Distance doubling visual acuity test: a reliable test for nonorganic visual loss.

Background: To determine the value of the distance doubling visual acuity test in the diagnosis of nonorganic visual loss in a comparative observational case series.

Methods: Twenty-one consecutive patients with nonorganic visual acuity loss and 21 subjects with organic visual loss as controls were included. Best corrected visual acuity was tested at the normal distance of 5 meters using Landolt Cs.