Ординатура / Офтальмология / Английские материалы / Pediatric Opthalmology_Mukherjee_2005

The diagnosis is by exclusion supported by x-ray, CT, MRI, USG and fine needle biopsy.

Ophthalmoplegic migraine

It is a frequent but missed cause of headache in children. It could be the beginning of migraine in adulthood. Generally there is history of migraine in the family. A typical episode comprises of pain in or around the eye on one side. The eye is non congested, vision is unaffected. There is associated nausea or actual vomiting. There is diplopia due to involvement of extra ocular muscles. Commonest group of muscles to be involved are those supplied by the third nerve. Other muscles may also be involved, the pupillary changes are not constant. The headache generally subsides with onset of ophthalmoplegia. Ophthalmoplegia generally subsides and clears with in one month, may not leave any residual sign or the recovery may be partial. Recurrence is common. There are no other neurological signs. The optic nerve is normal. Exact cause of the condition is not known. Most widely put forward cause is dilated edematous internal carotid pressing the third nerve.

Cyclic oculomotor palsy26

This is an unilateral condition most probably of congenital origin, birth trauma may be a contributory factor. It may be noticed in early childhood.

There are two phases :

1.A paralytic phase consisting of partial third nerve palsy resulting in ptosis, mydriasis, diminished accommodation, the eye is generally abducted.

2.Spastic phase. This begins with lid twitching, elevation of the lid, miosis and spasm of accommodation and the eye may be adducted. The cycles last for less than a minute. Exact cause is not known.

Aberrant regeneration of third nerve27

The two cranial nerves that can develop aberrant degeneration (misdirection) are third and seventh nerve. (The seventh nerve aberrant regeneration results in crocodile tear and facial sweating on movement of the jaw.)

The oculomotor aberrant regeneration follows injury to the third nerve trauma, aneurysm or neoplasia. There is abnormal sprouting of axons from the affected nerve that are misdirected to areas for which they are not destined. It takes three to four months for aberrant regeneration to take place. It is generally unilateral resulting into paradoxic movements.

There are three possible variations of paradoxic movements :

1.Elevation of lid on attempted movement of inferior rectus and medial rectus (Pseudo Grafe’s sign).

2.Adduction or retraction of globe on attempted downwards or up gaze (Inverse Duane’s syndrome).

3.Light near dissociation on attempted convergence (Pseudo Argyll Robertson pupil).

There are two forms of aberrant regeneration of the third nerve :

1.Primary without previous history of acute oculomotor palsy. Third nerve weakness develops gradually along with aberrant regeneration.

2.Secondary. Always follows acute non ischeamic oculomotor palsy during recovery.

The exact cause is not known. No medical treatment is known to be effective. Surgical intervention should be attempted after minimum six months of onset of aberrant regeneration that comprises of correction of ptosis and multiple muscle surgeries.

Double elevator palsy28,29,30

This is a congenital anomaly of elevators of eye. It is a unilateral condition where elevation of the eye is subnormal in abduction or adduction. Most probable cause is hypoplasia of elevator nucleus. There is true or pseudo ptosis of affected eye. The eye is hypotropic in primary position. Bell’s phenomenon is present. Hypo deviation may be manifest or latent. Chin is elevated. Elevated chin with hypotropia means absence of amblyopia, which is otherwise common.

There are three possible types of double elevator palsy

1.Prominent inferior rectus and normal superior rectus saccade

2.Weakness of elevation negative forced duction test, diminished superior rectus saccade.

3.Combination of both

Differential diagnosis consist of

1.Brown’s syndrome

2.Congenital fibrosis of inferior rectus

3.General fibrosis syndrome

4.Blow out fracture

5.Dysthyroid oculopathy (not seen in children)

6.Anomalous superior and inferior rectus muscle insertion.

Management

Surgery is the only definitive treatment indicated in large vertical deviation or abnormal head posture. Surgery consists of recession of inferior rectus and transposition of lateral and medial recti to superior rectus.

Double depressor palsy

This is rarer than former. It is a congenital anomaly that has paralysis of inferior rectus and superior oblique in the same eye. In primary position the affected eye is hypertropic.

Complete third nerve palsy

The eye is abducted, slightly depressed and intorted. There is associated ptosis, there is mild proptosis. All the muscles supplied by this nerve show no movement or very little movement. The pupil is dilated not reacting to light and accommodation, the eye does not converge. Common causes of complete third nerve palsy in children are head injury, and raised intra cranial pressure.

