Abstract
To see the role of the proprioceptors of the extrinsic eye muscles in the maintenance of body equilibrium we carried out the following examinations. Patients who had sustained head trauma and showed unilateral paralysis of the eye muscles were examined. A prismatic lens, with its base pointed to the ear side, was placed over the paralytic eye and resulting changes in eye and body reflexes were measured using the electronystagmograph (ENG) and statokinesimeter, respectively.
The results obtained were as follows:
(1) Placing a lens over the paralytic eye showed activation in optokinetic nystagmus in 53%, lack of change in 21% and inhibition in 26%.
(2) Patients who developed activation of optokinetic nystagmus when placing a lens over the paralytic eye tended to show simultaneous improvement of the righting reflex. In contrast, patients who developed inhibition of optokinetic nystagmus when placing the lens over the paralytic eye tended to show simultaneous aggravation of the righting reflex.
Furthermore, there was a tendency that in the former group, vertigo due to optokinetic stimulation was reduced, whereas in the latter, vertigo was rather activated.
From these findings, the following conclusions were drawn:
(1) The functional correlation between the retina and the proprioceptors of the extrinsic eye muscles is necessary, in order to have good development of equilibrium function of the eyes and body in response to optokinetic stimulation.
(2) Placing a prismatic lens over the paralytic eye is a good method to analyze the role of the proprioceptors of the extrinsic eye muscles in body equilibrium as related to optokinetic stimulation.
