Classification of visual impairment

Classification of visual impairment
Classification of impairment used by ophthalmologists, can be based on the degree of visual acuity, the time of appearance or because of ocular pathology.All these factors taken into consideration when making a diagnosis.

degree of visual impairment is set on the eye's ability to see two glowing dots with a minimum distance between them.Normal visual acuity equal to one - 1.0, corresponds to the human ability to distinguish on a special table of the tenth line of numbers and letters from a distance of 5 meters.In medicine, there are several classifications of visual impairment in humans.

Classification of violations based on visual acuity

as the main medicine used in the classification of visual impairment, depending on a person's ability to see.

  1. Blindness.Inherent complete lack of visual sensations or residual vision.If you wear glasses marked maximum visual acuity - 0.04, or just the ability to light perception.
  2. absolute or total blindness.Characteristically complete lack of visual sensations,
    or the presence of light perception, the vision shaped by the exigencies of 0.005 to 0.04.
  3. visually impaired blindness.Visual acuity of 0.05 to 0.2.In this vision, the eyes fulfill their informative function.

Classification of visual impairment, depending on the time of occurrence of the defect

Depending on the time of occurrence of the defect following classification of violations highlighted in ophthalmology view:

  • born blind.They are all born with an absolute blind or blinded until the age of 3 years;
  • blinded.These are people who have lost the ability to see over the age of 3 years -x.

The basis of this classification, impairment is the presence of partial or no understanding of the world around them.

Visual impairment in various diseases of the visual system

There is a classification of disorders of the visual function, depending on the causes of the defect:

  • refraction disorder.In this case, the image of the subject is not focused clearly to the retina;
  • accommodation disorder.This inability to clearly see all the objects that are at different distances;
  • disorder of peripheral vision.There is no clear image of objects in motion or at the sides of the eyes;
  • eye disorder adaptation ability.Deteriorating vision lighting conditions change.

This specification impairment is based on the change in a person's ability to see, but not at its full absence.

Each of these classifications, the ability to see violations using an ophthalmologist for an accurate diagnosis and is an important criterion to assess the person's general health.Therefore the degree of visual impairment is determined depending on the severity and causes of visual sensitivity of oppression.

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