Glossary

Aniridia

A congenital condition that involves the under-development of the iris. The iris is the part of the eye usually coloured blue, grey, brown, hazel or green. In severe forms of aniridia, the iris appears to be almost completely absent. Aniridia usually occurs with other abnormalities of the eye.

Autism

Autism is also known as autistic spectrum disorder (ASD) or autistic spectrum condition (ASC). It is a continuum condition typified by the "triad of impairments", that is impairments in:

• social relationships
• social communication
• social imagination.

The triad has been expanded to include difficulties in sensory domains. People with autism tend to be literal and concrete in their thinking, have difficulty empathising with others, have special interests or obsessions and require structure / routine in their lives.

There is much variability on the spectrum; people with Asperger syndrome have fewer problems using spoken language than most autistic people. Many are of average, or above average, intelligence. Most do not have the accompanying learning disabilities associated with autism, but they may have specific learning difficulties. These may include dyslexia, dyspraxia, attention deficit hyperactivity disorder (ADHD) and epilepsy.

Additional sources of information on autism are provided in the Resources section.

Braille

A tactile code for reading and writing used by people who are unable to read print because of severe visual impairment. It is based on different combinations of the six raised dots that form a braille cell. As well as English braille, there are different codes for mathematics, music and most other languages.

Alphabetic, or uncontracted braille, is the simplest form of braille. A single braille cell is used to represent each letter of the alphabet. There are separate signs for punctuation. Alphabetic braille was previously known as grade 1 braille.

Contracted braille is a more advanced form of the braille code than alphabetic braille. Word signs and contractions are used. There are rules about how and where these can be used within text. Contracted braille was previously known as grade 2 braille.

Additional sources of information on braille are provided in the Resources section.

Cataracts

An opacity (cloudiness) of the lens of the eye. The lens is convex and is formed of a clear, transparent substance that allows light to pass through unimpeded. Opacity of the lens obstructs the passage of light resulting in impaired vision.

CCTV: Close Circuit Television

An optical aid that enlarges print or other images onto a TV screen in front of the user. It enables the user to read print or to see images that would otherwise be too small. It enables the user to focus on a single word or picture if so desired. This has the effect of de-cluttering the source material.

Central vision

The middle part of the field of vision. This is the area of vision where the finest discriminations can be made. We use our central vision for reading.

Certificate of visual impairment

See also registration as severely sight impaired or blind / sight impaired or partially sighted.

In the UK, the Certificate of Vision Impairment is used to certify patients as severely sight impaired or sight impaired. The Certificate of Visual Impairment is the formal notification required by local authorities with social services responsibilities to register someone as sight impaired or as severely sight impaired.

Cornea

The transparent, smoothly curved front surface of the eye. The cornea bends rays of light as they enter the eye so that they come to a focus on the retina.

Crisis

Many children with autism have difficulty with anxiety. In addition, many become stressed in situations that would not stress a typically developing child. Stress and anxiety levels sometimes escalate so much that crisis is reached. This is the point at which the child's stress or anxiety becomes overwhelming.

Autistic children can also become overloaded with sensory stimulation. It is not always possible to determine whether a child is in crisis because of stress or anxiety, or whether he / she is overloaded with sensory stimulation.

Echo location

Use of reflected sound that helps to identify position of items in the environment. Used in conjunction with other aids to mobility, echo location can help a person who is severely visually impaired to move around without bumping into items. 'Flash-sonar' is an alternative phrase that is used to describe echo location.

Field of vision

The area that can be seen by an eye that is being held still at any given moment.

Functional vision

The way in which an individual uses their sight in everyday situations.

Impulsivity

Many people with autism have difficulty regulating their behaviour. They may have problems focusing and concentrating for more than a short period of time and need to be active. Impulsivity causes the child to act suddenly, without thinking through the consequences.

Landmarks

Permanent features that are used as location markers by people who are visually impaired. Landmarks may be of a visual, auditory or tactile nature.

