towards the light, and if you use a lens back of it,
you have to look through it obliquely. This not
only increases the strength of the lens, but pro-
duces an astigmatic effect.
HOW TO EXAMINE THE EYE. 101

Dr. Fox's Ophthalmoscope (Fig. 87) is a modifi-
cation of I/oring's. The advantage claimed for it
over Loring's is that it has a drive-wheel attached
to the lower part of the instrument, which enables
one to shift the lenses without removing the instru-
ment from its position and without touching the
face of the patient.
With the ophthalmoscope one should learn to
view the fundus with or without a myd^-iatic, and
the first thing for a beginner is to familiarize him-
self with the normal, condition of the fundus and
with its variations before attempting to measure
the amount of ametropia or examine for diseased
conditions. To see the fundus with its details, it
is necessary to follow out a fixed, settled plan,
and frequently it requires considerable time to be
able to get a satisfactory view. One of the prin-
cipal annoyances of the beginner is the bright
spots or the reflex images from the dioptric media.
These must be ignored in the examination of the
fundus.
With the ophthalmoscope we can quickly and
definitively ^recognize the ametropic eye in its vari-
ous forms and degrees. In the examination of the
eye with the ophthalmoscope for the anomalies of
refraction, there are two methods; namely, direct
and indirect.
Direct Method. By the direct method (Fig.
