Ординатура / Офтальмология / Английские материалы / Pediatric Opthalmology_Mukherjee_2005

11.Zwaan J.T. ; Nasolacrimal duct obstruction in children in Decision making in ophthalmology, edited by Heuven W.A.J. and Zwaan J.T., Edition, first Indian pp- 140-141, Harcourt, Brace and Comp., Singapore 1992.

12.Boger W.P. and Peterson R.A. ; Paediatric ophthalmology in Manual of ocular diagnosis and therapy, Third edition p-277, edited by Deborah Pavan Langston, 3rd edition.

13.Weinstein G.S., Biglan, A.W. ; Congenital Lacrimal Sac Mucocele, Amj. Oph. 1982 94 : 106-110.

14.Duke Elder S. ; System of ophthalmal mology Vol. III, Part 2 p-936-937, Henry Kimpton, London 1964.

15.Mukherjee P.K., Jain P.C., Mishra, R.K. ; Exenthemata ; A caus of chronicdacryocystitis in children IJO 17-27-30, 1969.

16.Mukharjee P.K. ; Rhinosporidiosis in current ocular therapy, fifth edition, edited by Fraunfelder F.T. and Roy F.H. pp-66-67, W.B. Saunders Company, Philadelphia 2000.

17.Mukharjee P.K. Shukla I.M. Deshpande and M. Praveena Kher ; Rhinosporidiosis of the lacrimalsac Ind. Jr. Oph. 30:513-514, 1982.

18.Shukla IM mukharjee P.K. Shushma Verma ; Primary rhinospori diosis of the eye int congress of oph Acta XXVI , Vol. 2, 864, 1982.

19.Axelord F.B, Soloman J.M. and D’Amico R. ; Familial dysautonomia unclassified diseases or conditions in Current Ocular therapy fifth edition p-285-287, edited by Fraunfelder F.T. and Roy F.H., Saunders Company, Philadelphia 2000.

19. (a) Hornblass A. ; Asimple test of lacrimal obstruction Arch OPH 90: 435-436, 1973.

19.(b) Hornblass A Ingris T.M. ; Lacrimal function tests. Arch oph. 97 : 1656-1679.

20.Kanski J.J. ; The lacrimal system in Clinical ophthalmology, second edition p-54-56 Butter Worth, London 1989.

21.Swartz N.G., Cohen M.S. ; Tearing and the lacrimal system in Ophthalmology Secrets , Edited by Vander J.F. and Gault J.A. , First Indian edition pp-226-227, Jay Pee Brothers, New Delhi 1998.

22.Piest K.L. and Walton M.A. ; Epiphora in Decision making in Ophthalmology, first Indian edition, P-82, edited by Van Heuven W.A.J. and Zwaan J.T., Harcour Brace and Company, Singapore 1998.

23.Scheie H.G. , Albert D.M. ; Ophthalmic raiodlogy. Im Text book of ophthalmology,

Ninth edition P-254-256, W.B. Saunders Company 1977.

23. (a) Miller S.J.H. ; Diseases of lacrimal apparatus in Parsons daises of the eye, Seventieth edition p-327, Churchill Livingstone, London 1984.

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25.Daughman D. ; corneal Physiology in Principle and practice of Ophthal mology, first Indian Edition, Edited by Peyman. G.A. Sander D.R. and Goldberg M.F. p-356-358, Jay Pee Brothers, New Delhi 1987.

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APPLIED ANATOMY OF CONJUNCTIVA1,2

For purpose of description, conjunctiva has been divided into three anatomical parts without any line of demarcation between two adjacent parts. They are :

1.Palpebral

2.Bulbar

3.Fornix

1. The palpebral part is divided into (a) Marginal, (b) Tarsal and (c) Orbital.

The marginal conjunctiva. The marginal part is a transitional zone between the skin of the lid on the outer side and conjunctiva proper. It stretches from middle of the lid margin to sulcus subtarsalis on the posterior surface of the lid. The sulcus sub-tarsalis is a groove running all along the tarsal conjunctiva, 2mm from the sharp inner border of the lid. It is more developed in the upper lid than in the lower lid and is a favoured spot for small foreign bodies to get lodged. The two lacrimal puncta open on the marginal conjunctiva.

The tarsal conjunctiva extends from the sub tarsal groove to the border of tarsus. A normal tarsal conjunctiva is transparent enough for the tarsal glands and blood vessels to be visible as light coloured streaks through the tarsal conjunctiva. The transparency of tarsal conjunctiva is lost in edema, hyperemia and scarring. The tarsal conjunctiva is attached to the underlying tarsal plate so firmly that it can neither be lifted off the tarsal plate nor can fluid accumulate under it.

