In article , "Major Scott"
wrote:

A long long time ago when I was applying to study in Universities, a lecturer
showed us a demonstration with a laser. As an aside, he told us to look at
the pattern projected by the laser onto the wall and do something which I
forget (move your head from side to side or something), and if the pattern
stayed still you had 20-20 vision. Does anyone know the details?

Haven't heard about that. Is it supposed to test acuity?