Cataract

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.