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Low Vision Practical Hi Tech Solutions for by jennyyingdi


									Rehabilitation Article

Low Vision: Practical and Hi-Tech Solutions for
Visual Impairment and Blindness

        ccess to care of the partially                                               reading the label on a prescription
        sighted and blind has been limit-                                            medication bottle, reading the daily
        ed, for the most part, to devel-                                             newspaper, being able to access the
oped nations. But that is all beginning                                              computer screen, travelling indepen-
to change in our ‘flat-world’ hi-tech                                                dently and safely in an unfamiliar area,
society.1                                                                            being able to see the Professor’s
   On December 16, 2004, the WHO                                                     PowerPoint presentation in college,
released new data on the prevalence of                                               being able to see the markings on the
global blindness.2 It was noted that,                                                insulin gauge, reducing glare in the
                                                                                                                                Dr Bruce P Rosenthal is the Chief
according to the figures compiled in A patient with age-related macular              environment, accessing your PIN code,
                                                                                                                                of the Low Vision Clinical Practice
2002, there were 161 million people who degeneration using a strong (microscopic) seeing the menu at a fast food restau-        at Lighthouse International in
are visually impaired.3 Of these, 124 mil- reading lens.                             rant, or using the ATM in the Bank. The    New York City, Adjunct Professor
lion are considered to have low vision4                                              history will also investigate comorbidi-   at Mt Sinai Hospital, Distin-
                                                                                                                                guished Professor at State
and 37 million are considered to be blind.5 Of these, 90%      ties, such as diabetes or stroke and how they may affect the
                                                                                                                                University of New York, and Chair
of the world’s blind live in developing countries: nine mil-   patient’s goals and objectives as well.                          of the Scientific Advisory Board of
lion in India, six million in China and seven million in          The low vision examination also consists of a spe-            the AMD Alliance International.
Africa.6                                                       cialised battery of tests designed to evaluate the patient’s     He lectures throughout the world,
                                                                                                                                has authored of eights books on
   But only four major eye conditions result in almost         visual function. It includes specially designed vision
                                                                                                                                visual impairment and macular
75% of the world’s individuals having low vision. They         charts that measure even the lowest levels of vision. The        degeneration as well as over 100
include age-related macular degeneration, glaucoma, dia-       preferred visual acuity chart for testing is the ETDRS           scientific articles.
betic retinopathy, and cataracts.                              (Early Treatment of Diabetic Retinopathy) chart which is
   Vision care has become very specialised in developed        also used for all clinical trials in the United States.7 These
                                                                                                                                Correspondence to:
nations. There are anterior segment (corneal, glaucoma,        logarithmic charts have been statistically validated to          Email: BROSENTHAL@
contact lens, and cataract specialists) posterior segment      record changes in vision over time as well as to record
(retinologists), paediatric, sports medicine, neuro, as well   vision as low as 1/40 (20/800). Patients with vision of less
as low vision specialists. The latter are involved in the care than 2/40 (20/400) may have need of other vision rehabil-
of the partially sighted or visually impaired. The low         itation services such as mobility in order to learn how to
vision clinicians include optometrists or ophthalmolo-         travel safely and independently in their environment.
gists worldwide who have special training in managing          Individuals possessing only light perception or no vision
individuals with reduced vision as well as irreversible        al all (functionally blind) will also be referred for mobili-
vision loss in both eyes.                                      ty training in the use of a cane.
   The specialty of low vision is considered to be a tertiary     Contrast sensitivity functional (CSF) testing was added
area of care in which patients are not only under the care     to the low vision battery of tests by the author and Eleanor
of a low vision clinician but the care of a specialist man-    Faye, MD in 1981. CSF measures the ability to see objects
aging the eye pathology (eg retinal or glaucoma special-       (eg print, road signs), as the contrast decreases. That is,
ist). The patient, in fact, may be managed in a multi-spe-     how black does an object have to be, before it can be seen.
cialty group practice taking care of all the vision related    Contrast sensitivity is becoming an important outcome
problems. They may also be in a private practice specialis-    measure in patient management as it relates to quality of
ing in low vision, as well as in a vision rehabilitation       life issues. It is affected by the major pathologies such as
organisation, a university or hospital based eye clinic, as    macular degeneration, cataracts, and diabetic retinopathy.
well as veterans administration blind rehabilitation cen-      Magnification, the usual method of improving perfor-
ters (in the US: Chicago, Atlanta, Palo Alto, W. Haven Ct.).   mance, may not be as effective as much as enhancing the
   Vision rehabilitation services and teamwork are gener-      contrast by strategies such as increasing the illumination
ally required and provided, regardless of whether it is a      in all environments.
congenital, early onset, or adventitious aetiology. The           It is important to map out the visual field using auto-
vision rehabilitation team includes the optometrist or         mated perimetry, as well, in eye diseases such as glaucoma,
ophthalmologist specialising in low vision and care of the     optic nerve disease and systemic conditions such as
partially sighted. It is their primary responsibility to per-  stroke. Trauma may also lead to significant loss of the
form the low vision evaluation as well as prescribe and        visual field as does retinitis pigmentosa. The latter is a
design low vision devices. The other members of the            progressive disease that generally results, not only in a loss
vision rehabilitation team include the social worker to        of the peripheral vision but night blindness, and signifi-
deal with issues such as: vision loss, depression, family      cant mobility problems. There is no treatment at this time
dynamics, and loss of independence. The team also              to slow the degeneration of the peripheral retina but
includes a vision rehabilitation specialist or occupational    exciting genetic research (eg ABCR gene)8 may lead to a
therapist (OT) to instruct patients in the use of the low      cessation of progression. Again mobility, or newer hi-tech
vision devices as well as to teach them independent living     methods such as use of the GPS, especially when the visu-
skills. Mobility specialists may be called upon, as well, for  al field is severely compromised, will be essential for inde-
the teaching of independent travel, along with educators       pendent travel.
of the visually impaired and job placement specialists.           The other examination components include a spe-
                                                               cialised low vision refraction test to determine whether a
The Clinical Low Vision Examination                            spectacle correction will be beneficial for distance, inter-
The specialised low vision evaluation is a functionally ori-   mediate, and near tasks, an Amsler grid to evaluate the
ented examination to determine patient specific objec-         central 20 degrees of the visual field, as well as an ocular
tives and needs, to maximise the residual vision with pre-     health analysis.
scriptive lenses, low vision devices, and hi-tech solutions.      The ability to enhance visual function is one of the
These objectives may include such diverse demands as,          objectives of the evaluation and magnification and

