Ординатура / Офтальмология / Английские материалы / Pediatric Opthalmology_Mukherjee_2005

develops at the end of second month as eight epithelial buds arising from superio -lateral part of conjunctiva. The buds get transformed into solid cords that get canalised by third month. The mesoderm condenses round these. The developing levator divides the gland into palpebral and orbital part by fifth month. Tear production starts by the first month post natal. The lacrimal glands are fully developed by third year6. The accessory glands develop from the conjunctiva as ectodermal invagination7.

(b) The tear spreading system

It is essential to keep the cornea and the conjunctiva wet through out the life. This is brought about by constant flow of tear from lacrimal glands. As formation of tear is a constant process it should also be removed from the eye least there is an over flow of tears. A delicate balance between production and exit of the tear from the eye exists. This is brought about by constant evaporation of tears from the cornea and conjunctiva, when the eyes are open and an intact drainage system that work through out day and night. For a smooth flow of tears from the superio temporal region to inferionasal quadrant, the lids should have sharp, regular and continuous margin that remains in contact with the globe and moves freely during blinking. The tear is spread across the globe not only by smooth movement of lid but also by gravity, capillary action and surface tension.

(c) The Lacrimal drainage system

1.Puncta. Puncta are two openings situated on the posterior part of each lid margin on the medial side. They are not visible unless the lid margins are everted. It is easier to see the lower punctum than the upper punctum especially in children. The puncta are located 6 and 6.5mm from the medial canthus, the upper punctum is nearer the canthus than the lower punctum, hence the puncta do not over lap each other, when the lids are closed. The punta are the openings of the canaliculi. The puncta are kept in contact with the globe and glide over the globe for drainage of the tear. The lower punctum is more important than the upper as far as drainage of tear is concerned. The lower punctum drains about 75% of total tear.

Damage to lower punctum causes more epiphora than upper.

2.Canaliculi. Each lid has one canaliculus that starts from the punctum and ends in common canaliculus. Each canaliculus has two parts i.e. a small vertical part and a longer horizontal part the vertical part is 2mm long while the horizontal part is an 8-8.5mm in length. The two parts join each other almost at right angle, each canaliculus pierces the lacrimal facia separately and the two join to form the common canaliculus which opens on the lateral side of the sac, occasionally the two canaliculi may open separately. The canaliculi lie superficially in the lid hence they are frequently damaged by wounds of lower lid.

3.Common canaliculus. The two canaliculi join to form common canaliculus before opening in the lacrimal sac.

4.Lacrimal sac. The lacrimal sac is the reservoir of tears between the canaliculi and the nasolacrimal duct. The normal sac which is 11-12mm in length, 4 to 5mm in width, and is flattened anterio posteriorly, the anterio posterior depth is only 2 to 3mm. Thus, it is more or less like a club that has been flattered anterio posteriorly. Its volume is 20 cu.mm when not distended. This much of fluid is sufficient to make the sac non visible and non palpable. In normal condition the sac lies in the fossa for lacrimal sac that is situated in the lower medial

part of the orbital rim. The frontal process of maxilla and lacrimal crest forms the fossa. The fossa has two ridges called lacrimal crests, one formed by maxilla is known as anterior lacrimal crest the other is called posterior lacrimal crest. The upper dome shaped part of the sac is called its fundus while most of the part is called body.

The part that joins the nasolacrimal duct is called the neck. There is no strict anatomical landmark to differentiate the three parts. The sac is surrounded by the lacrimal fascia that is formed by splitting of the periorbita. Between the lacrimal fascia and the sac is a plexus of veins. Non-kertanised squamous cells, goblet cells and some columnar cells resembling respiratory columnar cells line the inner wall of the sac. The ethmoidal cells and medial meatus form the medial relation of the sac, on the lateral side is the caruncle and palpebral part of the orbicularis, behind the sac lies the lacrimal part of the orbicular is and posterior limb of medial canthal ligament. Anteriorly, the anterior limb of the medial palpebral ligament crosses the sac mid way between the fundus and neck above the larimial fascia 4a. The angular vein runs vertically 8mm medial to the medial canthus, a tributary to this descends with in 3mm of the sac. This is an important landmark, while exposing the sac. The incision should be with in 3mm of the medial canthus. The incision to expose the sac should be concentric with the fibres of the orbicularis. The best landmark to locate the sac is to feel the medial palpebral ligament first and give a vertical incision over the ligament at right angles to the ligament. For ideal exposure the incision should begin 3mm above the medial palpabral ligaments. The medial palpebral ligament is felt as a horizontal band medial to the medial canthus when the lateral canthus is pulled laterally. As the sac has less space to distend at the fundus, the sac swellings are more marked under the medial canthal ligament. An oval swelling above the medial canthal ligament is more likely to be unrelated to the lacrimal sac.