Paralysis of individual muscles supplied by third nerve.

Superior rectus palsy

Superior rectus palsy is invariably associated with paralysis of levator palpebral superior. Isolated superior rectus palsy is very rare. Common cause is congenital either in the muscle

or in its nerve supply. In primary position the affected eye is hypotropic. The Bell’s phenomenon is absent. When the paretic eye fixes the sound eye becomes hypertropic due to over action of inferior oblique of the sound eye. The chin is elevated and head is tilted towards the sound side.

Medial rectus palsy

Isolated medial rectus palsy is very uncommon. The paretic eye is abducted due to unopposed action of lateral rectus on the same side. There is no change in position of chin or tilt of the head.

Inferior rectus palsy

Commonest cause of this rare palsy is congenital. Commonest acquired cause is fracture floor of the orbit. The depression of the involved eye is restricted along with the superior oblique of the contra lateral eye. The ipsilateral superior rectus is over active. The chin is depressed, the face is turned to the same side.

Inferior oblique palsy

The condition is rare. The affected eye is hypotropic in primary position. When fixation is shifted to sound eye, it becomes hypertropic. When the eyes are moved up and out, there is restriction of conjugate movement.

Characteristics of fourth nerve palsy

Fourth nerve under action is a common cause of vertical squint and compensatory head posture. It is however less common than third or sixth nerve palsy in children. In children two major causes of fourth nerve palsy are congenital anomaly and trauma. However infection, inflammation and neoplasm have their share towards fourth nerve palsy. Ischaemic lesion like diabetes, hypertension, arterio sclerosis which are major causes of trochlear nerve palsy in adults are not seen in children.

Congenital fourth nerve palsy

It may not be obvious unless it is severe, which presents as hypertropia in primary position. In moderate form the child may not complain of diplopia but may have compensatory head posture which gradually disappears when the palsy become concomitant, which is common. Hence old photographs may show abnormal head posture i.e. head tilted to the opposite shoulder. The anomaly may be seen in other members of the family. An old family photograph may show abnormal head posture in other members of the family as well. The child may read with one eye closed to avoid diplopia. Facial asymmetry is common, the antagonist may show contracture, difference between primary and secondary deviation is absent due to spread of comitance. There may be suppression in the affected eye that nullifies diplopia. Other neurological defects are generally not seen.

Effect of congenital palsy :

1.The palsy may be constant at birth and remain so.

2.The squint is small and the child may control it without compensatory head posture.

3.The squint manifests in particular gaze with binocular vision.

4.It may develop latent squint.

5.It may develop intermittent squint.

6.Intermittent squint becomes constant

Unilateral fourth nerve palsy

This is more common than bilateral. It can be congenital or acquired. It presents as ipsilateral hypertropia in primary position that increases when the eye is moved medially and increases more when the head is tilted on the same side (Park-Bielschowsky’s test). The above features are true for recent fourth nerve palsy where the child may complain of vertical diplopia and parent notice abnormal head posture. With passage of time there is spread of comitance and diplopia is minimised or abolished due to suppression. Associated exotropia is best measured by double Maddox rod test or Bagolinies striated glass32. It can be demonstrated on synoptophore with torsion slides. Exccyclotropia due to uniocular superior oblique palsy is about 7°.

The child may tolerate up to 4° of excyclotropia. Occasionally the contra lateral eye may show hypotropia when the child fixes with the paralysed eye.

Acquired superior oblique palsy should be differentiated from congenital palsy because an acquired palsy may be associated with other neurological findings. Second important point to remember is that the superior oblique may be absent in congenital palsy, which becomes obvious only during surgery.

Bilateral fourth nerve palsy

Recent unilateral superior oblique palsy is less difficult to diagnose than bilateral palsy. Trauma is a major cause of bilateral palsy than congenital anomaly which is otherwise an equally important cause of bilateral superior oblique palsy. Asymmetry in signs is common in bilateral palsy. In symmetrical bilateral case, there is either no vertical deviation or very little vertical deviation in primary position.

The child may be orthophoric or show mild exo or eso deviation. The esotropic eye generally shows V pattern. There is left hypertropia on right gaze and right hypertropia on left gaze.

Excyclotropia may be as much as 25°-30°. It increases in down gaze. Diplopia is present in all position of gaze except up gaze. Bielschowsky head tilt test is positive on both sides.

Occasionally the cases may present as unilateral palsy, may develop highly asymmetric palsy in the other eye.

