Ординатура / Офтальмология / Английские материалы / Pediatric Opthalmology_Mukherjee_2005

are very close to the eyeball at birth. The size of eyeball in children is an important factor in growth of the orbit. Smaller or absent eyeball retard the growth of orbit in children giving asymmetrical orbit. Bilateral microphthalmia or anophthalmos result in smaller orbit on both sides. Large eyeball i.e. congenital myopia, buphthalmos, retinoblastoma cause enlargement of the orbit. So do other intra orbital growths in children.

Congenital anomalies of orbit5

The common congenital anomalies are :

1.Hypertelorism

2.Hypotelorism

3.Shallow orbit

4.Orbital meningocele

5.Orbital encephalocele

6.Orbital and periorbital dermoids

7.Plexiform neurofibroma

8.Sturge Weber syndrome

9.Orbital teratoma

10.Cranio facial dysostosis.

Hypertelorism6,7,8

Hypertelorism is a condition where the intra orbital distance is more than 33 mm in adult and correspondingly less in children. It may be isolated defect but generally associated with other deformities of face and skull. It is inherited as autosomal recessive or dominant trait, sporadic cases are also known, there may be family history. The clinical features are broadening of nose bridge, depressed nose bridge, prominent forehead, exotropia, optic atrophy, astigmatism, displacement of lacrimal puncta laterally, ptosis, inverse epicanthus.

Hypertelorism is common in Crouzon’s and Apert’s syndrome. Generally the condition is bilaterally symmetrical, however it may be asymmetrical and does not require treatment.

Hypotelorism

This is a very rare condition where intra orbital distance is reduced. The eyes are set nearer as in Hallermann-Streiff syndrome. No treatment is required.

Shallow orbits - Shallow orbits are very common in craniofacial dysostosis resulting into proptosis.

Meningo encephalocele orbit8,9

During the development of the skull and orbit, the covering of the brain/ brain substance with its covering may herniate through a bony defect in the orbit. The common sites for such herniation are root of the nose and superio nasal angle of the orbit. When only the meninges herniate, this is called meningocele. This is rarer than encephalocele. The meningocele presents as round, soft, pulsatile growth that may have cough impulses. It is generally noticed at birth or soon after. The encephalocele commonly develop at root of the nose, may remain localised

or spread to the orbit. Ocular involvements depend on position and size of the encephalocele. It can cause lateral displacement of the globe, proptosis. Squint, may be associated with microphtlamia. The systemic findings include mental deficiency, hydrocephaly, spina bifida, harelip and cleft palate. Treatment is surgical removal of the growth and repair of the defect in the orbital bone.

A small meningocele or encephalocele near the medial canthus may be confused as congenital mucocele in infant and encysted mucocele in adult. The difference in two conditions is settled on CT and MRI.

Orbital and periorbital dermoids

Dermoids are choriostomas, which means that they are benign growths, which arise from tissues that are not normally found in the site of the origin of the growth i.e. skin and sebaceous glands in case of orbital dermoids, epidermoids and teratomas. These growths are due to sequestration of primitive ectoderm in case of epidermoid and dermoid while teratomas contain more than one germinal layer5, i.e. cartilage, bone, teeth etc. Dermoids result when deeper layer of skin containing sweat glands and sebaceous glands, hair follicles are incarcerated. Epidermoids contain only superficial layers of skin. It is not always possible to differentiate between the dermoid and epidermoid. The choriostomas generally arise at the suture lines of the orbit. Commonest site being superio temporal followed by superio medial in front of the orbitalseptum, sometimes they may arise from greater wing of sphenoid and cause proptosis. The dermoids arising on the globe are called limbal dermoids. Twenty five percent of dermoid anterior to the orbital septum are noticed at birth or soon after as palpable, non-tender, well circumscribed growth with rubbery consistency. They may be movable or immobile, generally cystic. On rupture they produce pultaceous material. The deeper dermoids are discovered in the first two decades, they may not produce proptosis and are palpable only if placed anteriorly. Posteriorly placed dermoids are seen in third decade and cause proptosis. The epidermoids are solid growths in contrast to dermoids that are cystic. Both produce sharply demarcated bone defect with well defined margin and sometime sclerotic bone changes. Occasionally the dermoid can be dumb-bell shaped. The radiology of deep orbital dermoids have classical cystic appearance with well defined wall. CT and MRI give better results. Treatment consist of surgical removal. Anteriorly placed cysts present no problem in removal. However, they should be differentiated from meningo encephalocele prior to surgery. The posterior orbital dermoids are best removed by lateral orbitotomy or craniotomy.

