82 THE POPULAR SCIENCE MONTHLY. 



This condition is known as over-sight, 1 technically, hypermetropic.. 

 When it exists in a degree beyond the adjustability of the len^, it 

 may be recognized by object-tests and trial-glasses ; but in less de- 

 grees it may escape detection by these means, because of the accom- 

 modating action of the lens. As in the case of near-sight, therefore, 

 atropia must be employed for its exact observation. 



Over-sight may, then, be defined as that condition of the eye in ichich 

 parallel rays, passively transmitted by the lens, reach the retina before 

 convergence, because of the shortened axis. 



While the subjects of this malformation are numerous, some in- 

 vestigators finding them even to exceed largely those of the opposite 

 condition, 2 and while the eyes so malformed are usually not dis- 

 eased, as in myopia, yet numerous local and general disturbances 

 are found to exist in very many of the cases. These are the result 

 of over-use, or straining of the muscle of accommodation. A special 

 interest has recently been excited in reference to them by an ad- 

 dress of Dr. George T. Stevens, of Albany, read last December be- 

 fore the Albany Institute, 3 in which the relation of cause and effect 

 is claimed to have been established by the author, between certain 

 visual defects, particularly over-sight, and such functional nervous 

 affections as neuralgia, the more common forms of headache, epilepsy, 

 St. Vitus's dance, hysteria, and insanity. About six months previ- 

 ously he had presented this theory to the New York Academy of 

 Medicine, but he then limited its application to St. Vitus's dance. 

 These views were " new and unexpected to the profession," and were 

 controverted by Dr. Charles S. Bull, of New York, in a paper read 

 before the New York Medical Journal Association, in April last. 4 

 He reports thirty-one cases of St. Vitus's dance in his own recent 

 practice, in which special attention was given to the discovery of any 

 such relation as Dr. Stevens affirms to exist. Fifteen of the thirty-one 

 had correct and sixteen had defective vision (over-sight). Of the 

 latter only five could be induced to purchase and wear the necessary 

 correcting glasses. But in these five cases there should have been 

 some improvement, at least, in the nervous symptoms consequent 

 upon their wearing the glasses ; this being, by the admission of Dr. 



1 This is not a disease, like near-sight, but a condition ; and it is not acquired, but is 

 congenital, always. It is also called far-sight and long-sight ; but it is thus liable to be 

 confused with an acquired condition producing a similar result, as in the sight of old 

 people which is not a flattening of the eyeball itself, nor of the cornea and the lens, but 

 it is an impairment of the power of accommodation due to the hardening of the lens, 

 which usually occurs at about the age of forty-five years, and is often called old sight, 

 but is technically known as presbyopia. 



2 See " A Preliminary Analysis of 1,060 Cases of Asthenopia occurring in the Practice 

 of C. R. Agnew, M. D.," which shows hypermetropia 359 to myopia 121, or nearly three 

 to one. 



3 New York Medical Journal for June. 



4 Medical Record, June 2d. 



