460 THE POPULAR SCIENCE MONTHLY. 



observe an artist at his work. Having arranged on his palette 

 a variety of pigments, he stands before the easel and applies 

 them to the canvas, but at intervals steps back some few feet in 

 order to get the effect of distance, as he says. It should be no- 

 ticed that almost without exception the artist when doing this 

 partly closes his eyes, pressing the lids together, making " clinge- 

 ment '' as the French call it, because, as he explains, " bet- 

 ter effects " are thus obtained. At the same time he tips his 

 head from one side to the other, the reason for which we will con- 

 sider later. Now, if the eyes of persons with ordinary occupa- 

 tions are changed, as we have seen, by the pressure of the upper 

 and lower lids upon the globe, it is but natural to infer that the 

 same result would follow even in a greater degree with persons 

 whose occupation from morning until night, year in and year out, 

 is such as to cause them to practice to an unusual degree this 

 habit of clingement, or lid pressure upon the cornea. Indeed, 

 this fact has long since attracted the attention of investigators 

 and has been demonstrated and elaborated by Bull, of Paris, and 

 others. Dr. Bull experimented on his own eyes, having them 

 measured exactly by an instrument of wonderful exactness known 

 as the ophthalmometer while he was making this lid pressure. 

 These measurements showed that even this slight momentary 

 contraction of the lids produced a perceptible increase of the 

 unequal curvature of the cornea, and also that a very high degree 

 of astigmatism could with little effort be produced by pressure 

 of the lids. 



Very strong a priori reasons, therefore, lead us to expect that 

 the eyes of artists are as a rule more imperfect than those of 

 persons with other occupations. I have taken pains, however, to 

 establish this fact by tests and measurements. The first results 

 of that investigation are given in the American Journal of 

 Ophthalmology for October, 1894, and tests have been made at 

 intervals since then of the vision of artists, record being kept of 

 the variety of work done, style preferred, whether the individual 

 practiced lid pressure habitually or not, and other details of a 

 technical nature. Excluding those on the one hand who were too 

 young in the profession to be really classed as " artists," and on 

 the other hand those whose eyes were practically in a diseased 

 condition, the list thus far includes eighty-four artists, or one 

 hundred and sixty-eight eyes. 



Among these, not a single eye was found to be without some 

 astigmatism. This is not surprising, but the degree of astigma- 

 tism is significant. 



In the series of two hundred eyes already referred to as ex- 

 amined by Dr. Roosa, which had every indication of being abso- 

 lutely perfect, an exact examination showed that there was, on the 