Orbital teratomas5

Orbital teratomas are uncommon, they may contain all the three germinal layers. Occasionally a miniature second foetus may be present in the orbit. Generally these are small at birth but grow fast enough to produce severe proptosis and exposure, with loss of vision. Treatment consists of complete surgical removal.

Cranio synostosis (Craniostenosis, craniofacial dysostosis) oxycephaly (Tower skull)

Oxycephaly is a common form of craniostenosis with ocular involvement. In this case there is premature closure of coronary and lambdoid sutures that results in growth of the skull vertically and arrested growth in anterio posterior and lateral planes before the brain growth is complete.1,2,8

Growth of brain is an essential factor in growth of skull like growth of eyeball influences growth of orbit, if the brain stops growing the skull remains small even with normal sutures resulting in microcephaly. The frontal and perital bones grow steeply and vertically. It is more common in boys. It is generally present at birth or noticed soon after birth. Orbital involvement is roughly symmetrical. Due to premature closure of the sutures, the orbit fails to develop in all directions, resulting in shallow orbit that is too small to house growing globe. The globe is generally normal, the effect on the globe is secondary to shallow orbit. The shallowness of the orbit is caused by medial and forward rotation of greater wing of sphenoid. The pituitary fossa is also small. 5

Most striking ocular feature is gradually increasing bilateral proptosis. In advanced degree of proptosis, the lids fail to cover the cornea and cause exposure keratitis leading to ulceration and perforation. In extreme proptosis, the globe may subluxate. The first dislocation is very frightening to the child and the parents who learn to reposit the globe themselves later. Proptosis is very often associated with divergent squint, nystagmus and other motility disorders. There may be associated developmental cataract.

Commonest symptom next to cosmetic blemish is diminished vision that is brought about by corneal changes, change in optic nerve. Optic nerve changes are caused by narrowness of optic canal leading to primary optic atrophy or post papilledematous atrophy due to raised intra cranial tension. Raised intra cranial tension leads to separation of non-fused sutures, thinning of the cranial bones and digital impression on the cranium. The vertical growth of the skull stops with completion of brain growth round about seven to eight years of age. There is no known treatment except craniotomy under six months of age. The exposed cornea should be kept moist by lubricants and antibiotic ointment. Tarsorrhaphy may be required in moderate cases and cases of frequent subluxation of globe. The tarsorrhaphy usually is ineffective in severe cases.

Other forms of congenital deformities of skull are5

1.Scaphocephaly (Scaphoid head)—Long narrow head due to premature union of sagital sutures.

2.Brachycephaly—The skull is short and broad due to fusion of coronal suture, may be considered as variation of oxycephaly.

3.Dolichocephaly—A prominent frontal region.

4.Trigonocephaly (Triangular head)—There is under development of frontal region of skull with over development of posterior part of the head. This results in close set orbits and optic atrophy.

5.Microcephaly (Microencephaly)—Overall dimension of the skull is smaller than normal, the primary fault lies in the smallness of the brain. There is premature fusion of all the sutures and closure of the fontanelle, neurological defects which include mental retardation, idiocy, paraplegia, diplegia. Epilepsy is common. The condition may be noticed at birth or soon after. The orbits are deformed. The child may not only be blind but deaf and dumb. Multiple ocular defects are met with.

6.Hydrocephalus - In this condition there is normal production of CSF with obstruction in its flow. There are three possible sites where the obstruction may develop.

(i) Sylvius aqueduct

(ii) Foramen of Magendie

(iii) Foramen magnum.