The orbital part of the palpebral conjunctiva is an ill defined area of loose conjunctiva extending from upper border of tarsal plate and blends with fornix.

The Muller’s muscle the non striated muscle of the upper lid lies just beneath this part of conjunctiva.

The bulbar conjunctiva. This part of conjunctiva extends from limbus to the beginning of fornices. It is firmly attached to the limbus. The conjunctival epithelium blends with the corneal epithelium at the limbus. The deeper part of the bulbar conjunctiva is loosely attached to Tenon’s capsule up to insertion of four recti. It is almost transparent, the white sclera is visible through normal bulbar conjunctiva. The conjunctival vessels are also visible in normal conjunctiva. With increase in number of vessels in the conjunctiva, the white conjunctiva become hyperemic. The bulbar conjunctiva is very loose 2-3 mm from the limbus and this laxity is used for sub conjunctival injection. A large amount of fluid can accumulate under this bulbar conjunctiva. The bulbar conjunctiva is transparent, moist and glistening in normal conditions. It is non keratanised but gets keratanised if exposed for long time as in lagophthalmos, proptosis, exophthalmos, ectropion of lower lid. It also gets keratanised in Vitamin A deficiency.

The limbus3, 4, 5. The limbus is an important surgical landmark of the eye. It is an ill defined arcuate zone that is junction of cornea on one side and conjunctiva and sclera on the other side. Besides having surgical importance the limbus has two more functions.

1.It supplies stem cells for corneal epithelium,

2.The limbal plexus are the sole sources of blood supply to the corneal periphery.

The limbus is a ring shaped zone widest superiorly and narrow on the side. The limbus has three lines that divide it into two surgical zones.

These lines are :

1.Anterior limbal border,

2.Posterior limbal border,

3.Mid limbal line.

The anterior limbal line represents the termination of conjunctiva and Tenons capsule at the corneal periphery, this overlies the termination of Bowman’s membrane.

The posterior limbal line lies over the scleral spur 2mm away, concentric with anterior limbal line. It’s presence is not well felt under operating microscope. It is best demonstrated under sclerotic scatter.3

The mid limbal line lies in between the anterior and posterior limbal line. It is 1 mm away from the anterior limbal line. It represents the termination of the Descemets membrane and overlies the Schwalbe’s line, looks blue under microscope and the limbus beyond it is white.

The limbus contains trabecular meshwork internally.4

The Caruncle. The caruncle developmentally is a part of the lower lid that gets separated from the lower lid by the developing lower canaliculus. It is a transient zone between the skin and the conjunctiva, hence has mucocutaneous functions and shares structure of skin as well as conjunctiva. It is an oval structure that lies medial to plical semilunaris in the medial canthus, has a size of 5mm x 3mm. It is covered by stratified epithelium. As a part of conjunctiva it has goblet cell, Krause’s cells and accessory lacrimal gland. As part of skin it is endowed by presence of hair follicles and sweat glands. It does not have any definite function but shares pathological processes common both to the skin and conjunctiva.

The plica semilunaris. This represents the vestigial nictitating membrane of the lower vertebrates. It is a crescent shaped fold of conjunctiva with concavity towards cornea lateral to the caruncle in the medial canthus. The lateral border is free with a blind recess underneath that disappears if the eye ball is moved laterally. Histopathologically it is similar to bulbar conjunctiva. It also contains melano phores and few non striated muscle fibers. It also does not have any definite function.

The Fornix6

The fornix is an irregular annular caul de sac formed by the junction of tarsal and bulbar conjunctiva. The caruncle and plica semilunaris intrude into it on the medial side. It is divided into four unequal parts : (1) The superior fornix, (2) The inferior fornix, (3) The lateral fornix and (4) The medial fornix

The superior fornix is largest and deepest of all conjunctival fornices. It is located at the level of superior orbital margin. The deepest part is at 12’O clock i.e. roughly 13 mm from the superior limbus. It gradually becomes shallow on either side. Few slips of levator palpebral superior are attached to the deeper surface of the conjunctiva to give it its depth. It is a common site for foreign bodies to be lost causing intractable conjunctival discharge. It is the only part of the conjunctiva that requires double eversion to examine.

The inferior fornix is smaller than superior fornix. It is located near the inferior orbital margin, its maximum depth is about 8mm at six o’ clock position.

The lateral fornix is more ill defined than the former two, it extends 14mm from equator on the lateral side.