5. Naso lacrimalduct. The naso lacrimal duct is down ward extension of the lacrimal sac in a bonny canal. It extends from the sac to the interior turbinate of the nose. It’s about 18mm in length. It is directed down words. back wards and laterally. The directions of the naso lacrimal duct be taken into consideration while probing in children least a false passage is formed. The resiratory type of columnar cells are more in NLD than in sac. The duct has a larger in introseous (12.5mm) part and a smaller intra mural part. The NLD is surrounded by rich vascular plexus that is similar to seen in interior turbinate. The nasolacrimal canal is formed by maxilla, lacrimal bone and inferior nasal concha. The intramural part open under inferior turbinate that is 30-40mm form the anterior nares in adults and 20mm in children. The lacrimal passage gets its blood supply from superior and inferior branches of the ophthal micartery, in praorbital artery angular artery and spheno palatine artery. The venous drainage is via angular intra orbital, and nasal veins. The lymphalies drain in submandibular and deep cervical glands.

Development of the lacrimal drainage system

The lacrimal drainage passages have a common origin. They are ectodermal in origin embedded in mesoderm. The lacrimal sac and naso lacrimal duct develop beneath a furrow formed by the lateral nasal process and maxillary process. The lacrimal sac develops as a solid cord of ectoderm at 10mm stage, by 15mm it sends two columns in to the lid to form the canaliculi. The lower canaliculius separates a part of the lid to form the caruncle. At 15mm stage the solid cord descend down to form the nasolacrimal duct that is met by similar structure

arising from the primitive nasal cord7. The solid cord starts canalisation from both the ocular and nasal ends5 in segments. By birth there is a complete cavity of the sac and patent nasolacrimal duct however some of the ectodermal derbies may remain in the naso lacrimal duct causing congenital ductal block, in about 10% of infants. The canaliculi and puncta become patent after the two lids have separated.

CONGENITAL ANOMALIES IS LACRIMAL DRAINAGE SYSTEM

All the structures from lacrimal puncta to opening of nasolacrimal duct in the inferior meatus may be effected by developmental anomalies singly or in combination.

Common congenital anomalies are9

A.Congenital block of nasolacrimal duct

B.Congenital mucocele of the sac

C.Congenital fistula of the sac.

D.Atresia of puncta and canaliculi.

A. Congenial Block of Nasolacrimal Duct

Congenital block of the nasolacrimal duct is commonest developmental anomaly of the lacrimal apparatus. It is a very frequent anomaly in a child and commonest anomaly of the eye and adexa. It is found in about 6% of new born8. It is more common in premature children. It may be unilateral or bilateral both the sexes are equally involved there may be a positive family history9 commonest site of the obstruction is at the inferior osteum of the duct. The nasolacrimal duct develops as a solid cord in a groove situated in the frontal process of maxilla and lacrimal bone beneath the skin. The duct gradually gets canalised from both the ends but predominantly from upper end. By birth the duct should be fully canalised, there may be few insignificant blocks that get cleared by first month post partum. However in about six percent of cases the canalisation is not complete. Generally there is single obstruction at the lower end. However there may be more than one block. The blockage is caused by epithelial debries. Atrasia of the inferior osteum by a membrane is very common cause of obstruction.

The effect of nasolacrimal duct block is not visible until three to four weeks, after birth because the lacrimal gland does not start secreting adequality before third week. A typical presentation is watery discharge in a congested eye with out photophobia. After few days the conjunctiva gets inflamed and there is mucopurulent discharge. At this stage pressure over the sac may result in positive regurgitation. In few months the sac gets distended and there is copious reflux following pressure over the sac. Rest of the eye is not involved in congenital nasolacrimal duct block but becomes prone for recurrent infection.

