Study of pathophysiology and treatment of superior oblique palsy.

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A superior oblique muscle has actions of infraduction, abduction and incyclotorsion. Other extra ocular muscles can compensate dysfunction of superior oblique muscle. Compare to infraduction and abduction, incyclotorsion is rarely compensated by other muscles and most patients with acquired Superior oblique palsy complain torsional diplopia. Fusional amplitude of cyclotorsion is large in normal subjects, but it is very narrow in the patients with central nervous system problems. We therefore performed the following studies on superior oblique muscles. 1) The relationship between ocular torsional movement and structure of extraocular muscles. 2) the relationship between ocular torsional movement and binocular vision.1)In the patients with superior oblique palsy, if the superior oblique muscle is hypoplastic, patients have vertical deviation, exotropia and they often require larger number of muscles to be operated to achieve satisfactory result. We reported the effectiveness of the surgery to correct the relative position between the eyeball and extraocular muscles. We confirmed that imaging studies are important to evaluate muscle functions. We reported the position of extraocular muscles after strabismus surgery. The positions of extraocular muscles did not alter in the deep orbit. The alteration occurred only anterior to the equator.We studied the amount of retinal rotation and subjective cyclotorsion alter macular translocation surgery. We found that the patients who underwent macular translocation surgery exceeded 1 5 degrees often complain diplopia. Normal subjects adapt cyclotorsion up to 15 degrees, and the patients who underwent macular translocation surgety also adapted up to 15 degrees of cyclotorsion. We reported that the patients whose superior oblique tendon migrating into the Tenon's capsule showed poor stereopsis and recovering binocularity after strabismus surgery was difficult.