Types of visual impairment

The World Health Organization (WHO) International Classification of Impairment, Disabilities, and Handicaps (ICIDH) system is used to classify the types of visual impairment.

This system, as the name suggests, is used to classify disorders, impairments, disabilities, and handicaps.

Definition of impairment

Impairment is defined as “any loss or abnormality in an anatomical structure or a physiological or psychological function.”

Similarly a disability is “any restriction or lack (resulting from an impairment) of ability to perform an activity in the manner or within the range considered normal for a human being.”

This places an individual in a handicap that is a person’s disadvantaged position in society due to an impairment or disability.

Definition of visual impairment

Visual impairment is defined as the limitation of actions and functions of the visual system.

The National Eye Institute defines low vision as a visual impairment not correctable by standard glasses, contact lenses, medication or surgery that interferes with the ability to perform activities of daily living.

Types of visual impairment

According to the CDC and the World Health Organization the classification of visual acuity and impairment includes (1, 2) –

  • Low visual acuity means vision between 20/70 and 20/400 with the best possible correction, or a visual field of 20 degrees or less
  • Blindness is defined as a visual acuity worse than 20/400 with the best possible correction, or a visual field of 10 degrees or less
  • Legal blindness in the US means visual acuity of 20/200 or worse with the best possible correction, or a visual field of 20 degrees or less.
  • Visual acuity of 20/70 to 20/400 (inclusive) is considered moderate visual impairment or low vision.

Causes of visual impairment

Types of impairment are different for different causes of visual impairment. In total vision loss for example there may be total darkness of the visual fields. Other types include visual impairment in glaucoma, age-related macular degeneration and so forth. (1-5)

Visual impairment in glaucoma

This condition is due to the rise of normal fluid pressure inside the eyes. The type of vision is usually like a tunnel.

The intact vision remains in the center while progressively the peripheries start decreasing. The center of the tunnel reduces in size progressively till total vision is lost if left uncorrected.

Age-Related Macular Degeneration

A central area of woolly or cottony opacity obscures the central part of the vision.

The peripheries may be normally seen. AMD usually blurs the sharp, central vision that is needed for closely viewed activities like reading, sewing, and driving. This is a painless condition.


There is general clouding of the vision. As the whole eye lens is affected the blurring of vision may be diffuse until it is totally lost.

There may be other symptoms like photophobia – inability to see the light; diplopia – double vision etc. Cataracts are very common in older people.

Diabetic Retinopathy

Diabetes leads to damage of the smaller arteries and blood vessels at the back of the eyes over the retina.

Diabetic retinopathy is the most common diabetic eye disease and a leading cause of blindness in adults.

Usually vision impairment in diabetics begins as black spots or floating shapes that appear in the field of vision. Slowly complete vision may be lost if left unchecked.

Near sightedness

Myopia or near sightedness or short sightedness means a person can see nearby objects clearly but distant objects appear blurred. High myopia may lead to vision impairment.

Retinitis Pigmentosa

This is a genetic or inherited condition. Initially it manifests as night blindness.

As the disease progresses there may be a tunnelling of vision with loss of peripheral vision followed by complete blindness.

Further Reading

Last Updated: Jun 7, 2023

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Mandal, Ananya. (2023, June 07). Types of visual impairment. News-Medical. Retrieved on July 23, 2024 from https://www.news-medical.net/health/Types-of-visual-impairment.aspx.

  • MLA

    Mandal, Ananya. "Types of visual impairment". News-Medical. 23 July 2024. <https://www.news-medical.net/health/Types-of-visual-impairment.aspx>.

  • Chicago

    Mandal, Ananya. "Types of visual impairment". News-Medical. https://www.news-medical.net/health/Types-of-visual-impairment.aspx. (accessed July 23, 2024).

  • Harvard

    Mandal, Ananya. 2023. Types of visual impairment. News-Medical, viewed 23 July 2024, https://www.news-medical.net/health/Types-of-visual-impairment.aspx.


  1. Joy Gillatt-Young Joy Gillatt-Young United Kingdom says:

    Hi my grandson was born blind in one eye he wears glasses for  the good eye. would he be classed as visually impaired - the condition he has is Microphthalmia

  2. Shirley Mailer Shirley Mailer United Kingdom says:

    I have just had my eye removed and they tell me I am not visually impaired ?

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Vision problems linked to increased risk of dementia