Obstructed CSF circulation results in accumulation of CSF in ventricles, which get dilated, pressing the overlying brain, and thinning of the skull resulting into enlargement of the head in all direction with normal face. The sutures are wide open. The face looks triangular in relation to monstrous head, which the child may not be able to hold. The skin over the forehead is stretched, dragging the upper lid leading to lagophthalmos and lid retraction. The lower lid is similarly pulled up and covers the lower part of the cornea compensating the up drawn upper lid. The eyes are pushed down, giving a setting sun appearance.

There may be associated proptosis, paralytic squint. In spite of accumulation of CSF, papilledema is rare and primary optic atrophy is more common. The condition may be noticed on ultrasonography before birth, may cause obstructed labour or may be noticed soon after the birth. Some of the predisposing factors are high maternal age, Rh incompatibility, maternal rubella and hydramnios.

Crouzon’s Syndrome5,6,13

This craniofacial dysostosis has important ocular manifestation. This is an autosomal dominant trait seen more commonly in boys. It is a bilateral condition that may be suspected at birth or within few months. The child has dolicocephaly and frog like face. Bilateral exophthalmos is commonest feature caused by shallow orbit with normal sized eyeball. There is downward slant of outer canthus. Other findings are exotropia with tendency towards V pattern. Paralysis of extra ocular muscles, nystagmus, under developed maxilla resulting small upper jaw and large lower jaw, hypertelorism and optic atrophy without papilledema. X-ray shows sutural closure with increased digital marking. There may be hearing loss and various degrees of mental retardation.

Management consist of protection of cornea from exposure keratitis that may end up in perforation. Early craniotomy have been advocated to arrest the progress of disorder.

Apert’s syndrome (Acrocephalo syndactylia)

This is a combination of oxycephaly with fusion of fingers of both extremities of variable nature. It may run in families in various combinations and inheritance is autosomal dominant however sporadic cases are frequent. Increased maternal age is a contributing factor like in Crouzon’s disease, the orbits are widely separated and shallow resulting in to hypertelorism, proptosis and anti mongoloid slant of palpebral fissure. The forehead is prominent, maxilla is hypoplastic with high arched palate. The ears are low set. The middle third of the face is more involved than the lower two third, causing crowding of the teeth, parrot shaped nose. Oculo motor disorders are more common, commonest being exotropia with V pattern followed by vertical squint that is brought about by displacement of trochlea at the superior orbital margin. There may be over action of inferior oblique. Due to pushing forward of the globe, there is stretching of extra ocular muscles, resulting in various degree of external ophthalmoplegia.

Diminished vision is brought about by corneal changes, astigmatism, amblyopia and optic atrophy. Generally intra cranial tension is normal. Occasionally papilledema has been reported. Mental retardation is common so are cardiac and visceral malformation.

Management consists of protection of cornea by lubricant, antibiotic. Tarsorrhaphy may give temporary respite, early craniotomy may arrest the progress of the disease.

First and second branchial arch syndromes5,6,8,14

Abnormal development of first and second branchial arches lead to a group of congenital disorders of face and eye, that are called mandibulo facial dysostosis without proptosis. Common syndromes are -

1.Franceschettis syndrome

2.Pierre Robin syndrome

3.Goldenhar’s syndrome

4.Hallermann Streiff syndrome

5.Waarden burg syndrome

Franceschettis

Franceschettis syndrome (also known as Treacher Collins syndrome when the ears are not deformed)—The syndrome is bilateral, symmetrical. There is no gender predilection. No race is immune. It has autosomal dominant inheritance. Sporadic cases are not uncommon. Severity increases with successive generations. Claims of unilateral cases are doubted. Increased parental age increases chances of the syndrome. Both upper and lower facial bones are involved, resulting in to hypoplasia of maxilla and mandible. The general features are striking with macrostomia, micrognathia, abnormal hair line, deformity of external and middle ear, hearing loss, sinus between the ear and angle of mouth, coloboma of the lip, high arched palate and abnormality of dentition has been seen.

