DISORDERS OF EYELIDS

Ptosis, i.e. drooping of upper eyelids with narrowed palpebral fissure, may be congenital or acquired.

Normally, upper eyelid covers ~ 2 mm of cornea below the upper limbus.

Congenital ptosis is usually unilateral, due to dystro­phy of levator palpebrae superioris or rarely, third cranial nerve palsy.

Acquired ptosis may be bilateral in neuromuscular disorders, e.g. myasthenia gravis, muscular dystrophy, Horner syndrome (with miosis and anhidrosis), III nerve involvement in CNS disorders; or unilateral due to local pressure from a lid mass, e.g. lid hemangioma or plexiform neurofibromatosis. Marcus Gunn jaw-winking syndrome is a rare but interesting cause of ptosis, which presents with blinking movements during chewing or sucking due to abnormal synkinesis between 3^rd and 5^th cranial nerve.

Apart from a cosmetic deformity, long-standing ptosis in visually immature young children may lead to: (a) amblyopia due to partial obliteration of visual axis, (b) astigmatism due to distortion of eye globe by lid pressure, and (c) strabismus due to deprivation amblyopia. In severe cases, child tends to maintain a typical chin-up head posture to maintain binocular vision.

Lagophthalmos or lid retraction denotes difficulty or inability to close the lids completely over eye-globe, which may be: (a) physiological, e.g. during sleep, (b) structural, due to post-traumatic/inflammatory lid scarring or in collodion babies, (c) paralytic, e.g. facial palsy, (d) spastic,

e. g. thyrotoxicosis, or (e) secondary due to proptosis and buphthalmos. Prolonged lagophthalmos may lead to corneal xerosis, infection and ulceration, which may be prevented by use of artificial tear-drops or tarsorrhaphy in severe cases.

Ectropion, i.e. eversion of lid margin, is usually due to post-inflammatory scarring of lids, but may be congenital or associated with facial palsy, due to weight of flaccid lower eyelids.

Entropion, i.e. inversion of lid margin, is more troublesome defect, due to associated in turning of eyelashes (Trichiasis). It is almost always caused by post-inflammatory scarring of lids, e.g. in trachoma and ocular injuries.

Clinically, it presents with constant foreign body sensation due to in-turned eyelashes (Trichiasis), leading to frequent rubbing, recurrent ocular infections and corneal abrasions/ulcers; and hence to be treated surgically as early as possible. The term Epiblepharon denotes in-turned eyelashes without inversion of eyelids. Blepharitis, i.e. acute, chronic or recurrent inflammation of eyelids, presents with erythema and itching of eyelids, with ulceration/scaling in severe cases.

Acute blepharitis is usually a Staph. aureus or epidermidis infection, frequently progressing to cause hordeolum (Stye), conjunctivitis or keratitis. Treatment involves regular removal of crusts with hot-moist compresses and topical antibiotics with/without steroids.

ChronicIrecurrent blepharitis is usually seborrheic in origin, with greasy scales and scalp seborrhea. Regular lid cleaning as above, along with scalp care using selenium sulfide solution is necessary. Blepharitis due to lice infestation (Phthiriasis) may need mechanical removal of nits along with topical application of 20% fluorescein with/without systemic Ivermectin therapy in resistant cases.

Hordeolum internum or externum (Stye) are localized staphylococcal infections of Meibomian or Zeis glands respectively, which present as acute, tender and focal swelling over inner or outer margins of eyelids respectively. Stye tends to be more superficial and small. Treatment includes frequent warm compresses and topical antibiotics, with/without surgical drainage. Rare cases may progress to cause orbital cellulitis.

Chalazion is a non-tender, relatively chronic, nodular swelling of lid (d/d acute and tender hordeolum) due to granulomatous inflammation of Meibomian gland, which may subside spontaneously.

Congenital lid anomalies include:

Lid coloboma, i.e. cleft-like lid deformity of variable size is rare congenital abnormality, which may be isolated or associated with other facial malformations, e.g. Treacher Collins syndrome and Goldenhar syndrome.

Epicanthic folds, i.e. vertical or oblique folds of skin covering inner canthii are normal in some races and in newborns (disappear with age), but may also indicate chromosomal defects, e.g. Down syndrome.

Oblique or slanting palpebral fissure, i.e. Mongoloid slant (outer canthus at a higher level than inner canthus) or anti-mongoloid slant (inner canthus higher than outer canthus) may be normal, though more commonly seen in chromosomal disorders, e.g. Down syndrome.

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