Mr . Home's Lecture 
i6 
To see how far the two eyes had the same focus, she was 
desired to look at an object in the field of a microscope, and 
it was found that she saw most distinctly with both eyes at 
the same focal distance, although the object was considerably 
more distinct to the perfect eye than to the other ; so that the 
focuses of the two eyes were the same. 
I desired her to cover the perfect eye, and endeavour to ac- 
quire an adjustment of the other to near objects, by practising 
the use of that alone. At first she was unable to see at all 
with the imperfect eye, but in some weeks she has improved 
so much as to be able to work at her needle with it ; this she 
cannot do long at any one time, the eye being soon fatigued 
and requiring rest, though without giving pain. She is unable 
to read with the imperfect eye. These trials have only been 
made in the course of two months, for a few hours in the day, 
and her friends think that she squints less frequently than she 
did. 
In this case it is probable that the imperfect eye never had 
acquired the power of adjustment to near objects ; for as dis- 
tinct vision seems necessary to direct the muscles in their ac- 
tions, the perfect eye would require less practice to adjust itself 
than the other; and as soon as the near object became distinct 
to one eye, no information being conveyed to the mind of the 
failure in the other, all efforts to render its adjustment perfect 
would be at an end, and it would ever after be neglected, while 
the perfect eye was in use. 
Squinting, according to these observations, appears to arise 
from the vision in one eye being obscure. It may, however, 
be acquired in degree by children who have the lenses of their 
eyes of different focuses; or have one eye less perfect in its 