The ocular manifestation consists of normal globe with fairly good vision. The orbit is egg shaped, most of the anomalies are located in the lower lid with changes in the lateral canthal ligament and lower lid margin. The change in lower lid contains various types of colobomas of different length and depth. The minimal change is a S-shaped curve in the outer third of a lower lid. There may be a full thickness defect with loss of lashes and tarsus. Sometimes a large coloboma may cause deficiency of outer third. There may be trichiasis, distichiasis. The orbicularis is also under developed. All these lead to abnormal tear film, corneal irritation and corneal exposure. Various types of strabismus are possible. There is always some degree of astigmatism. Squint, astigmatism and corneal opacity lead to amblyopia, which is the main cause of defective vision. Optic nerve does not show any atrophy or papilledema. Intelligence and growth of the child is good. The condition can be noticed at birth if looked-for carefully, especially if there is a positive family history or it becomes evident by first year. Presence of syndrome can be seen on intra uterine ultrasonography.

The ocular changes do not require any treatment except correction of error of refraction, management of amblyopia and protection of cornea. Facial deformities are managed by plastic surgeons. The children are prone to repeated respiratory problems due to narrow upper respiratory passage, which may cause difficulty in anaesthesia.

Pierre Robin syndrome8,15

This syndrome has fewer ocular features. Main features are micrognathia. U Shaped cleft palate without cleft lip, glossoptosis, bird like face, dysphasia, difficulty in feeding lead-

ing to failure of development. Ocular findings are microphthalmia, high myopia, glaucoma, and retinal degeneration.

Goldenhar’s syndrome (Oculo auriculo vertibral syndrome)5,16

This syndrome is sporadic, slightly more in boys. Right side is more commonly involved than the left. The triad consists of ocular changes, changes in external ear and changes in cervical vertebra. Heart and central nervous system may also be effected. There is hypoplasia of temporo mandibular and pterygo mandibular complex16A.

1.The ocular components are—coloboma of upper lid, dermoid or dermolipoma, nasolacrimal duct obstruction, reduced corneal sensation, squint, microphthalmia, persistent pupillary membrane.

2.The auricular components consists of—Pre auricular appendages, distorted pinna, absent auditory meatus.

3.Vertebral changes are—Fusion of cervical vertebra, hemivertebrae, occipitalisation of atlas.

The condition can be diagnosed by ante natal ultrasonography. Post natal—it can be diagnosed at birth due to limbal dermoid, coloboma of lid and auricular appendages. The limbal dermoids are met within three fourth of cases, out of which about 25% are bilateral. The dermoids are uniformly situated at lower temporal area.

Management of the cases is multidisciplinary. Ocular treatment consists of repair of upper lid coloboma and removal of limbal dermoid. The coloboma and dermoid can cause permanent corneal scarring and astigmatism.

Hallerman Streiff syndrome

This relatively rare syndrome, which is sporadic, consists of a parrot beak nose, loss of eyebrow and lashes, microphthalmia, congenital cataract, micrognathia, short stature. There is an antimongoloid slant of the inter palpebral fissure. Hypotelorism, nystagmus and squint are some of the other ocular features. Vision is generally poor and does not improve with glasses, may be due to corneal or lenticular changes, cataract is generally bilateral and may become mature and soft, predisposing lens induced uveitis and glaucoma. Systemic conditions are infection of respiratory system, difficulty in breathing.

Management consists of lensectomy either with posterior chamber implant, failing which aphakia is corrected by contact lens or spectacle.

Waardenberg syndrome (White forelock syndrome)32

The syndrome is autosomal dominant32A in nature. There is a defect in melanocyte, which runs in the families. The syndrome consists of band of grey forelock, fusion of prominent eyebrows, broad nose bridge, displacement of medial canthus along with lacrimal puncta. The puncta may be shifted as much as the lower part of cornea, there is heterochromia of the iris, albinism and unilateral deafness. The condition is compatible with normal life except occasional aganglionic megalocon. Visual loss is minimal. Ocular conditions do not require much attention. However deafness requires early management.

