Ординатура / Офтальмология / Английские материалы / Ophthalmology A Short Textbook_Lang_2000

Congenital ptosis. The disorder is usually hereditary and is primarily autosomal dominant as opposed to recessive. The cause is frequently aplasia in the core of the oculomotor nerve (neurogenic) that supplies the levator palpebrae muscle; less frequently it is attributable to an underdeveloped levator palpebrae muscle (myogenic).

Acquired ptosis:

Neurogenic causes:

–Oculomotor palsy (paralytic ptosis).

–Lesions in the sympathetic nerve (sympathetic ptosis) is Horner’s palsy (ptosis, miosis, and enophthalmos).

Myogenic ptosis: myasthenia gravis and myotonic dystrophy.

Traumatic ptosis can occur after injuries.

Symptoms. The drooping of the upper eyelid may be unilateral (usually a sign of a neurogenic cause) or bilateral (usually a sign of a myogenic cause). A characteristic feature of the unilateral form is that the patient attempts to increase the palpebral fissure by frowning (contracting the frontalis muscle). Congenital ptosis (Fig. 2.4) generally affects one eye only; bilateral symptoms are observed far less frequently (7%).

Diagnostic considerations: Congenital ptosis. The affected eyelid in general is underdeveloped. The skin of the upper eyelid is smooth and thin; the superior palpebral furrow is absent or ill-defined. A typical symptom is “lid lag” in which the upper eyelid does not move when the patient glances down. This important distinguishing symptom excludes acquired ptosis in differential diagnosis. In about 3% of all cases, congenital ptosis is associated with epicanthal folds and blepharophimosis (Waardenburg syndrome).

Congenital ptosis can occur in varying degrees of severity and may be complicated by the presence of additional eyelid and ocular muscle disorders such as strabismus.

Congenital ptosis in which the upper eyelid droops over the center of the pupil always involves an increased risk of amblyopia.

Acquired ptosis:

Paralytic ptosis in oculomotor palsy (see also Chap. 17) is usually unilateral with the drooping eyelid covering the whole eye. Often there will be other signs of palsy in the area supplied by the oculomotor nerve. In external oculomotor palsy, only the extraocular muscles are affected (mydriasis will not be present), whereas in complete oculomotor palsy, the inner ciliary muscle and the sphincter pupillae muscle are also affected (internal ophthalmoplegia with loss of accommodation, mydriasis, and complete loss of pupillary light reflexes).

Myasthenia gravis (myogenic ptosis that is often bilateral and may be asymmetrical) is associated with abnormal fatigue of the striated

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extraocular muscles. Ptosis typically becomes more severe as the day goes on.

Sympathetic ptosis occurs in Horner’s palsy (ptosis, miosis, and enophthalmos).

Rapidly opening and closing the eyelids provokes ptosis in myasthenia gravis and simplifies the diagnosis.

Treatment:

Congenital ptosis: This involves surgical retraction of the upper eyelid (Fig. 2.5a–c), which should be undertaken as quickly as possible when there is a risk of the affected eye developing a visual impairment as a result of the ptosis.

Acquired ptosis: Treatment depends on the cause. As palsies often resolve spontaneously, the patient should be observed before resorting to surgical

intervention. Conservative treatment with special eyeglasses may be sufficient even in irreversible cases.

Because of the risk of overcorrecting or undercorrecting the disorder, several operations may be necessary.

Prognosis and complications: Prompt surgical intervention in congenital ptosis can prevent amblyopia. Surgical overcorrection of the ptosis can lead to desiccation of the conjunctiva and cornea with ulceration as a result of incomplete closure of the eyelids.

2.4.2Entropion

Definition

Entropion is characterized by inward rotation of the eyelid margin. The margin of the eyelid and eyelashes or even the outer skin of the eyelid are in contact with the globe instead of only the conjunctiva. The following forms are differentiated according to their origin (see Etiology):

Congenital entropion (Fig. 2.6).

Spastic entropion (Fig. 2.7).

Cicatricial entropion.

Epidemiology: Congenital entropion occurs frequently among Asians but is rare among people of European descent, in whom the spastic and cicatricial forms are more commonly encountered (see also Chap. 18).

Etiology:

Congenital entropion: This results from fleshy thickening of the skin and orbicularis oculi muscle near the margin of the eyelid. Usually the lower eyelid is affected. This condition may persist into adulthood.

