What is Blindness: Understanding Definitions and Global Criteria
As a doctor, I have often seen that the word "blindness" is used very casually in day-to-day life. But for a person who is actually experiencing vision loss, this word carries deep emotional, physical, and social meaning.
Blindness is not just about not being able to see. It is about how a person experiences the world, adapts to daily life, and maintains independence. In this blog, I will explain what blindness really means in simple language, using globally accepted definitions.
What is Blindness?
Blindness refers to a condition where a person has a complete or severe loss of vision that cannot be corrected with glasses, contact lenses, or surgery.
However, blindness is not always “total darkness.” Many people still have some level of vision, such as light perception or blurred shapes.
WHO Definition of Blindness
According to the World Health Organization (WHO):
Blindness is defined as visual acuity less than 3/60 in the better eye with best possible correction, or corresponding visual field loss.
In simple terms, this means:
- A person sees at 3 meters what a normal person sees at 60 meters
- Or the field of vision is significantly reduced
Indian Definition of Blindness
"blindness" means a condition where a person has any of the following conditions, after best correction—
(i) Total absence of sight; or
(ii) Visual acuity less than 3/60 (or less than 10/200) by Snellen's chart in better eye with best possible corrections; or
(iii) Limitation of field of vision subtending an angle of less than 10 degree in better eye.
This definition is important for certification, disability benefits, and national health programs in India.
Understanding Visual Acuity (3/60)
Visual acuity is a way to measure how clearly a person can see.
For example:
- 6/6 vision = normal vision
- 3/60 vision = very poor vision
If someone has 3/60 vision, they need to be very close to an object to see it compared to a person with normal vision.
Visual Field Restriction
Sometimes, a person may see clearly in the center but lose side vision.
If the field of vision becomes less than 10 degrees, it is like looking through a narrow tunnel. Even if central vision is present, this is considered blindness in many definitions.
Visual Impairment vs Blindness
Not all vision loss is blindness.
- Visual impairment includes mild, moderate, and severe vision loss
- Blindness is the most severe category
This classification is used in systems like ICD-11.
ICD-11 Vision Impairment Categories
- Mild visual impairment
- Moderate visual impairment
- Severe visual impairment
- Blindness
Why Definitions Matter
These definitions are not just technical terms.
They are used for:
- Medical diagnosis
- Disability certification
- Government policies
- Global health statistics
More importantly, they help ensure that people with vision loss receive proper recognition, support, and care.
Simple Eye Anatomy
Understanding basic eye structure helps in understanding blindness.
Image showing simple eye anatomy.
References
- World Health Organization. Blindness and vision impairment. Geneva: WHO; 2023. Available from: https://www.who.int/news-room/fact-sheets/detail/blindness-and-visual-impairment
- Government of India. Guidelines for the Evaluation of Various Disabilities and Procedure for Certification. New Delhi: Ministry of Social Justice and Empowerment; 2018. Available from: https://divyangjan.depwd.gov.in/upload/uploadfiles/assessment_guidelines.pdf
Features
- Health Blogs
- Free Multiple Choice Questions
- Awareness Campaigns
- Authentic Sources
Disclaimer: We do not offer any kind of medical advice in any form. The information in the blog is not replacement of medical, diagnostic, endorsement, treatment, prescription or legal advice. The Blog is for informational purposes only. Although, we try to update but medical science is very vast and evolve at very fast pace. Nothing here should be used as a substitute for medical advice, diagnosis, or treatment. We do not endorse any healthcare advice that contradicts a physician’s guidance. Kindly read our policies before reading the website content.
Placement of a link, graphic or text link is to be used only as a marker or reference to various home pages or content (like from Centers for Disease Control and Prevention (CDC), ATSDR or HHS websites; Ministry of Health and Family Welfare India (MOHFW); World Health Organization (WHO); European Centre for disease prevention and control; NHS or any other). A link does not indicate any form of endorsement or approval from any such source.
- Policies – Click Here
- Full Disclaimer – Click Here
- Terms and Conditions – Click Here
- Contact if any discrepancies – contact@sensingmedicine.com
Information
Follow Us
Physical Medicine & Rehabilitation
FAQs
What is Physical Medicine and Rehabilitation?
Physical Medicine and Rehabilitation (PM&R), also known as physiatry, is an allopathic medical specialty that involves restoring function for a person who has been disabled by disease, disorder, or injury. It provides integrated, multidisciplinary care addressing physical, emotional, medical, vocational, and social needs.
Who is a “Physiatrist”?
A physiatrist is a physician specializing in physical medicine and rehabilitation. (In India: MBBS followed by MD/DNB in PMR.)
What is Rehabilitation?
Rehabilitation is the process of helping a person achieve the highest level of function, independence, and quality of life possible. It does not undo damage but restores optimal health, functioning, and well-being.
Is PM&R only for people with disabilities?
No. PM&R serves anyone experiencing a decline in physical function—from athletes with injuries to elderly individuals recovering from surgery, falls, or pain.
Can physiatrists perform surgery?
Yes. In India, physiatrists perform rehabilitation surgeries such as deformity corrections, tendon transfers, and revision of amputations.
How does PM&R help in managing chronic pain?
Physiatrists use a multimodal approach—evaluation, diagnosis, medication, therapy, injections (e.g., nerve blocks, trigger point/joint injections), and lifestyle modifications—to reduce pain and improve daily function.
What conditions do physiatrists treat?
Common conditions include stroke, spinal cord injuries, traumatic brain injury, cerebral palsy, amputations, sports injuries, chronic musculoskeletal pain, post-surgical rehabilitation, osteoarthritis, osteoporosis, and more.
Discover more from Sensing Medicine
Subscribe to get the latest posts sent to your email.