Ординатура / Офтальмология / Английские материалы / Comprehensive Ophthalmology_Khurana_2007

glands are arranged in a row. The splitting of the eyelids when required in operations is done at the level of grey line.

STRUCTURE

Each eyelid consists (from anterior to posterior) of the following layers (Fig. 14.2):

1.The skin. It is elastic having a fine texture and is the thinnest in the body.

2.The subcutaneous areolar tissue. It is very loose and contains no fat. It is thus readily distended by oedema or blood.

3.The layer of striated muscle. It consists of orbicularis muscle which forms an oval sheet across the eyelids. It comprises three portions: the orbital, palpebral and lacrimal. It closes the eyelids and is supplied by zygomatic branch of the facial nerve. Therefore, in paralysis of facial nerve there occurs lagophthalmos which may be complicated by exposure keratitis.

In addition, the upper lid also contains levator

palpebrae superioris muscle (LPS). It arises from the apex of the orbit and is inserted by three parts on the skin of lid, anterior surface of the tarsal plate and conjunctiva of superior fornix. It raises the upper lid. It is supplied by a branch of oculomotor nerve.

4.Submuscular areolar tissue. It is a layer of loose connective tissue. The nerves and vessels lie in this layer. Therefore, to anaesthetise lids, injection is given in this plane.

5.Fibrous layer. It is the framework of the lids and consists of two parts: the central tarsal plate and the peripheral septum orbitale (Fig. 14.3).

i. Tarsal plate. There are two plates of dense connective tissue, one for each lid, which give shape and firmness to the lids. The upper and lower tarsal plates join with each other at medial and lateral canthi; and are attached to the orbital margins through medial and lateral palpebral ligaments. In the substance of the tarsal plates lie meibomian glands in parallel rows.

ii.Septum orbitale (palpebral fascia). It is a thin membrane of connective tissue attached centrally to the tarsal plates and peripherally to periosteum of the orbital margin. It is perforated by nerves, vessels and levator palpebrae superioris (LPS) muscle, which enter the lids from the orbit.

6.Layer of non-striated muscle fibres. It consists of the palpebral muscle of Muller which lies deep to the septum orbitale in both the lids. In the upper lid it arises from the fibres of LPS muscle and in the lower lid from prolongation of the inferior rectus muscle; and is inserted on the peripheral margins of the tarsal plate. It is supplied by sympathetic fibres.

7.Conjunctiva. The part which lines the lids is called palpebral conjunctiva. It consists of three parts: marginal, tarsal and orbital.

GLANDS OF EYELIDS (Fig. 14.4)

1.Meibomian glands. These are also known as tarsal glands and are present in the stroma of tarsal plate arranged vertically. They are about 30-40 in the upper lid and about 20-30 in the lower lid. They are modified sebaceous glands. Their ducts open at the lid margin. Their secretion constitutes the oily layer of tear film.

2.Glands of Zeis. These are also sebaceous glands which open into the follicles of eyelashes.

3.Glands of Moll. These are modified sweat glands situated near the hair follicle. They open into the hair follicles or into the ducts of Zeis glands. They do not open directly onto the skin surface as elsewhere.

4.Accessory lacrimal glands of Wolfring. These are present near the upper border of the tarsal plate.

BLOOD SUPPLY

The arteries of the lids (medial and lateral palpebral) form marginal arterial arcades which lie in the submuscular plane in front of the tarsal plate, 2 mm away from the lid margin, in each lid. In the upper lid another arcade (superior arterial arcade) is formed which lies near the upper border of the tarsal plate. Branches go forward and backward from these arches to supply various structures.

Veins. These are arranged in two plexuses: a posttarsal which drains into ophthalmic veins and a pretarsal opening into subcutaneous veins.

Lymphatics. These are also arranged in two sets: the pre-tarsal and the post-tarsal. Those from lateral half of the lids drain into preauricular lymph nodes and those from the medial half of the eyelids drain into submandibular lymph nodes.

NERVES OF LIDS

Motor nerves are facial (which supplies orbicularis muscle), oculomotor (which supplies LPS muscle) and sympathetic fibres (which supply the Muller’s muscle). Sensory nerve supply is derived from branches of the trigeminal nerve.

CONGENITAL ANOMALIES

1. Congenital ptosis. It is a common congenital anomaly. It is described in detail in the section of ptosis on page 356.

2.Congenital coloboma. It is a rare condition characterised by a full thickness triangular gap in the tissues of the lids (Fig. 14.5). The anomaly usually occurs near the nasal side and involves the upper lid more frequently than the lower lid. Treatment consists of plastic repair of the defect.

