Orbital Examination

The external examination of the patient should assess the facial features and critically evaluate the symmetry of the ocular, eyelid, and orbital structures. Phys ical examination of the periorbital structures, including eyelids and conjunctiva, should include inspection of appearance and function, which are commonly altered by a space-occupying lesion in the orbit. The horizontal distance between interpalpebral fissures and the width of the palpebral fissures should be measured and recorded. Additionally, the distance between the margin of the upper eyelid and the upper eyelid crease, as well as the amount of inferior scleral exposure, should be measured (Figure 6.6). The comparison of these values to those of the fellow eye is usually helpful because most orbital tumors present with unilateral structural abnormalities.

Levator function should be determined on both sides and carefully recorded. Although there are many methods to assess the levator function, it is usually sufficient to measure the margin reflux (MRD: dis

Optic Disc Haemorrhage
FIGURE 6.4. Optic disk changes in orbital disease: optociliary shunts (arrows) in (A) and (D) and optic nerve atrophy with retinal infarction (B) in optic nerve meningioma (C). (S, sclera; RD, retinal detachment; CH, choroid.)
Orbital Tumor Adults

tance between the margin of the upper eyelid and the corneal light reflex) and to obtain the full range of vertical motion [Burke levator function (BLF)] of the upper lid. Normal values for MRD and BLF are 3-5 and 15-18 mm, respectively.19

The appearance of the eyelids in relation to the globe should be observed individually by alternate cov-

FIGURE 6.6. Normal eyelid and periorbital distances in a young adult (A) versus an elderly patient with bilateral proptosis (B). (VPF, vertical palpebral fissure; HPF, horizontal palpebral fissure; MRD, margin reflex distance; MCD, margin crease distance; IPD, inter-palpebral distance.)

FIGURE 6.6. Normal eyelid and periorbital distances in a young adult (A) versus an elderly patient with bilateral proptosis (B). (VPF, vertical palpebral fissure; HPF, horizontal palpebral fissure; MRD, margin reflex distance; MCD, margin crease distance; IPD, inter-palpebral distance.)

erage of the eyes while the physician is facing the patient; then the eyes should be viewed simultaneously from the same distance. Slowly growing masses of the orbit usually do not alter the anatomic relationship of the eyelids to the globe, and extraocular motility is affected only at extreme gazes; therefore, when observed one side at a time, these patients may look normal or close to normal. When both eyes are observed simultaneously, however, the proptosis of one eye and/or lid distortion becomes much more obvious.

The most important structural feature to rate in the examination of an orbit with a space-occupying lesion is proptosis, which is also known as exoph-thalmos, protrusion, or the displacement of the globe beyond the orbital rim.20 Proptosis is an old term having its roots in Galenic terminology, meaning "falling forward" or "falling out." In its original context, however, it was used for traumatic prolapse of the uvea, particularly of the iris.21 Exophthalmos, on the other hand, is a rather new term, initially appearing in the seventeenth century, to describe the forward thrust of the eyes resulting from a systemic straining, such as hanging. After Robert Graves's association of the protrusion of the eyes with thyroid disease, exophthal-mos came to be commonly referred to as a manifestation of thyroid-associated orbitopathy or Graves disease.

The term "proptosis" is commonly used to describe a forward displacement of the eye, secondary to a space-occupying lesion in one orbit, in most cases a tumor or a cyst. The displacement of the eye is determined based on the distance in an anterior-posterior plane between the front surface of the cornea and the anterior margin of the zygomatic arch. This distance normally varies from 16.5 to 21.5 mm in white men and 15.5 to 20 mm in white women. In black adults the measurements are increased by approximately 2 mm.22 The degree of global displacement is determined with a device called an exophthalmometer.

Many exophthalmometers have been designed, but only a few have gained popularity for practical use in the clinic. One of the earlier exophthalmometers was a simple and a very useful device, designed by Luedde, that consisted of a piece of transparent plastic ruler with a groove to fit onto the lateral orbital rim. Millimetric scales were engraved on both sides of the plastic bar. When the corresponding measurements on both sides of the ruler are aligned, one can superimpose the apex of the cornea on the ruler and read that as the degree of displacement in millime-ters.23 Although dependable measurements can be obtained with this device, it measures the displacement of one eye at a time, and the accuracy of the measurement is dependent on the integrity of the orbital rim anatomy. If there is asymmetry between the two sides, the comparison of measurements would not be accurate.24,25

