Introduction to Usher syndrome

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Introduction to Usher syndrome Powered By Docstoc
					An Introduction to Usher
With thanks to

Mary Guest, SENSE UK
Amerigo Iannola
Sergio Lavo
Elena Radutzky
Mason Perkins Deafness Fund

Special thanks to the LIONS Club Accademia
who made the printing of this booklet possible.

Written by James Edge and Akiko Matsumoto

Consultant Steven D. Collins, Gallaudet University

Translated by Giorgia Aloisio

November 2007
What is Usher syndrome?
History of Usher syndrome
Effects of deafblindness
Usher syndrome types
Usher syndrome Type 1
Usher syndrome Type 2
Usher syndrome Type 3
Retinitis pigmentosa
Night blindness
Loss of peripheral vision – tunnel vision
The eye
Providing information
Main features
Similar conditions
Communicating with deafblind people
Aids and adaptations
Guidelines for meetings
The school environment
Recognition of deafblindness a distinct disability
Useful organisations

This booklet provides a general description of Usher
syndrome and associated issues, such as diagnosis,
communication, and adaptations. It is only a starting point to
finding out about Usher syndrome. For more information
you should consult medical professionals who are familiar
with the condition. Useful organisations are listed at the end
of this booklet.

What is Usher syndrome?
Usher syndrome (US) is the most common condition that
involves both hearing impairment or deafness and
progressive loss of vision. The visual impairment is caused
by Retinitis Pigmentosa (RP), which can also occur as a
separate condition without hearing loss. It is believed that
hearing loss in Usher syndrome is due to a problem with the
sensory nerve cells in the cochlea, which is responsible for
transmitting sound to the brain.

The degree of hearing and vision loss depends on the type
of Usher syndrome and can vary widely from person to
person, even within the same family. There are three types
of US known as Type 1, 2 and 3. The important distinction
between the three types is the degree of hearing loss and

History of Usher syndrome
Usher syndrome was first described in 1858 by Albrecht
Von Graefe in Germany. He published the case of a
congenitally deaf man who also had retinal pigment
degeneration. The man also had two brothers with the same
condition. However, the syndrome was later named after
Charles Usher in 1914, a British ophthalmologist who
described the hereditary nature of the syndrome.
Usher syndrome accounts for around half of all cases of
deafblindness. Its occurrence has been estimated to be
3 - 6% of the deaf population and about the same for people
who are hard of hearing. Accurate statistics for Usher
syndrome do not exist for Italy. However, it is estimated that
for Western countries around 4 - 6 babies in every 100,000
of the population have Usher syndrome.

Effects of deafblindness
The effects of losing both sight and hearing may be far-
reaching and may elicit feelings of grief and loss, isolation,
and frustration for both the person affected, their friends and
families. Usher syndrome may also have an affect on:

       Communication
       Employment and finances
       Orientation and mobility
       Independence and daily living
       Access to information and everyday experiences
       Concentration and tiredness
       Education and training
       Relationships
       Confidence and self-esteem

Usher syndrome will undoubtedly have a wide impact on the
individual‟s life, but with the appropriate support people can
continue to live independently. People with Usher syndrome
get married, have children, study, travel, go to work and
continue to have a range of hobbies and pastimes.

Usher syndrome types

Three main types of US have been identified - Type 1, Type
2 and Type 3. Type 1 and 2 are the most common and
account for between 90 - 95% of all cases. While each US
Type differs in a number of ways, it should also be
remembered that there is also a lot of variation among
people with the same Type in terms of the degree of
hearing and sight loss and age of onset.

Type 4 Usher syndrome has been identified in some
populations although there has been little research on this
type to date and has so far been isolated to specific
geographical regions.

Usher syndrome Type 1
People with US Type 1 are born profoundly deaf and have
severe balance problems. Most people with Type 1 will use
sign language as their primary method of communication
and typically identify with the Deaf community.