Methods of surgical retraction of the upper eyelid.

c

26 2 The Eyelids

Congenital entropion.

Fig. 2.6 Congenital inward rotation of the margins of the upper and lower eyelids is a frequent finding in Asian populations and is usually asymptomatic.

Spastic entropion.

Fig. 2.7 Displaced fibers of the orbicularis oculi muscle cause the eyelashes of the lower eyelid to turn inward. Surgical intervention is indicated to correct the laxity of the lower eyelid.

Spastic entropion: This affects only the lower eyelid. A combination of several pathogenetic factors of varying severity is usually involved:

–The structures supporting the lower eyelid (palpebral ligaments, tarsus, and eyelid retractor) may become lax with age, causing the tarsus to tilt inward.

–This causes the fibers of the orbicularis oculi muscle to override the normally superior margin of the eyelid, intensifying the blepharospasm resulting from the permanent contact between the eyelashes and the eyeball.

–Senile enophthalmos, usually occurring in old age as a result of atrophy of the orbit fatty tissue, further contributes to instability of the lower eyelid.

Cicatricial entropion: This form of entropion is frequently the result of postinfectious or post-traumatic tarsal contracture (such as trachoma; burns and chemical injuries). Causes can also include allergic and toxic reactions (pemphigus, Stevens-Johnson syndrome, and Lyell’s syndrome).

Symptoms and diagnostic considerations (see also etiology): Constant rubbing of the eyelashes against the eyeball (trichiasis) represents a permanent foreign-body irritation of the conjunctiva which causes a blepharospasm (p. 93) that in turn exacerbates the entropion. The chronically irritated conjunctiva is reddened, and the eye fills with tears. Only congenital entropion is usually asymptomatic.

Treatment:

Congenital entropion: To the extent that any treatment is required, it consists of measured, semicircular resection of skin and orbicularis oculi muscle tissue that can be supplemented by everting sutures where indicated.

Spastic entropion: Surgical management must be tailored to the specific situation. Usually treatment combines several techniques such as shortening the eyelid horizontally combined with weakening or diverting the pretarsal fibers of the orbicularis oculi muscle and shortening the skin vertically.

Cicatricial entropion: The surgical management of this form is identical to that of spastic entropion.

An adhesive bandage may be applied to increase tension on the eyelid for temporary relief of symptoms prior to surgery.

Prognosis and complications:

Congenital entropion is usually asymptomatic and often resolves within the first few months of life.

Spastic entropion: The prognosis is favorable with prompt surgical intervention, although the disorder may recur. Left untreated, spastic entropion entails a risk of damage to the corneal epithelium with superinfection which may progress to the complete clinical syndrome of a serpiginous corneal ulcer (see p. 29).

Cicatricial entropion: The prognosis is favorable with prompt surgical intervention (i.e., before any corneal changes occur).

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2.4.3Ectropion

Definition

Ectropion refers to the condition in which the margin of the eyelid is turned away from the eyeball. This condition almost exclusively affects the lower eyelid. The following forms are differentiated according to their origin (see also Etiology):

Congenital ectropion.

Senile ectropion.

Paralytic ectropion.

Cicatricial ectropion.

Epidemiology: Senile ectropion is the most prevalent form; the paralytic and cicatricial forms occur less frequently. Congenital ectropion is very rare and is usually associated with other developmental anomalies of the eyelid and face such as Franceschetti’s syndrome.

Etiology:

Congenital ectropion: See Epidemiology.

Senile ectropion: The palpebral ligaments and tarsus may become lax with age, causing the tarsus to sag outward (Fig. 2.8).

Paralytic ectropion: This is caused by facial paralysis with resulting loss of function of the orbicularis oculi muscle that closes the eyelid.

Cicatricial ectropion: Like cicatricial entropion, this form is usually a sequela of infection or injury.

Senile ectropion.

Fig. 2.8 The structures supporting the eyelid are lax, causing the lower eyelid sag outward.

Symptoms and diagnostic considerations: Left untreated, incomplete closure of the eyelids can lead to symptoms associated with desiccation of the cornea including ulceration from lagophthalmos. At the same time, the eversion of the punctum causes tears to flow down across the cheek instead of draining into the nose. Wiping away the tears increases the ectropion. This results in chronic conjunctivitis and blepharitis.