3.Epicanthus. It is a semicircular fold of skin which covers the medial canthus. It is a bilateral condition and may disappear with the development of nose. It is a normal facial feature in Mongolian races. It is the most common congenital anomaly of the lids. Treatment consists of plastic repair of the deformity.

4.Distichiasis. Congenital distichiasis is a rare anomaly in which an extra row of cilia occupies the

Fig. 14.5. Congenital coloboma upper eyelid.

position of Meibomian glands which open into their follicles as ordinary sebaceous glands. These cilia are usually directed backwards and when rubbing the cornea, should be electroepilated or cryoepilated.

Acquired distichiasis (metaplastic lashes) occurs when due to metaplasia and differentiation, the meibomian glands are transformed into hair follicles. The most important cause is late stage of cicatrizing conjunctivitis associated with chemical injury, Stevens-Johnson syndrome and ocular cicatricial pemphigoid.

5. Cryptophthalmos. It is a very rare anomaly in which lids fail to develop and the skin passes continuously from the eyebrow to the cheek hiding the eyeball (Fig. 14.6).

Fig. 14.6. Cryptophthalmos.

6. Microblepharon. In this condition, eyelids are abnormally small. It is usually associated with microphthalmos or anophthalmos. Occasionally the lids may be very small or virtually absent and the condition is called ablepharon.

OEDEMA OF THE EYELIDS

Owing to the looseness of the tissues, oedema of the lids is of common occurrence. It may be classified as inflammatory, solid and passive oedema.

I Inflammatory oedema. It is seen in the following conditions.

1.Inflammations of the lid itself, which include dermatitis, stye, hordeolum internum, insect bites, cellulitis and lid abscess.

2.Inflammations of the conjunctiva, such as acute purulent, membranous and pseudo-membranous conjunctivitis.

3.Inflammations of the lacrimal sac, i.e., acute dacryocystitis and lacrimal abscess.

4.Inflammations of the lacrimal gland, i.e., acute dacryoadenitis.

5.Inflammations of the eyeball, such as acute iridocyclitis, endophthalmitis and panophthalmitis.

6.Inflammations of the orbit, which include orbital cellulitis, orbital abscess and pseudo-tumour.

7.Inflammations of the paranasal sinuses, e.g., maxillary sinusitis.

II. Solid oedema of the lids. It is chronic thickening of the lids, which usually follows recurrent attacks of erysipelas. It resembles oedema of the lids but is harder in consistency.

III. Passive oedema of the lids. It may occur due to local or general causes.

1.Local causes are: cavernous sinus thrombosis, head injury and angioneurotic oedema.

2.General causes are congestive heart failure, renal failure, hypoproteinaemia and severe anaemia.

INFLAMMATORY DISORDERS OF

THE EYELIDS

BLEPHARITIS

It is a subacute or chronic inflammation of the lid margins. It is an extremely common disease which can be divided into following clinical types:

Seborrhoeic or squamous blepharitis,

Staphylococcal or ulcerative blepharitis,

Mixed staphylococcal with seborrhoeic blepharitis,

Posterior blepharitis or meibomitis, and

Parasitic blepharitis.

Seborrhoeic or squamous blepharitis

Etiology. It is usually associated with seborrhoea of scalp (dandruff). Some constitutional and metabolic factors play a part in its etiology. In it, glands of Zeis secrete abnormal excessive neutral lipids which are split by Corynebacterium acne into irritating free fatty acids.

Symptoms. Patients usually complain of deposition of whitish material at the lid margin associated with mild discomfort, irritation, occasional watering and a history of falling of eyelashes.

Signs. Accumulation of white dandruff-like scales are seen on the lid margin, among the lashes (Fig. 14.7). On removing these scales underlying surface is found to be hyperaemic (no ulcers). The lashes fall out easily but are usually replaced quickly without distortion. In long-standing cases lid margin is thickened and the sharp posterior border tends to be rounded leading to epiphora.

Treatment. General measures include improvement of health and balanced diet. Associated seborrhoea of the scalp should be adequately treated. Local measures include removal of scales from the lid margin with the help of lukewarm solution of 3 percent soda bicarb or baby shampoo and frequent application of combined antibiotic and steroid eye ointment at the lid margin.

Ulcerative blepharitis

Etiology. It is a chronic staphylococcal infection of the lid margin usually caused by coagulase positive strains. The disorder usually starts in childhood and may continue throughout life. Chronic conjunctivitis and dacryocystitis may act as predisposing factors.

