Uncorrected distance visual acuity (UDVA / UCVA)

Method

Distance visual acuity on a logMAR chart (ETDRS or equivalent) read with the eye in its native refractive state and no optical aid in place, at the chart's stated test distance and luminance.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

Excludes any measurement taken through spectacles, contact lenses, or a phoropter after subjective refraction - that is the best-corrected acuity node, which shares this unit, this chart and this visit and is the dominant near-miss. In keratoconus and post-refractive-surgery cohorts the two dissociate strongly, because optical correction masks the irregular astigmatism the intervention is aimed at, so an agent can improve one and leave the other flat. The same logMAR convention applies, so the same CRITICAL SIGN INVERSION against Snellen and decimal acuity holds: those improve by RISING, this improves by FALLING.