Diagnosis. Diagnosis is straightforward an infant develops epiphora after 3 weeks with or without discharge and positive regurgitation, conditions that may be mistaken as congenital nasolacrimal duct obstruction (congenital dacryocystitis, or neonatal dacryocystitis) are ophthalmic neonatorum, corneal abrasion, primary buththalmos, retino blastoma, Congenital coloboma of the lower lid is a common cause of ipiphora with negative regurgitation test.

Ophthalmianeonatorum becomes obvious with in first week. It is generally bilateral and there is copious mucopuralent or purulent discharge without regurgitation. Corneal injuries are generally unilateral without mucopurulent discharge and stain with fluoreseein, congenital glaucoma is generally associated with photophobia and the cornea is large, ofcourse the tension is high.

The term congenital dacryocystitis is not very appropriate because inflammation of the sac is secondary to duct obstruction, the sac is sterile at birth and the inflammation is noticed after third week post partum hence it will be better to call it as congenital nasolacrimal duct obstruction.

Management

Management of the condition is simple provided the treatment is initiated before twelve weeks. The treatment consists of opening of the block by external pressure over the sac and treatment of associated infection.

Relief of the obstruction is achieved by application of gentle and firm pressure over the sac to force the fluid down the nasolacrimal duct, which dislodges the epithelial derbies. The application of pressure is generally called massaging of the sac. This give relief in 95-98% of cases. The mother is taught this simple method by repeated demonstration and is asked to perform the same in presence of the doctor. She is instructed to trim finger nails and keep the hands clean. Infact she should be asked to wash her hands with soap and water every time before she massages the sac. The sac is pressed with the pulp of the index finger. After the sac has been pressed the mucopurutent discharge should be removed by wet cotton swab and a broad spectrum antibiotic drop is instilled. The process of cleaning the hands pressing the sac, removing the discharge, instilation of antibiotic should be under gone for five to six times a day for six week.

After few days of repeated pressure application on the sac, the discharge changes to watery from mucopurulent. The block is often relieved after 3 to 4 weeks but the process should be continued for an other two to three weeks to keep the passage patent. Success of this method depends upon proper compliance, repetition and continuation of the process for five to six weeks. Sooner the massage is started better is the result generally 95% of the cases will be cured by massage and local antibiotic. However this process may not be helpful (1) It started after three weeks of on set of eiphora. (2) There is atrasia of boney canal (3) There is a nasal cause (4) Improper method. In that case probing of the nasolacrimal duct under general anaesthesia through upper puncta is indicated. A single probing done properly results in permanent cure. However sometimes repeated probing may be required. For a successful result the probe should be directed downwards, laterally and backwards10. If repeated probing fails than the condition should be treated either by conventional dacryo cysto rhinostomy, or endoscopic D.CR. Incubation of nasolacrimal duct is another alternative.

Complication of Naso Lacrimal Duct Obstruction

Commonest organism that is isolated from infected sac is pneumococcus which is a potential danger to the cornea, mild corneal abration in presence of infected sac may result in to disastrous keratitis and corneal ulceration. A chronically infected sac may lead to acute dacryocystites, and fistula of the sac.

B. Congenital Mucocele (Dacryocystocele)4a,11

This is a rare condition present at birth as a bluish diffuse swelling medial to the medial canthus. This can be sometimes bilateral. The condition is caused by simultaneous non canalisation of both the canaliculi and nasolacrimal duct. The condition may be confused with a haemangioma. The conditions waxes and wanes size and may altogether disappear following gentle pressure over the sac12,13 otherwise. Probing under general anaesthesia is indicated other condition that may be confused with is meningocele in infants for which suitable tests including C.T. may be done.

C. Congenital Fistula of the Lacrimal Sac

In this condition of fistulous track develops between the lower part of the sac and the skin on the side of the nose below the medial palpebral ligument . The opening of the fistila may be so small that it may not be noticed. Otherwise there is constant flow of tear form opening . It may occasionally be bilateral. The exact mode of development of the condition is not well under stood. One of the theories put forward is failure of embryonic tissue to close fully14. The diagnosis is confirmed by injection a coloured fluid in the sac through inferior puncta. The dye is seen to trickle through the opening, treatment consists of removal of the fistulous tract and closure of gap in the sac and skin.

