Table 1 Categories of severity of visual impairment according to the International Statistical Classification of Diseases [1].
Category of visual impairment | Visual acuity with best possible correction | Or central visual field* | Classified as | |
|---|---|---|---|---|
| Â | Maximum less than | Minimum equal to or better than | Â | Â |
1 | 6/18 3/10 (0.3) 20/70 | 6/60 1/10 (0.1) 20/200 | Â | Low vision |
2 | 6/60 1/10 (0.1) 20/200 | 3/60 1/20 (0.05) 20/400 | Â | Low vision |
3 | 3/60 1/20 (0.05) 20/400 | 1/60 (finger counting at 1 metre) 1/50 (0.02) 5/300 (20/1200) | 10° or less but more than 5° | Blindness |
4 | 1/60 (finger counting at 1 metre) 1/50 (0.02) 5/300 | Light perception | 5° or less | Blindness |
5 | No light perception | Â | Blindness | |
9 | Undetermined or unspecified | Â | Unspecified | |