examples of abnormalities
C h a p t e r
7
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The Head and Neck
229
Anatomy and Physiology and Techniques of Examination
Absence of a red reflex suggests
an opacity of the lens (cataract)
or possibly of the vitreous. Less
commonly, a detached retina or,
in children, a retinoblastoma may
obscure this reflex. Do not be fooled
by an artificial eye, which has no red
reflex.
Steps for Using theOphthalmoscope
(
continued
)
Examiner at 15-degree angle
frompatient’s line of vision,
eliciting red reflex
converges nor diverges light. Keep your finger on the edge of the lens disc
so you can turn the disc to focus the lens when you examine the fundus.
◗◗
Hold the ophthalmoscope
in your right hand and use your right eye
to examine
the patient’s right eye
;
hold it
in your left hand and use your left eye to examine
the patient’s left eye
.
This keeps you from bumping the patient’s nose and gives
you more mobility and closer range for visualizing the fundus. At first, you may
have difficulty using your nondominant eye, but this will abate with practice.
◗◗
Hold the ophthalmoscope firmly braced against the medial aspect of your
bony orbit, with the handle tilted laterally at about a 20-degree slant from
the vertical. Check to make sure you can see clearly through the aperture.
Instruct the patient to look slightly up and over your shoulder at a point
directly ahead on the wall.
◗◗
Place yourself about 15 inches away from the patient and at an angle
15
degrees lateral to the patient’s line of vision
. Shine the light beam on the
pupil and look for the orange glow in the pupil—the
red reflex
. Note any
opacities interrupting the red reflex.
◗◗
Now, place the thumb of your other hand across the patient’s eyebrow.
(This technique helps keep you steady but is not essential.) Keeping the
light beam focused on the red reflex, move in with the ophthalmoscope on
the 15-degree angle toward the pupil until you are very close to it, almost
touching the patient’s eyelashes.
Try to keep both eyes open and relaxed, as if gazing into the distance, to help
minimize any fluctuating blurriness as your eyes attempt to accommodate.
You may need to lower the brightness of the light beam
to make the exami-
nation more comfortable for the patient, avoid
hippus
(spasm of the pupil),
and improve your observations.
*Some clinicians like to use the large round beam for large pupils, and the small round beam for
small pupils. The other beams are rarely helpful. The slitlike beam is sometimes used to assess
elevations or concavities in the retina, the green (or red-free) beam to detect small red lesions,
and the grid to make measurements. Ignore the last three lights and practice with the large or
small round white beam.
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