| Value | Category | Cases | |
|---|---|---|---|
| 1 | no difficulty seeing | 31 |
96.9%
|
| 2 | some difficulty | 0 |
0%
|
| 3 | a lot of difficulty | 1 |
3.1%
|
| 4 | cannot see at all | 0 |
0%
|
| 8 | don't know | 0 |
0%
|
| Sysmiss | 12917 |