Laurence Moon Bardet Biedl Syndrome (LMBBS)

A genetic disorder that is characterised by a degenerative abnormality of the retina. Children with LMBBS may also have learning difficulties, obesity, delayed or absent puberty and abnormalities of the fingers. Sometimes a distinction is made between Laurence Moon Syndrome and Bardet Biedl (or Biedl Bardet) Syndrome although the differences between them are not very clear.

Learning difficulties

Complex Learning Difficulties and Disabilities (CLDD)

A new category of learning difficulties has very recently been formerly recognised. This is a result of the Complex Learning Difficulties and Disabilities Project. The definition is as follows:

• Children and young people with Complex Learning Difficulties and Disabilities have conditions that co-exist. These conditions overlap and interlock creating a complex profile. The co-occurring and compounding nature of complex learning difficulties requires a personalised learning pathway that recognises children and young people's unique and changing learning patterns. Children and young people with CLDD present with a range of issues and combination of layered needs - e.g. mental health, relationships, behavioural, physical, medical, sensory, communication and cognitive. They need informed specific support and strategies which may include transdisciplinary input to engage effectively in the learning process and to participate actively in classroom activities and the wider community. Their attainments may be inconsistent, presenting an atypical or uneven profile. In the school setting, learners may be working at any educational level, including the National Curriculum and P scales.

This definition could also be applicable to learners in Early Years and post-school settings.

Moderate learning difficulty (MLD)

Children with moderate learning difficulties have attainments significantly below expected levels in most areas of the curriculum, despite appropriate interventions. Their needs will not be met by normal differentiation and adaptations. Additional educational provision has to be made to help them to access the curriculum. Children with moderate learning difficulties have much greater difficulty than their peers in acquiring basic literacy and numeracy skills and in understanding concepts. They may also have associated speech and language delay, low self-esteem, low levels of concentration and under-developed social skills.

Severe learning difficulty (SLD)

Children with severe learning difficulties have significant intellectual or cognitive impairments. This has a major effect on their ability to participate in the school curriculum without support. They may also have difficulties in mobility and co-ordination, communication and perception and the acquisition of self-help skills. Children with SLD need support in all areas of the curriculum. They may also require teaching of self-help, independence and social skills. Some children use sign and / or symbols.

Profound and multiple learning difficulty (PMLD)

Children with profound and multiple learning difficulties have complex learning needs. In addition to very severe learning difficulties, children with PMLD have other significant difficulties, such as physical disabilities, sensory impairment or a severe medical condition. Children with PMLD require a high level of adult support, both for their learning needs and also for their personal care. They are likely to need sensory stimulation and a curriculum broken down into very small steps. Most children with PMLD communicate using pre-language means such as facial expression, body language, vocalisation, gesture and eye pointing.

Leber's amaurosis

An inherited disorder of the

retina affecting both peripheral and central vision that is present from birth.

Light perception

The ability to see the difference between light and dark. People who have severe visual impairment may have light perception.

Long cane

A mobility aid for people who have severe visual impairment. It comprises a light weight metal "stick" coloured white with a specially designed tip. The user sweeps it from side to side in front of them whilst walking. This helps the user to detect changes of level, environmental features, hazards and surface textures. The long cane should not be confused with a symbol cane.

Mainstream School

A school that is primarily for children who do not have special educational needs. Almost all mainstream schools have some children who have special needs and who require access to the curriculum to be modified in order to meet their needs.

Mobility officer / teacher / habilitation officer

An individual who has received specialist training to teach mobility and daily living skills to children who are blind or partially sighted. Similar practitioners working with adults may be called rehabilitation officers.

Moon

A system of tactile reading that uses embossed symbols, partially based on capital letters of the Roman alphabet. The symbols are made up of raised curves, angles, and lines. They are easier to distinguish than braille dots. There is a different Moon symbol for each letter of the alphabet. The main disadvantage of Moon is that there is no simple mechanical system for writing it.

Additional sources of information on Moon are provided in the Resources section.

N print size

The designation of print size by the letter 'N' followed by a number, e.g. N9, N18, N24, N36 etc. The larger the number, the larger the print. The standard size for print used in everyday situations is N12, although RNIB recommends N14 in its Clear Print Guidelines.