                                                                                                                                 Rehabilitation Article

enhancing the CSF are ways of achieving this            speech recognition systems that allow for voice        dichotomy in the preferred method of travel
objective. Increasing the magnification can be          input commands, screen synthesisers also               among the different vision rehabilitation
done in three ways: relative size, relative dis-        known as text to speech systems that allow             organisations in the US.
tance, and angular magnification. In relative           blind users to play back their Word document              One of the newer methods of travel is by use
size magnfication, the object of regard can be          including the words, numbers, and punctua-             of the GPS systems such as Trekker. They have
physically enlarged such as the print in a large        tion. Other programmes for the blind include           adapted the system for people who are blind or
print book. The object of regard can be brought         refreshable Braille in which a line of print is dis-   visually impaired and allow them access to talk-
closer to the eye, in relative distance magnifica-      played and then will refresh to play another           ing menus, talking maps and GPS information.
tion, so that the object subtends a larger retinal      line, a Braille embosser that has the capability       There are other features enabling the user to
image and appears much larger. In angular               of transferring computer generated images into         determine his or her position, including the
magnification the object can be made to appear          embossed Braille, talking word processors, as          street address and the surrounding intersec-
to be closer to the eye and thus appear larger (eg      well as large print processors.9 In addition           tions.
seeing the train or airport departure board).           Microsoft has included tutorials for the blind            There are traditional as well as hi-tech strate-
   Low vision devices will generally allow the          and visually impaired for programmes ranging           gies that will significantly improve the quality
user to bring an object closer to the eye and           from Windows XP to accessing the internet.             of life, regardless of the extent of vision loss.
thus magnify the retinal image size. Enhancing             Accessing the ATM has been difficult if not         And accessing those strategies is easy for
the contrast is a different story and may require       impossible for the blind and partially sighted.        everyone through websites such as
a hi-tech device, a filter, as well as techniques       This has begun to change with the Northern   
such as using a bold line pen when writing.             Bank and Clydesdale Banks in Belfast and                  Access to low vision care, as well as access to
   In addition to prescriptive lenses for distance      Glasgow as well as Bank of America in San              reimbursement for low vision devices varies
(televison, theatre), intermediate (reading             Francisco launching systems that are truly             tremendously around the world. The Medicare
music, the computer screen), and near tasks             accessible. The Northern Bank’s ‘cashpoint’ is         programme in the United States, for example,
(reading) are specialised low vision devices. The       used by plugging a set of headphones into a            does not cover the cost of a low vision evalua-
low vision devices includes strong reading lens-        jack, which is fitted to the front of the ATM.         tion or low vision devices. Governments as well
es (microscopic lenses), magnifying systems             The machine uses an automated voice to give            as non-governmental organisations have to
(hand and stand magnifiers), telescopic systems         instructions about the exact location of items         begin recognising the low vision health crisis
(for use in museums, independent travel or,             such as the numbers on the keypad, the cash            throughout the world as well as include the
classroom work), absorptive lenses and filters          dispenser and all other devices on the machine.        visually impaired in health care programmes.
(for reducing glare as well as increasing the           It also talks through each stage of the process,       We have the solutions for improving the quali-
contrast), and hi-tech devices that are known as        whether a user wants to check a balance or             ty of life in visually impaired people of all ages.
closed-circuit televisions.                             withdraw cash. Sighted users can also use the          We must now look for the collective strategy as
   High plus microscopic lenses are readily             machine by following instructions displayed on         well as funding to increasing access and avail-
available up to 12x (48 diopters – focal distance       screen.10,11                                           ability, regardless of level of vision impairment,
of less than 2.03cm) magnification. Optical                Even shopping in mega stores such as                as well as socio-economic status.
magnification, for all practical purposes is good       WalMart in the United States is becoming more
up to 6x (24 diopters; focal distance 4.1cm).           accessible. WalMart has begun to install state-
