Ophthalmology A Short Textbook - part 8 pot

15.3.1.1.2 Craniofacial Dysostosis Premature fusion of the coronal and sagittal sutures also results in a high skull and abnormally small orbits. This condition is also characterized by a wide root of the nose and a prominent chin. Enucleation in early childhood can result in orbital hypoplasia as the globe provides a growth stimulus for the orbital cavity. Therefore the patient should promptly receive a prosthesis. 15.3.2 Mandibulofacial Dysplasia 15.3.2.1 Oculoauriculovertebral Dysplasia Epibulbar dermoids near the limbus are present in addition to outer ear anomalies and rudiments of a branchial passage in the cheek (see Fig. 4. 19). 15.3.2.2 Mandibulofacial Dysostosis Also known as Treacher Collins’ syndrome (incomplete type) or Frances- chetti’s syndrome (complete type), this anomaly of the first branchial arch is characterized by orbital deformities with , , low-set ears, and a hypoplastic mandible with dental deformities. 15.3.2.3 Oculomandibular Dysostosis In addition to the typical bird-like face, this anomaly may be accompanied by bilateral microphthalmos associated with cataract, nystagmus, and stra- bismus. 15.3.2.4 Rubinstein–Taybi Syndrome This craniomandibulofacial dysplasia is primarily characterized by antimon- goloid palpebral fissures, ocular hypertelorism, epicanthal folds, and enoph- thalmos. Cataracts, iris colobomas, and infantile glaucoma have also been described. 15.3.3 Meningoencephalocele Incomplete fusion of the cranial sutures in the orbital region can lead to evaginations of dural sac with brain tissue. Clinical findings occasionally include or, in extreme cases, a . 15 Orbital Cavity Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 411 15.3.4 Osteopathies Many of these disorders can produce orbital changes. The most common of these diseases include Paget’s disease of bone, dysostosis multiplex (Hurler’s syndrome), and marble-bone disease of Albers-Schönberg in which compres- sive optic neuropathy also occurs. 15.4 Orbital Involveme nt in Autoimmune Disorde rs: Graves’ Disease Definition Autoimmune disorder with orbital involvement frequently associated with thy- roid dysfunction. Histologic examination reveals inflammatory infiltration of the orbital cavity. Epidemiology: Women are affected eight times as often as men. Sixty per cent of all patients have hyperthyroidism. Ten per cent of patients with thy- roid disorders develop Graves’ disease during the course of their life. Graves’ disease is the most frequent cause of both unilateral and bilateral exophthalmos. Etiology: The precise etiology of this autoimmune disorder is not clear. Histo- logic examination reveals lymphocytic infiltration of the orbital cavity. The ocular muscles are particularly severely affected. Fibrosis develops after the acute phase. An autonomous adenoma of the thyroid gland is not associated with Graves’ disease. Some patients with Graves’ disease never exhibit any thyroid dysfunction during their entire life. Symptoms: The onset of this generally painless disorder is usually between the ages of 20 and 45. Patients complain of reddened dry eyes with a sensa- tion of pressure (symptoms of keratoconjunctivitis sicca) and of cosmetic problems. Ocular motility is also limited, and patients may experience double vision. Diagnostic considerations: Cardinal symptoms include exophthalmos, which is unilateral in only 10% of all cases, and eyelid changes that involve development of a characteristic eyelid sign (Table 15. 3 and Fig. 15.3). Thicken- ing of the muscles (primarily the rectus inferior and medialis) and sub- sequent fibrosis lead to limited motility and double vision. Elevation is impaired; this can lead to false high values when measuring intraocular pressure with the gaze elevated. 15.4 Autoimmune Disorders and the Orbit: Graves’ Disease Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 412 Table 15.3 Eyelid signs in Graves’ disease Eyelid sign Explanation ❖ Dalrymple’s sign Upper eyelid is retracted with visible sclera superior to the limbus and widened palpebral fissure with developing exposure keratitis (overactive muscle of Müller). ❖ von Graefe’s sign Upper eyelid retracts when the eye depresses (over- active muscle of Müller). ❖ Gifford’s sign Upper eyelid is difficult to evert (due to eyelid edema). ❖ Stellwag’s sign Rare blinking. ❖ Kocher’s sign Fixed gaze. ❖ Eyelid flutters when closed Patient with Graves’ disease, more severe in the left than in the right eye. Fig. 15.3 Typical signs include ex- ophthalmos, which here is readily apparent in the left eye, re- traction of the upper eyelid with visible sclera su- perior to the lim- bus (Dalrymple’s sign), conjuncti- val injection, and fixed gaze (Kocher’s sign). The tentative clinical diagnosis of Graves’ disease is supported by thicken- ing of the extraocular muscles identified in ultrasound or CT studies (Fig. 15.4). The further diagnostic work-up requires the cooperation of an internist, endocrinologist, and radiologist. 