D. Atresia of Puncta and Canaliculus14

This condition is brought about by failure of budding out of upper part of lacrimal passage into the lid or failure of to canalis the solid mass of cells that eventually become canaliculi. The punctum may be altogether absent or may be rudimentary. Symptoms are epiphora without infection.

INFLAMMATION OF LACRIMAL SAC (DACRYOCYSTITIS) IN CHILDREN

Inflammation of lacrimal sac in children is rarer than seen in adults. The sac may have either acute dacryocystites or chronic dacryocystitis.

A. Acute dacryocystitis

Acute dacryocystitis is generally pericystic cellulilis secondary to chronic infection of the sac. It may proceed to form an abscess over the sac that may eventually burst on the skin to result into a lacrimal fistula that connects the lumen of the sac with the skin out side. Acute dacryocyititis in children develop when a congenital nasolacrimal duct block has not been relieved, this is generally seen under 5 years of age. Another type develop in presence of chronic bacterial dacryocystitis without congenital block in old children.

Symptoms of acute dacryocystitis consist of painful, pink, diffuse swelling between the lateral side of nose and medial canthus which may develop fluctuation and pus forming at most dependent part. Submandibular and preauricular glands are enlarged. Condition may subside only to recur or may form a fistula.

Management of acute dacryocystitis is systemic broad spectrum antibiotic (common organisms are H. influenza and pneumococcous) oral or injection, hot fomentation, oral

analgestic. Local antibiotics are not effective, if the pus points it is drained by stab incision and pus expressed out. The wound is dressed with magsulf and glycerine dipped ribbon gauge. The wound is allowed to heal from beneath. Syringing and probing is contra indicated. When acute infection subsides, external or endoscopic DCR is performed.

B. Chronic dacryocystitis in children

Chronic dacryocystitis in children is less common than adults. In adults it is caused due to acquired nasolacrimal duct obstruction mostly in females in third and fourth decade who have narrow nasolacrimal canal which gets obstructed due to spread of infection from nose and throat.

In children chronic dacryocystitis is caused due to unrelieved partial stenosis of nasolacrimal duct . It may follow chicken pox15 measels, where infection travels down from the conjunctiva, as well ascends from nasopharynx. Other possibility is mid fascial trauma with fracture bony nasolacrimal duct. Lastly rhinosporidiosis is a common cause of chronic inflammation of sac in children in endemic area.16

The symptoms consist of epiphora with or without conjunctivitis, diffuse painless swelling (mucocele) under the medial canthal ligament, regurgitation of pus from the puncta on pressure over the sac.

Generally the condition is unilateral.

The Signs are mucoid discharge near the medial canthus, mucocele, positive regurgitation test. The mucopurulent discharge may come from any or both puncta. Persistent absence of regurgitation from any puncta in presence of mucocele denotes corresponding canalicular block.

Positive regurgitation test is a due to nasolacrimal duct obstruction which is confirmed

by -

1.Taste test

2.Lacrimal Syringing

3.Jones I and II test

4.Dacryocystography

5.Lacrimal scintilography31

RHINOSPORIDIOSIS OF SAC16

Chronic dacryocystitis of the sac due to rhinosporidiosis is rarely seen outside endemic area of rhinosporidiosis. The disease is most prevalent in tropical and subtropical countries like India, Sri Lanka, Indonesia, Philipines. India from where large number of cases17,18 have been reported too have pockets where the disease is prevalent. These area have high rain fall, humid and warm climate as in Kerala, Tamilnadu, coastal Andhra, Orissa, West Bengal and Chhattisgarh.

The disease is caused by an organism Rhinosporidium Seebri Exact mode of spread of infection is not known. A widely put forward theory is what the patients get the infection from infected cattle. When the persons share the same pond for bathing with infected water

buffalo, the water borne spores get lodged in the anatomical recesses like fornices, plica, nasolacrimal duct. The organism derives its name from the fact that it was first described as a nasal lesion. Nasal lesion happens to be most common involvement. Incubation period of the disease is not known. All persons in the same locality do not get the same disease.