Nightblindness will generally occur between infancy and
early childhood. Loss of peripheral vision will usually occur
by age ten.

Usher syndrome Type 2
People with US Type 2 are born with moderately to severely
hard of hearing with better detection of low tones and
normal balance. A small amount of additional hearing loss
can occur (up to around 10db) into adulthood, although the
amount of hearing loss varies greatly between individuals.

People with Type 2 generally communicate using speech
and many use hearing aids.

Visual problems usually occur later than in Type 1.
Nightblindness usually occurs in the teens. Loss of
peripheral vision occurs from the late teens to early 20s and
is characterised by blind spots appearing in the late teens.
As vision deteriorates it becomes increasingly more difficult
to read people‟s lips. This can severely affect
communication, in particular in dark and noisy
environments, such as pubs and restaurants. As a result,
some people may learn sign language, try using FM
systems, or perhaps avoid these situations altogether.

Usher syndrome Type 3
Type 3 Usher syndrome is less common than the other two
types and accounts for only around 5% of people with
Usher syndrome. Around 40% of people with US Type 3
have been identified in Eastern Finland.

People with US Type 3 are born with no hearing loss, but
their hearing deteriorates over time. Balance is normal or
only slightly affected but can become more pronounced
over time.

There can be a significant difference in the rate of sight and
hearing loss, even among people in the same family.
Children start to become hard of hearing by the late teens
and then go progressively deaf until mid to late adulthood.
Children will develop nightblindness during puberty. Blind
spots start to appear by the late teens. Tunnel vision occurs
in the early 20s and then eyesight progressively
deteriorates until mid adulthood.

Balance (or equilibrium) helps us to stand upright, walk, run
and move without falling and is assisted by our ears. People
with US Type 1 and 3 have problems with balance, although
it can be more pronounced in Type 1. Babies with Type 1
will have difficulty sitting up and generally do not learn to
walk until around 18 months.

Balance is controlled by our vestibular system that is
located inside our inner ear. The vestibular organs,
including the semi-circular canals, share the same temporal
bone space and fluid as the cochlea. The vestibular system
also uses information from our muscles and vision in order
to establish our body‟s orientation and way our head is
positioned. In Usher syndrome the semi-circular canals do
not function from birth.

Babies will have difficulty crawling and walking and may not
begin to walk until 15-18 months or later. Young babies may
crawl using their heads to help them keep their balance –
what is called a „five-point‟ crawl. Once children have
developed good muscle control they will have no problem
walking or running as long as they also have good vision or
know where they are going.

As a person with Usher syndrome starts to experience
nightblindness and greater loss of vision they may have
further difficulties with mobility. There are a number of
techniques to improve how to get around, for example using
a cane and rearranging furniture around the home or
workplace. Many people with Usher syndrome will have
already made some adjustments to their activities without

Retinitis pigmentosa

An inherited degenerative disease of the retina called
Retinitis Pigmentosa (RP) causes the progressive loss of
vision associated with Usher syndrome.

The retina is a thin, light-sensitive tissue located at the back
of the eye. It is responsible for converting light-based
images into electro-chemical signals that pass through the
optic nerve to the brain. These light-sensitive cells found in
the retina are called rods and cones. The cone cells,
located in the central area of retina, are responsible for the
perception of fine detail and colour. The rod cells, located
further away from the centre of the retina, control peripheral
vision and the ability to see in dim light.

With the onset of RP, the rods and cones begin to break
down, resulting in progressive loss of vision. The symptoms
of RP are variable and the time of onset and degree of loss
may differ from person to person. Most people do not
become completely blind and retain the ability to detect

Night blindness
Night blindness occurs when the rod cells begin to
degenerate. Symptoms associated with night blindness
include trouble seeing in the dark or reduced lighting – it is
related to light levels not the time of day. Additionally there
are problems adapting to sudden variations in light
conditions. Several eye conditions also cause night
blindness, but it is particularly evident in RP.

