1. total absence of sight; or
2. visual acuity not exceeding 6/60 or 20/200 (Snellen) in the better eye with the correcting lenses; or
3. limitation of the field of vision subtending an angle of degree 20 or worse.

In the definition given by the Planning Commission of India, a disabled person means a person who is

1. blind
2. deaf
3. having orthopaedic disability; or
4. having neurological disorder
5. mentally retarded

1. total absence of sight;
2. limitation of the field of vision subtending an angle of 20 degrees or worse.

Deaf
A person shall be deemed to be deaf if he/she has lost 60 decibels or more in the better ear in the conversational range of frequencies. 

1.  Total absence of sight;
2.  Visual acuity not exceeding 6/60 or 20/200 (Snellen) in the better eye with correcting lenses.
3. Limitation of the field of vision surrounding an angle of degree 20 or worse.

1. Mild retardation IQ – 50 – 9
2. Moderate retardation IQ – 35 – 49
3. Severe retardation IQ – 20 – 34
4. Profound retardation IQ under 20

Disability means – Blindness, Low vision, Leprosy cured, Hearing impairment, Mental retardation, Mental illness.

‘Blindness‘ refers to a condition where a person suffers from any of the
following conditions, namely –

•  1. Total absence of sight; or
•  2. Visual acuity not exceeding 6/60 or 20/200 (Snellen) in the better eye with correcting lenses; or
• 3. Limitation of the field of vision subtending an angle of 20 degrees or worse.

1. loss of sensation in hands or feet as well as loss of sensation and paresis in the eye and eye-lid but with no manifest deformity;
2. manifest deformity and paresis but having sufficient mobility in their hands and feet to enable them to engage in normal economic activity ;
3. extreme physical deformity as well as advanced age which prevent him from undertaking any gainful occupation, and the expression leprosy cured shall be construed accordingly.

The term ‘disability‘ summarizes a great number of different functional limitations occurring in any population in any country of the world. People may be disabled by physical, intellectual or sensory impairment, medical conditions or mental illness.

The term handicap means the loss or limitation of opportunities to take part in the life of the community on an equal level with others. It describes the encounter between the persons with a disability and the environment. The purpose of this term is to emphasize the focus on the shortcomings in the environment and in many organized activities in society, e.g., information, communication and education, which prevent persons with disabilities from participating on equal terms.

Categories of the disabled

The disabled are people with one or more physical, mental and sensory impairments which limit one or more of the basic life activities such as seeing, hearing, talking, walking, using hands, understanding, learning,  communicating, etc. The following five categories were officially used in India before thePersons with Disability (Equal Opportunities, Protection of Rights and Full Participation) Act, 1995:

1. The visually handicapped;

2. The speech and hearing handicapped;

3. The locomotor handicapped;

4. The mentally retarded;

5. The neurologically handicapped – in this category, the concern is restricted to only the cerebral palsied.

The Persons with Disabilities (Equal Opportunities, Protection of Rights and Full Participation) Act, 1995, identifies the following seven categories of disability, which will now be used in India :

1. Blindness

2. Low vision

3. Leprosy cured

4. Hearing impairment

5. Mental retardation

6. Mental illness

It is difficult to conceive of a rigid and precise definition acceptable to all those providers, who in order to ration the supply of their limited services in the face of immense demand, prefer to use definitions which exclude even genuine people with disabilities. On the other hand, it is equally difficult to accommodate the expectations of those who use a flexible definition to include even those at the borderline. There are hundreds of different disabilities and there are as many causes of these. Some people are born with disabilities, others become disabled later on in their lives. Some disabilities exhibit themselves only periodically like fits and seizures, others are constant conditions and are life-long. The severity of some stays the same. Others get progressively worse like muscular dystrophy and cystic fibrosis. Some are hidden and not obvious like epilepsy or haemophilia (impairment of blood clotting mechanism).

Some disabilities can be controlled and cured, others still baffle the experts. Thus, finding a consensus on the different and frequently varying definitions of disabilities, whether sophisticated or practical, has never been easy.

The definitions of mental retardation based on IQ levels are outmoded. It is not possible to decide retardation just on the basis of IQ levels since the IQ tests’ usefulness is limited to indicating how well a person may do in education and not how well he or she might do at work or life.  While it may be argued that there cannot be a universal blueprint of definitions, it is, however, necessary to have a fresh look at the definitions and include other categories such as disability due to epilepsy, learning disability, the definitions should be uniformly used throughout the country for the schemes of concessions / facilities provided for people with disabilities.

Americans with Disabilities Act, 1990 (ADA) classifies an individual as disabled if his/her physical or mental impairment “substantially limits one or more of the major life activities”.

In the Disability Discrimination Act, 1992 of Australia, ‘disability‘ in relation to a person, means-

1. total or partial loss of the person’s bodily or mental functions; or

2. total or partial loss of a part of the body; or

3. the presence in the body of organisms capable of causing disease or illness; or

4. the presence in the body of organisms causing disease or illness; or

5. the malfunction, malformation or disfigurement of a part of the person’s body; or

6. disorder or malfunction that results in the person learning differently from a person without the disorder or malfunction; or

7. disorder, illness or disease that affects a person’s thought processes, perception of reality, emotions or judgment or that results in disturbed behaviour and includes a disability that:

   • presently exists; or

   • previously existed but no longer exists; or

   • may exist in the future; or

   • is imputed to a person.

According to the Disability Discrimination Act, 1995 of the British Government, a person has a disability for the purposes of this Act if he has a physical or mental impairment which has a substantial and long-term adverse effect on his ability to carry out normal day-to-day activities.

In order to apply the durability test, the British Act uses three different terms: loss of faculty, disability and disablement. These are meant to be separate concepts.

Loss of Faculty
Loss of faculty is any pathological condition or any loss or reduction of normal physical or mental functions of an organ or part of the body. A loss of faculty in itself may not be a disability but is an actual cause of one or more disabilities, e.g., the loss of one kidney.

Disability
A ‘disability’ means an inability to perform a normal bodily or mental process. It could either be complete inability to do something (such as walking) or it can be partial inability to do something ( such as one can lift weights but not heavy ones).

Disablement
It is the sum total of all the separate disabilities an individual may suffer from. It means an overall inability to perform the normal  activities of life. The loss of health, strength and power to enjoy a normal life. While assessing an individual his/her physical and mental condition, inconvenience, genuine embarrassment or anxiety is taken into account.

Medical and Social Models 
There are two major models which explain disability and suggest approaches to deal with it in practical ways, the  medical model and social model.

The medical model views disability as a personal tragedy. Disability such as the impairment of limb, organ or function has traumatic physical and psychological effects on a disabled person. Disabled people, in this model, are regarded as people with limitations who cannot ensure a reasonable quality of life because of their impairment. The medical model expects individuals to find ways of adapting to society. It puts the duty of adjusting and adapting to the society of able-bodied or people and their environment on the disabled.

The social model presents disability as a consequence of oppression, prejudice and discrimination by the society against disabled people. It is  the society which constructs economic, social, health, architectural, legal, cultural and other barriers in order to deliberately prevent people with impairments enjoy full benefits of the society. The social model shifts the emphasis from a disabled individual to the society and its disabling attitudes and environment.