A. Symptoms of Orbital Diseases

38orbital tissue. Processes associated with tissue contraction such as some breast cancer

metastases can produce enophthalmos. The

enophthalmos in Horner syndrome is usually only slight. The upper lid is often lower in enophthalmos. Enophthalmos is also measured withtheHertel exophthalmometer. A reduction in the size of the eye as in congenital microphthalmos or phthisis bulbi can mimic enophthalmos.

●A motility deficit (strabismus, Ac) is caused by the fact that space-occupying and destructive processes in the orbit often reduce the mobility of the eyeball by interfering directly with the ocular muscles (mechanical paresis) or by damaging the motor nerves (neurogenic paresis). If there is a difference in the reduction in eyeball motility between the two sides, strabismus results, usually with double vision.

●Exposure keratitis and sometimes a corneal ulcer can develop in exophthalmos as blinking and moistening of the surface of the eye are impaired.

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A. Symptoms of Orbital Diseases (continued)

Other symptoms of orbital diseases:

●Disorders of visual function can occur when an orbital space-occupying lesion compresses the optic nerve directly or indirectly through an increase in the pressure in the orbit, thus leading to a loss of visual field or visual acuity. Lesions of the optic nerve with loss of visual function also occur not infrequently because of injuries or orbital infections. A reduction in vision also results when there is central corneal opacification due to exposure keratitis.

●Swelling of the head of the optic nerve (papilledema) is a frequent though rather nonspecific finding in orbital processes. In contrast to papilledema due to raised intracranial pressure, papilledema because of processes in the orbit is often associated early with a reduction in function.

●More prolonged optic nerve compression leads to a loss ofganglion cell axons and blood vessels in the region of the optic disc (optic atrophy, Aa). The disk becomes pale as a result.

●Anastomoses sometimes develop between the vessels on the disk and those of the peripapillary choroid due to chronic optic nerve compression (e.g., with slowly progressing optic nerve tumors) (opticociliary shunt vessels, Aa).

●Compression of the globe from behind can produce folding of the choroid (choroid folds, Ab). These choroid folds are usually arranged in parallel and are visible on funduscopy, but are seen even better on angiography. They tend to reduce visual function only slightly.

●More rarely, orbital tumors indent the globe (globe indentation), so that the appearance is that of an intraocular tumor.

●Alterations of the lids, such as retraction of the upper lid, are typical of endocrine orbitopathy but also occur in all forms of advanced exophthalmos. Swelling of the lacrimal gland often gives the upper lid lateral ptosis like an S-shape (Ac).

●Orbital diseases are often associated with alterations of the conjunctiva. Inflammatory conditions of the orbit usually and tumor processes occasionally cause redness (injection) and swelling (chemosis) of the conjunc-

tiva. Carotid-cavernous sinus fistulas are characterized by dilatation of conjunctival and episcleral vessels because of the raised orbital venous pressure.

●There can be an increase in intraocular pressure as the aqueous humor is drained into the orbital veins. Compression of these veins sometimes leads to congestion of the aqueous humor and so to an increase in ocular pressure. An abnormality of venous orbital outflow with ocular hypertension is typical of carotid-cavernous sinus fistulas. In endocrine orbitopathy, there can be an increase in pressure depending on the direction of gaze (“pseudo-glaucoma”).

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A. Investigations of Orbital Processes

The diagnosis begins with the history and clinical examination. Depending on these findings, imaging procedures are employed.

History. Obtaining an accurate history often provides valuable diagnostic hints. An inquiry is made about the development (acute or slow), the duration and nature of the symptoms, pain (inflammation is usually painful, tumors are usually not painful), and any previous injury.

Clinical examination. The eye is examined in bright light and with the slit lamp, and the examination also includes measurement of exophthalmos with the Hertel exophthalmometer. Anteriorly located processes should be palpated where possible to determine their consistency. Crackling subcutaneous emphysema on palpation is suggestive of a fracture of the ethmoid cells.

Examination of function. Simple tests used in the functional investigation of diseases of the orbit include measurement of visual acuity, the position and mobility of the eyes, and examination of pupillary reaction (swinging flashlight test). Examination of the visual field (perimetry) is usually also necessary. A reduction or loss of sensation in the area of distribution of the infraorbital nerve with a corresponding history indicates a fracture of the orbital floor. Occasionally, more complex diagnostic procedures are required such as measurement of the visual evoked potentials (VEP).