15 Orbital Cavity Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 413 CT image of a patient with Graves’ disease. Fig. 15.4 The image shows obvious thickening of the extraocular muscles in the right orbit, primarily the rectus medi- alis (1) and rectus lateralis (2), and of the rectus me- dialis (3) in the left orbit. Differential diagnosis: Rarer clinical syndromes such as orbital tumors and orbital pseudotumors must be excluded. Treatment: The main principles in treating the disease in its acute stage include management of the thyroid dysfunction, systemic cortisone (initially 60 –100 mg of prednisone) and radiation therapy of the orbital cavity. Surgical decompression of the orbital cavity is indicated in recurrent cases that do not respond to treatment to avoid compressive optic neuropathy. Exposure ker- atitis (keratitis due to inability to close the eye) should be treated with artifi- cial tears or tarsorrhaphy (partial or complete suture closure of the upper and lower eyelid to shorten or close the palpebral fissure). In the postinflam- matory stage of the disease, eye muscle surgery may be performed to correct strabismus. Clinical course and prognosis: Visual acuity will remain good if treatment is initiated promptly. In the postinflammatory phase, exophthalmos often per- sists despite the fact that the underlying disorder is well controlled. 15.5 Orbital Inflammation Because of the close proximity of the orbital cavity to the paranasal sinuses, which are particularly susceptible to inflammation, orbital inflammation represents the second most frequent group of orbital disorders after Graves’ disease. Orbital cellulitis is the most severe of these. 15.5 Orbital Inflammation Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 414 15.5.1 Orbital Cellulitis Definition Acute inflammation of the contents of the orbital cavity with the cardinal symptoms of limited motility and general malaise. Orbital cellulitis is the most frequent cause of exophthalmos in children. Etiology: Acute orbital inflammation posterior to the orbital septum is usu- ally an inflammation that has spread from surrounding tissue. Over 60% of all cases (as high as 84% in children) may be classified as originating in the sinuses, especially the ethmoidal air cells and the frontal sinus. In infants, tooth germ inflammations may be the cause. Less frequently, this clinical pic- ture occurs in association with facial furuncles, erysipelas, hordeolum, panophthalmitis, orbital injuries, and sepsis. Symptoms: Patients report severe malaise, occasionally accompanied by fever and pain exacerbated by eye movement. Diagnostic considerations: Typical symptoms include exophthalmos with severe chemosis (conjunctival swelling), eyelid swelling, and significantly limited ocular motility (“cemented” globe; see Fig. 15.5). Patients may exhibit leukocytosis and an increased erythrocyte sedimentation rate. Where there is clinical evidence of suspected involvement of the paranasal sinuses, an ENT specialist should be consulted to evaluate the sinuses and initiate any necessary treatment. Patient with orbital cellulitis. Fig. 15.5 Typical symptoms in- clude chemosis (conjunctival swelling), exoph- thalmos, and sig- nificantly limited ocular motility (the right eye does not move with the left eye). 15 Orbital Cavity Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 415 Differential diagnosis: Preseptal cellulitis, which is more frequently encoun- tered , should be excluded. The inflammation in preseptal cellulitis is anterior to the orbital septum; chemosis and limited motility are absent. Rarer clinical syndromes that should also be considered in a differential diagnosis include an orbital pseudotumor, orbital periostitis which may be accompanied by a subperiosteal abscess, and an orbital abscess. The crucial characteristic feature of orbital cellulitis for differential diag- nosis is the significantly limited ocular motility (“cemented” globe). A rhabdomyosarcoma should also be considered in children. Treatment: This consists of high-dose intravenous antibiotic therapy with 1.5 g of oxacillin every four hours combined with one million units of penicil- lin G every four hours. Infants are treated with ceftriaxone and school-age children with oxacillin combined with cefuroxime in the appropriate doses. Treatment of underlying sinusitis is indicated in applicable cases. Clinical course and complications: Orbital inflammation can lead to optic neuritis with subsequent atrophy and loss of vision. Purulent thrombophle- bitis of the orbital veins can result in cavernous sinus thrombosis with menin- gitis, cerebral abscess, or sepsis. Orbital cellulitis can progress to a life-threatening situation (cavernous sinus thrombosis). 