DISORDERS OF LACRIMAL SYSTEM

Tears are regular formed in lacrimal and accessory lacrimal glands, located under upper lid at lateral canthus. After formation, these tears bathe the conjunctiva to prevent drying and drain via punctual openings at medial canthus to nasolacrimal duct (NLD) into the nose.

Tear-film is actually a three-layer structure with—(a) inner-most mucin layer from goblet cells of conjunctiva, which fixes the tear-film to conjunctiva/cornea, (b) middle aqueous layer of tears from lacrimal glands, and (c) outer lipid layer from meibomian gland, to retard evaporation of tears. Epiphora (tear-overflow) usually indicates lacrimal gland disorder, while Alacrima (dry eye) is usually due to disorders of other tear layers.

Congenital Dacryostenosis (NLD obstruction) is commonest congenital eye problem, present in ~5% newborns due to incomplete canalization of NLD as it enters the nose (valve of Hasner).

Clinically, it manifests soon after birth with persistent epiphora, mucoid discharge due to lacrimal sac reflux, secondary infection (dacryocystitis) and periocular maceration of skin.

Management of uncomplicated cases includes—(a) frequent massage over the side of nose to clear the duct,

(b) daily cleaning of eyelids with lukewarm water, and

(c) topical antibiotics if discharge is mucopurulent. Most cases (gt;95%) resolve spontaneously by 6-12 months of age. Some may require repeated punctal probing or, very rarely, dacryocystorhinostomy.

Lacrimal mucocele is a bluish subcutaneous mass just below the medial canthus due to NLD blockade at both, nasal and punctual end, which is managed on similar lines with massage and probing.

Dacryoadenitis, i.e. inflammation of lacrimal gland, is uncommon in children. Acute dacryoadenitis may occur in viral (mumps, influenza, infectious mononucleosis) or staphylococcal infections; while chronic dacryoadenitis is associated with syphilis, tuberculosis and sarcoidosis.

Mikulicz syndrome is a rare disorder, associated with simultaneous enlargement of lacrimal and salivary glands.

Dry-eye (Alacrima), i.e. absence or deficiency of tears, indicates congenital or acquired defect in any one or more of the three layers of tear film. Important causes of complete or partial dry eye are—(a) vitamin A deficiency,

(b) ocular injury in chronic infections, burns, irradiation,

(c) Stevens-Johnson syndrome, (d) familial dysautonomia (Riley-day syndrome), (e) Sjogren syndrome, and (f) anhidrotic ectodermal dysplasia. Apart from the correction of underlying problem, treatment includes frequent instillation of artificial teardrops, occlusion of lacrimal puncta or occasionally, tarsorrhaphy.

Crede's method, i.e. topical instillation of 1% silver nitrate at birth has virtually eliminated gonococcal conjunctivitis, though not practiced currently due to low incidence of disease and potential risk of chemical conjunctivitis.

Bacterial conjunctivitis in post-neonatal period is usually caused by S. aureus, non-typeable H. influenzae, and S. pneumoniae.

Unlike viral conjunctivitis, it is usually sporadic and typically purulent. Most cases are preceded by other ocular pathologies, e.g. trachoma, viral conjunctivitis, eye injuries, etc, with superadded bacterial infection. Staphylococcal conjunctivitis may also present as phlyctenular conjunctivitis, discussed later.

Post-neonatal bacterial conjunctivitis usually responds well to warm saline washes and topical antibiotics and systemic antibiotics are rarely required.

Viral conjunctivitis, is the commonest cause of con­junctivitis in children at present, typically presenting as localized seasonal outbreaks, specially in summer season.

Etiologically, most of these outbreaks are caused by changing strains of adenoviruses or enteroviruses.

Clinically, these cases present with watery discharge, marked hyperemia/chemosis and disproportionately less ocular discomfort. Adenoviral infections are frequently associated with follicles over palpebral conjunctiva, while enteroviral conjunctivitis is often hemorrhagic.

Diagnosis is largely clinical, based on epidemiological profile though conjunctival swabs may be collected in cases with suspicious superadded bacterial infection.

Management: While most cases recover spontaneously in 2-3 days, local pain and inflammation may be minimized with warm saline washes and topical steroids. Topical antibiotics are indicated only in cases with suspected bacterial superinfection.

Epidemic keratoconjunctivitis is an uncommon but special form of viral conjunctivitis due to adenovirus type 8, characterized by large oval follicles and/or pseudomembrane formation, along with acute pharyn­gitis and pre-auricular adenopathy.