Loss of peripheral vision – tunnel vision
Loss of peripheral vision signifies a reduction in the field of
vision, with the loss starting from the outer edges and
advancing toward the centre. The field of vision slowly
worsens to a state often referred to as „tunnel vision‟ in
which individuals only see within an irregular, circular-
shaped area. The amount of vision loss varies considerably
between individuals with tunnel vision.

When the cones begin to degenerate, the ability to
distinguish details becomes more difficult. This type of
vision loss makes tasks such as reading fine print become
more difficult. Additionally, it is not unusual for people to
also develop blind spots.

Normal vision              Vision with cataracts

Legal definition of blindness
In Italy, the definition of legal blindness is measured as
visual acuity up to 10%. People with visual acuity between
10% and 30% are considered „partially sighted‟.

The World Health Organization (WHO) divides visual
impairment into five categories according to measurements
of visual acuity and visual field. According to this definition,
legal blindness is defined as visual acuity of 5% or less in
the better eye with correction, or a visual field of less than
10 degrees.

Categories of visual impairment (WHO)

      Category               Visual         Visual Field
Moderate low vision        10% - 30%
Severe low vision          5% - 10%
Profound low vision         2% - 5%        Less than 20º
Near-total blindness        1% - 2%        Less than 10º
Total blindness               0%

* in better eye with correction

People with Usher syndrome may fall into any of these
categories depending on the degree of peripheral field loss,
visual acuity or other visual impairment such as blind spots
or cataracts.

The eye


Early diagnosis of Usher syndrome is very important in
order to reduce the traumatic effect of discovering vision
loss later in life, and to make appropriate preparations. The
time of diagnosis of US can be particularly upsetting for the
individual and their family. However, it should be
remembered that many children with US might already have
started adapting to reduced vision before diagnosis.
Individuals may orient their heads in order to compensate
for a reduction in peripheral vision or avoid situations where
there is poor lighting.

There are several reasons for the gap between initial
suspicions of vision loss and formal medical diagnosis.
These can include:

        Lack of routine vision checks in school;
        Difficulty conducting accurate vision tests for deaf
        History of negative experiences at clinics in
         communicating with medical professionals;
        Gap in time from initial screening results to setting
         up appointment with eye specialist; and
        Eye specialists prolonging confirmation of diagnosis
         of US.

Early signs of US may include balance problems in early
childhood. Later children and adolescents may start
bumping into things and be told that they are being clumsy.

Poor night vision is also an indicator of RP. People should

        An assessment by an ear, nose and throat
         specialist to ensure the correct diagnosis of hearing
        An assessment by an ophthalmologist to assess
         the presence and severity of Retinitis Pigmentosa;
        A specialist hearing and vision tests, such as an
         electro-retinogram (ERG) that measures electrical
         activity in the retina.

There is currently no treatment for Usher syndrome nor to
stop or slow down the degeneration of nerve cells in RP.
Some researchers believe that for certain cases of RP,
vitamin A can help slow down the degenerative process.
This research is very recent and more research needs to be
conducted to show its effectiveness.

Ongoing research is looking at stem cell research and
retinal cell transplantation as a possibility for treatment. This
research is still in the very early stages and for more
information you should consult eye specialists and review
research posted on the Internet.

Providing information

Information should be provided about Usher syndrome to
the person who has been diagnosed and their parents or
carers at the time of diagnosis.

If you are a health professional who is providing information,
it should be presented in an accessible way and without
medical jargon. In the case of children, use language that is
appropriate for the age of the child.

The amount of information given to individuals who have
been diagnosed will largely depend on their age and
maturity. At the time of diagnosis it may be too soon to look
for services specifically for blind people as it can take many
years for sight to deteriorate further.

Main features
  Hearing Loss           Balance         Vision Loss (RP)

Type 1

Born deaf with       Inner ear balance   Nightblindness in
profound hearing     absent.             early infancy or
loss.                                    early childhood.
                                         Tunnel vision
                                         usually by 16.

