall, G. H., The Eyes and Vision, 8th edition, n.d.
Roy, F. D., Ocular Syndromes & Systemic Diseases, 2nd edition, Saunders, Philadelphia, 1989.
Vaughan, D. & Asbury, T,. General Ophthalmology, 13th edition, Lange Medical Publication, California, 1992

Environmental Considerations

Contrast:

• consider the contrast of work surfaces - use contrasting coloured cloth (eg a piece of black felt), coloured tray, a place mat, contact a surface or paint the surface with a mat, contrasting colour
• consider making visual stimulus more visible - eg putting stripes on a drinking cup with electrical tape
• consider areas in the school environment which need to be made more visible - eg edge of steps, outlining a light switch, defining doorways. A painted strip (usually yellow or white) can be used to provide greater contrast in these areas.
• consider the clothes you wear - eg don’t ask a student to look at a red object you are holding in front of your red jumper
• wearing lipstick can highlight the teacher’s face. A glitter wig also provides an excellent contrast.
• a class teacher wearing bright clothes is easy to find, particularly when on excursions (in unfamiliar environments)
• when producing materials for a student, consider contrast - eg does the student require bold lines around the compics or shapes to cut around? Is colour appropriate to use to highlight compics?
• work production - bold line paper and black felt tipped pens increase contrast for a student
• allow students to use texta colours when drawing/colouring.

Lighting:

• ensure lighting conditions are appropriate to the student’s vision impairment -
  ie does the student require high or low levels of illumination?
• additional lighting maybe required - eg use of a desk lamp to increase the contrast on the work surface
• torches can be useful to a student experiencing difficulties in areas of low illumination eg locker, school bag and dark corners of a room
• consider position, colour, type and intensity of light source
• consider lighting conditions in all areas of the school environment (inside and outside) in which the student will be operating - eg stairs, covered walkways, locker areas and toilets.

Glare:

• is the student sensitive to glare - eg photophobia?
• never position a student facing a light source (natural or artificial)
• teach from a position without a light source coming in from behind you
• consider sunglasses and a hat, particularly when working/playing outside (some students may not be able to tell you that they are experiencing difficulties - check their medical report)
• reduce glare in the classroom - eg use blinds, curtains, posters to cover windows producing glare. Position a beach umbrella over the students table to reduce glare from overhead lighting.
• avoid glare on tasks, work surfaces etc eg avoid using glossy paper and toys/work surfaces painted in high gloss
• consider the placement of computer screens to minimize glare.

Seating:

• discuss with Visiting Teacher, Physiotherapist and/or Occupational Therapist involved as to most appropriate seating position prior to vision stimulation
• ensure the student is in a comfortable position before beginning vision stimulation activities
• consider vision impairment - where is the student’s best field of view? (including null position)
• consider low vision aids - if the student is using a telescopic aid, they may need to sit towards the back of the room
• if contact lenses and/or spectacles are worn what distance/s have they been set at?

Organisation:

• keep classroom environment static
• alert student to any changes in the room layout
• a student may need extra storage room for equipment etc.

Other Considerations

Time:

• a student with a vision impairment may require additional time to investigate a visual stimulus
• allow the student time to respond to visual stimuli
• some students may experience epileptic ‘absences’ (during an ‘absence’ a student’s pupil may dilate, the student may increase eye blinking and/or the student’s body may ‘still’). During the ‘absence’ cease any vision stimulation activities and repeat activity (including instructions) when student has stopped having any epileptic activity. (Refer to student’s medical information).
• allow the student additional organisational time eg when asked to pack up and collect school bag, coat and home work.

Visual Responses:

• a student’s responses to a visual stimulus may be subtle - eg turning head to avoid stimulus, turning head to look, body startling, widening of eyes, blinking, increase or decrease of body activity, a change in breathing patterns and/or smiling
• record the responses the student uses (including the stimulus responded to) for future reference
• make use of checklists
• share the information with others involved in the student’s program
• work with a partner when observing visual responses
• learning may be subtle and occur slowly over time ‘good’ evaluation requires careful programming and assessment.

Size:

• consider the size of stimulus used - eg toys, compic - do the diagrams need enlarging or reducing?
• record student responses to sizes trialed
• consider the size of print the student requires to access information on the chalk/white board.

Teaching Strategies:

• ensure activities are age appropriate
• use opportunities in student’s daily routine to stimulate vision
• consider generalisation of skills
• reduce visual clutter
• consider vision fatigue. Watch for signs of vision fatigue - eg red eyes, rubbing eyes, watering eyes and/or headaches. Allow for rest breaks or alternate with visual and non visual activities - eg listening to taped materials
• encourage eye contact. Eye contact is important in developing social skills
• verbalise environments/activities using directional language
• provide verbal warnings - eg say the student’s name and verbalise what is about to happen
• encourage ‘looking’ by using words such as ‘look’, ‘find’ and ‘see’
• ensure all relevant staff are aware of the student’s vision impairment and the related implications.

Low Vision Aids and Equipment:

• consider the appropriateness of using low vision aids (hand held magnifiers and/or telescopic aids) eg when learning to read presentation of material in large print is usually preferable to the use of regular print in conjunction with a magnifier.

WHO Classification

A modification of the World Health Organisation’s internationally accepted Classification of Visual Performance has been adapted for educational purposes and provides a useful frame of reference to determine the degree of vision for distance tasks.

HM - Hand Movements
LP - Light Perception
NLP - No Light Perception

Reference: Colenbrander, A. A Dimension of Visual Performance. Trans. Am. Acad. Ophthalmol. Otolaryngol. 1977 83:332 - 337.

The following link provides further information about the services offered by Visiting Teachers - Vision Impaired and referral processes
Educational Vision Assessment Clinic
About Visiting Teachers - Vision Impairment

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