WHO Definitions and Legal Categories
WHO definitions
The World Health Organization defines blindness and low vision based on visual acuity and visual field:
| Category | Visual acuity | Visual field |
|---|---|---|
| Moderate low vision | > 2/20 and < 7/20 with best correction | > 20° |
| Severe low vision | < 2/20 or equal to 1/20 with best correction | > 10° but < 20° |
| Blindness | < 1/20 with best correction | < 10° |
| Deep blindness | No light perception — no movement perception | Not evaluable |
Differences between Italy and the rest of Europe
- The legal definition of blindness is the same everywhere: visual acuity ≤ 1/20 or visual field < 10°.
- Italy inserts three extra levels after the blindness line — mild, moderate and severe low vision — for benefits, tax breaks and rehabilitation services.
- Most other European countries keep only two “low-vision” bands (moderate / severe) as defined by the WHO.
- The WHO and many European countries express visual acuity using the Snellen scale, with fractions such as 2/20. In Italy, decimals are usually used, like 2/10. They are equivalent — just different formats.