Schwarzbach. — The Effects of School Life on Sight. 475 



small number, this question was of little or no importance, but now, espe- 

 cially when England and its colonies are about to extend the benefit of 

 school-education to all children, the question how to prevent short sight 

 deserves serious consideration. 



I mentioned in the beginning, that not only Myopia, but also a decrease 

 of acuteness of vision, so-called Amblyopia, is frequently developed during 

 school-life. Often this serious condition is the result of a positive disease 

 in the interior of the eye, which is of too individual a character to be con- 

 sidered here. However, amblyopia of one eye, is mostly produced by 

 unsuitable arrangements for work, which disturbs the common action of 

 the two eyes, and weakens the eye which is excluded from use. 



But even more frequently than this defect is a decrease of endurance of 

 the vision — Asthenopia. This very frequent affection, which has destroyed 

 many a career, prevented the development of many a fine intellect, and 

 deprived many of the fruits of then- laborious exertions and persevering 

 industry, arises principally from two causes. The first is a congenital con- 

 dition, called hypermetropia, which can be corrected by convex glasses, and 

 which cannot therefore be laid at the door of school-life. The second is a 

 disturbance of the harmonious action of the muscles of the eye — a defect 

 which is generally caused by unsuitable arrangements for work. 



It is not my intention to enter here on a scientific explanation of the 

 various causes of these disturbances of the organ of sight, for the three 

 anomalies I have mentioned all arise from the same circumstances — 

 viz., insufficient or ill-arranged light, or from a wrong position during 

 work. 



Insufficient or ill-arranged light obliges us to lessen the distance between 

 the eye and the book while reading or writing. When the eye looks at a 

 very near object, the accommodating apparatus and the muscles which 

 turn the eyes, so that the axes converge towards the same object, are brought 

 into a condition of greater tension, and this is to be considered as the prin- 

 cipal cause of shortsightedness and its increase. 



How can these evils be prevented ? In answering this important ques- 

 tion, I do not pretend to express an original opinion only. As a disciple of 

 those great men who have made ophthalmology a flowery limb on the great 

 tree of medical science, I must confine myself to repeat their teaching, and 

 I do so in the firm belief of teaching the truth. But common sense even 

 could answer the question before us. 



The light must be sufficiently strong and fall on the table from the left- 

 hand side, and, as far as possible from above, The children ought to sit 

 straight, and not have the book nearer to the eye than ten inches at the 

 least. Light coming from the right-hand is not so good as from the left, 