It is rarely seen in other the members of the same family, bilateral lesions are infrequent, simultaneous involvement of sac and conjunctiva is also rare. Most probably the infected child has a pre existing total or partial block. Selective involvement of a few persons in the same locality with similar life style point towards an immune mediated mechanism.

There are two types of ocular involvement .

A.Primary where either the sac or conjunctiva is involve without nasal involvement.

B.Secondary. Here the infection spreads to the sac from the nose via nasolacrimal duct and conjunctiva is generally spared.

Appearance of the lacrimal sac is similar in both the types. There is a defuse pain less swelling over the sac, the swelling is non tender, skin over the swelling has an orange peel appearance. Though there is associated chronic dacryocystitis, eiphora is not a dominant symptom. The condition is generally unilateral there is no regurgitation, following syregning the swelling increases in size. Which disappears by firm pressure. The nasolacrimal duct is either open or partially blocked. Generally there is bleeding from the nose in case of associated nasal involvement. Lymph nodes are not involved.

Management There is no specific systemic or local medial treatment. Associated conjunctivitis should be treated with local antibiotic drops. Definite treatment is surgical removal of the sac. Precaution should be taken to remove whole of the sac without repture. Complete removal of sac ensures freedom from the symptoms and recurrence. It part of the tissue is left behind the condition is bound to recur.

CONGENITAL ANOMALIES OF LACRIMAL GLAND1,9

Congenital anomalies to lacrimal gland are far rarer than that of lacrimal passage. Common anomalies of lacrimal gland are -

A.Absence of the lacrimal gland

B.Alacrima.

C.Aberrant lacrimal gland

D.Fistula of lacrimal gland

E.Congenital cyst of lacrimal gland

F.Crocodile tear.

A. Absence of lacrimal gland

The lacrimal gland develops from the conjunctiva of the upper fornix as buds going up and out from the developing conjunctiva. It is but natural that the lacrimal gland will be absent in absence of the conjunctiva as in cryptopthalomus. Lacrimal gland is present in anophthalmos where the eye ball is absent but conjunctiva is present.

B. Alacrima

In this condition there is partial or total absence of tear production in presence of lacrimal gland and its ducts. It is generally a bilateral condition. The parents may notice that though the child has redness of the eye and intolerance to light, the eyes do not water as is expected and has only thick mucus discharge. On investigation both basic and reflex tearing are absent , exact mechanism is not known most widely accepted theory is that there is lack of neural communication between the gland and the lacrimal nucleus . Others feel that the lacrimal gland itself is hypoplastic. It may be associated with multiple cranial nerve anomaly specially sixth and seventh or may be part of congenital autonomic dysfunction known as RileyDay syndrome.

Riley—Day syndrome1,19

Is a rare disorder mostly seen in Jewish children caused by sever depletion of parasympathomimetic neurones in spheno palatine ganglion. It has wide spread systemic features which include, Episodes of systemic hypertension, excess of sweting, cyclic vomiting muscular hypotony, emotional out burst, feeding difficulty. The children are less sensitive to pain, decreased tenden reflexes is common. Ocular symptoms consist of alacrima, absence of emotional tear production, absence of basic and reflex tear production, loss of corneal sensation, corneal opacity, vascularisation. The pupil constricts with very weak solution of pilocarpine (0.0625%). There is no specific treatment management is symptomatic ocular treatment consists of local tear substitute drops by day and ointment by night, local anti biotic.

C. Aberrant lacrimal gland

Aberrant lacrimal glands other than accessory lacrimal gland are found at any location under the conjunctiva, commonest site is outer half of conjunctiva. It may be seen at limbus and mistaken for limbal dermoid. It can even be seen on iris and choroid.

D. Fistula of lacrimal gland

Lacrimal gland fishila are seen on outer side of the upper lid above the tarsal plate, they may occasionally be associated with malformation of outer canthus or with congenital cyst of lacrimal gland . The opening is generally associated with a tuft of hair around it. As the opening, communicates with the lacrimal gland, it is obvious that tear should flow out from the opening. The flow is enhanced when there is stimulation of fifth nerve. The tract is common site for recurrent infection. Treatment consists of removal of the tract and closure of the communication with the gland.

