Levels of Visual Impairment Explained

Terms like "low vision," "legally blind," and "visual impairment" get used loosely in everyday conversation, but they actually have specific, defined meanings in ophthalmology — here's what each one means, in plain language.

Normal vision

Best-corrected vision better than 6/18 in the better eye (for example 6/6, 6/9 or 6/12) is not classed as low vision under Indian law. The WHO does count vision worse than 6/12 as mild impairment. Read our guide on what 6/60, 6/18 and 3/60 mean if you're not familiar with the notation. For doctors and students, the full criteria (RPwD 2016, WHO and US) are in our visual impairment categories guide.

Low vision

Low vision describes vision reduced enough to affect daily tasks, even with the best glasses or contact lens correction. Under India's Rights of Persons with Disabilities (RPwD) Act, 2016, low vision means best-corrected vision of 6/18 or worse, down to 3/60, in the better eye, or a field of vision narrowed to less than 40° (down to 10°). So 6/24, 6/36 and even 6/60 count as low vision today. People with low vision can often still read, recognise faces, or move around independently, sometimes with visual aids, but tasks like reading small print or recognising faces at a distance become difficult.

Blindness — and why the definition matters

"Blindness" doesn't always mean a total absence of sight. It's a specific clinical and legal classification, and includes any of the following:

• Total absence of sight
• Best-corrected visual acuity worse than 3/60 in the better eye
• A field of vision narrowed to less than 10 degrees

These are the definitions in India's RPwD Act, 2016. The older 1995 law used a cut-off of 6/60, which is why you may still hear "6/60 is legally blind". Today, best-corrected vision worse than 3/60 in the better eye meets the legal definition of blindness — a classification relevant for disability certification, government benefits, and support services, not just a clinical description.

"Legally blind" vs. "totally blind"

This distinction trips people up often, and it's worth being clear about: legally blind is a formal classification threshold (in India, best-corrected vision worse than 3/60 or a field under 10°; in the US, 20/200 or worse) used for certification and support eligibility — it does not mean a person has no vision at all. Many legally blind individuals retain some functional vision. Totally blind specifically means no light perception whatsoever. The two terms are often confused, but they describe very different levels of vision.

Why this classification exists

Beyond clinical relevance, formal visual impairment classification in India ties directly to disability certification, which affects eligibility for government benefits, educational accommodations, and workplace support. If you or a family member may need a disability certificate related to vision, an accurate, documented eye examination is the essential first step.

Getting an accurate assessment

Dr. Dhaval Patel, MD (Ophthalmology, AIIMS New Delhi), provides thorough visual acuity and field assessments, with clear guidance on what your results actually mean and whether they meet formal disability classification thresholds. Learn more about visual field testing at Sadbhaav.