Treatment:

Congenital ectropion: Surgery.

Senile ectropion: Surgery is indicated. A proven procedure is to tighten the lower eyelid via a tarsal wedge resection followed by horizontal tightening of the skin.

Paralytic ectropion: Depending on the severity of the disorder, artificial tear solutions, eyeglasses with an anatomic lateral protective feature, or a “watch glass” bandage (Fig. 2.9) may be sufficient to prevent desiccation of the cornea. In severe or irreversible cases, the lagophthalmos is treated surgically via a lateral tarsorrhaphy.

Cicatricial ectropion: Plastic surgery is often required to correct the eyelid deformity.

Prognosis: The prognosis is favorable when the disorder is treated promptly. Sometimes several operations will be required. Surgery is more difficult where scarring is present.

Watch glass bandage for paralytic ectropion.

Fig. 2.9 In patients with lagophthalmos resulting from facial paralysis, a watch glass bandage creates a moist chamber that protects the cornea against desiccation.

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2.4.4Trichiasis

Trichiasis refers to the rare postinfectious or post-traumatic inward turning of the eyelashes. The deformity causes the eyelashes to run against the conjunctiva and cornea, causing a permanent foreign-body sensation, increased tear secretion, and chronic conjunctivitis. The eyelash follicles can be obliterated by electrolysis. The disorder may also be successfully treated by cryocautery epilation or surgical removal of the follicle bed.

2.4.5Blepharospasm

Definition

This refers to an involuntary spasmodic contraction of the orbicularis oculi muscle supplied by the facial nerve.

Etiology: In addition to photosensitivity and increased tear production, blepharospasm will also accompany inflammation or irritation of the anterior chamber. (Photosensitivity, epiphora, and blepharospasm form a triad of reactive clinical symptoms.) Causes of the disorder include extrapyramidal disease such as encephalitis or multiple sclerosis. Trigeminal neuralgia or psychogenic causes may also be present.

Symptoms: Clinical symptoms include spasmodically narrowed or closed palpebral fissures and lowered eyebrows.

Treatment: This depends on the cause of the disorder. Mild cases can be controlled well with muscle relaxants. Severe cases may require transection of the fibers of the facial nerve supplying the orbicularis oculi muscle. The disorder may also be successfully treated with repeated local injections of botulinum toxin.

Prognosis: The prognosis is good where a cause-related treatment is possible.

Essential blepharospasm does not respond well to treatment.

2.5Disorders of the Skin and Margin of the Eyelid

2.5.1Contact Eczema

Epidemiology: Light-skinned patients and patients susceptible to allergy are frequently affected.

Etiology: Contact eczema is caused by an antigen – antibody reaction in patients with intolerance to certain noxious substances. Cosmetics, adhesive bandages, or eyedrops and eye ointments are often responsible, particularly the preservatives used in them such as benzalkonium chloride.

Contact eczema.

Fig. 2.10 This disorder is frequently caused by preservatives such as those used in eyedrops. They cause typical reddening, swelling, and lichenification of the skin of the eyelid.

Symptoms: Reddening, swelling, lichenification, and severe itching of the skin of the eyelid occur initially, followed by scaling of the indurated skin with a sensation of tension (Fig. 2.10).

Treatment: This consists of eliminating the causative agent. (Allergy testing may be necessary.) Limited use of corticosteroids usually brings quick relief of symptoms.

Prognosis: The prognosis is good if the cause can be identified.

2.5.2Edema

Definition

This refers to swelling of the eyelid due to abnormal collection of fluid in the subcutaneous tissue.

Epidemiology: Edema is a frequently encountered clinical symptom.

Etiology: The skin of the eyelid is affected intensively by infectious and allergic processes. With the upper eyelid’s relatively thin skin and the loose struc-

32 2 The Eyelids

ture of its subcutaneous tissue, water can easily accumulate and cause edema.

Symptoms: Depending on the cause (Table 2.2), the intensity of swelling in the eyelid will vary. The location of swelling is also influenced by gravity and can vary in intensity. For example, it may be more intense in the early morning after the patient rises than in the evening (Fig. 2.11).

Fig. 2.2 Differential diagnosis of edema

Edema.

Fig. 2.11 With its relatively thin skin and its subcutaneous tissue that contains little fat, the upper eyelid is particularly susceptible to rapid fluid accumulations from pathologic processes.