Both the contra lateral synergists i.e. both inferior recti show over action. Asymmetric palsy develops ocular torticolis more often than symmetric palsy.

Neurological characteristics of fourth nerve palsy

Traditionally all cranial nerve palsies have been put into nuclear, fascicular, basilar, cavernous and orbital types except the fourth nerve because

1.The fourth nerve nucleus and its fascicles are so close to each other making it impossible to differentiate between nuclear and fascicular vision.

2.There are no structure in the viscinity that may cause other neurological signs as seen with third and sixth nerve.

3.Only structure that passes through the mid brain adjacent to fourth nerve fascicles is ocular sympathetic. The lesions are best put as nuclear-fascicular lesion.34

Nuclear-fascicular lesion produce contra lateral superior oblique palsy, may be associated with contra lateral Horner’s syndrome. A lesion in the anterior medullary velum will involve both the fourth nerves causing bilateral superior oblique palsy. In children commonest cause of which is head injury.

The basilar part of the fourth nerve winds round the brain stem and passes between the posterior cerebral and superior cerebellar arteries lateral to the third nerve and then passes forward to enter the cavernous sinus. At this location it gets involved in head injury. The nerve is pressed against the tentorium and damaged causing palsy of superior oblique on the same side without any other localising sign.

Cavernous sinus lesion

The fourth nerve is generally involved along with third and sixth nerve in various combinations along with fifth and oculo sympathetic in the cavernous sinus.

Orbital lesions—Orbital lesions can be of two types :

1.Involving the nerve along with third and sixth nerve.

2.Injury to the muscle itself, or trochlea of the muscle. Such injuries involves the orbital rim in the superio medial aspect.

Causes of fourth nerve palsy in children

In adults the cause of fourth nerve palsy are mostly vascular. They produce ischaemia, bleeding or compression by aneurysm. Other cause is neoplasm. In contrast to this, the causes in children are rarely vascular. They are mostly congenital, traumatic, infective. In one third cases no cause can be found out.

Other causes of vertical squint

Vertical squints are less common than horizontal squint. Small degree vertical squint may be missed due to development of compensatory head posture. However in later life there may be decompensation and the squint may manifest with diplopia and obvious deviation.

There are some conditions that may look vertical deviation when actual deviation is absent. The binocular vision is intact. These are called pseudo vertical squints.

The causes of pseudo vertical squints are :

1.Asymmetry of orbit.

2.Cranio facial dysostosis

3.Orbital growth pushing the globe vertically.

5.Ectopic macula

6.Vertical angle kappa.

The true vertical squint can be latent or manifest. It can be concomitant or paralytic. In paralytic vertical squint, spread of comitance is common.

Causes of non comitant vertical squint

These are due to involvement of cyclovertical muscles. Involvement of muscle may be restricted to one muscle in one eye, to involvement of multiple muscles in both eyes in various combinations. The non concomitant vertical squint can be neurological or restrictive. The neurological causes may be :

•Supra nuclear

•Nuclear

•Infra nuclear

The supra nuclear lesions are :

■Vertical gaze palsy

■Skew deviation

■Double elevator palsy

■Parinaud’s syndrome

The nuclear and infra-nuclear lesion have been discussed in lesions of third, fourth and sixth nerve.

The other lesions are :

■Dissociated vertical deviation

■Brown syndrome

■Inferior oblique over action

■Superior oblique over action

■Inferior rectus muscle paresis

■Superior oblique myokymia

The restrictive causes of vertical squint are :

1.Fracture floor of the orbit.

2.Myasthenia gravis

3.Dysthyroid ophthalmopathy

4.General fibrosis syndrome

5.Progressive external ophthalmoplegia

Vertical gaze palsy35

The vertical gaze movements are under bilateral cerebral and brain stem centres.

Transient tonic vertical deviation downwards is seen in neonates which does not indicate any neurological defect and does not require investigation. Another vertical gaze palsy seen in children is setting sun sign in infantile hydrocephalus. This is associated with retraction of the lid. The condition is serious but reversible and is treated by ventricular decompression by standard neurosurgical procedure.

The condition consists of inability to move the eye vertically up or down. There are three types of vertical gaze palsies :

1.The most common, inability in up gaze

2.Difficulty in both up and down gaze

3.Least common difficulty in down gaze.

The condition may be associated with light near dissociation, rigid pupil correctopia, dyscoria, spasm of accommodation, lid retraction or ptosis, convergence palsy, vertical nystagmus.

