Ординатура / Офтальмология / Английские материалы / Pediatric Opthalmology_Mukherjee_2005

(f) Cortical blindness

(g) Sagital mild line defects.

Half of the cases of diminished vision in children are genetic in origin.17

EXAMINATION OF PUPILLARY REACTION TO LIGHT

This is most reliable test to determine presence of vision except in cortical blindness. The test is best performed in a semi darkned room because the infants pupil are smaller than normal and constricts in presece of bright light in the room. In the semi dark room the pupil comes to a state of semidilatation that reacts briskly. The light used should be small well focused and bright. All forms of light reflexes i.e. direct, indirect and swing light responses are noted. If the pupil is small and it is difficult to appreciate pupillary reaction a hand held slit lamp may be used.

Small sluggish irregular pupil are indication of inflammation, congenital miosis or persistent pupillary membrane.

OTHER EXTERNAL EXAMINATIONS CONSISTS

A.Face. Examination of face for craniofacial and mandibulo facial anomalies, albinism, hemangioma.

B.Orbit. Anophthalmos, microphthalmos, cystic eye ball, proptosis.

C.Lid. The lids are examined for Ptosis, coloboma, hemangioma. Lagophthalmos is far rarer than ptosis. Unilateral ptosis draws attention earlier than bilateral ptosis. Other anomalies present at birth that draw attention are : epicanthus and ankyloblepharon.

D.Palpebral fissure of new born is smaller than adult. It is narrow in ptosis wide palpebral fissure is seen in lagophthalmos, proptosis and rarely in buphthalmos. There is apparent shorting in length in epicanthus. Epicanthus also gives a false impression of pseudo convergent squint that may not be appreciated at birth but becomes obvious after few months. Blepharophimosis that is frequently seen with ptosis and epicanthus and causes shortening of length of I.P.A.

E.Lacrimal system. Only anomaly visible in a neonate is congenital mucocele of lacrimal sac. Neonatal nasolacrimal duct obstruction when present is asymptomatic and non elicitable. Ophthalmianeonatorum does not develop within first twenty four hours.

F.Conjunctiva Only important finding that may be present in conjunctiva is subconjunctival haemorrhage which is of no consequence and is due to birth trauma the conjunctival sac at birth is sterile that soon gets infected by bacteria, virus and chlamydia.

G.The Cornea Even a normal cornea in a new born looks large because of narrow I.P.A. The cornea of a new born is 10-10.5mm at birth any cornea larger than 12mm is abnormal may be buphthalmic. When in doubt about diameter of the cornea it is better measured. Most reliable measuremnent is taken by a corneal calliper, a transparent scale may be usedfor rough estimation. Most important cause of large cornea is buphthalmos that requires early referral, the other cause is megalocornea.

Microcornea is frequent , more common than megalocornea, it may be associated with microphthalmous and coloboma of the uvea all three may be present singly in an eye or in various combinations. Bilateral small cornea is frequent.

Other signs that should be looked for are:

1.Corneal haze.

2.Frank corneal opacity.

3.Limbal dermoid.

4.Rupture in Descemet’s membranes.

1. Corneal haze

Most of the cornea in new borns are relatively hazy, which become bright in few days. Some of the pathological cause of corneal haze are :

(a) Buphthalmos

(b) Rupture in Descemet’s membrane (c) Dysgenesis of anterior chamber (d) Mucopoly saccharidosis.

Rupture in Descemet’s membrane is mostly traumatic due to faulty instrumentation during delivery.

It is difficult to examine the cornea and conjunctiva due to tightness of the lids, and small palpebral fissure. There is no condition in new born eyes where eversion of the upper lid is needed. Rarely a lid retractor may be required to see the upper limbus and upper bulbar conjunctiva. An infant size lid retractor should be used, if at all necessary.

H. Anterior Chamber. The anterior chamber of new born is fully developed but shallow. The angle is wide and pupil can be dilated with out rise of I.O.P.

A deep chamber is seen in buphthalmos and megalocornea. Congenital aphakia is a clinical curiosity. Sub luxation of lens is not appreciated unless carefully looked for.