Type 2

Born hard of         Inner ear balance   Night blindness
hearing with         normal.             begins in the
particular loss of                       teens.
high frequency                           Tunnel vision in
sounds.                                  the late teens to
                                         early 20s.

Type 3

Born with good       Inner ear balance   Blind spots
hearing or mild      normal but may      develop during
hearing loss that    worsen over time.   late teens.
worsens from the                         Night blindness in
first 10 years.                          childhood or
Can look like Type                       teens.
2 in young adults                        Tunnel vision
and Type 1 in                            more pronounced
older people.                            in the 20s.


Usher Syndrome is passed on from both the mother and the
father who each must carry the Usher syndrome gene
(although they may not have Usher syndrome themselves).
This is what is called an autosomal recessive gene.
Autosomal means that the gene is not sex-linked, so the
condition can equally affect males and females. Recessive
means that it is possible to carry one Usher syndrome gene
but not have Usher syndrome.

Both parents may be unaware that they have the gene until
Usher syndrome is diagnosed in their child. A child with
Usher syndrome will carry two recessive genes, which will
also be passed on to their children.

Researchers have so far identified 15 genes that can cause
the different types of Usher syndrome. Genetic research
suggests that each US type may be due to several different
genes located on different chromosomes. It has been
estimated that one in 75 people can carry one of these
Usher genes. If parents carry genes for different types of
Usher syndrome their children will not inherit the condition
but may be a carrier for both types.

The following outcomes are possible for Usher syndrome

        If a person with US has children with another Usher
         person (of the same Type), all their children will
         have US.

       If a person with US has children with someone
        without the syndrome, the children are unlikely to
        have the condition, but they will carry the US gene.

       If a person with Usher syndrome has children with
        another Deaf person, they should be tested to see
        if they have the condition, or carry an Usher gene.

The diagram below shows the possible outcomes for two
parents who each carry the same Type of Usher gene.

Similar conditions

There are a number of conditions that may have similar
symptoms to Usher syndrome. It is possible that a Deaf
person also develops an eye condition or visual impairment
that is not related to Usher syndrome. Similarly, someone
with visual impairments may become hard of hearing or
deaf, in particular associated with aging. Professional
advice and proper diagnosis are essential.

Maternal Rubella (German Measles) is a viral infection
that can cause hearing loss, cataracts, glaucoma and retinal
disorders in babies when contracted while pregnant. It used
to be confused with US or Retinitis Pigmentosa because of
light and dark spots appearing on the retina. However, as
Rubella is now less common than 30 years ago, Usher
syndrome should be considered where this retinal
pigmentation occurs.

Choroideremia is a rare inherited disorder that could be
confused with Retinitis Pigmentosa as the symptoms also
include night blindness and tunnel vision. In a complete eye
examination the differences are clear, especially as the
condition progresses.

Laurence Moon and Bardet Biedel syndromes (inherited
syndromes) also show changes to the retinal pigment
changes plus progressive neurological changes and
learning difficulties.

Bacterial and viral infections, such as bacterial
meningitis, cytomegalovirus (CMV), can cause hearing or
vision loss or both.

Cataracts are not a result of Usher syndrome but can still
occur in older age and further affect visual acuity. Cataracts
result from the lens in one or both eyes becoming cloudy or
opaque. When the condition becomes more advanced they
can normally be treated using laser treatment and lens

Normal vision              Vision with cataracts


People with Usher syndrome can use a number of ways to
communicate, including sign language (LIS), tactile sign
language (LIST), lip reading and speech. Most people with
Type 1 will use sign language, and might later use tactile
sign language. People with Type 2 and 3 generally use
spoken language but may later find it very useful to learn
sign language as it becomes more difficult to lip read.

     “I always advise, before, when one still sees quite well,
     learn before, not after the onset of blindness. After
     blindness, it does not go well. After, no.”