15.5.2 Cavernous Sinus Thrombosis Definition Rare but severe acute clinical syndrome in which the spaces of the cavernous sinus posterior to the orbital cavity become thrombosed, usually in the pres- ence of adjacent purulent processes. This is not an orbital disorder in the strict sense. Etiology: These are purulent inflammations that have spread from the middle ear, petrous bone, orbital cavities, or from the facial skin via the angu- lar vein. Symptoms: Patients present with an acute clinical picture with headache, stupor, fever, and vomiting. Clinical findings: The ophthalmologist will usually diagnose bilateral exoph- thalmos and episcleral and conjunctival venous stasis in combination with multiple pareses of the cranial nerves. Neurogenic paralysis of all ocular muscles is referred to as total ophthalmoplegia. Where the optic nerve is also involved, the condition is referred to as orbital apex syndrome. 15.5 Orbital Inflammation Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 416 The limited motility of the globe is primarily neurogenic and due to damage to the nerves in the cavernous sinus as opposed to the mechanical limitation of motility due to the orbital inflammation in orbital cellulitis. Diagnostic considerations and treatment: This lies primarily in the hands of ENT specialists, neurosurgeons, and internists. High-dose systemic anti- biotic therapy and anticoagulation are indicated. 15.5.3 Orbital Pseudotumor Definition Lymphocytic orbital tumor of unknown origin. Symptoms and findings: Painful, moderately severe inflammatory reaction with eyelid swelling, chemosis, and unilateral or bilateral exophthalmos. Involvement of the ocular muscles results in limited motility with diplopia. Diagnostic considerations: The CT and MR images will show diffuse soft- tissue swelling. A biopsy is required to confirm the diagnosis. Occasionally the CT image will simulate an infiltrative tumor. Differential diagnosis: Various disorders should be excluded. These include Graves’ disease and orbital cellulitis, which isusually bacterial. Special forms of orbital pseudotumor include myositis and Tolosa–Hunt syndrome (pain- ful total ophthalmoplegia produced by an idiopathic granuloma at the apex of the orbit). Treatment: High-dose systemic cortisone (initially 100 mg of prednisone) usually leads to remission. Orbital radiation therapy or surgical intervention may be indicated in cases that fail to respond to treatment. 15.5.4 Myositis This a special form of orbital pseudotumor in which the lymphatic inf iltra- tion primarily involves one or more ocular muscles. Aside from significant pain during motion, symptoms include limited ocular motility with double vision (diplopia). Depending on the extent of the myositic changes, exophthalmos with chemosis and eyelid swelling may also be present. Ultrasound studies (Fig. 15. 6) will reveal thickening of the ocular muscles with tenonitis (inflam- mation of Tenon’s capsule). In Graves’ disease, only the muscle belly is thickened. In myositis, the entire muscle is thickened. 15 Orbital Cavity Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 417 15.5.5 Orbital Periostitis This is an inflammation of the periosteum lining the orbital cavity, usually due to bacterial infection such as actinomycosis, tuberculosis, or syphilis. Less frequently, the disorder is due to osteomyelitis or, in infants, tooth germ inflammations. The clinical symptoms are similar to orbital cellulitis although significantly less severe and without limitation of ocular motility. Liquefac- tion of the process creates an orbital abscess; large abscesses may progress to orbital cellulitis. 15.5.6 Mucocele These mucus-filled cysts may invade the orbital cavity in chronic sinusitis. They displace orbital tissue and cause exophthalmos. Treatment is required in the following cases: ❖ Displacement of the globe causes cosmetic or functional problems, such as lagophthalmos or limited motility. ❖ Compression neuropathy of the optic nerve results. ❖ The mucocele becomes infected (pyocele). 