• What is visual Impairment?

    In India, the broad definition of visual impairment as adopted in the Persons with Disabilities (Equal Opportunities, Protection of Rights and Full Participation) Act, 1995 as well as under the National Programme for Control of Blindness (NPCB) is given below:

  • Blindness !

    Refers to a condition where a person suffers from any of the following conditions, namely:

    • Total absence of sight; or
    • Visual acuity not exceeding 6/60 or 20/200 (Snellen) in the better eye even with correction lenses; or
    • Limitation of the field of vision subtending an angle of 20 degree or worse.
    • For deciding the blindness, the visual acuity as well as field of vision have been considered.

      Low Vision !

      The Persons with Disabilities Act, 1995 also recognizes low vision as a category of disability and defines it as follows:

      “Low vision are those who suffer visual acuity between 20/200 to 70/200 (Snellen) or 6/18 to 6/60 in the better eye after the best possible correction or a Field of Vision between 20 to 30 degrees”.

      Explanation of Various Terms In defining visual impairment, three aspects of vision namely visual acuity, field of vision and visual functioning are considered simultaneously. In a broad sense, visual defects result into loss of clear vision, central vision or peripheral vision. All these losses are considered by measuring visual acuity, field of vision and level of visual functioning.

      Visual Acuity It refers to the ability of the eye to see details. The visual acuity for distance is measured as the maximum distance at which person can see a certain object, divided by the maximum distance at which a person with normal eyesight can see the same object. Thus a visual acuity of 6/60 means that the person examined cannot see, at a distance of 6 meters, the object which a person with normal eyesight would be able to see at 60 meters. If vision is so impaired that to see the biggest E of the E-chart, the person has to come within 6 meters or even nearer, he is considered blind. The simplest method of testing visual acuity is to see whether the person can count fingers at a distance of six meters.

      Field of Vision It refers to the field which both the eyes can easily see in the front. The normal field of vision is 180 degrees in front of eye. It is determined by the Confrontation Test in which mapping is done on a chart having concentric circles marked upon it. The simplest method of testing is to bring snapping finger from the side of the ear to the front, move it up and down, and mark the position where the person can see the finger.

      Visual Functioning It relates in part to the condition of the eye. It is determined by the experience, motivation, needs and expectation of each individual in relation to whatever visual capacity is available to satisfy curiosity and accomplishment activities for personal satisfaction. The visual functioning refers to the degree to which/ability of a person to use vision for all (daily) activities.