Nystagmus

Involuntary movements of the eyes. Movements can be side to side, up and down or rotational. Nystagmus is sometimes known as "wobbly eye". The effect on vision of nystagmus is very variable. It usually occurs in conjunction with another eye condition or a neurological impairment. Occasionally it occurs in isolation with no known cause.

Oculocutaneous albinism

An inherited condition resulting in a reduction of colouration (pigmentation) of the skin and eyes. The structure of the eyes is also affected.

Optic nerve hypoplasia

Congenital under-development of the optic nerves which carry the visual signals from the eyes to the brain.

Overloaded

Many autistic children have difficulties coping with sensory stimulation. This is particularly likely for those who are single channelled. If a child is exposed to too much sensory stimulation, he / she may become overloaded. This is the point at which the sensory stimulation becomes overwhelming.

Autistic children can also become overwhelmed as a result of stress or anxiety, and reach crisis. It is not always possible to determine whether a child is in crisis because of stress or anxiety, or whether he / she is overloaded with sensory stimulation.

Partial sight

Reduced vision that is of a severe and permanent nature but which allows the person to function by visual means.

See also Registration as severely sight impaired or blind / sight impaired or partially sighted and Certificate of visual impairment.

Additional sources of information on visual impairment are provided in the Resources section.

Peripheral vision

Vision that falls outside the central part of gaze. It involves the sides and the upper and lower areas of vision. Peripheral vision is less acute than central vision but it is very responsive to movement. Movements that are detected by peripheral vision will usually result in gaze being focused on the source of movement.

Proprioceptive sense

Proprioception is the system that is stimulated by the information gained from our joints, tendons and muscles. It informs us about the position of our body parts in relation to each other. A poorly developed proprioceptive sense can lead to many difficulties, including:

• poor stability
• poor motor skills (gross and fine)
• difficulty imitating movements
• poor coordination
• a need to stimulate the proprioceptive (and vestibular) sense by increased movement.

Registration as severely sight impaired or blind / sight impaired or partially sighted

See also certificate of visual impairment

Registration is a formal process undertaken by the social services department of a local authority in the UK. It means that a person satisfies the legal definition of being severely sight impaired (ie having severe visual impairment) or blind. This is that, whilst wearing any prescribed spectacles or lenses, the person has:

• visual acuity of less than 3 / 60 with a full field of vision
• visual acuity between 3 / 60 and 6 / 60 with a severe reduction of field of vision, such as tunnel vision
• visual acuity of 6 / 60 or above but with a very reduced field of vision, especially if a lot of sight is missing in the lower part of the field.

A person can be registered as sight impaired or partially sighted if, whilst wearing any prescribed spectacles or lenses, he / she has:

• visual acuity of 3 / 60 to 6 / 60 with a full field of vision
• visual acuity of up to 6 / 24 with a moderate reduction of field of vision or with a central part of vision that is cloudy or blurry
• visual acuity of up to 6 / 18 if a large part of your field of vision, for example a whole half of your vision, is missing or a lot of your peripheral vision is missing.

Additional sources of information on visual impairment are provided in the Resources section.

Residual vision

Any useful sight of a person who has a severe visual impairment. The person may have a very limited amount of vision, but is often able to make good use of this in everyday situations. For example, a person who has light perception only may use this to orientate towards a window, so helping to understand where they are in a room.

Resource base

Special provision for children with a designated special need (eg visual impairment or autism) sited in a mainstream school. The resource base usually forms a centre from which specialist staff work. Children who have the designated special need may attend a school that has a resource base, but may not necessarily live within the school's mainstream catchment area.

Retina

The retina is at the back of the eye. It contains light-sensitive cells and is responsible for converting light into neural energy so that messages can be sent to the brain.

Self stimulatory activities

Activities such as rocking, hand flapping, head weaving, tapping and twirling which provide sensory stimulation.

Sensitivity to light

An intolerance of light, especially glare or bright light. It results in a person being in discomfort and having reduced vision when affected by glare or bright light. It is also known as 'photophobia'.