Commonest anomaly of anterior chamber is mesodermal dysgenesis of Reigers. Other condition being, Peter’s anomaly, which causes irregular shallowing of A.C.

I. Uvea. Common congenital anomalies are persistent pupillary membrane, coloboma of the iris and ciliary body, anisocoria and cryptocoria.

Aniridia is a rare anomaly but is a vision threatening condition that may have Wilm’s tumour in the abdomen.

The iris of new born is lighter in colour. Presence of few blood vessels is common and non pathological.

Posterior uvea is examined by direct and indirect ophthalmoscope with dilated pupil.

J. Pupil. Pupil of a new born child is relatively moitic due to stronger constrictors than dilators of pupil. It is difficult to dilate the pupil of new born due to same cause.

The pupil is examined for it shape, size position and number. Commonest cause of irregular pupil is persistent pupillary membrane. Other causes are mesodermal dysgenesis, Peter’s anomaly and coloboma of iris.

A. Recording of vision

The vision generally ranges between 6/60 to 6/36 i.e. the child can recognise faces by sight, develops preference for toys and picks up particles from the ground. However vision can not be tested with usual optotypes. The child follows a moving target first by moving the eyes then by turning and lilting the head and moves towards an object of interest. Presence of squint, nystagmus, persisting staring and inattention to object10 are ominous signs sometimes parents may be able to state if the child’s vision is subnormal or not, by comparing it with older siblings or children of the same age.

This is the age when the children are brought by anxious parents with a definite question “ Does this child has vision ?”. This is a very difficult question to answer. Nothing is worse than informing the parents that the child is blind or normal, that turns out to be opposite later. There are some children who have delayed visual maturation (DVM)7 and behave like a child with sub normal vision.

Vision should be considered normal in a child under one year if the media are clear, there is no error of refraction, pupil are central circular and react briskly to direct and indirect light, there is no squint or nystagmus, fundus is normal with normal milestones.

Presence of pupillary reaction to light is not equivalent to visual ability, it merely gives an indication that both afferent and efferent paths of light reflex are intact10.

Dilatation of pupil in presence of direct light stimulus is seen is Lebers congenital amaurosis, optic nerve hypolplasia congenital cone dystrophy and stationary night blindness7,11

In cortical blindness the pupillary reaction is present, this is due to the fact that the lesions is in optical cortex, commonest cause in children being trauma. However nystagmus is absent in cortical blindness.12

All children suspected to be blind should also under go :

1.Electrophysiological investigations-electro-encephalogram, electro-retinogram and visually provoked response.

2.CT and MRI of ocular structures and brain.

Prematurity, low birth weight, prenatal asphyxia, convulsion congenital anomalies of brain may have occipital lesions which requires. CT and MRI to evaluate prognosis.

In grown up children the routine is to record the vision in each eye separately followed by binocular vision. In children under three examination of vision with both eyes open is noted first followed by recording of vision in each eye separately, while examining each eye separately it is better to examine the supposed to be good eye first than the suspected faulty eye. This helps gaining confidence of the child. A child who has gross diminished vision in one eye always resents when the better eye is closed, the child may start crying and try to remove the occluder. While testing one eye the other eye should be fully occluded if necessary by a cotton pad and tape otherwise the child may peek over the occluder in the better eye. While recording vision the approximate near vision also be noted in preverbal child. It is good practice to let one of the attendants preferably one of the parents present during examination of the vision. The attendant should be asked not to prompt the child when the vision is being recorded. If the

child has glasses the power of the glasses should be noted and vision in each eye is recorded as with glasses. It is better not to darken the room, this scares the child it should be semi lit.

B. Accommodation, fusion and convergence17 Accomodation is present at one month but is relatively poor. It is well developed by four months. Fusion starts at two months, Fusional convergence develops by six month. It takes steriopis to reach adult level by five to six years of age. It is well developed by four months though it is considered to be present by second month.

Once the vision has been recorded other clinical signs should be noted according to a strict protocol instead of jumping from one structure to the other. The other eye should also get same attention as the diseased eye even when the lesion is suspected to be unilateral. The parents may not like this due to preformed idea that the wrong eye is being examined. The parents at this stage should be explained the purpose of examining both eyes.