Imaging procedures (Aa–f). Processes located in the anterior orbit are readily accessible to ultrasound. This can be used to measure the thickness of the extrinsic ocular muscles, optic nerve sheath, and sclera and the extent and consistency of tumors, and to detect foreign bodies. Conditions at the apex of the orbit can also be imaged with computed tomography (CT) and magnetic resonance imaging (MRI). As a rule, orbital soft-tissue processes can be imaged better with MRI, and primary or secondary changes in the orbital bone better with CT. The circulatory relationships in the orbit (e.g., in carotid-cavernous sinus fistulas) can be examined using color duplex Doppler ultrasound. Angiography can be indicated in certain cases. Biopsy. If an orbital process cannot be classified on the basis of the clinical and imaging investigations, a biopsy should be taken by fineneedle or excisional biopsy, at least when there

is a progressive condition suggestive of malignancy. If a mixed tumor of the lacrimal gland (pleomorphic adenoma) is suspected, the entire lacrimal gland should be removed as an incisional biopsy in this situation is associated with an increased risk of recurrence.

B. Malformations

Malformations of the orbit are relatively rare apart from dermoid cysts. Defects of the sphenoid bone are sometimes found in neurofibromatosis. If the development of the bony orbit is abnormal, the meninges or brain can prolapse into the orbit (meningocele or encephalomeningocele). In Crouzon disease (craniofacial dysostosis) there is a narrow, shallow orbit so that the eyes protrude. Papilledema and optic atrophy can occur because of optic nerve compression. Orbital changes also form part of the mandibulofacial dysplasias such as Goldenhar, Rubinstein-Taybi or Haller- mann-Streiff syndromes.

Investigations/Malformations

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A. Vascular Anomalies

Carotid-cavernous sinus fistulas are character-

44clusively.

Orbital pseudotumor (Bc). This acute inflam-

mation of orbital structures, probably of im-

munological origin, often affects the muscles (myositis). The very painful, usually unilateral disease responds very quickly and well to longterm corticosteroids. Recurrences and a variable course are not unusual.

Vasculitis such as Wegener disease or polyarteritis nodosa can be associated with orbital involvement.

Endocrine orbitopathy (Bd; see p. 43, Aa). This orbital inflammation is usually associated with autoimmune hyperthyroidism. The classical symptom triad of exophthalmos, goiter, and tachycardia (Merseburger triad) was described by Karl von Basedow/Robert Graves, so that the disease is also known as Basedow/Graves disease. It is very much more common in women than in men and commences acutely or subacutely. If it is untreated, there is spontaneous (partial) remission or transition to a scar stage. The symptoms are exophthalmos, which is usually bilateral, retraction, especially of the upper lids, and edema of the lids and conjunctiva. The commonest lid signs bear the name of their describers, von Graefe (lid lag when looking downward), Dalrymple (visible sclera at the upper border of the cornea), and Stellwag (reduction in the rate of blinking). There is often a motility deficit and strabismus, and exposure keratitis and optic nerve compression occur only in severe cases of the disease. The pressure of the thickened muscles on the globe on looking upward often causes a rise in ocular pressure (“pseudo-glaucoma”). In treatment, thyroid function must first be normalized. The inflammation is treated with corticosteroids. Immunosuppression is sometimes necessary. If loss of function due to optic nerve compression threatens, resection of orbital fat or opening of the paranasal sinuses must be performed to decompress the optic nerve. Cosmetic correction is performed in the noninflamed state.

Vascular Anomalies/Inflammatory Conditions

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A. Tumors

The spectrum of orbital tumors is markedly different in children from that in adults, and benign and malignant tumors occur at every age (A, Table 1). The commonest malignant orbital tumor in childhood is the rhabdomyosarcoma (Aa), which is characterized by rapid growth and an often inflammatory appearance. A biopsy confirms the diagnosis. The chances of cure are very good after adequate therapy, which consists of chemotherapy and radiotherapy.