Sensory integration

At its simplest, the term sensory integration means "The organisation of sensory input for use". The "use" may be a perception of the body (how the brain interprets or gives meaning to sensory information), an adaptive response, a learning process, or the development of some neural function. Through sensory integration, the many parts of the nervous system work together so that a person can interact with the environment effectively and be able to participate successfully in as wide a variety of activities as they need to in order to live a full and satisfying a life.

Septo-optic dysplasia

A congenital condition, this results in the under development of the optic nerves, which carry the visual signals from the eyes to the brain, deficiency of the function of the pituitary gland and some brain abnormality.

Severe visual impairment

A profound permanent reduction or absence of vision that cannot be corrected with spectacles or contact lenses.

See also Registration as severely sight impaired or blind / sight impaired or partially sighted and Certificate of visual impairment

Additional sources of information on visual impairment are provided in the Resources section.

Sighted guide

A person with good vision who provides assistance to someone who has severe visual impairment. The correct technique involves the visually impaired person holding the arm of the sighted person just above the elbow.

Single channelled

Many children with autism have difficulties attending simultaneously to information from more than one channel (sense). They can become easily distracted or overloaded when multi-channel information is received and therefore tend to function best when information is presented via one channel (sense) at a time.

For example, when a single-channelled child is listening, he / she cannot also look; when looking, he / she cannot also listen to and understand what someone else is saying.

Special School

A school for children with special educational needs, such as learning difficulties, visual impairment or autism.

Symbol cane

Much shorter than a long cane, a symbol cane is a short white cane used by people who are partially sighted. Held statically in front of the user, it acts as a symbol to others that the user has poor sight.

Tactile defensive

A term that is often applied to a child who has an aversion to using their hands to explore objects by touch, especially when required to do so by an adult. A child who has tactile defensiveness will resist being encouraged to feel items and will withdraw his / her hands from the engagement. The child will usually show displeasure and discomfort when required to touch items.

Tinted spectacles

Spectacles that have coloured lenses. Usually, the purpose of the colouration of the lenses is to reduce the amount of light or glare that enters the eye. Too much light or glare can have an adverse effect on vision. Sometimes tinted lenses are used to help children who have a specific learning difficulty connected with reading.

Trail

Trailing involves using a hand to feel the way along a wall or other environmental feature. A trail can be specially constructed between two points to provide a person who is blind with specific clues as to their position.

Transition

Although this term has one basic meaning (that is "change"), it has several uses. Perhaps the most frequent use in relation to autistic children refers to a change of location, that is to moving ("transitioning") around the physical environment. However, "transition" can be used to refer to a change in any aspect of daily life, such as a transition from one activity / member of staff to another.

Because many autistic children do not cope well with change, Resource Pack users are advised to refer to the strategy supporting the child to cope with transitions in the Underlying principles section. Transitions of location are also referred to in several strategies in the section on Promoting mobility and independence.

"Transition" is also used to refer to changes such as that at the age of 11 from primary school to secondary school and, later from school to college. The latter may also involve a transition from living at home to living away from home. Transitions of this kind can be particularly difficult for children who have visual impairment and autism.

Tunnel vision

The small area of central vision that can be perceived by someone who has a severe, generalised loss of peripheral vision. As vision is clearest in the centre of the field of vision, a person with tunnel vision may be able to see very clearly over this very small area.

Vestibular sense

The vestibular system controls our sense of balance. It is linked with:

• posture and mobility
• planning and carrying out a sequence of movements
• perceptual awareness
• use of vision
• auditory processing
• breathing.

Visual acuity

A measure of the finest detail that can be seen under optimum conditions. Distance visual acuity is often expressed as a fraction-like figure e.g. 6/60, 6/36. These mean that a person with impaired vision can only read at 6 metres distance what a person with normal sight would be able to read at 60 (6/60) or 36 (6/36) metres. Normal visual acuity is shown as 6/6. Increasingly, visual acuity is expressed in logarithmic terms with 6/6 having a value of 0.00 and 6/60 having a value of 1.00.