The first step is to observe the child in normally lit room from a distance of about a meter without touching the child.

C. The points to be noted in diffuse light are

1.Is the child comfortable, does he keep his lids forcefully shut this means photophobia and blepharosm for the same reason a child may hide his face from any source of bright light, the child may open the eye if the room is darkened sufficiently. A child with searching movement, most probably does not have vision in either eye. Diminished vision in one eye generally goes unnoticed by the parents unless associated with other causes like squint, corneal opacity or white reflex in pupillary area.

2.Look for symmetry of face, and skull : Asymmetry of face is generally seen in cranio facial anomalies. All children with skull larger or smaller than normal should get paediatric consultation.

D. The eyebrows have scanty, fine hair normally and the eyebrows are symmetrically arched on both sides. Raised eyebrow with furrows in forehead denotes ptosis. Even a child of one year may have a raised eyebrow in case of ptosis. Unilateral ptosis attracts more attention than bilateral ptosis in children. The chin may be elevated .

Flattening of eyebrows, absence of forehead crease and wide IPA denotes lagophthalmos.

Persistent abnormal head posture like head turning, tilting or abnormal chin position in various combinations point towards possibility of paralytic squint (for details see examination of strabismus)

E. The lids are examined for hemangioma, coloboma of lid margin and distichiasis.

Epicanthic fold gives a false impression of pseudo convergent squint while telecanthus gives an impression of divergence.

Narrow palpebral fissure is seen in various types of ptosis and pseudo ptosis.

In blepharophimosis the horizontal length of palpebral fissure is reduced. It is generally seen with epicanthus and ptosis.

F. In all cases of watering from the eye of long duration under one year of age the first condition that needs to be excluded is congenital dacryocystitis which should better be

haemorrhage in children before universal immunisation came in to vouge. Even today it is seen in non immunised children in developing countries, leukaemia and purpura are common causes of subconjunctival haemorrhages.

(b) Petechial haemorrhages are seen in epidemic haemorrhagic conjunctivitis and pneunococcal conjunctivitis.

(c) In cases of sub conjunctival haemorrhage where its outer limit is not visible child should be examined for possibility of head injury.

6.Colour Changes in conjunctiva are common. A pale conjunctiva is indicative of anaemia, blue conjunctiva denotes cyanosis. Yellow discoloration is seen in jaundice, patches of black flat spots are due to congenital melanosis. Faints blue hue is universal in children due to thin sclera through which the underlying uvea shines.

7.Conjunctival redness is common in all types of conjunctivitis mostly infective. It can be localised in:- Subconjunctival haemorrhage, abrasion and laceration of conjunctiva, rarely phlycten, spring catarrh and hemangioma.

Generalised congestion specially bilateral is seen in infective conjunctivitis. The congestion is most marked in the periphery in infective conjunctivitis.

8.Circumciliary congestion or circum corneal flush is seen in (a) Keratitis, corneal abrasion, corneal ulcer.

(b) Uveitis : Anterior uveitis and panuveitis. (c) Glaucoma : Acute and chronic congestive.

9.Episcleral congestion is rarely seen in children when present they are mostly due to buphthalmos or raised episcleral pressure due to an orbital mass.

10.Conjunctival discharge : Purulent discharge is mostly due to gonococci infection or sever other bacterial infection. Mucopurulent discharge is seen in other bacterial infection. Watery discharge is seen in allergic, viral and chemical conjunctivitis.

11.Conjunctival Xeroxis is a common feature and ominous sign of vitamin A deficiency. Bitots spots generally do not develop during first year because if a child is breast fed, mothers milk contains sufficient vitamin. A for the child for first six month. The child usually gets a prophylactic dose of 50,000 of vitamin A at six months.

H. Examination of Cornea

Consists of examination of transparency, size, shape, curvature, encroachment over the cornea, sensation, vascularisation and deposits on both surfaces.

1. Transparency of cornea. Mild bilateral corneal haze is universal in all full term babies and more common in pre term. The haze passes off within a few days to few weeks. Presence of dense opacities requires attention and management.

