Vernier acuity measures the ability to detect a misalignment or positional offset between visual stimuli. for example between two vertical lines when reading a vernier scale. It is considered a form of visual hyperacuity due to its detectable thresholds being considerably smaller than the diameter of a foveal cone receptor. which limits the spatial resolution of classical visual acuity. https://www.patsyrenzart.com/product-category/accessories/