Symptoms. These include chronic irritation, itching, mild lacrimation, gluing of cilia, and photophobia. The symptoms are characteristically worse in the morning.

Signs (Fig. 14.8). Yellow crusts are seen at the root of cilia which glue them together. Small ulcers, which bleed easily, are seen on removing the crusts. In between the crusts, the anterior lid margin may show dilated blood vessels (rosettes).

Complications and sequelae. These are seen in longstanding (non-treated) cases and include chronic conjunctivitis, madarosis (sparseness or absence of lashes), trichiasis, poliosis (greying of lashes), tylosis (thickening of lid margin) and eversion of the punctum leading to epiphora. Eczema of the skin and ectropion may develop due to prolonged watering. Recurrent styes is a very common complication.

Treatment. It should be treated promptly to avoid complication and sequelae. Crusts should be removed

after softening and hot compresses with solution of 3 percent soda bicarb. Antibiotic ointment should be applied at the lid margin, immediately after removal of crusts, at least twice daily. Antibiotic eyedrops should be instilled 3-4 times in a day. Avoid rubbing of the eyes or fingering of the lids. Oral antibiotics such as erythromycin or tetracyclines may be useful. Oral anti-inflammatory drugs like ibuprofen help in reducing the inflammation.

Posterior blepharitis (Meibomitis)

1.Chronic meibomitis is a meibomian gland dysfunction, seen more commonly in middle-aged persons with acne rosacea and seborrhoeic dermatitis. It is characterized by white frothy (foam-like) secretion on the eyelid margins and canthi (meibomian seborrhoea). On eversion of the eyelids, vertical yellowish streaks shining through the conjunctiva are seen. At the lid margin, openings of the meibomian glands become prominent with thick secretions (Fig. 14.9).

2.Acute meibomitis occurs mostly due to staphylococcal infection.

Treatment of meibomitis consists of expression of the glands by repeated vertical lid massage, followed by rubbing of antibiotic-steroid ointment at the lid margin. Antibiotic eyedrops should be instilled 3-4 times. Systemic tetracyclines for 6-12 weeks remain the mainstay of treatment of posterior blepharitis. Erythromycin may be used where tetracyclines are contraindicated.

Parasitic blepharitis

Blepharitis acrica refers to a chronic blepharitis associated with Demodex folliculorum infection and

Phthiriasis palpebram to that due to crab-louse, very rarely to the head-louse. In addition to features of chronic blepharitis, it is characterized by presence of nits at the lid margin and at roots of eyelashes (Fig. 14.10).

Treatment consists of mechanical removal of the nits with forceps followed by rubbing of antibiotic ointment on lid margins, and delousing of the patient, other family members, clothing and bedding.

EXTERNAL HORDEOLUM (STYE)

It is an acute suppurative inflammation of gland of the Zeis or Moll.

Etiology

1.Predisposing factors. It is more common in children and young adults (though no age is bar) and in patients with eye strain due to muscle imbalance or refractive errors. Habitual rubbing of the eyes or fingering of the lids and nose, chronic blepharitis and diabetes mellitus are usually associated with recurrent styes. Metabolic factors, chronic debility, excessive intake of carbohydrates and alcohol also act as predisposing factors.

2.Causative organism commonly involved is

Staphylococcus aureus.

Symptoms

These include acute pain associated with swelling of lid, mild watering and photophobia.

Signs

Stage of cellulitis is characterised by localised, hard, red, tender swelling at the lid margin associated with marked oedema (Fig. 14.11).

Fig. 14.11. Hordeolum externum (stye) upper eyelid.

Stage of abscess formation is characterised by a visible pus point on the lid margin in relation to the affected cilia.

Usually there is one stye, but occasionally, these

may be multiple.

Treatment

Hot compresses 2-3 times a day are very useful in cellulitis stage. When the pus point is formed it may be evacuated by epilating the involved cilia. Surgical incision is required rarely for a large abscess. Antibiotic eyedrops (3-4 times a day) and eye ointment (at bed time) should be applied to control infection. Anti-inflammatory and analgesics relieve pain and reduce oedema. Systemic antibiotics may be used for early control of infection. In recurrent styes, try to find out and treat the associated predisposing condition.

CHALAZION

It is also called a tarsal or meibomian cyst. It is a chronic non-infective granulomatous inflammation of the meibomian gland.

Etiology

1.Predisposing factors are similar to hordeolum externum.