The cornea is uniformly hazy in congenital glaucoma both, primary or secondary that is generally a bilateral diseases, associated with enlargement of cornea, corneal edema and rupture in Descemets membrane that may result in Haabs lines. This requires differentiation from another common cause i.e. injury during forceps delivery, Haabs striations are horizontal may have whirl like appearance while injury by forceps are generally vertical. Out of all

cases of corneal clouding congenital glaucoma due to what ever cause requires immediate attention to save the sight.

Other causes of uniform corneal haze are relatively rare, they arecongenital hereditary endothelial dystrophy, congenital hereditary stromal dystrophy, various mucopoly saccharidoses, mucolipidoses and cystinosis13. In congenital rubella syndrome the opacity is relatively dens but clears in few weeks. Interstitial keratities is seen after five years of age. Peripheral localised opacities are seen sclerocornea and limbal dermoid. In case of Peter’s anomaly the opacity is generally localised centrally with clear periphery frequently associated with other malformations of anterior segment.

Kerato malacia : may be seen as bilateral haziness without circum corneal congestion is developing countries, in children born to mothers who suffer from malnutrition and have not received prophylactic dose of vitamin A in last trimester and the child has not been immunised against measles nor has been administered prophylactic vitamin A. However there are circumstances where the child develops signs of vitamin A Deficiency disease (VAD). These are ;

1.In sever drought the mother’s vitamin A store is depleted during gestation and remains low thereafter.

2.The child is deprived of mothers milk due to death of mother, sever malnutrition in mother, or the child has been abandoned and children of orphanage.

3.The child suffers from measles, or chronic diarrhoea.

2.Size of cornea. In a new born child the cornea looks large because of smaller I.P.A. Bilateral large corneas are missed by parents unless associated with watering but unilateral enlarged cornea draws attention early even without tearing, the cornea is enlarged in buphthalmos and megalocornea. The former require urgent management. In case of positive history of buphthalmos in family and suspected rubella syndrome the corneal diameter should be measured by corneal calliper. Any cornea larger than 12 mm should be considered to be buphthalmic unless proved otherwise by measurement of I.O.P. examination of angle and evaluation of optic nerve head. Any cornea larger than 13 mm is definitely buphthalmic.

Small cornea is seen in microphthalmos, and microcornea.

3.Shape of cornea. Distortion of shape of cornea is seen in microcornea microphthalmos and phthisis.

4.Corneal curvature. Increased corneal curvature suggestive of keratoconess that is extremely rare in first year. Flattening of cornea is more common and is seen in microcornea, microphthalmos and cornea plana. The former two are generally associated with gross incorrectable vision loss. Phthisis which is rare in first year of life may also present with flat cornea.

5.Enchromement over cornea. The corneal periphery may be as opaque as sclera in a rare instance of sclerocornea, where the opacity extends well into the cornea from the sclera obliterating the limbus. The peripheral opacity may be vascularised. In still rarer occasions the whole of the cornea may be as opaque as sclera. Dermoid14 is more common than the former. The commonest site being the limbus where a dry raised circular plaque of fibro fatty tissue is seen astride the limbus, they generally have few hairs growing over the growth. However they may develop in the middle of the cornea as well.

6.Sensation of cornea. Corneal sensitivity can be elicited from birth. It is reduced over the opacities, keratanisation and herpes simplex keratities. There is a very rare condition where corneal sensation is absent from birth called congenital dysautonomia.

7.Vascularisation of cornea. Vascularisation of cornea is rare under one year of age. Vascularisation of cornea always denotes pathology either in conjunctiva or in cornea. The former produces supefecial vascularisation. The corneal vascularisation can be superficial or deep. Causes of superficial vascularisation are infective and allergic kerotoconjunctivitis. The only cause of deep vascularisation in children between 3-5 years is interstitial keratitis.

8.Deposits on the cornea are mostly inflammatory.

I. Examination of Sclera. Sclera is not a tissue to have many findings in a child under one year. The sclera of an infant is relatively thin it is not as opaque as adult sclera but not translucent also. The uvea under neath gives it a bluish hue that passes off within few months but not in case of blue sclera brittle bone syndrome in osteogeneses imperfecta.