Benign dermoid cysts, which arise from skin dermis displaced deeply, are located preferentially at the upper temporal entrance of the orbit. Not infrequently there are strands of tissue between the cyst and bony structures. Dermoid cysts are bordered by stratified keratinized squamous epithelium and filled with masses of keratin, sometimes containing hair. There are skin appendages (hairs and sebaceous glands) and not rarely inflammatory infiltrates in the region of the cyst wall. Complete surgical excision is usually done before the child starts school. Hemangiomas (Ab) and lymphangiomas of the orbit in children are usually operated only when visual function is endangered due to amblyopia (e.g., due to tumor-induced ptosis) or optic nerve compression. Optic nerve glioma, occasionally occurring in neurofibromatosis (see p. 39, Aa, and p.41, Aa), and optic sheath meningioma (see p.43, Ac) very often cause considerable losses of function despite being biologically benign. Surgical excision usually leads to deterioration in function on the affected side but can be indicated to prevent growth of the tumor into the chiasm and the opposite side. Tumors of the optic nerve can be irradiated successfully.

In adults, the commonest primary malignant tumors are non-Hodgkin lymphoma (NHL, see p.43, Ad), adenoid cystic lacrimal gland carcinoma, which is often associated with severe pain because of nerve infiltration, and malignant fibrous histiocytoma.

However, metastases from breast, bronchial, prostate, and gastrointestinal carcinomas and from cutaneous melanomas are commoner than primary malignancies (Ac and p.41, Ab); orbital invasion from carcinomas of the paranasal sinuses, the lacrimal sac, and especially malignant tumors of the lids and conjunctiva (basal cell carcinoma, squamous cell

carcinoma, conjunctival melanoma) also occur. Both in children (retinoblastoma) and in adults (malignant choroid melanoma), primary intraocular tumors can perforate the sclera and mimic an orbital tumor through intraorbital growth. Occasionally (sphenoid) meningiomas grow into the orbit from inside the skull. Outpouchings of the paranasal sinus mucosa (mucocele) into the orbit can give the impression of an orbital tumor.

The treatment of malignant orbital tumors in adults, depending on the type and extent of the neoplasm, consists of radiation, surgical excision, or exenteration of the orbit, where the entire orbital contents including the globe and periosteum are removed (Ad). Benign tumors of the orbit can be observed if function is normal and progression does not occur.

Tumors

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A. Injuries

Blunt force to the eye, e.g., due to sports balls or a blow from a fist, lead to brief but considerable compression of the orbital soft tissues. As a result of the increase in intraorbital pressure, fracture of the thin orbital bone in the region of the orbital lamina of the ethmoid and especially of the orbital floor often occurs (“blow-out fracture,” Aa and b). Orbital floor fractures are often associated with a lossofsensation in the area of distribution of the infraorbital nerve. If tissue is incarcerated in the wound gap, enophthalmos and a motility deficit are often found. Subcutaneous emphysema, which is usually characterized by the typical sensation on palpation in the region of the lids, is typical of fractures in the region of the ethmoid cells. Fractures of the orbit without significant bone dehiscence, enophthalmos, and motility deficit do not always have to be operated. However, systemic antibiotics and a prohibition on sneezing are recommended in order to prevent penetration of bacteria from the paranasal sinuses into the orbit. Fractures of the orbital floor associated with greater tissue prolapse are treated surgically, usually by insertion of a plate.

Traumatic hematomas of the orbit have to be decompressed surgically if significant compression of the optic nerve is present (examination of pupil reactions). In these cases there is usually massively increased lid tension. Midface fractures occur not infrequently in conjunction with head injuries. If the fracture line passes through the optic canal as in LeFort II and LeFort III fractures, there is a danger of injury to the optic nerve by bone fragments or overstretching (traumatic optic neuropathy). However, stretching of the optic nerve can also occur in the region of the optic canal in the absence of a fracture. The decision on treatment is difficult as neither high-dose corticosteroids nor surgical decompression of the optic nerve canal has yielded convincing results.

The extent of penetrating injuries of the orbit (Ac) is often underestimated. There can often be a major optic nerve injury even when the external wound is small. Penetration of a foreign body into the orbit and penetration of the globe must always also be considered. Operative wound management may be required depending on the situation. Organic foreign bodies in

particularshouldberemovedastheyotherwise usually cause a severe inflammatory reaction. Foreign bodies made of certain metals (most forms of steel, silver, gold, aluminum), glass, or porcelain can sometimes be left in the orbit as they normally do not cause any significant tissue reaction.

B. Systematic Classification

The flow chart in B opposite shows the systematic classification of all orbital diseases.