Combining all of the findings noted above, we hypothesised that LASIK treatment might similarly improve accommodation when performed on young myopic patients, resulting in more accommodative response postoperatively than preoperatively to Sirius's fixation target despite setting it at optical infinity
. The issue of persistent accommodation against the fixation target of Scheimpflug devices at optical infinity
has also been discussed by Nishimura et al.
Being at optical infinity, their rays are parallel, which makes them ideal compasses.
But the light compass relies critically on the celestial object being at optical infinity. If it isn't, the rays are not parallel but diverge like the spokes of a wheel.
It really is neat to have that little red dot seemingly hanging in the air at optical infinity
. But the way the dot gets there also accounts for one criticism.
Tactical aviation HUD images are collimated to focus them at optical infinity (0 diopter), with the intention of allowing pilots to keep their eyes focused (i.e., lenses accommodated) on distant objects while viewing the HUD.
If the effects of micropsia - whatever the cause - are of concern with a HUD focused at optical infinity, then a focal distance of 2.0 m can only amplify the problem.
(1985) presented participants with imagery of a runway scene that was collimated to be focused at optical infinity. They varied the focal distance of head-up and head-down instrumentation symbology from very near (0.25 m) to the same optical distance as the outside scene.
Values approaching 0.0 D have been reported for targets located at or near optical infinity
(Hull et al., 1982; Iavecchia et al., 1988; Simonelli, 1979).