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English
How to use a Binocular Indirect
Ophthalmoscope
d) Direct the patient’s gaze to where you intend to begin the
examination, and ask them to fixate at some point. It is
best to examine the complete periphery first to allow the
patient to acclimatise to the light before examining the
posterior pole.
e) Hold the condensing lens between the thumb and forefinger
with the silver side (least convex side) towards the patient
at a little less than arm’s length away. The lens can be
steadied by resting the other fingers on the patient’s cheek
or forehead.
f)
With the condensing lens held to one side, direct the light
beam at the patient’s pupil and obtain a red retinal reflex.
g) Begin by placing the condensing lens in the light path
approximately 1 inch from the patient’s pupil. Centre the
pupil in the lens.
Keeping the pupil centred and the lens parallel to the
headset, slowly move the condensing lens away from the
eye, directly upward toward the headset, until an image of
the fundus spreads to completely fill the lens (this will
occur at the fixed focal length of the condensing lens
selected, see page 114).
h) It is imperative at the moment the retinal image fills the
lens that any movements or minor adjustments are made
very delicately. If the lens is moved even slightly too far
from the eye, an inverted, minified image will come into
view.
Conversely, if the lens is not brought out far enough from
the eye, strong, white reflections will be visible. To remove
these reflections, gently pull the lens directly back toward
the headset, until achieving the proper focal length from the
patient’s eye for that lens.
