In middle age PRESBYOPIA becomes apparent in all but the near-sighted. It is generally involuntary and made to see objects clearly at any distance.
See myopic defocus.mechanism of accommodation Process by which the eye focuses onto an object.
In these conditions, the accommodative system of the eye tends to return to its position of rest (or tonic accommodation).
Examples: looking at an empty field; looking through a very small artificial pupil (0.5 mm or less). See components of accommodation; resting state of accommodation.psychic accommodation See proximal accommodation.range of accommodation The linear distance between the far point and the near point.
Consequently, myopes require more accommodation and hyperopes less accommodation when they transfer from spectacles to contact lenses.
However, this change in accommodative demand is accompanied by a similar change in convergence, so that a myope transferring to contact lenses accommodates and converges more than with spectacles and the reverse applies for a hyperope. See far point sphere.ill-sustained accommodation See accommodative insufficiency.inert accommodation See accommodative infacility.insufficiency of accommodation See accommodative of accommodation 1.The ciliary muscle is controlled by the parasympathetic system, which is triggered by an out of focus retinal image. See push-up method; near point rule; near point sphere; Scheiner's test.negative accommodation 1.