Studies on Mild School Myopia Part Ⅲ. The Accommodative Enlargement of Mariotte's Blind Spot in Mild School Myopia

By examining 160 eyes of 80 students with mild school myopia below-3D age ranging 12 to 25 years and 60 eyes of 30 normal students from the age of 19 to 25 years as the control for their subjective symptoms, the degree of refraction, fundus findings, and the accommodative enlargement of Mariotte's blind spot, the author studied the differences between the students with myopia and the normal students, and obtained the following results: 1. No difference in the size of the blind spot beween the students with myopia and the control can be recognized both before and after wearing eyeglasses (+4D). 2. The degree of the remaining accommodative enlargement and consensual enlargement of blind spot are both greater in myopia than in normal eyes. Therefore, it seems that there exists dys-function of Briicke's muscle in myopia. 3. There is no mutual relationship between the degree of remaining enlargement of the blind spot and the severity of myopia. 4. Likewise there exists no mutual relationship between the degree of subjective symptoms and the degree of remaining enlargement of the blind spot. 5. The absence of the mutual relationship above mentioned seems in all probability to be due to the fact that sclerotic expands and the orbital axis elongates along with the progress of myopia resulting in the loosening of ciliary muscle tension. 6. As for the fundus findings in mild myopia, such symptoms as milky relfex, redness of the disc, and venous dilatation, all pointing to the circulatory disturbances of the retinochorioidea, can de recognized in high percentage. 7. From these results it can be assumed that there exists a marked dysfunction of Brucke's muscle in school myopia.