Ancillary Special Tests
Exopthalmometry
The presence of an abnormally wide open eye or buggy appearing eyes
should alert you to the possibility of exophthalmos. This may result secondary
to a space occupying orbital lesion (tumor) or endocrine Graves disease.
Whenever in doubt check the condition using an exophthalmometer. The Hertel
exophthalmometer is one of the most accurate.
Procedure
- 1. The patient must be on the same level, eye to eye, which will help
prevent errors in your readings.
- 2. Have the patient close their eyes and locate the orbital notch on
the temporal side of the orbit with you finger.
- 3. The exophthalmometer has grooved arcs on each end. The left groove
is placed firmly in the right orbital notch. The exophthalmometer is opened
so the groove on the right side can be firmly placed in the left orbital
notch. The separation of the exophthalmometer is very important an must
always be noted and the exophthalmometer must always be set at that separation
on future or repeated readings.
- 4. The patient is then told to open their eyes and look straight ahead.
Poor fixation, convergence, parallax errors, and head movements will affect
the trustworthiness of your readings. Also, if the grooved arcs are placed
too far medially (separation too narrow) the readings you get will be erroneously
Low. Conversely, if the grooved arcs are placed too far temporally (separation
too wide) the readings will be erroneously High.
5. Look into the two mirrors located at each end of the exophthalmometer.
Note where the apexes of the corneas, seen in the lower mirror, align with
the measuring scale seen in the upper mirror and record these readings.
The findings are recorded in the following manner:
- The "H" stands for Hertel Exophthalmometer, the 105 is the
lateral separation of the exophthalmometer, 18 is the forward position
of the corneal apex reading of the right eye and 19 the reading of the
left eye.
Expected normal ranges:
Caucasian males 12 - 21 mm's
Caucasian females 12 - 20 mm's
African American males 12 - 24 mm's
African American females 12 - 23 mm's
Depending on the author the diagnostic difference between the two eyes
varies from 2mm's to 3mm's and warranting further testing. In monitoring
a suspect patient be alert for progressive increases in the measurements.
Increasing measurements indicates an active change in the condition. Order
the follow: CBC, T3, T4, and TSH tests. The later three should they be
elevated may have indications leading to a diagnosis of thyrotoxicosis
and exophthalmos.
T3 = Bound Thyroxin
T4 = Free Thyroxin
TSH = Thyroid stimulating hormone
Schirmer's Tear Tests
- Schirmer's #1:
a.) Measures the reflex secretory tear level (without anesthetic) which
may be influenced by irritation, resulting in an over production of tears.
b.) Measures the basic secretory tear level (with anesthetic) which removes
the irritation influence.
Both the above tests are performed for a period of 5 minutes and then
the amount of wetting of the strip by the tears is measured. A normal tear
secretion would measure 10 mm's of wetting in the 5 minutes. Between 5
and 10 mm's of wetting would be considered borderline and less than 5 mm's
insufficient or diagnostic of a dry eye.
The basic (b) is done when the reflex (a) test measurements are greater
than 10 mm's.
- Schirmer's # 2:
Not often used, but can have some diagnostic value. Topical anesthetic
is used and the Schirmer strips are put in place in the normal way. The
strip is folded and place in the outer third of the lower palpebral conjunctiva
or cul-de-sac. A cotton applicator is inserted up the patients nostril
and the nasal mucosa is gently irritated for 15 seconds. Measurements of
less than 15mm's in 2 minutes is diagnostic of a reflex secretion problem.
The Schirmer test should not be used alone as a diagnostic test, but rather
in conjunction with tear break up time, slit lamp evaluation of the tear
prism and corneal staining.
TRANSILLUMINATION OF THE GLOBE & SINUSES
Transillumination of the globe and iris can be accomplished with either
a pen light of transilluminator. This method is used to grossly inspect
the contents of the intraocular structures, checking the iris for transillumination
iris defects (TID's), corneal for edema or scars, lens for cataracts, and
ciliary orbital tumors. The light source is placed on either the upper
or lower lid (usually on the temporal side) approximately 8mm's behind
the limbus. It is best if all lights are turned off to maximize any visually
apparent defects of the iris, crystalline lens, and ciliary body. TID appear
just as they do when using a slit lamp. Cataracts appear as dark opacities
within the retroillumination of the pupil. Ciliary masses appear as dark
shadowed areas at or near the limbus.
If the patient's chief complaint is headaches the sinuses must
always be transilluminated using a transilluminator. If the patient reports
they wake up with this same type of headache you usually can rule out visually
related eye strain. Since the sinuses do not drain well during sleep they
are usually the causing factor. Sinusitis is one of the leading causes
of headache complaints. The patient is instructed to keep their eyes
close and keep looking down. All room lights are turned off to maximize
the visibility of the frontal and maxillary sinuses.
- Frontal sinuses: The light source is placed under the supra-orbital
ridge near the nose. The frontal sinus will glow and any blockage will
appear as a dark area. The height of the transillumination between the
two sinuses must be compared. If one of the sinuses transilluminates higher
than the other this indicates there is some blockage and is in the sinus
that transilluminates the leased.
Maxillary sinuses: The light source is placed on the infra-orbital
ridge near middle-center. The patient tilts their head back and opens their
mouth. The maxillary sinus should glow through the roof of the mouth. Again,
any blockages will appear as dark areas against the red glow. The degree
of transillumination of the two sinuses are compared.
