[The effect of treatment with prisms on head position in persons with nystagmus--preliminary report].

The aim of the work is to inspect the influence of the treatment by using hyper-correcting prisms on the vertical deviations of the eyes and on the head's position in persons with nystagmus. We observed 4 persons with nystagmus without strabismus and 3 persons with convergent squint. In persons without strabismus the prismatic correction placed with an edge in the direction of the "calm's zone" (quiet's zone) to obtain the straight position of the head when looking forwards was applied. Twice a day during 10 minutes the patients were making the movement's exercises in the vertical and horizontal direction looking by the prism separately by each eye. This prism (often 35 D prism) was placed with the edge in the direction of greater deviation of the oblique inferior muscles and the left rectus inferior muscle. Patients with convergent strabismus were treated according to the principles of localization method with consideration of the localize exercises by using hyper-correcting prisms in the vertical and horizontal directions. Two patients had a surgery in order to eliminate not aesthetic and strong prisms which were applied because of large horizontal squint. One patient with convergent alternate squint with hyperactivity of both inferior oblique muscles and inferior rectus muscle of the left eye was treated without surgery, only by the conservative treatment with prisms. In all patients we obtained a straight position of the head despite of the nystagmus still existing during the eyes movements in some directions. The treatment by using hyper-correcting prisms can completely replace the surgical treatment or is able to supplement it and prevent relapses.