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 genuinely means, in plain language.

Normal vision

A visual acuity of 6/6 to 6/18 (with correction, such as glasses, in the better eye) is generally considered within the normal to mildly reduced range. Read our guide on what these numbers mean if you're not familiar with the notation.

Low vision

Low vision describes vision reduced enough to affect daily tasks, even with the best glasses or contact lens correction. In India, this generally refers to best-corrected vision between 6/18 and 6/60 in the better eye, or a significantly reduced field of vision. 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 genuinely 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 light perception
• Best-corrected visual acuity below 6/60 in the better eye
• A visual field restricted to 20 degrees or less

In India, a person with best-corrected vision below 6/60 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 (below 6/60 or a severely restricted visual field) 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.