Most individuals cannot manage the close                of-the art point of sale devices in their stores to
working distance or the restricted depth of field       protect the privacy and security of shoppers
in high magnification systems. Illuminated              with visual impairments. They explain that             References
magnifiers, especially illuminated stand magni-         the12 new devices have tactile keys arranged like      1. Friedman TL. The World is Flat. A Brief History of the
                                                                                                                   Twenty-first Century Farrar, Straus, and Giroux, NY,
fiers that sit on the page are available up to 15x      a standard telephone keypad and will allow                 2005.
(60 diopters). The image stays in focus since the       shoppers who have difficulty reading informa-          2.
magnifier sits on the page but the field of view        tion on a touchscreen to privately and indepen-        3. Visual impairment is vision loss involving the loss of an
as well as ease in reading significantly decreases      dently enter their PIN and other confidential              area of visual function (e.g. Visual acuity, visual field,
as the magnification increases.                         information.                                               contrast sensitivity, color vision)
   That is where the closed circuit television             But the holiday season will also be accessible      4. The definition of low vision used by the WHO: Low
comes into play. As the world moves ahead to a          throughout the world with talking catalogues,              vision is visual acuity less than 6/18 (20/60) and equal
                                                                                                                   to or better than 3/60 (in the better eye with best cor-
hi-tech age, so will the field of low vision,           accessible accounting and cheque writing pro-              rection).
enabling individuals with the most profound             grammes for the blind and visually impaired,           5. Blindness refers to a total loss or no usable vision.
vision loss access to information on the web.           talking barcode readers, as well as talking            6.
The closed-circuit television, which is a dedi-         mobile phones and PDAs.13                              7. Ferris Fl3rd, Kassoff A, Bresnick GH, Bailey I. New visu-
cated system that can enlarge print up to over             One of the ways to keep up with innovations             al acuity charts for clinical research. Am J Ophthalmol
40 times the size of the original print as well as      for the blind and visually impaired is through             1982;94:91-96.
enhance contrast, has been around for 35 years.         the use of websites such as VisionConnection           8. Foundation Fighting Blindness;
The ability to reverse polarity, that is changing       from Lighthouse International in the United      
the black letters on a white background to white        States. VisionConnection allows for customisa-         9. Resource Guide for Individuals with Visual Difficulties
                                                                                                                   and Impairments;http:
on black is perhaps the major feature of the            tion of the screen with the ability to change the          //
closed-circuit television. There are brightness         font size as well as enhance the contrast.             10. VisionConnection
and contrast controls as well as systems that              Additional vision rehabilitation services may 
allow a user to isolate a line. This feature is         be indicated when the vision is severely com-              News/AnotherBankIntegratesTalkingATMsIntoIts
extremely beneficial when it is difficult to locate     promised. As mentioned mobility may be indi-               Services.htm
or isolate a line of print. It is also helpful in the   cated when the visual field is reduced, especial-      11. VisionConnection;
loss of the visual field from a stoke or tumour.        ly when it is less that 6 to 8 degrees in diameter.        News/EuropesFirstTalkingCashpoint.htm
   Assistive technology has become much more            Cane travel is generally taught by individuals         12. VisionConnection;
common in the workplace in the United States.           who have lost their vision later in life from con-
Microsoft found that 27% of computer users              ditions such as macular degeneration. It is gen-           News/WalMartMakesShoppingMoreAccessible.htm
have a vision difficulty and have added much            erally the most frequent recommendation by             13. VisionConnection;
greater accessibility in their programme                vision rehabilitation organisations in the       
updates. These include screen enlargers that            United States. Individuals with congenital and             olidays.htm
move around the screen like a magnifier, screen         early childhood loss however, may be taught the        14.
readers that present graphics and text as speech,       use of guidedogs as well. There is a significant           default.htm

                                                                                                                           ACNR • VOLUME 5 NUMBER 6 • JANUARY/FEBRUARY 2006   I 17

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