Symptomatology of orbital disorders

The orbits are surrounded by paraorbital air sinuses from all sides except anteriorly and laterally, the brain with its coverings lies above the roof of the orbit, the optic foramen, and superior orbital fissure communicate with the brain, the ophthalmic veins, the vena verticosae open in the cavernous sinus. The orbit besides the globe, contains muscles, vessels, nerves, fascia, meninges and fat. Hence the orbits are seats of many diverse disorders that spread between intra uterine life to ripe old age.

The symptoms of orbital disorder can be broadly divided into two groups :

1.Forward propulsion of the globe—the proptosis/exophthalmos

2.Retraction of globe—Enophthalmos

All other symptoms are sequelae or complications of these two symptoms. Incidentally proptosis (exophthalmos) and enophthalmos themselves are signs of other clinical importance as well.

Signs and symptoms of proptosis are :

1.Pain

2.Conjunctival congestion and chemosis

3.Diminished vision

4.Ptosis

5.Lagophthalmos

6.Squint

7.Diplopia

8.Exposure keratitis

9.Loss of corneal sensation

10.Rise of intraocular tension

11.Rise of intra orbital tension

12.Marcus Gunn pupil

13.papilledema

14.Optic atrophy

15.Central vein stasis

16.Central retinal artery occlusion

17.Choroidal fold

18.Change in refraction

19.Pressure changes in the bones

20.Systemic involvement

All the signs and symptoms need not be present in all eyes at the same time. They may be present in various combinations. There is no fixed chronological order, some signs and symptoms may be of acute onset, others may be slow in progression.

1. Pain - Children have greater threshold of pain, a non-verbal child may cry in discomfort. Gradually progressing proptosis is generally devoid of pain. Some of the painful proptosis are :

—Accumulation of fluid under periorbita i.e. periorbital abscess or hematoma.

—Acute orbital cellulitis and abscess.

—Cavernous sinus thrombosis.

—Exposure of cornea is always associated with some degree of pain.

2.Conjunctival congestion and chemosis are very common when the child is unable to close the eye. Common causes of chemosis of conjunctiva are orbital cellulitis, panophthalmitis, almost all cases of proptosis have some degree of conjunctival congestion.

3.Diminished vision in proptosis can be due to following :

(i) Error of refraction

(ii) Corneal changes

(iii) Fundus changes

(iv) Squint

(v) Amblyopia

(i) Errors of refraction are brought about by compression of the globe at various sites. Pressure on the cornea by the lids produce astigmatism, pushing of the retina from behind resulting in to hypermetropia, distortion of the globe due to pressure from the orbital side produces irregular astigmatism.

(ii) Amblyopia is caused by :

(a) Over hanging lid over the cornea, corneal opacity cause deprivation amblyopia.

(b) Astigmatism—Common causes of astigmatism are—Capillary haemangioma, neuro fibromatosis, dermoids, epidermoids and dermolipoma.

(iii) Changes in cornea results from exposure keratitis due to lagophthalmos.

(iv) Fundus changes consist of optic nerve changes i.e. optic atrophy, venous congestion, rarely central retinal artery occlusion, retinal haemorrhages and fold in the choroid.

4. Ptosis is not a very consistent feature it can be :

(ii) Paralytic as part of - Paralysis of third nerve, isolated paralysis of third nerve is rare in proptosis. It may be an early manifestation of wide range of paralysis of other extra ocular muscle due to involvement of third, fourth and sixth nerve, may be associated with corneal hyposensation.

5.Lagophthalmos (Inability to close the eyes)—It can be mechanical due to extreme degree of proptosis which does not allow the two lids to meet or due to paralysis of orbicularis.

6.Squint - Ocular deviation can be brought about by paralysis of extra ocular muscles, mechanical restriction of extra ocular muscle movement. Concomitant squint is generally associated with errors of refraction, opacity in media and optic nerve changes.

7.Exposure keratitis—Exposure of the cornea is one of the most unpleasant complications that may lead to sloughing and perforation of cornea. It is caused due to inability to close the lids and diminished corneal sensation, any of these alone or in combination with infection cause corneal involvement. Post keratitis corneal opacity is a cause of persistent diminished vision.