15.5.7 Mycoses (Mucormycosis and Aspergillomycosis) These rare disorders occur primarily in immunocompromised patients, such as those with diabetes mellitus or AIDS. The disorder often spreads from infected paranasal sinuses. The clinical picture is similar to those of inflam- matory orbital disorders. Diagnosis of myositis. Fig. 15.6 The ultrasound image (B-mode scan) shows thickening of the entire hypoechoic rec- tus medialis (arrow). 15.5 Orbital Inflammation Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 418 15.6 Vas cular Disorders These changes are rare. The most important and most frequently encountered disorder in this group is pulsating exophthalmos. 15.6.1 Pulsating Exophthalmos Definition Acute exophthalmos with palpable and audible pulsations synchronous with the pulse in the presence of a cavernous sinus fistula or arteriovenous aneurysm. Etiology: An abnormal communication between the cavernous sinus and the internal carotid artery (a direct shunt) or its branches (indirect shunt) results in distention of the orbital venous network. Eighty per cent of all cases are attributable to trauma; less frequently the disorder is due to syphilis or arte- riosclerosis. Symptoms: Patients report an unpleasant sound in the head that is reminis- cent of a machine and synchronous with their pulse. Diagnostic considerations: The increased venous pressure leads to dilation of the episcleral and conjunctival vessels (Fig. 15.7), retinal signs of venous stasis with bleeding, exudation, and papilledema. Intraocular pressure is also increased. The increased pressure in the cavernous sinus can also result in oculomotor and abducent nerve palsy. Sounds near the direct fistula are clearly audible with a stethoscope. Fistula between the carotid artery and cavernous sinus. Fig. 15.7 The episcleral and conjunctival ves- sels are signifi- cantly dilated and describe tortuous corkscrew courses. 15 Orbital Cavity Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 419 Doppler ultrasound studies can confirm a clinical suspicion. However, only angiography can determine the exact location of the shunt. Treatment: Selective embolization may be performed in cooperation with a neuroradiologist once the shunt has been located. Small shunts may close spontaneously in response to pressure fluctua- tions such as can occur in air travel. 15.6.2 Intermittent Exophthalmos This rare clinical picture characterized by intermittent unilateral or bilateral exophthalmos is caused by varicose dilation of the orbital veins, such as can occur following trauma or in Osler’s disease (polycythemia vera). Patients report protrusion of the eyeball of varying severity. Exophthalmos is usually unilateral and is especially prone to occur when the resistance to venous drainage is increased, as can occur when the patient presses, bends over, screams, or compresses the vessels of the neck. Occasionally the exophthal- mos will be associated with increased filling of the episcleral and/or conjunc- tival vessels. The disorder can be diagnosed in ultrasound studies using the Valsalva maneuver. A differential diagnosis should exclude a fistula between the carotid artery and cavernous sinus or an arteriovenous aneurysm, which is usually accompanied by a dramatic clinical picture with pulsation and increased intraocular pressure. In these clinical pictures, the ultrasound examination will reveal generalized dilation of the orbital veins. Surgical removal of orbital varices entails a high risk of damaging crucial delicate neu- rovascular structures in the orbital cavity. However, it may be indicated in rare cases such as cosmetically unacceptable exophthalmos or where symp- toms of keratoconjunctivitis sicca occur due to exposure that fails to respond to treatment. 15.6.3 Orbital Hematoma Orbital bleeding is usually post-traumatic but may occur less frequently due to coagulopathy resulting from vitamin C deficiency, anticoagulants, or leukemia. Retrobulbar injections prior to eye surgery and acute venous stasis such as may occur in coughing fits, asphyxia, or childbirth can also cause orbi- tal hematomas. Exophthalmos may be accompanied by monocle or eyeglass hematoma, eyelid swelling, and subconjunctival hemorrhage; limited motility is rare. Surgical decompression of the orbital cavity (transfornix orbital decom- pression or orbitotomy) is indicated where damage to the optic nerve or blockage of the central retinal artery is imminent. 15.6 Vascular Disorders Lang, Ophthalmology © 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. [...]