     Amerigo Iannola

Adapted Sign Language is where visual signs are
adjusted or adapted for people with reduced sight. When
signing to someone with reduced peripheral vision, the
signing space will need to be reduced. This can be
achieved either by signing in a smaller visual area of around
25cm x 25cm, or by standing between 90cm and 180cm
away from the person with Usher syndrome. Finger-spelling
and other hard-to-see signs, such as DOG or SKIRT (in
American Sign Language) may need to be reduced in
frequency, slowed down or dropped altogether.

      Signing Space

It has been observed that people with restricted peripheral
vision also reduce their own signing space. This could
indicate the size of their preferred signing space for
receiving signs.

Tactile sign language is used when people do not have
enough residual vision or hearing to understand sign or
speech. The person receiving the message places one or
both hands on the hands of the person giving the message
in order to feel the handshape, location and movement of
the signs.

The hand position of the receiver can vary from person to
person. For example, when finger spelling, the receiver may
use one hand on the back of the sender‟s, into the palm of
the receiver or by wrapping both hands around the sender‟s

Tactile sign language differs in a number of ways to sign
language. Meaning in visual sign language can be
conveyed through hand-shape, movement, facial
expression and body movement, whereas in tactile sign
language this information has to be given through touch
alone. For people who already know sign language
(typically people with Type 1 Usher syndrome) learning the
tactile form will not be too difficult, particularly if they start
practicing before their eyesight deteriorates.

Tracking is used by people with enough residual vision to
understand signs by holding the wrist or wrists of the signer
to follow the movement of the signs. People with tunnel
vision, for example, will find tracking useful for following
signs that move beyond their field of vision.

Print-on-palm is where letters of the alphabet are drawn
onto the receiver‟s palm to spell out words. A short or long
pause indicates spaces between words or sentences.
Braille print-on-palm can be used with deafblind people
fluent in Braille.

Braille is a system of raised dots that is used to represent
letters, words and numbers. Non-electronic and electronic
aids are available with options to translate Braille into print
text, and print into Braille. Non-Braille users can use Braille
cards by guiding the deafblind person‟s finger to the Braille
letters with printed letter equivalents.

Communicating with
deafblind people

     Wear comfortable clothes – wear clothes that are
      loose enough to move around freely.

     Having pockets can be useful to put things to keep
      your hands free.

     Use shoes that give you good balance.

     Clothes that feel nice to the touch can be nicer!

     Tops (shirts, jumpers etc) should be non-reflective.

     The colour of your top should contrast with your
      skin colour, but dark enough not to reflect light.

     Sit comfortably - it can be tiring to sign for a long
      time with one person standing and the other

     Take opportunities to stretch and rest.

Aids and adaptations

Many people with vision loss can benefit from the use of
assistive devices. Large print materials and low vision aids
could be helpful with the loss of visual acuity. Low vision
aids include reading glasses, hand magnifiers, telescopes
and closed circuit televisions, which all serve to enlarge

Also consider the layout and design of your living and
working environment – for example, keep everything in its
place and reduce clutter to ease finding what you are
looking for. Increasing the contrast between doorways,
furniture and household items by using light and dark
colours can also help with moving around the home and

Textphones and mobile phones are devices that are
commonly used among deaf and hard of hearing people to
communicate through telephone lines. A modified version
with a larger text display may be more useful for Usher

The Teletouch is a portable device that consists of a
standard keyboard, Braille keys and small tactile pad.
Typed messages are displayed as Braille produced by
raised pins.

Computers have also become more accessible through the
advancement of both software and hardware devices.
Software programs now enable users to display text and
graphics at various levels of magnification. Another option is

to attach a Braille readout device to the computer.
Keyboards come in a variety of formats, such as with Braille
or large print characters.
Hearing aids amplify sound to the ear. Some hearing aids
can be modified to suit different types of hearing loss.
Hearing aids are used by many deaf and partially deaf
people. They do not fully restore hearing. Different types of
hearing aid exist:

       behind the ear or post-aural aids
       „in the ear‟ aids
       bone vibrating aids
       inductive coils

A cochlea implant is an electronic device that is implanted
in some deaf people. The implant is composed of an
internal part that is surgically inserted in the ear and an
external part, the vocal processor. Some people with Usher
syndrome who progressively lose visual acuity may benefit
from a bilateral cochlear implant.