Another device, the Hertel exophthalmometer, is commonly used in today's orbit clinic.26-29 This instrument with binocular measurements allows the observer to view the images of the cornea profiles and su-

Exophthalmometer
FIGURE 6.7. Evaluation with Hertel exophthalmometer.
Hertel Orbit
FIGURE 6.8. Evaluation with Naugle exophthalmometer. Dr. Nau-gle demonstrates the proper application of the instrument. (Courtesy of Dr. Thomas Naugle Jr, New Orleans.)

perimpose them on the measuring scale (Figure 6.7). The Hertel exophthalmometer offers accurate and reproducible measurements and the advantage of comparing one eye with the other during the same examination. In Hertel exophthalmometry, the distance between the two lateral orbital rims is engraved on the horizontal bar, which carries the sliding mirrors. This baseline measurement should be kept at a constant in repeat examinations to ensure dependable comparisons between measurements; ideally the same person should perform the exophthalmometry at each evaluation.

The Naugle exophthalmometer (orbitometer) is another instrument used to measure globe displacement (Figure 6.8). This device is designed to sit on vertical fixation bars that rest on superior and inferior periorbital rims, rather than the lateral canthi. Therefore, it measures not only enophthalmos and exophthalmos, but hypo- and hyperophthalmos as well. The main advantage of this instrument is that it renders accurate measurements even when the lateral rim is irregular or missing.30,31 This instrument is particularly useful in evaluating patients with maxillofacial trauma.32

An exophthalmometry measurement above 21 mm or a difference of more than 2 mm between the two eyes is usually considered abnormal. Measurements less than 14 mm are considered to be an enophthalmos.33,34

The direction of the globe displacement may carry diagnostic significance; if the globe is pushed down and out, natural location for the space-occupying lesion is superiotemporal (i.e., a lacrimal gland tumor) (Table 6.2).35 The degree of asymmetry may also be important. Slowly growing, benign lesions may produce extreme asymmetrical proptosis. On the other hand, the thyroid disease usually produces less symmetrical displacement of the globes. The proptosis direction is usually downward because the majority of the primary orbital tumors develop in the upper half of the orbit. Lateral displacement, on the other hand, is usually seen as a result of secondary orbital lesions, such as a mucocele or squamous cell carcinoma, originating from the ethmoidal sinuses. Squamous cell carcinoma may displace the globe upward when it originates from the maxillary sinus. In some instances, simple transillumination with a muscle light reveals the cystic nature of an orbital lesion; this is particu larly true for anterior orbital masses (Figure 6.9). Displacement of the globe toward the nose is quite rare because very few space-occupying lesions develop on the lateral aspect of the orbit.

The proptotic eye should also be examined from the standpoint of ocular motility in cardinal positions and compared with the normal eye. Recordings of deviations should be made whenever applicable. Although accurate recordings of prism values may be useful for the posttreatment follow-up of the patient, detailed diplopia measurements in prism diopters are not always possible or necessary. The amount of deviation can be quickly approximated by a red glass test in the clinic.36 The author's preference is to use a modified Maddox cross engraved on transparent plastic that has a white fixation light in the center (Figure 6.10). When the patient is seated with straight head position at 50 cm, the numbers on the cross indicate the amount of deviation in degrees. A red glass is positioned in front of the fixating eye, and the patient is asked to point at the "white light" and the "red light" on the surface of the device (Figure 6.11).

The position of the visual axis in a proptotic eye may provide useful information. In some patients with slowly growing orbital masses, the proptotic eye adapts to the fellow normal eye and may have parallel visual axis. This is commonly seen in der-moid cysts, benign mixed tumors of the lacrimal gland, and slowly growing neural tumors. In contrast, rapidly growing or posteriorly located masses, as well as metastatic tumors to the extraocular muscles, invade the nearest neuromuscular structures,

TABLE 6.2. Differential Diagnosis of Proptosis.