2.Pathogenesis. Usually, first there occurs mild grade infection of the meibomian gland by organisms of very low virulence. As a result, there occurs proliferation of the epithelium and infiltration of the walls of the ducts, which are blocked. Consequently, there occurs retention of secretions (sebum) in the gland, causing its enlargement. The pent-up secretions (fatty in nature) act like an irritant and excite non-infective granulomatous inflammation of the meibomian gland.

Clinical picture

Patients usually present with a painless swelling in the lid and a feeling of mild heaviness. Examination usually reveals small, firm to hard, non-tender swelling present slightly away from the lid margin (Fig. 14.12). It usually points on the conjunctival side, as a red, purple or grey area, seen on everting the lid. Rarely, the main bulk of the swelling project on the skin side. Occasionally, it may present as a reddish-grey nodule on the intermarginal strip (marginal chalazion). Frequently, multiple chalazia may be seen involving one or more eyelids.

Clinical course and complications

Complete spontaneous resolution may occur rarely.

Often it slowly increases in size and becomes very large. A large chalazion of the upper lid may press on the cornea and cause blurred vision from induced astigmatism. A large chalazion of the lower lid may rarely cause eversion of the punctum or even ectropion and epiphora.

Occasionally, it may burst on the conjunctival side, forming a fungating mass of granulation tissue.

Secondary infection leads to formation of hordeolum internum.

Calcification may occur, though very rarely.

Malignant change into meibomian gland carcinoma may be seen occasionally in elderly people.

Fig. 14.12. Chalazion upper eye lid.

Treatment

1.Conservative treatment. In a small, soft and recent chalazion, self-resolution may be helped by conservative treatment in the form of hot fomentation, topical antibiotic eyedrops and oral anti-inflammatory drugs.

2.Intralesional injection of long-acting steroid (triamcinolone) is reported to cause resolution in about 50 percent cases, especially in small and soft chalazia. So, such a trial is worthwhile before the surgical intervention.

3.Incision and curettage (Fig. 14.13) is the conventional and effective treatment for chalazion. Surface anaesthesia is obtained by instillation of xylocaine drops in the eye and the lid in the region of the chalazion is infiltrated with 2 percent xylocaine solution. An incision is made with a sharp blade, which should be vertical on the conjunctival side (to avoid injury to other meibomian ducts) and horizontal on skin side (to have an invisible scar). The contents are curetted out with the help of a chalazion scoop. To avoid recurrence, its cavity should be cauterised with carbolic acid. An antibiotic ointment is instilled and eye padded for about 12 hours. To decrease postoperative discomfort and prevent infection, antibiotic eyedrops, hot fomentation and oral anti-inflammatory and analgesics may be given for 3-4 days.

4.Diathermy. A marginal chalazion is better treated by diathermy.

INTERNAL HORDEOLUM

It is a suppurative inflammation of the meibomian gland associated with blockage of the duct.

Etiology. It may occur as primary staphylococcal infection of the meibomian gland or due to secondary infection in a chalazion (infected chalazion).

Clinical picture. Symptoms are similar to hordeolum externum, except that pain is more intense, due to the swelling being embedded deeply in the dense fibrous tissue. On examination, it can be differentiated from hordeolum externum by the fact that in it, the point of maximum tenderness and swelling is away from the lid margin and that pus usually points on the tarsal conjunctiva (seen as yellowish area on everting the lid) and not on the root of cilia (Fig. 14.14). Sometimes, pus point may be seen at the opening of involved meibomian gland or rarely on the skin.

Treatment. It is similar to hordeolum externum, except that, when the pus is formed, it should be drained by a vertical incision from the tarsal conjunctiva.

MOLLUSCUM CONTAGIOSUM

It is a viral infection of the lids, commonly affecting children. It is caused by a large poxvirus. Its typical lesions are multiple, pale, waxy, umbilicated swellings scattered over the skin near the lid margin (Fig. 14.15). These may be complicated by chronic follicular conjunctivitis and superficial keratitis.

Treatment. The skin lesions should be incised and the interior cauterised with tincture of iodine or pure carbolic acid.

Fig. 14.13. Incision and curettage of chalazion from the conjunctival side.

Fig. 14.14. Hordrolum internum lower eyelid.

ANOMALIES IN THE POSITION OF

THE LASHES AND LID MARGIN

TRICHIASIS

It refers to inward misdirection of cilia (which rub against the eyeball) with normal position of the lid margin (Fig. 14.16A). The inward turning of lashes along with the lid margin (seen in entropion) is called pseudotrichiasis.

