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Every 5 seconds, one individual in the world goes blind. It is an emerging problem in developing countries across the globe.

Types of blindness

Blindness can be classified into many types.

Economic blindness

When the level of blindness affects the individual from earning adequately, it denotes economic blindness. 

The inability to count fingers from a distance of six meters with the better eye, with the best possible correction, clinically defines economic blindness.

Legal blindness

This indicates the level of blindness that necessitates welfare measures and legal protection. Vision is <6/60 in the better eye with correction, and/or a visual field less than 10 degrees centrally is used to define legal blindness clinically.

Social blindness

This denotes the type of blindness that prevents the individual from socially interacting with family and peer groups in a satisfactory manner. The inability to count fingers at a distance of 3 meters with the best correction is used to define social blindness. 

Manifest blindness  

Visual acuity of 1/60 in the better eye is used for categorising manifest blindness.

Absolute blindness

The inability to perceive light in any eye denotes the stage of absolute blindness.

Curable blindness

The cause of blindness is treatable, which is stated as curable blindness, for example, Cataract.

Preventable blindness

This refers to the loss of blindness that could have been completely prevented by the institution of effective preventative or prophylactic measures. Examples include Xerophthalmia, Trachoma and Glaucoma.

Avoidable blindness

Sum total of preventable or curable blindness is referred to as avoidable blindness.

Incurable blindness

This denotes the type of blindness that is beyond treatment.

Causes of blindness

Blindness is caused due to,

  • Aging
  • Genetic endowment
  • Smoking
  • Diet
  • Surgical phobia
  • Self medications
  • UV radiation
  • Dehydration
  • Lack of awareness

Vision 2020

Vision 2020 is the right to sight, is a global initiative to eliminate avoidable blindness. The program is an initiative between the World Health Organization and the International Agency for the prevention of blindness.

When Vision 2020 was launched five conditions were identified for priority action globally. The five conditions are:

  1. Cataract
  2. Refractive errors
  3. Trachoma
  4. Onchocerciasis
  5. Vitamin A deficiency

Cataract surgery has to be made affordable and accessible to everyone, especially for the undeserved population.


Trachoma is the most common preventable cause of blindness in the world. Trachoma is common in areas of the world that are socioeconomically deprived of basic needs.

SAFE Strategy is followed to treat Trachoma -Surgery, antibiotics, facial cleanliness and environmental cleanliness.


Onchocerciasis is one of the leading causes of blindness in Africa. Ivermectin is the drug of choice to eliminate onchocerciaisis.

Refractive errors

The aim is to eliminate visual impairment and blindness due to refractive errors or other causes of low vision. The steps in the provision of refraction services and low vision care include:

  • Screening
  • Refraction
  • Manufacture of spectacles
  • Dispensing of spectacles

Follow up for repair of spectacles or devices and repeat dispensing.

The main strategies include:

  • Creating awareness among school-going children regarding refractive errors.
  • Develop accessible refractive services
  • Ensure optical services and provide glasses at an affordable rate
  • Availability of low vision aids


 In India, more accurate and advanced procedures are coming up to correct preventable blindness. The affected people can also make lifestyle changes to keep them safe and work independently if they tend to have low vision. Still, they should come forward and not ignore the warning signs to get it treated early and work for hand in hand with the medical professionals towards the vision 2020 programme.


The Information including but not limited to text, graphics, images and other material contained on this blog are intended for education and awareness only. No material on this blog is intended to be a substitute for professional medical help including diagnosis or treatment. It is always advisable to consult medical professional before relying on the content. Neither the Author nor Star Health and Allied Insurance Co. Ltd accepts any responsibility for any potential risk to any visitor/reader.

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