Common causes of vertical gaze palsy in children are : Stenosis of aqueduct, hydrocephalus. Tumors of the third ventricle, mid brain and pineal body.35

Skew deviation36,37

In this supra nuclear defect, there is divergence of the eyes in vertical plane which is large. It may vary in different position of gaze. The deviation is more in uniocular lesion. There is no restriction on forced duction test. No single muscle could be pin pointed as cause of skew deviation on Park Bielschowsky three step procedure. The condition may be associated with inter nuclear ophthalmoplegia. Commonest cause is a posterior fossa lesion that is confirmed by CT and MRI. Other causes are vestibular or cerebellar. It may develop in congenital esotropia for which no cause is detectable. The pathology is generally ipsilateral to the involved eye.

Parinaud’s syndrome

This is an acquired lesion. It is bilateral, there is paresis of up gaze. In an attempt to look up, the eyes converge. The pupils are semi dilated, there is light near dissociation. There may be lid retraction on down gaze. This is seen more commonly in children with setting sun sign of hydrocephalus. Other common cause is tumor of pineal body.

Dissociated vertical deviation (DVD)42

Dissociated vertical deviation is a neuro-muscular anomaly of obscure nature. It is known by many other names also. Common among them are : dissociated hyper deviation, alternate sursum-duction, alternate hyper phoria.38

As the last term indicates, it is basically a latent squint that manifests under cover, however, in some instances when the child is tired or day dreaming, one of the eyes may deviate upwards.

It is a binocular disorder with variable asymmetry in two eyes. The difference may be so much that one eye seems to divert all the time and the other looks normal.

It can be an isolated feature without any squint. It’s association with strabismus is more frequent than without. When it presents as manifest deviation, it can be intermittent or constant. It can be seen with any types of squint but commonest squint associated with dissociated vertical deviation is infantile esotropia. It is more common with non accommodative esotropia. It is rare if squint is acquired after eighteen months39. In case of infantile squint, it takes about two years for DVD to set in. It is seen in about 40-50% of cases of infantile esotropia. Another group of children who develop DVD are those who have undergone successful surgical correction for infantile esotropia. In such cases the anomaly develops two years following initial surgery. It is better if the parents are informed about its’ possibility at the time of first surgery.

The other common features are :

1.Development of manifest nystagmus that may become latent.

2.It is possible to have binocular single vision with DVD.

3.Extorsion of the deviated eye.

4.The eye intorts as the child looks down.

5.Cover test. The eye under cover deviates slowly up. The drift is more on prolonged cover. It is more for distant than near. Once the cover is removed, the eye gradually comes down and may over shoot the normal position and become hypotropic.

6.Measurement of deviation is made by using base down prism in front of the deviating eye. The occluder is shifted to the other eye, which starts deviating and base down prism is added to measure the deviation.

7.The Bielschowsky phenomenon.

Besides DVD, the other condition where an eye deviates upwards under cover is alternation hyper phoria. The two conditions are differentiated by positive Bielschowsky phenomenon or Dark wedge test.

Any of the eyes is occuluded by a translucent occluder (Spielmann occluder) through which the movement of the eye can be seen behind the occluder. The other eye fixes a spot light at distance. A Sbiza bar is placed before the fixing eye and density of the filter is gradually increased. The eye under Spielmann occluder is noticed to drift down and pass below the mid line if DVD is present. Now the filter density is gradually reduced and the eye under cover is seen to elevate once again. This phenomenon is absent in alternating hypertropia.

Sbiza bar (Bagolini filter). This instrument consist of a series of red filters of the density (photo metric neutral density filter). The end has lightest red colour, the other end has darkest colour. The instrument is generally used to measure depth of suppression in amblyopia for which the test is done at one third of a meter in contrast to Bielschiwsky phenomenon where the test is done at six metres. The bar is placed before the fixing eye in increasing density until diplopia develops. The strength of the density gives the depth of suppression40,41.

8.DVD may be associated with A and V pattern.

9.There may be associated oblique muscle over action.

Differential diagnosis consists of all conditions that cause upward shift of eye in primary position. They are :

1.Alternate hyper phoria

2.Inferior oblique over action

3.Superior oblique over action

4.Inferior rectus palsy

5.Skew deviation

Treatment

Treatment is correction of error of refraction and amblyopia when present. Surgery is indicated if vertical deviation occurs spontaneously so frequently that it causes cosmetic blemish. The alternatives available are :

I.Weakening of superior rectus

1.Recession of superior rectus 7-8 mm

2.Retro equatorial myopexy (Faden operation). II. Strengthening of inferior rectus (resection).