E. Congenital cyst of the lacrimal gland

Congenital cyst of lacrimal gland is seen only in the orbital part of the gland as a tense swelling under the superio temporal aspect of orbit, this may cause a ptosis, S shaped curve in the upper lid and proptosis. It may be present at birth or may become obvious later. Treatment consists of removal by orbitotomy if there is moderate to server proptosis.

F. Crocodile Tear4a,11 This is a paradoxical reflex feature that is generally unilateral caused by congenital misdirection of seventh nerve towards lacrimal gland through spheno palatine ganglion. In this condition there is unilateral tearing during mastication. More common is aquired paradoxical tearing following seventh nerve palsy due to aberrant degeneration.

Systemic condition that produce unilateral tearing due to gusto lacrimal reflex are : brain stem lesions, Ipsilateral sixth nerve palsy is common in congenital crocodile tear.

THE LACRIMAL GLAND DISEASES IN CHILDREN

Disorders of lacrimal gland can be :

A.Congenital (very few)

B.Acquired.

B. The acquired disorders can be :

More common than above are :

1.Excessive production of tear—Lacrimation

2.Scanty production of tear—Ocular surface disorders.

The symptoms of lacrimal gland disorders are :

1.Painful swelling of the main lacrimal gland.

2.Slow progressive swelling of lacrimal gland (chronic dacryodenitis)

3.Discharging sinus

4.Lacrimation.

5.Ocular surface disorder.

6.Proptosis

7.S Shaped Curve of upper lid

8.Ptosis.

ACUTE DACRYOADENITIS4a,4b

It is seen between five years to late teens. It is generally unilateral. The viruses infect the lacrimal glands more commonly than bacteria. Commonest virus is mumps followed by infective mononucleosis rarely by herpes zoster. The disease starts with chills rigor and pain in the superio temporal aspect of orbit. There is a tense swelling over the lacrimal gland, mild proptosis, ptosis, S shaped curvature of upper lid. Conjunctival congestion and rarely restricted movements and optic neuritis, infact any part of the eye except lens and vitreous can be involved by the disease.

The disease is caused by mumps virus single attack gives life long immunity. Parotids and other salivary glands are invariably attacked along with lacrimal gland. It commonly

infects the gonads. Rarely it can cause central nervous system involvement in the form of meningitis, encephalitis, myelitis and cranial neuritis differential diagnosis consists of stye, infected chalazion, acute unilateral ineffective conjunctivitis, cellulitis lid and orbital cellulitis.

Management consist of

Prophy laxis. Alive, attenuated mumps virus vaccine is safe and effective in child hood. It gives life long immunity. In many countries this has been included in routine vaccination in childhood.

Curative there is no known anti mumps chemotheraptic agent.

Supportive. Bed rest, analgesic, cool wet compresses, use of steroids is restricted to CNS involvement. Keratitis, scleritis, uveitis are treated by usual methods.

Chronic dacryo adenitis is infrequent in children. It may be because by tuberculosis, saccoidosis and rarely fungi.

DISCHARGING SINUSES OF LACRIMAL GLAND

Discharging sinuses of lacrimal gland can be congenital, traumatic or post infective. The sinus opens on the skin surface treatment is excision of the sinus. Recurrence is common.

LACRIMATION

Lacrimation is defined as excessive production of tear. It may be with normal drainage or obstructed drainage.

It is due to

A.Reflex Stimulation of Fifth nerve either in the Eye or Nasal mucous

B.Psychogenic

C.Supra Neuclear Lesion.

A. Reflex Stimulation of Fifth Nerve can be Brought about by

1.Physical factors. Bright light, cold wind, heat.

2.Chemical. Irritative gases and fumes.

3.Corneal condition that lead to lacrimation are Corneal abrasion, foreign body on the cornea and tarsal plate, super ficial and deep keralitis, corneal ulcer, phlyctenular kerato conjunctivitis, rupture in Desmet’s membrane (buphthalmos ) endothelial decompensation.

4.Uveal conditions that lead to lacrimation are acute and chronic anterior uveitis

5.Acute allergic conjunctivitis.

6.Glaucoma. Primary congenital buphthatmos, secondary buphthalmos, secondary angle closure glaucoma.

7.Reflex irritation of nasalmucosa.

8.Allergic rhinitis, looking at bright light, tickling of nasal mucosa sheezing coughing.