Etiology. Common causes of trichiasis are : cicatrising trachoma, ulcerative blepharitis, healed membranous conjunctivitis, hordeolum externum, mechanical injuries, burns, and operative scar on the lid margin.

Symptoms. These include foreign body sensation and photophobia. Patient may feel troublesome irritation, pain and lacrimation.

Signs. Examination reveals one or more misdirected cilia touching the cornea. Reflex blepharospasm and photophobia occur when cornea is abraded. Conjunctiva may be congested. Signs of causative disease viz. trachoma, blepharitis etc. may be present.

Complications. These include recurrent corneal abrasions, superficial corneal opacities, corneal vascularisation (Fig. 14.16B) and non-healing corneal ulcer.

Treatment. A few misdirected cilia may be treated by any of the following methods:

1.Epilation (mechanical removal with forceps): It is a temporary method, as recurrence occurs within 3-4 weeks.

B

Fig. 14.16. Trichiasis; A, Diagramatic depiction; B, Clinical photograph.

2.Electrolysis: It is a method of destroying the lash follicle by electric current. In this technique, infiltration anaesthesia is given to the lid and a current of 2 mA is passed for 10 seconds through a fine needle inserted into the lash root. The loosened cilia with destroyed follicles are then removed with epilation forceps.

3.Cryoepilation: It is also an effective method of treating trichiasis. After infiltration anaesthesia, the cryoprobe (–20 °C) is applied for 20-25 seconds to the external lid margin. Its main disadvantage is depigmentation of the skin.

4.Surgical correction: When many cilia are misdirected operative treatment similar to cicatricial entropion should be employed.

ENTROPION

It is inturning of the lid margin.

Types

1.Congenital entropion. It is a rare condition seen since birth. It may be associated with microphthalmos.

2.Cicatricial entropion (Fig. 14.17). It is a common variety usually involving the upper lid. It is caused by cicatricial contraction of the palpebral conjunctiva, with or without associated distortion of the tarsal plate.

Common causes are trachoma, membranous conjunctivitis, chemical burns, pemphigus and Stevens-Johnson syndrome.

3.Spastic entropion. It occurs due to spasm of the orbicularis muscle in patients with chronic irritative corneal conditions or after tight ocular bandaging. It commonly occurs in old people and usually involves the lower lid.

4.Senile (involutional) entropion. It is a common variety and only affects the lower lid in elderly people (Fig. 14.18). The etiological factors which contribute for its development are : (i) weakening or dehiscence of capsulopalpebral fascia (lower lid retractor); (ii) degeneration of palpebral connective tissue separating the orbicularis muscle fibres and thus allowing pre-septal fibres to override the pretarsal fibres; and (iii) horizontal laxity of the lid.

5.Mechanical entropion. It occurs due to lack of support provided by the globe to the lids. Therefore, it may occur in patients with phthisis bulbi, enophthalmos and after enucleation or evisceration operation.

Clinical picture

Symptoms occur due to rubbing of cilia against the cornea and conjunctiva and are thus similar to trichiasis. These include foreign body sensation, irritation, lacrimation and photophobia.

Signs. On examination, lid margin is found inturned. Depending upon the degree of inturning it can be divided into three grades. In grade I, only the posterior lid border is inrolled. Grade II entropion, includes inturning up to the inter-marginal strip while in grade III the whole lid margin including the anterior border is inturned.

Complications. These are similar to trichiasis.

Treatment

1. Congenital entropion requires plastic reconstruction of the lid crease.

Fig. 14.17. Cicatricial entropion.

Fig. 14.18. Senile entropion lower eyelid.

2. Spastic entropion. (i) Treat the cause of blepharospasm e.g. remove the bandage (if applied) or treat the associated condition of cornea. (ii) Adhesive plaster pull on the lower lid may help during acute spasm. (iii) Injection of botulinum toxins in the orbicularis muscle is advocated to relieve the spasm. (iv) Surgical treatment similar to involutional (senile) entropion may be undertaken if the spasm is not relieved by above methods.

3. Cicatricial entropion. It is treated by a plastic operation, which is based on any of the following basic principles : (i) Altering the direction of lashes, (ii) Transplanting the lashes, (iii) Straightening the distorted tarsus.

Surgical techniques employed for correcting cicatricial entropion are as follows:

i.Resection of skin and muscle. It is the simplest operation employed to correct mild degree of entropion. In this operation an elliptical strip of skin and orbicularis muscle is resected 3 mm away from the lid margin.