| NINDB | National Institute of Neurological Diseases and Blindness |
|---|---|
| NSPB | National Society for the Prevention of Blindness |
| TMB | transient monocular blindness |
| XN | night blindness |
| legal blindness | Generally, visual acuity of less than 6/60 or 20/200 using Snellen test types, or visual field restriction to 20 |
|---|---|
| functional blindness | Apparent loss of vision related to suggestibility. (05 Mar 2000) |
| letter blindness | Visual agnosia for letters. The subject sees the letters but cannot identify them; caused by a lesion in the occipital cortex. (05 Mar 2000) |