Associated findings

Location/Pathology

Type of displacement

(may or may not be present)

Benign lacrimal fossa lesions

Inferonasal proptosis

Choroidal folds; good EOM

(e.g., pleomorphic adenoma, cysts)

Malignant lacrimal fossa lesions

Inferonasal proptosis

Pain; poor EOM; enlarged lymph nodes

(e.g., adenocarcinoma, adenoid

cystic carcinoma)

Benign superionasal lesions

Inferotemporal proptosis

Usually without choroidal folds

(e.g., dermoid)

Anterior lesions

Mild proptosis away from the site of

Conjunctival and/or lid involvement

(e.g., lymphoma, dermoid)

lesion

Benign muscle cone lesions

Axial proptosis

Posterior choroidal folds; venous

(e.g., cavernous hemangioma,

congestion; early disk edema

schwannoma)

Extraconal and intraconal lesions

Massive proptosis without a rule

Lid, conjunctiva involvement;

(e.g., vascular tumors;

choroidal folds; ON dysfunction and

rhabdomyosarcoma)

disk edema; amblyopia

Diffusely infiltrating lesions

Axial with or without "frozen"

EOM is abnormal at all gazes; ON

(e.g., metastatic carcinoma, diffuse

proptosis or enophthalmos

dysfunction with/without disk

pseudotumor)

edema, enlarged lymph nodes

Inferior lesions

Superior proptosis

Pain; sensory deficit in lower

(e.g., SCC of maxillary sinus)

periorbital area

Medial lesions

Lateral and superiolateral proptosis

Pain; horizontal EOM limitation or

(mucocele; secondary SCC from

diffuse

ethmoid sinus)

Posterior orbit, apical lesions

Minimal, late proptosis

ON dysfunction with normal disk;

(e.g., meningioma, glioma,

diffuse EOM abnormality

paraganglioma)

EOM, extraocular motility; ON, optic nerve; SCC, squamous cell carcinoma.

EOM, extraocular motility; ON, optic nerve; SCC, squamous cell carcinoma.

FIGURE 6.9. (A, B, D) A recurrent cystic basal cell carcinoma pushes the left globe up significantly. (C) Transillumination reveals the cystic nature of the anterior-inferior orbital tumor.

resulting in malfunction of the motility with consequent strabismus.

The rotation of the proptotic eye should be assessed. The rotation disturbance caused by proptosis can be grouped into one of two categories: (1) abnormal rotation of the eye turning toward the affected quadrant, usually seen with slowly growing masses, or (2) abnormal rotation resulting from secondary neuromuscular invasion. In the latter situation, the abnormal rotation of the eye is not limited toward the direction of the affected sector. Infiltrating orbital lesions, on the other hand, produce the most severe impairment of ocular rotation, whether they are neo-plastic or inflammatory in origin. Orbital cellulitis, diffuse pseudotumor, secondary squamous carcinoma from the ethmoid sinus involving the posterior orbit,

FIGURE 6.10. Maddox cross with a fixation light in the center. The scale of the cross is adjusted so that when the patient is at 50 cm, the engraved numbers on the plastic panel indicate the amount of deviation in degrees.

and metastatic scirrhous breast carcinoma are good examples of this pathology (see Chapter 24).

Generally, extraocular motility disturbance accompanying acute inflammatory disorders develops rapidly and may be painful. The ophthalmoplegia of Graves disease, on the other hand, develops gradually without pain and may, in some instances, appear prior to exophthalmos. In patients with known hyperthy-roidism, ophthalmoplegia is usually noted in upward gaze secondary to slow infiltration of the superior rec-tus muscle by glycoproteins and chronic inflammatory cells. As the disease progresses, the extraocular motility disturbance becomes generalized, and finally, the eye may come to a standstill in the abnormal position of upward or downward gaze owing to extensive scarring of the extraocular muscle, in the direction of the deviation. The infiltrating tumors, on the other hand, have a tendency to "freeze" the eye in the primary position of gaze because of their haphazard infiltration into the muscles and the soft tissues of the orbit.

External examination must include the changes of the soft tissues of the eyelids, conjunctiva, and periorbital skin. Edema, hyperemia, and tenderness of these tissues may be a part of the clinical picture in orbital tumors; however, anteriorly located tumors such as lymphomas may cause a certain degree of lower lid edema and conjunctival chemosis. Edema of the lids, greater in the lower than in the upper eyelid, is occasionally associated with hemangioma and neu-rogenic tumors, presumably secondary to long-standing venous stasis. Soft tissue involvement with the resulting edema and/or retraction is more commonly associated with Graves disease and pseudotumor (Figure 6.6B). Hyperemia is also more often encountered with inflammatory lesions, particularly in acute pre-

FIGURE 6.11. Evaluation of diplopia with a red glass positioned in front of the fixating eye of the patient. The patient points to white and red lights on the Plexiglas surface of the Maddox cross.