... See Chapter 18 15 .8 Orbital Surgery Access to the orbital cavity is gained primarily through an anterior approach (transconjunctival or transpalpebral approaches yield good cosmetic results) or through a lateral approach The lateral Krönlein approach provides better intraoperative exposure Transantral, transfrontal, transcranial, and transnasal orbitotomies are used less frequently Orbital exenteration... with unilateral aphakia or who do not tolerate contact lenses will require implantation of an intraocular lens Correction of unilateral aphakia with unilateral glasses is usually contraindicated because it result in aniseikonia of approximately 25% 16.4 Impaired Accommodation 16.4.1 Accommodation Spasm Definition An accommodation spasm is defined as inadequate protracted contraction of the ciliary muscle... stigma (point) and literally means lack of a focal point The disorder is characterized by a curvature anomaly of the refractive media such that parallel incident light rays do not converge at a point but are drawn apart to form a line Epidemiology: Forty-two per cent of all humans have astigmatism greater than or equal to 0.5 diopters In approximately 20%, this astigmatism is greater than 1 diopter and... Optics and Refractive Errors Treatment of irregular astigmatism: This form cannot be corrected with eyeglasses External astigmatism may be managed with a rigid contact lens (Fig 16.13 b), keratoplasty, or surgical correction of the refractive error Irregular internal astigmatism is usually lens-related In this case, removal of the lens with implantation of an intraocular lens is indicated Only regular astigmatism... insufficient refractive power in a normal-length globe (refractive hyperopia; Fig 16.10 e) Axial hyperopia is usually congenital and is characterized by a shallow anterior chamber with a thick sclera and well developed ciliary muscle Hyperopic eyes are predisposed to acute angle closure glaucoma because of their shallow anterior chamber This can be provoked by diagnostic and therapeutic mydriasis Special forms... chemotherapy and radiation therapy, curative treatment is possible in many cases 15.7.2 Metastases In children, the incidence of metastasis is higher in the orbital cavity than in the choroid In adults, it is exactly the opposite The most common orbital metastases in children originate from neuroblastomas Malignant tumors from adjacent tissue can also invade the orbital cavity Lang, Ophthalmology ©... Posterior to the retina Lack of a focal point Myopia (nearsightedness) Hyperopia (farsightedness) Astigmatism Anomalies in the curvature of the normally spherical surfaces of the refractive media (cornea and lens) Eyeball too short (axial hyperopia) O Insufficient refractive power (refractive hyperopia) O Eyeball too long (axial myopia) O Excessive refractive power (refractive myopia) O Causes Overview of... classified as follows: O External astigmatism: astigmatism of the anterior surface of the cornea Internal astigmatism: the sum of the astigmatic components of the other media Astigmatism can also be classified according to the location of the meridian of greater refraction: O With-the-rule astigmatism (most common form): The meridian with the greater refractive power is vertical, i.e., between 70 and... Emmetropia and Ametropia Refraction is defined as the ratio of the refractive power of the lens and cornea (the refractive media) to the axial length of the globe Emmetropia is distinguished from ametropia Emmetropia (normal sight): The ratio of the axial length of the eye to the refractive power of the cornea and lens is balanced Parallel light rays that enter the eye therefore meet at a focal point... refractive media are totally irregular, resulting in multiple focal points b Correction of irregular corneal astigmatism with a rigid contact lens O O O Advanced keratoconus Cataract Lenticonus Symptoms: Patients with astigmatism see everything distorted Attempts to compensate for the refractive error by accommodation can lead to asthenopic symptoms such as a burning sensation in the eyes or headache . craniomandibulofacial dysplasia is primarily characterized by antimon- goloid palpebral fissures, ocular hypertelorism, epicanthal folds, and enoph- thalmos. Cataracts, iris colobomas, and infantile glaucoma have. typical bird-like face, this anomaly may be accompanied by bilateral microphthalmos associated with cataract, nystagmus, and stra- bismus. 15.3.2.4 Rubinstein–Taybi Syndrome This craniomandibulofacial. better intraoperative exposure. Transantral, transfrontal, transcranial, and trans- nasal orbitotomies are used less frequently. Orbital exenteration is indicated with advanced malignant tumors.