[Oblique muscle dysfunction and cyclotropia].

The disc-fovea angle was calculated from the fundus photo by measuring the distance of fovea to the geometric center of the disc and the distance of fovea to the horizontal meridian through the disc center. The authors found the average disc-fovea angle of 40 normal individuals to be extorsion 7.43 degrees; and the diagnosis of cyclotropia was made for patients with extorsion over 14.20 degrees or intorsion, and those in whom the disc-fovea angle difference between both eyes was 8 degrees or over. In 9 cases of AV syndrome, 86% (12/14) of the V pattern cases associated with inferior oblique overaction were excyclotropic, and 75% (3/4) of the A pattern cases were incyclotropic. In 5 cases of superior oblique paresis, 86% (6/7) of the diseased eyes were excyclotropic, whether the function of the antagonistic was normal. The authors concluded that fundus photos could serve as a basis for diagnosis of cyclotropia.