FIGURE 6.12. Bilateral ecchymosis of eyelid and periorbital skin in a patient with multiple myeloma and amyloidosis. Note the dark bruised lesion in the left upper lid; this area corresponds to a thumb imprint, which was made during indirect ophthalmoscopy. (Courtesy of Dr. David Hinkle, New Orleans.)

FIGURE 6.12. Bilateral ecchymosis of eyelid and periorbital skin in a patient with multiple myeloma and amyloidosis. Note the dark bruised lesion in the left upper lid; this area corresponds to a thumb imprint, which was made during indirect ophthalmoscopy. (Courtesy of Dr. David Hinkle, New Orleans.)

should also be observed, since they may be a part of orbital xanthogranuloma or systemic disease (see Chapter 15).41

The value of palpation of the orbit is limited except for a few specific findings. First, because of the close proximity of tissues, orbital structures are difficult to palpate and may cause a considerable amount of discomfort to the patient unless done under general anesthesia (Figure 6.13). The degree of ballottement is usually measured subjectively and gives an idea about the compressibility or firmness of the underlying mass lesions. Anteriorly located tumors, including lymphomas, lacrimal gland tumors, and mucocele and der-moid cysts, can be palpated. The examiner may get a feel of the nature of their anterior surface; however, in this age of advanced imaging, feeling the tumor to determine its nature is rarely rewarding. On the other hand, palpation of a mass to guide a biopsy needle accurately may be a useful adjunct. Palpation of the orbital rim to feel an irregular edge indicative of tumor infiltrate or an old trauma site may add to the usefulness of the examination. Furthermore, crepitation within the orbit and, in some instances, arteriovenous

FIGURE 6.11. Evaluation of diplopia with a red glass positioned in front of the fixating eye of the patient. The patient points to white and red lights on the Plexiglas surface of the Maddox cross.

sentations.37 However, redness of the eyelids may be seen in any rapidly growing malignant tumor that is located anteriorly, such as more malignant types of lymphoma, leukemia, rhabdomyosarcoma, and meta-static tumors.38'39 Ecchymosis should not be confused with hyperemia. The former is most often seen in met-astatic neuroblastoma but may also be encountered with amyloid and leukemic infiltrates (Figure 6.12). A typical feature of ecchymosis, secondary to neuro-blastoma, is its changing appearance from day to day.40 Xanthelasmas on the eyelids and periorbital skin

FIGURE 6.13. Palpation of the orbit under general anesthesia prior to surgery.
FIGURE 6.14. Examination of the orbit with Doppler instrument.

shunts, can be felt and may be useful findings in the differential diagnosis.42 Auscultation with a stethoscope or Doppler testing is a much more dependable approach to detect bruit in the orbit (Figure 6.14). The use of a color Doppler instrument with conventional B-scan ultrasonography may be useful to study vascular tumors of the orbit as well as the blood flow characteristics of other tumors (see Chapter S).43,44

During the clinical evaluation, one should keep in mind that the orbit is a small chamber, occupied by tissues of many types, located in a very compact fashion. Because of the close relationship of different tissue types, certain disease entities of different etiology and different tissue origin may clinically present with remarkably similar signs and symptoms. For example, a vascular tumor, a cholesteatoma, and a sarcoidosis granuloma may develop very similar clinical and radiological features. Another example of this dilemma may be experienced in the early stages of a subperiosteal abscess, secondary to ethmoiditis, which may mimic a secondary squamous cell carcinoma originating from the same sinus. Furthermore, there is surprising variability in the clinical manifestations of individual disorders; good examples of this are metastatic tumor to the orbit, idiopathic orbital inflammation, and Graves disease. Similar confusion may occur in the evaluation of ultrasonography, computed tomography scans, and magnetic resonance images. Although many diseases tend to be confidently interpreted on the basis of imaging, others may be very confusing. For instance, although the enlargement of extraocular muscles is quite typical of Graves disease, it may be seen in other conditions, including metastatic carcinoma, hematoma, rhabdomyosarcoma, inflammatory orbital pseudotumor, and parasitic infections.

The ophthalmologist should have a systematic approach to the workup of orbital tumor patients and keep in mind that one aspect of evaluation will not necessarily offer the final diagnosis. Therefore, a systemic history and physical examination, ocular/or bital examination, laboratory, imaging, and consultation findings should be evaluated as a whole to ensure proper assessment of the patient.

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