The choice of whether or not to have a cochlear implant is
complex and controversial. It is very important to gather as
much information as possible about what can be expected
and whether the person is a suitable candidate. An
evaluation must be carried out by professionals (speech
therapist, psychologist, specialists).

Specialised lighting can be used which minimises glare,
such as egg box lighting or florescent lighting. Increase the
amount of light in dark spaces, such as cupboards.

Labels and markers can be used to help locate switches,
handles and buttons of different types of equipment, for

example the oven or microwave. Labels can be made using
a special florescent paint that leaves a raised mark, self-
adhesive plastic bumps, and self-adhesive paper labels with
a raised dot.

Alerting devices with flashing lights and/or vibrating pagers
can be used for doorbells, telephones, alarm clocks and
smoke alarms.

Guidelines for meetings

Particular care should be taken when communicating with
an Usher person or organising meetings where Usher
people will be present. Extra time should be allowed to
organise and arrange the most appropriate seating and
lighting for each individual.

Lighting should be adapted to suit the people present. As
RP makes it difficult to adjust quickly to changing light
conditions lighting should be bright without glare but not too
bright nor too low. Neon overhead lighting is often best for
people with Usher syndrome. The person with Usher should
never have to look into the light or directly at a window
(although this can be difficult to achieve for group

More light may be needed to see the facial expressions and
hands of people with dark skin because dark colours absorb
light. Find out if the lighting levels are right for each person.
Interpreters should avoid standing under overhead lighting.

Background sounds should be minimised for people who
have some hearing. Turn off the radio or TV if they are not
being used. In public places, try to sit away from sources of

Seating should be planned around where people with
Usher syndrome will sit in relation to each other, the
speaker and to the interpreter(s). Allow space for people to
move closer or further away according to their own
requirements and allow time to make sure each person is in

the right position. If the people with Usher Syndrome are
part of a larger group it may be helpful to allow them to sit
down first.

Overhead presentations and handouts should also be
available in large print. They should be handed out before
the presentation because it can be difficult to view the
interpreter and slides at the same time.

Large Print materials should be written in a clear font,
such as Arial or Helvitica, and be size 18 or above. It is best
to ask the people you are producing information for what
size they prefer. Keep the line spacing regular and the text
justified to the left – this will ensure that the spacing
between words remains regular. Use clear and bold
headings. If you need to use pictures and diagrams, ensure
that they have a high contrast and a written description.

Suggested seating plan for meetings

Adapted from SENSE Usher Syndrome factsheet (2003)

There should ideally be at least one interpreter for every
four people with Usher. Someone who needs tactile sign
language will need one to one interpretation. Interpreters
should avoid sitting in front of a cluttered background or
wear clothing the same colour as the background that may
make their signing difficult to see. Interpreters may be better
seated so they are at the same eye-level as the receivers.


Since 3 - 6% of congenitally deaf children have Usher
syndrome, it is particularly important for parents, teachers
and medical staff who are in contact with deaf children to
become more aware of the symptoms and behavioural
features associated with the onset of RP.

The school environment
Academic programmes must be tailored to students with
Usher syndrome, taking into account the symptomatic
progression of the condition from early night blindness, to
loss of peripheral vision and then reduction or loss of central

Modifications within the school environment should be
conducted on several levels: whole school, individual
classroom and amongst students. Modifications should be
carefully considered amongst the teachers and staff in
keeping with the individual needs of the student. Equally,
the student with Usher syndrome would have to make
accommodations with the full acknowledgement of their
particular visual problem.