8.Loss of corneal sensation is met in cavernous sinus thrombosis, superior orbital fissure syndrome and pseudo tumour of the orbit where fifth nerve is involved along with other cranial nerves.

9.Rise of intra ocular tension—Glaucoma in proptosis is mostly due to extra ocular causes i.e. increased episcleral pressure, pressure of the globe from outside and restrictive squint.

10.Rise of intra orbital pressure—There is no known method to measure intra orbital pressure but clinically this happens if there is an expanding orbital lesion with intact orbital septum.

11.Marcus Gunn pupil—Presence of Marcus Gunn pupillary reaction denotes involvement of optic nerve resulting in conduction defect in unilateral proptosis.

12.Papilledema—Swelling of optic disc denotes either raised intra cranial pressure, which is common in congenital anomalies of skull, extension of growth in to the cranial cavity or compression of central retinal vein.

13.Optic atrophy—Both primary as well as post papilledematous optic atrophy are possible. The first is seen in glioma of optic nerve while the second is noted as end result of papilledema.

14.Central vein stasis results in dilatation of retinal veins, brought about by many expanding lesions of the orbit. However full blown central vein thrombosis has not been observed.

15.Central retinal artery obstruction and optociliary shunts are rare phenomenon.

16.Change in refraction - Refractive errors are induced due to change in curvature of the cornea or due to pushing of posterior pole by a retrobulbar mass. Paralysis of third nerve leads to loss of accommodation.

17.Pressure changes in the orbital bones are evident on X-ray.

18.Some of the orbital disease may be associated with systemic disorders i.e. Storage disease, leukaemia, parasites, neuroblastoma, Ewing’s sarcoma, thyroid eye disease and secondaries.

Evaluation of a case of proptosis

Orbit is a Pandora’s box that contains so many tissues. Involvement by diverse etiology and presentation make it difficult to pinpoint the exact nature of the disorder. Hence proptosis requires meticulous evaluation under following heads.

1.History

2.Ocular examination

3.Systemic examination

4.Investigation

5.Therapeutic trial

History

Detailed history is one of the most important clinical methods in evaluation of proptosis. The child may be non-verbal, or may not co-operate. In such cases parents should be quizzed about the disorder, children have a tendency to hide history of trauma, they have greater threshold for pain. A child who has good sleep without analgesic and sedation most probably has mild or no pain.

History should comprise of :

1.Age of onset

2.Mode of onset

3.Duration

4.Recurrence

5.Trauma

6.Pain

7.Diminished vision

8.Diplopia

1.Age of onset. Proptosis can be present at birth and the causes are invariably congenital. They are craniostenosis, meningocele, meningoencephalocele, and microphthalmia with congenital cyst. In infancy above conditions continue to be the cause of proptosis and may cause progression of proptosis. To this list are added following benign growth in first decade.

Dermoid, epidermoid, haemangioma, neurofibroma. Lymphangiomas are generally seen after first decade. Average age for optic nerve glioma is seven years. Intra orbital meningiomas too manifest in early part of second decade. It must be kept in mind that all the above growths have congenital background.

The malignant growths that cause proptosis in infancy and childhood belong to two distinct groups i.e. primary malignant tumours and secondaries. Commonest primary malignant orbital tumour in childhood is rhabdomyosarcoma followed by Burkitts lymphoma,

Common secondaries are neuroblastoma, Ewing sarcoma, Wilm’s tumours leukaemias. Orbital retinoblastoma have a place of its own though orbital extension of retinoblastoma is a late feature that is preceded by latent stage and stage of secondary glaucoma. Sometimes there may be extension of retinoblastoma before stage of secondary glaucoma.

Less common causes of proptosis are orbital varix and fibrous dysplasia. Though the list of new growths is long and impressive, infections are the foremost cause of proptosis in children. They are—Orbital cellulitis, orbital abscess, cavernous sinus thrombosis, panophthalmitis, retained intra orbital foreign bodies.

Orbital pseudo tumours manifest in late childhood, occasionally retro bulbar haemorrhage or emphysema may result in proptosis in children mostly due to trauma.