Vision Exam Measures

The VEHSS system measures visual function based on best-corrected visual acuity in the better-seeing eye and tracks monocular impairment based on the best-corrected acuity in the worse-seeing eye. The VEHSS system will seek to include other vision measures such as contrast sensitivity and high-myopia in future efforts as the data becomes available.

Visual Acuity Categories, best corrected or presenting

Visual Acuity Categories, best corrected or presenting
Description Definition
Normal Vision 20/12.5 – 20/25 (better-seeing eye)
Any Vision Loss ≤20/32 (better-seeing eye)
Visual Impairment 20/32 – 20/160 (better-seeing eye)
US Defined Blindness ≤20/200 (better-seeing eye)
World Health Organization (WHO) Defined Blindness ≤20/400 (better-seeing eye)
Monocular Vision Loss ≤20/70 in worse eye, mild or normal in better-seeing eye
Uncorrected Refractive Error ≤20/50 (presenting in better-seeing eye, improving to ≤20/40 with correction)
Missing Acuity No acuity measure classified above