Diseases of the eye should not be considered in isolation from the rest of the body as the eye can be involved in a variety of systemic disorders. Ocular symptoms in children may often be the first clue to systemic disorder. Many neurological, developmental, metabolic, allergic, infective, collagen, vascular and deficiency disorders can be diagnosed with careful examination of eyes. Though the management of eye problems is the domain of the ophthalmologist, it is necessary for a pediatrician to conduct examination of the eye with a torch and an ophthalmoscope for proper diagnosis and management of the child as a whole.

The following account describes in brief the principles of ocular examination in a child. It is followed by description of those manifestations of the eye which are associations, reflections or extension of a systemic disease.

Disorders of Orbit

Look for abnormal protrusion of the eyeball (proptosis), retraction of the eye back into its orbit (enophthalmos), wide separation of the eyes (hypertelorism) and small palpebral fissures (microphthalmos). Palpate for any bony defects or swellings.

In a proptosed eye, a rim of sclera can be seen between lower limbus and lower eyelid and the amount of exposed sclera indicates the degree of proptosis.

Proptosis may occur due to diminished orbital volume as in craniostenosis or increase in the orbital tissue mass such as with malignant deposits, cavernous sinus thrombosis, orbital hemorrhage and cellulitis. Proptosis caused by thyrotoxicosis is multifactorial.

Enophthalmos occurs as a feature of Horner’s syndrome which is associated with ptosis, absent ciliospinal reflex, anhidrosis and miosis. It is caused by lesion of lower cervical and upper thoracic sympathetic nerve fibers, which supply the eyes.

Hypertelorism can be determined by calculating :

Inner-canthal distance

Canthal index =—————————-x 100

Outer canthal distance

which is normally 38 in males and 38.5 in females (SD ± 2.4). This index is increased in hypertelorism.

Microphthalmos and hypertelorism are frequently encountered in Down’s syndrome and intrauterine infections (CMV, rubella and toxoplasmosis).

Disorders of Eyelids

Keep one hand firmly on the forehead to prevent action of the frontalis muscle and ask the patient to lift the upper eyelid. Normally the upper eyelid should cover about 2 mm of cornea below the upper limbus. Drooping of upper eyelid below this level is known as ptosis. An upper lid that rests above the upper limbus is referred to as lid retraction. Inability to completely close the palpebral fissure (lagophthalmos) should also be looked for. Inspect for any lid inflammation (blepharitis), vascular anomalies (nevus or telangiectasias) and swelling of lid. Notice the placement of the palpebral fissure. It is oblique, short and wide with the highest point at the centre of the lid in Down’s syndrome (mongoloid slant). Also note any skinfolds above the inner canthus (epicanthic folds) which are characteristic of many chromosomal disorders.

Ptosis may be congenital or acquired due to hemangioma (Sturge-Weber syndrome), plexiform neuroma (neurofibromatosis), myasthenia gravis, Horner’s syndrome, lesions affecting the third nerve, lid tumors and following drugs such as vincristine.

Lagophthalmos and Lid retraction may occur as part of thyrotoxicosis.

Disorders of Lacrimal System

Conjunctival irritation of one eye only or watering are clues to lacrimal involvement. Look for any signs of inflammation and production of tears. The lacrimal gland is undeveloped at birth and tears are produced only after first month of life. Non canalization of lacrimal passages lead to apparent increase in tears (epiphora).

Acute and bilateral inflammation of lacrimal gland (dacryoadenitis) occurs with influenza, mumps and infectious mononucleosis. Chronic dacryoadenitis is associated with syphilis, tuberculosis and sarcoidosis.

Alacrima (Dry eye) occurs in Riley-Day syndrome and ectodermal dysplasia. Deficiency of conjunctival mucus following Steven-Johnson syndrome is another cause of alacrima. Formation of tears is reduced in dehydration.