The medial fornix is fully occupied by caruncle and plica semilunaris. The fornices have Krause’s gland on the deeper side.

Histology

Microscopically the conjunctiva is broadly divided into two parts—

1.The epithelium,

2.Substantia propria.

The conjunctival epithelium is multi layered stratified squamous in nature. It is multi layered. Number of layers vary at different locations. The substantia propria is a combination of lymphoid and fibrous tissue over which the epithelium rests. The lymphoid tissue is not present at birth. It takes three to four months for the lymphoid tissue to develop fully hence follicular reaction is not seen in new born. There are no lymphoid tissues in the inter marginal strip as well, even in adults.

The conjunctival glands. One of the functions of conjunctiva is to keep the ocular surface moist for which a stable tear film is a pre-requisite that is given by secretions from various glands present in the conjunctiva.

The glands of the conjunctiva are2, 6 :

1.The goblet cells

2.The gland of Krause

3.The gland of Wolfring and

4.Henles gland.

The goblet cells are not true glands, they are long unicellular structure. Density of goblet cell vary in various parts of conjunctiva. They are most numerous in fornices, less in bulbar conjunctiva and least in palpebral conjunctiva. Main function of goblet cells is to secrete mucin which is the inner most layer of tear film.

The gland of Krause. These are accessory lacrimal glands, they are similar to main lacrimal gland in structure, in development and function. They secrete aqueous part of tear film. Glands of Krause’s are found in depth of connective tissue in the fornices. The upper fornix has about 40 glands while the lower fornix has only 6-8 glands.

The gland of Wolfring. These are also accessory lacrimal glands. They are larger than Krause’s glands but far less in number. There are about 3-5 glands mostly in the upper palpebral conjunctiva at the upper border of superior tarsus.

Henles gland. Like goblet cells these also are not true glands. They are folds of mucous membrane between the tarsal conjunctiva and fornix.

Blood supply of the conjunctiva6. Conjunctiva is very rich in blood supply. This makes large conjunctival wounds to heal fast. The conjunctiva is supplied by palpebral branches

of nasal and lacrimal artery, anterior ciliary arteries. The conjunctival veins drain in superior and inferior ophthalmic veins.

The conjunctiva is very rich in lymphoid tissue and lymphatics. The lymphatic drainage from lateral half of the conjunctiva is in the pre auricular glands while those from the medial side drain in sub mandibular lymph nodes.

Nerve supply of the conjunctiva. The sensory supply of the conjunctiva is through trigeminal via frontal, nasociliary and lacrimal branches.

Development of the conjunctiva. Development of conjunctiva is closely associated with development of the lids. Epithelium of the conjunctiva develops from surface ectoderm like cornea. Rest of the conjunctiva is mesodermal in origin.2

Congenital anomalies of conjunctiva. Primary conjunctival anomalies of conjunctiva are few and rare. Most of the congenital anomalies are secondary to maldevelopment of the lids. Some of the congenital anomalies met with are : Epitarsus, Congenital lymphedema, Choristomas (dermoids and dermolipomas) and telangiectasia.

Epitarsus. This is a rare anomaly. There is an apron like fold of conjunctiva parallel to tarsal plate and attached to it. The edge of the fold is open. Both the surfaces are covered by mucosa, a probe can be passed between the tarsal conjunctiva and the inner surface of epitarsus for some distance. The epitarsus does not require any treatment. However foreign body may get lodged under this causing chronic infection. It may be confused as inflammatory membrane.

Congenital conjunctival lymphadenoma. In this rare condition there is congenital solid edema of the lid with similar edema of the limbs. There is a strong hereditary tendency. It may be present at birth or may develop at puberty.

Choristomas. These are common congenital growths of the conjunctiva. They have been defined as normal tissue at abnormal location.7 The dermoids were destined to be skin but were displaced on the eye. Conjunctival choristomas are of two types - dermoids and dermolipomas.

Dermoids are commonest epibulbar congenital tumours in children. They consist of both ectodermal as well as mesodermal tissue, the former consists of hair, sebaceous glands, nerves, smooth muscles while the latter consists of blood vessels cartilage. Commonest site being at the inferio temporal limbus, but can arise anywhere at limbus. It is generally single. Sometimes they develop solely on the cornea8 without involving the conjunctiva. When developing at the limbus they are observed to be astride on the limbus partly on cornea partly on conjunctiva. They vary in size. They may be very small and missed at birth and infancy. All dermoids have tendency to increase in size at puberty. They may be large enough to protrude through inter palpebral fissure. They are circular, raised dirty white coloured, may have central pigmentation. Conjunctiva over the dermoid can not be moved. The growth itself is fixed to the sclera. There may be small hairs on the surface of the growth which become prominent with age. The dermoid never show neoplastic change. Rarely they arise on the caruncle. Main symptom of dermoid is visible white growth against the black of the eye. It may be sufficiently large to obstruct the pupil and cause diminished vision. Even when it is seen partially over the cornea it produces irregular astigmatism. In rare instance a dermoid

may be found to extend inside the eye in the vicinity of iris and ciliary body. About one third case of limbal dermoids are associated with systemic syndromes out of which Goldenhar Gorlin syndrome is the commonest.

