Highest hyperacuity
Dr Dennis M. Levi
United States (College of Optometry, University of Houston.)
The human eye is capable of judging relative position with remarkable accuracy, reaching limits of between 3 and 5 seconds of arc.
In April 1984, Dr Dennis M. Levi (USA) of the College of Optometry, University of Houston, Texas, USA, repeatedly identified the relative position of a thin bright green line within 0.85 seconds of arc. This is equivalent to a displacement of some 6 mm (0.25 in) at a distance of 1.6 km (1 mile).