97th DOG Annual Meeting 1999
V484
PRIMARY POSITIONS IN NORMALS AND PATIENTS WITH CONGENITAL AND ACQUIRED FOURTH NERVE PALSIES
H. Steffen 1,2, D. Straumann1,3, D. S. Zee1,4
To find out whether the primary position is affected in patients with a fourth nerve palsy.
Methods: 14 patients with a fourth nerve palsy (10 congenital, 4 acquired) and 10 normals were required to fixate nine light emitting diodes (LED's) arranged on a flat screen 124 cm from the subject. Targets were arranged in a 3x3 matrix covering a range of +/-20º horizontally and vertically. Eye position was measured binocularly using the three-axis magnetic search coils and expressed as rotation vectors. For all data, a planar regression was used to fit torsional position as a function of horizontal and vertical eye position in order to calculate the horizontal (hPP) and vertical (vPP) component of primary position.
Results: hPP in the paretic eyes was shifted temporally (11.6º ± 12.2º) which was significantly more than in the contralateral (nonparetic) eyes (3.5º ± 6.5º; p = 0.02, t-test) or in the eyes in normal subjects (4.4º ± 6.0º, p = 0.03). vPP did not differ between the eyes of normal subjects (9.08º ± 4.83º) and paretic eyes (7.43º ± 7.46º). However, there was an upward shift of vPP in the normal eyes of patients (13.3º± 7.4º) as compared to their paretic eyes (p=0.02) and the eyes in normal subjects (p = 0.04).
Conclusions: Temporal rotation of primary position is a typical feature in patients with a fourth nerve palsy. The significance of the upward shift of primary position of the nonparetic eye in patients with fourth nerve palsy is unclear.
1The Johns Hopkins Hospital, Depts. of Neurology1 and Ophthalmology4, 600 N Wolfe Street, Baltimore, MD 21287, U.S.A.
2Dept. of Ophthalmology, University of Heidelberg, INF 400, D-69120 Heidelberg,
3Universitäts-Spital, Dept. of Neurology, Frauenklinikstr. 26, CH-8091 Zürich
supported by DFG (Ste 860/2-1), Schweizerischer Nationalfonds 3231-051938.97, and NIH EYO1849.
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