The sclera develops yellowish tinge in jaundice, sub-conjunctival patches of black pigmentation are very common and may cause worry in parents.

Sclera is devoid of any inflammatory process under one year of age.

Conjenital ectasia may be seen rarely more common cause of ectasia is buphthalmos.

J. Examination of anterior chamber :

1.An infants anterior chamber is fully formed at birth is of equal depth in both eyes it reaches adult depth by age of one year AC should be devoid of any thing but aqueous. Difference in depth of AC in two eyes is abnormal so in presence of mesodermal tissue.

2.Deep AC is seen in buphthalmos, keratoglobus and congenital axial myopia.

Congenital aphakia is a clinical curiosity only a few cases of spontaneous absorption of lens have been reported in first year, ofcourse surgical aphakia gives a deep A.C. in infants who have undergone lensectomy without IOL. A very few infants may have iris clip IOL16 as part of management of congenital cataract and have relatively deep A.C. In P.C. I.0.L. the depth of A.C. is almost normal.

3.Shallow A.C. is seen in micro cornea, microphthalmos, cornea plana, mesodermal dysgenesis of anterior chamber, Peters anomaly.

4.Contents of anterior chamber Normal content of AC is aqueous humour that is crystal clear, without any visible suspended particle. It is very difficult to detect mild to moderate turbidity under one year of age.

Presence of blood is more common in this age group which is mostly traumatic than pus. Presence of any white material in A.C. should be considered to be pus unless proved otherwise. Common cause of white material in A.C. are: hypopyon, pseudohypopyon, cortical material.

K.Measuring intra ocular pressure. All infants with large cornea, history of buphthalmos in siblings and abnormal tissue in A.C. should undergo measurement of 10P under general anaesthesia.

L.Examination of iris. Iris of a new born has lighter colour than what is expected to be at adult life due to lack of pigment, however the iris becomes pretty dark by one year if not

as dark as adult. An iris that is abnormally light with pink pupil and trans illuminates in a fair child is due to albinism.

Iris of one eye may differ from the other eye and is called heterochromia iridium in contrast to difference of colour in the same eye that is known as heterochromia iridis which can be unilateral or bilateral.

Presence of congenital holes in iris other than pupil is called polycoria that generally lacks iris sphinters and called pseudopolycoria. True polycoria is rarer, these extra pupil have independent constrictor and dilator muscles and react to light independent of main pupil.

Congenital coloboma of the iris is generally situated in lower pole of pupil, may be localised to iris only or may be part of more extensive colobomatous anomaly of uvea. The coloboma of iris may be present as isolated anomaly of the eye or may be seen in microcornea and microphthalmos. Perhaps most common anomalous finding in the iris is persistent pupillary membrane where strands of mesodermal tissue originate from the iris collarette and may pass across the pupil giving an irregular pupil. It disappears with age. Presence of few blood vessels in first two months are no consequence they also disappear with in few months.

M. Examination of pupil Examination of pupil alone gives much more information regarding presence of many anomalies than any other examination. Pupil reacting briskly to direct and indirect light stimulus is confirmed sign of intact afferent and efferent precortical visual path.

Pupil is examined for

1.Number,

2.position,

3.shape

4.size,

5.colour and

6.pupillary reaction.

1.Number. In rare instances there may be more than one pupil in the same eye either as pseudopolycoria which is more frequent than less common true polycoria both the conditions are associated with multiple anomalies of the eye. Cryptocoria is congenital absence of pupil .

2.Position. Single Pupil with slight nasal and medial shift is normal. However there may be corectopia where a pupil is shifted away from its normal place a part of multiple ocular anomalies.

3.Shape. Normal pupil is circular. All irregularity of pupil are not pathological only irregularity due to inflammation needs treatment. Persistent pupillary member is the commonest cause of irregular pupil under one year of age. Other causes are coloboma of iris, mesodermal dysgenesis of A.C., pseudopolycoria.

4.Size. Pupil of a child under one year is smaller than that of a child of three year due to parasympathetic over action when compared to sympathetic. The constrictor muscles are better developed than sympathetic. Unilateral small pupil with narrow I.P.A. is suggestive of