In order to create a successful environment for the student
with Usher syndrome, it is important for the child with Usher
syndrome, parents, teachers, counsellors and medical
professionals to work together collaboratively. It is important
for children with Usher syndrome to develop positive
attitudes about themselves and have the benefit of learning
directly from adult role models with Usher syndrome.

Recognition of
deafblindness a distinct

People with Usher syndrome are part of the deafblind
population. This does not mean that all deafblind people
have Usher syndrome. In every instance, a person with
Usher syndrome can have the same problems as all
deafblind people the world over. Within this group are
people with greatly differing levels of deafness and vision.

Being deafblind is very different from being deaf or being
blind, and it cannot be considered a simple "sum" of the two
conditions. The person who is blind or deaf compensates
for her deficit by making use of the integral sensorial
channels -auditory in the case of the blind person and visual
in the case of a deaf person. A deafblind person may be
able to make some compensations using the other senses
or residual abilities, each person is different – perhaps more
so than people with other disabilities. While all disability
services should be uniquely tailored to each individual, this
is especially true for deafblind people. This is why the legal
recognition of deafblindness as a specific condition is so

Some associations are advocating for deafblindness to be
legally recognized as a specific disability, such as Deafblind
International worldwide, the European Deafblind Network
and the Lega del Filo D'Oro in the European Union. For

more information visit their websites listed at the end of this

Deafblind International
Created 30 years ago, it is represents thousands of people
all over the world; it is an international organization that
promotes services and projects on the deafblind
(publications, conference and advertising campaigns) and it
advocates the recognition of this condition all over the

European Deafblind Network
An association that is closely connected to Deafblind
International, and it advocates for the legal recognition of
deafblindness in Europe. In the European Union at present,
deafblindness is not recognized as a specific disability: the
only two nations that recognize it are Romania and
Norway. To date, this association has issued a written
declaration that was adopted in April of 2004 by the
European Parliament, aimed at promoting this juridical
recognition throughout the European Union.


Professional trained in the science of audiology who may
assess hearing, determine auditory capacity for processing
sound. A trained person who specializes in hearing
assessments rehabilitation of deaf and people who are hard
of hearing.

Inability to see; absence or severe reduction of vision.

Printed raised dots that represent letters and numbers so
that blind people can read text.

Condition in which the lens of the eye appears cloudy or

Central Field Loss
Eye condition in which affected individuals can see well
from the sides but have poor or no central vision (the
opposite of tunnel vision).

A very rare hereditary condition that must include at least
four of the following six symptoms: C - coloboma (defect or
lesion of the eye), H - heart defect/disease, A - atresia of
the choanae, R - retarded growth and development, G -
genital abnormalities, E - ear abnormalities and/or

Condition in which vision is affected first with the onset of
night blindness, then visual field restrictions, and then acuity
and colour vision. Results in blindness in later years and
occurs more in males.

Snail-shaped structure in the inner ear containing the organ
of hearing.

Cochlear implant
Prosthetic for hearing that must be surgically implanted
behind the ear.

Term applied to those who are deaf or hard of hearing in
addition to vision loss.

Decibel (dB)
Measurement used for intensity (loudness) of sounds.

Ear Canal
„Tunnel‟ that connects the pinna and the eardrum.

Eardrum (Tympanic Membrane)
Layer of tissue shaped like a cone at the end of the ear
canal whose movements causes the bones in the middle
ear to move. It separates the middle ear from the outer ear.

Fingerspelling is the manual/visual form of spelling used by
deaf people. Letters of the manual alphabet that
represent letters of the written alphabet are produced by the
signer and combined to form three-dimensional
representations of written words.

Traits or characteristics passed on from one generation to

Hearing aid
Device with a sound receiver that amplifies speech and
environmental sounds.

