VISION. 237 



image. Such is the condition in the farsighted per- 

 son, the condition is called hyperopia. The term 

 farsightedness does not mean that the subject can 

 see farther than the average individual but that he 

 can see far more easily than near. If a subject with 

 V=| can see as clearly or more clearly when the 

 4-0.75 D. lens is in front of the eye there is no 

 reasonable doubt that hyperopia in some form is 

 present. 



(10) Let the subject direct the line of vision toward 

 the center of the chart for testing astigmatism. It is 

 probable that not all of the radiating lines will appear 

 equally clear cut and black, for most persons have a 

 small degree of astigmatism. If the lines are unequal- 

 ly clear, where are the clearest ones located? Do they 

 describe a diameter across the circle ? If so, 

 describe the location of the clear diameter, 180 

 being the horizontal diameter, and 90 90 the verti- 

 cal one. 



(11) () If the subject has normal vision with no 

 astigmatism or normal vision despite a slight as- 

 tigmatism, he may be given a better conception 

 of just what a moderate degree of astigmatism is 

 by putting a+ 1 D. cyl. lens before his eye; or a 

 rather high degree of simple astigmatism by try- 

 ing a + 2 D - C Y 1 - or + 3 D. cy 1 - 



(<) How may the subject be made artificially hy- 



peropic? 



(<:) How, artificially myopic ? 

 II. To test the light sense. 



With the photometer test the subject's power to deter- 

 mine the difference in the illumination of the two discs 

 of the instrument. 