Allergic conjunctivitis is characterized by typical seasonal pattern, similar family history, presence of eosinophils in discharge and excellent response to topical steroids. Presence of chemosis, i.e. severe swelling of conjunctiva without significant hyperaemia strongly indicates allergic angioneurotic edema.

Vernal conjunctivitis is a typical form of allergic conjunctivitis with cobble-stone papillary lesions over palpabral conjunctiva, more common in adolescents.

Phlyctenular keratoconjunctivitis is an interstitial conjunctivitis, considered as a delayed hypersensitivity response to endogenous antigens, e.g. tuberculosis, staphylococci and parasitic antigens.

Phlycten is a tiny pinkish-yellow nodule or bleb usually at the limbus, which may encroach over cornea and expand centrally. A small fascicular ulcer is often present over the head of advancing lesion. Most cases recover spontaneously in 5-7 days.

No specific treatment is required in asymptomatic cases, though topical steroids may be used to reduce inflammation, along with topical antibiotics (in sus­pected bacterial infection) or atropine drops (if cornea is involved). Anti-tubercular therapy is not indicated as a routine, but active tuberculosis should be excluded by chest skiagram and tuberculin test.

Chemical conjunctivitis may develop after exposure to topical drugs, e.g.

Red-eye is the commonest clinical presentation of many ocular infections, e.g.: (a) conjunctivitis, (b) keratitis, (c) iridocyclitis, (d) acute blepharitis or orbital cellulitis; and non-infective inflammations, e.g. (e) foreign body or other ocular trauma, and (f) eye-strain in severe refractive errors. Important differentiating features of three common ocular infections with red-eye are given in Table 26.4.

Trachoma is the one of the commonest cause of pre­ventable blindness in Indian children, caused by Chlamydia trachomatis. Infection is more prevalent in poor hygienic and overcrowded living conditions, acquired via hand-to-hand contact or flies.

Clinically, early acute stage presents in as follicular conjunctivitis, which gradually progresses into chronic ocular disease with persistent conjunctival follicles, cicatrisation, scarring and secondary deformities, e.g. entropion and corneal opacities.

Diagnosis is largely clinical, based on following WHO criteria: (a) lymphoid follicles on upper tarsal conjunctiva, (b) conjunctival scarring, (c) vascular pannus, and (d) limbal follicles. It may be confirmed in acute stage by direct staining and culture.

TABLE 26.4: D/D of Red-eye in children

Ab: Antibiotics; C: Cycloplegic agents, e.g.

Management involves eradication of infection by prolonged use of topical antibiotics (Tetracycline/ Erythromycin) with/without a short course of oral antibiotics (Azithromycin 3 days) and correction of secondary deformities.

Symblepharon is a cicatricial adhesion between palpebral conjunctiva and the eye-globe, following infection, injury, e.g. chemical burns/surgery, or other inflammatory disorders, e.g. Stevens-Johnson syndrome. It may cause diplopia by restricting ocular movements and adhesions need to be separated surgically, followed by mucosal graft, if necessary.

Subconjunctival hemorrhages may be spontaneous or secondary to trauma, infection, severe cough, (e.g. pertussis) or blood dyscrasia, e.g. thrombocytopenia. As the blood is usually reabsorbed spontaneously in 4-6 weeks, no intervention is required in most cases except exclusion of more severe ocular lesions and primary pathology.

Vitamin A deficiency is associated with various conjunctival lesions, e.g. Xerosis, i.e. dry, wrinkled, lusterless or muddy conjunctiva due to cornified epithelium, not limited to interpalpabral region (d/d exposure conjunctivitis/muddy sclera) and Bitot's spots, i.e. chalky-gray triangular plaques due to heaped-up dry epithelium, usually over temporal conjunctiva. These lesions persist for long time even after recovery from the deficiency state. Corneal and retinal involvement should be excluded in severe cases (Ch 6.2).

Pinguecula is an idiopathic, yellowish-white, focal degenerative lesion of bulbar conjunctiva, usually in interpalpebral region. These lesions are more common in Gaucher disease. No treatment is needed except excision, if cosmetically warranted.

Pterygium is an idiopathic degenerative lesion of conjunctiva, presenting as fleshy triangular lesion over nasal interpalpabral region, which may encroach upon cornea. It is sometimes considered as related to the exposure to ultraviolet light. No treatment is required except cosmetic excision. Recurrence is common.

26.2.5