Inner ear
Includes the semicircular canals, the cochlea and the
auditory nerve. Problems in this part of the ear may include
damaged or missing nerve cells and damage to the balance

LIS (lingua dei segni italiana)
LIS is the Italian Sign Language used by the majority of
deaf people as their natural and preferred form of
communication. It is a complete language like any vocal
language. It has it‟s own grammar which differs from that of
spoken Italian and uses the visual/movement channels
through which meaning is produced and received.
Examples of other sign languages include, BSL (British Sign
Language), ASL (American Sign Language) and LSF
(langue des signes française).

The tactile form of Italian Sign Language (LIS) adapted for
people with reduced vision.

Low vision aids
Optical and non-optical devices of various types, such as
magnifiers, lenses, hand-held telescopes, and reading
stands, which are useful to people with visual impairments.

Small area of the retina of the eye that surrounds the fovea
and that, with the fovea, is responsible for detailed central
Middle ear
Includes the eardrum, three tiny middle ear bones (malleus,
incus, and stapes), and the Eustachian tube. Problems in
this part of the ear may include infection, hole in the
eardrum, broken middle ear bones or bony growth.

Night Blindness
An individual with this condition may be able to see with no
problems by day or in good light, but is unable to see at
night or in low light. It can be caused by any eye condition
that affects the rod cells in the retina.

Doctor who routinely examines and treats eye infections,
injury, and malformations. They also test for visual acuity
and problems with visual field, colour and contrast

Optic Nerve
Nerve that transmits information from the retina to the brain.

Professional who grinds lenses, fits them into frames, and
dispenses and adjusts glasses or other optical devices from
an optometrist‟s or GP‟s prescription.

Licensed, eye practitioner who treats vision problems non-
medically through the use of glasses, prisms and eye
exercises. They may also diagnose and treat some eye
conditions with medication.

Process through which an individual who is visually
impaired uses his/her remaining senses to establish his/her
position and relationship to all other significant objects in the
Outer ear
Also known as the auricle or pinna, including the earflap
and the ear canal. It gathers and enhances sound and
channels it to the middle ear. Problems in this part of the
ear may include wax buildup in the canal, a foreign object in
the ear canal or outer ear or the ear canal not forming
correctly or missing.

Peripheral vision
Outer part of the visual field.

Residual vision
Vision available to an individual who is not totally blind.

Thin sensory tissue that lines the back of the eye. It
contains millions of photoreceptors (rods and cones) that
capture light and convert them into electrical impulses to
send the information to the brain.

Retinal detachment
Separation of the inner layer of the retina from the outer
layer resulting in loss of retinal function.

Retinitis CMV (Cytomegalovirus)
Virus that leads to a variety of effects on the fetus. Vision
problems include blurred vision, photophobia, distorted
images and central blind spots.

Retinitis Pigmentosa
A rare hereditary disease that is characterized by retinal
degeneration and progressive blindness. It begins with night
blindness in adolescence or in adult life.

Tactile sign language
Is the tactile form of sign language adapted for blind people
or with reduced vision.

Tunnel Vision
Eye condition in which the field of vision is 20 degrees or

Usher syndrome
Inherited condition characterized by sensorineural hearing
loss, present at birth or shortly thereafter, and a progressive
loss of vision due to Retinitis Pigmentosa.

Vestibular nerve
Carries information about balance from the ear to the brain.

Vestibular system
A system comprised of the semicircular canals and
vestibular nerve.

Ability of the brain to process information received from the

Visual field
Space visible to the eyes when they are fixating straight

Visual tracking
Ability to follow the movement of an object with the eyes.

Useful organisations

Ente Nazionale Sordomuti - ENS
Sede Centrale E.N.S.
Via Gregorio VII, 120
00165 Rome

Tel : (0039) 06 398 051
Fax : (0039) 06 3980 5231

Mason Perkins Deafness Fund
Via Nomentana 56
00161 Rome

Tel : (0039) 06 44 23 45 11
Fax : (0039) 06 44 23 60 59

Lega del Filo d’Oro
Sede centrale di Osimo:
Via Montecerno, 1
60027 Osimo (AN)

Tel : (0039) 071 72451
Fax : (0039) 071 717102