ICD-11

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

For capturing and coding of “No vision impairment”, use QA00.62 (QA00.6 Examination of eyes or vision).

Near vision refers to the ability to perform tasks that require detailed vision at a close distance. It should be measured with both eyes open at the subject’s preferred viewing distance and with the subject’s habitual near vision correction (if any). Near vision impairment is characterised by a presenting near visual acuity worse than N6.