Yoked prism can be prescribed to reduce extraocular muscle contracture in patients with incomitant strabismus, or applied during the ocular calisthenics exercises.
Ocular calisthenics procedures can be applied in patients with incomitant strabismus to reduce muscle contracture in the paretic eye.
This is reasonable, since some types of strabismus such as incomitant strabismus
may fixate poorly on a specific direction only.
Mitchell (8) reported incomitant strabismus
in 52.4%, nystagmus in 19%, and congenital esotropia in 10.9% of 630 patients with ocular torticollis.
In Incomitant strabismus
, one or more extra ocular muscles show signs of under action or paralysis.
Demer, "Incomitant strabismus
associated with instability of rectus pulleys," Investigative Ophthalmology and Visual Science, vol.
(3) The same author considers incomitant strabismus
when the angle of ocular deviation varies in different fields of gaze.
This is very common, occurring in over 50% of people with CP, (39) with both exotropia and esotropia (rarely accommodative) seen often and an increased incidence of nystagmus and incomitant strabismus
, often due to intracranial trauma.