III.Total anterio positioning of inferior oblique.

Inferior oblique over action

Inferior oblique over action is common in infantile esotropia where it develops between one to six years of age. However it may develop in exotropia less commonly. Generally there is no hypertropia in primary gaze.

Hyper deviation is best seen in adduction. Secondary hypertropia is seen in under action of antagonist superior oblique. There may be pseudo paresis of contra lateral superior rectus. Associated V phenomenon is common. Latent nystagmus is frequent. Negative Bielschowsky phenomenon differentiates it from DVD. Cause may be mechanical or innervational.

Treatment consists of weakening of inferior oblique either by recession or myectomy.

Superior oblique over action

Superior oblique over action can be primary or secondary. It can be unilateral or bilateral. In bilateral cases it can be asymmetric enough to seem to be unilateral. All bilateral cases are primary. In unilateral cases, a vertical deviation is common in primary position. The side of over action causes hypotropia. It may be associated with A pattern. In case of bilateral over action of superior oblique bilateral, weakening of SO is indicated.

Inferior rectus muscles palsy

Palsy of inferior rectus is rare. It can be congenital due to mal-development of the muscle or its faulty insertion. Trauma is more common. Commonest type of injury is fracture floor of the orbit with or without entrapment of the muscle. The muscle may be injured at the time of original injury or may be accidentally injured during repair of fracture floor of the orbit. If the muscle is not entrapped, the eye become hypertropic in primary position. In entrapment of the muscle the eyeball may fail to elevate and hypotropia results. It is commonly associated with reduced down and out movement due to inter action of contra lateral superior oblique. The compensatory head posture comprises of face turned towards the paretic side, chin depressed and head tilted on the same side.

Treatment consists of strengthening the muscle by resection of involved muscle and recession of ipsilateral superior rectus.

Brown syndrome (superior oblique sheath syndrome) :

Brown syndrome is one of the common conditions of abnormal head posture in children. It is mostly congenital but can be acquired, it may be intermittent or constant. It is bilateral in 10% of cases. Congenital Brown syndrome may spontaneously resolve over years. Post inflammatory Brown’s syndrome also resolve with treatment.

Probable congenital causes of Brown syndrome are :

1.Short anterior sheath of superior oblique.

2.Inelastic superior oblique tendon

3.Defective innervation of both the obliques.

4.Thickened muscle not moving freely over the trochlea.

5.Anomalous insertion of superior oblique.

The acquired causes are

1. Trauma. Trauma, accidental or surgical is the commonest acquired cause of Brown syndrome. The traumas that result in the syndrome are - direct trauma to the trochlea either blunt or penetration. There may be post traumatic scar formation round the trochlea, hematoma or blood cyst formation in the muscle. Orbital floor fracture with entrapment of inferior oblique muscle.

The surgical traumas responsible are—excessive tucking of superior oblique, ptosis correction, injury to superior oblique or entrapment during scleral buckling.

The next common cause is rheumatoid conditions involving the trochlea. Frontal sinusitis and frontal osteoma may also cause the disorder.

The presenting symptoms and signs consists of -

In mild cases, the disorders may go unnoticed as there is no deviation in primary position. Otherwise sometimes parent notice abnormal head posture and defective eye movements. Vision may be diminished and amblyopia is common if squint is present.

The chin is slightly elevated, the head is tilted towards the affected side and face turned away from the affected side.

On cover test mild to moderate latent hypo deviation may be noticed.

The affected eye fails to elevate is adduction. There may be down shoot of the eye in adduction and there may be widening of the inter palpebral fissure in attempted adduction.

Elevation capacity increases as the eye is abducted. There is over action of contra lateral synergist. AV phenomenon is common when squint is manifest. There is positive forced duction test.

Brown’s syndrome has been put in three grades i.e. mild, moderate and severe.

In mild form, there is no hypotropia in primary gaze, there is no down shoot on adduc-

tion.

Moderate form also does not show hypotropia in primary gaze but down shoot is demonstrated on adduction.

Severe form has hypotropia in primary gaze, down shoot in adduction and abnormal head posture.

The mild and moderate forms go unnoticed as there is no manifest squint, minimal abnormal head posture. They constitute about sixty percent of all cases.

Binocular single vision is present in primary position and lower field.

Management

Any error of refraction is treated following refraction under cycloplegia. Amblyopia when present should be treated vigorously.