Vision impairment including blindness

**Definition:** !markdown The table below gives a classification of severity of vision impairment based on visual acuity. For epidemiological studies, it is recommended to collect the following information on visual acuity for each eye, for both eyes open and for distance and near.

a. Uncorrected visual acuity (9D96)

b. Presenting visual acuity (9D94)

c. Best corrected visual acuity (9D95)

Blindness is also categorized according to the degree of constriction of the central visual field in the better eye to less than 10 degrees.

| Category | Visual acuity *1 <br> Worse than: | <br> Equal to or better than: | |----------|--------------------------------|---------------------------------------------| | No vision impairment | | 6/12<br>5/10 (0.5)<br>20/40<br>0.3 | | 1 Mild vision impairment | 6/12<br>5/10 (0.5)<br>20/40<br>0.3 | 6/18<br>3/10 (0.3)<br>20/70<br>0.5 | | 2 Moderate vision impairment | 6/18<br>3/10 (0.3)<br>20/70<br>0.5 | 6/60<br>1/10 (0.1)<br>20/200<br>1.0 | | 3 Severe vision impairment | 6/60<br>1/10 (0.1)<br>20/200<br>1.0 | 3/60<br>1/20 (0.05)<br>20/400<br>1.3 | | 4 Blindness | 3/60<br>1/20 (0.05)<br>20/400<br>1.3 | 1/60 or counts fingers (CF) at 1 metre<br>1/50 (0.02)<br>20/1200 or counts fingers (CF) at 1 metre<br>1.8 | | 5 Blindness | 1/60<br>1/50 (0.02)<br>5/300 (20/1200)<br>1.8 | Light perception | | 6 Blindness | No light perception | | | 9 | Undetermined or unspecified | | | Near vision impairment | N6 or M 0.8 at 40cms | |

*1 Presented in metres, decimals, feet and logMar