Treatment—Small dermoids need no treatment, larger dermoids have to be removed for cosmetic purpose.

Dermolipoma

This choristoma is less common than dermoid and develop away from the limbus. Commonest site being superior temporal aspect of fornix or lateral canthus. It is diffuse, soft in consistency. It mostly contains fat, other tissues like hair, skin or teeth are not present. The Conjunctiva can be moved over the growth. It has pale yellow colour. It may extend back in the orbit. It does not produce any visual change. It is better not to remove the growth unless there is facility to remove the tumour in toto may be by orbitotomy. Choristomas have been found in microphthalmos, Goldenhar’s syndrome, optic nerve anomaly and macular hypoplasia.

Congenital telangiectasis of conjunctiva. This is a hereditary anomaly of mucous membrane and skin. Out of the mucous membrane the conjunctiva is very commonly effected. It may be discovered at birth or infancy. Commonest age group being late adolescence and early adulthood. It may be associated with telangiectasia of retina. It may be seen anywhere on the conjunctiva but common site is bulbar and lower palpebral conjunctiva where it may be present as a star shaped bunch of vessels or a mass of vessels. As similar changes are seen in their mucous membranes the patient may have epistaxis, haematuria. Traumatic conjunctival bleeding is common. Small a telangiectasia may be obliterated by cryo.

SIGNS OF PATHOLOGICAL DISORDERS

Some pathological signs of conjunctival disorders are :

Last three groups are not encountered in paediatric age group.

Pallor of conjunctiva

Conjunctiva is highly vascular, normal conjunctiva is transparent through which the subconjunctival structures like meibomian glands are visible as bluish streaks. The vessels are visible as dark red streaks against the white sclera. In anaemia the conjunctiva like other mucous membranes become pale. Pallor of conjunctiva acts as a rough indication of presence of systemic anaemia. However conjunctiva can be blanched by instillation of vasoconstrictors. Conjunctiva may become pale as porcelain in alkali burn.

Hyperemia of conjunctiva. Increased vascularity of conjunctiva is the commonest sign of conjunctival disorder. It may be caused by abnormality of vessels or development

of abnormal vessels as telangiectasia or haemangioma. Conjunctival vessels may become dilated either by an active process that is arterial in origin, which is far more common than passive dilatation of conjunctival veins.

Active arterial dilatation is called conjunctival congestion or conjunctival injection. It can be acute or chronic, unilateral or bilateral. It can be localised or generalised. Simple hyperemia may not be associated with other changes but it is frequently accompanied by follicles, papillae and discharge in various combination.

Simple hyperemia is generally mild localised to fornices or on the bulbar conjunctiva. Transient hyperemia is universal following sleep that passes off after few minutes. Otherwise lack of sleep, uncorrected errors of refraction, fumes, dust, cold or hot wind are other causes of hyperemia. Reflex hyperemia is seen in cases of common cold, disorders of nasopharynx. Foreign body, inturned lash or entropion causes mechanical irritation of conjunctiva resulting into dilatation of vessels.

Commonest type of conjunctival congestion is seen in conjunctivitis infective or allergic. This type of inflammatory hyperemia should be differentiated from ciliary congestion.

Passive congestion of conjunctiva

Passive congestion of conjunctiva is less frequent in children. They are seen either in mechanical obstruction of venous flow or rarely due to increased blood viscosity. Mechanical causes of passive congestion of conjunctiva can be either in the globe, orbit or systemic.

Causes are :

1. Intraocular growth and absolute glaucoma.

2.Orbit—Proptosis, exophthalmos-Increased intra thorasic pressure, polycythemia.

3.Systemic.

Treatment of hyperemia of conjunctiva is directed towards the cause :

Non inflammatory congestion is treated by instillation of local vasoconstrictors. They produce immediate whitening of the eye that may last from few minutes to few hours only to appear again. There may be rebound congestion or tachyphylexis.

Inflammatory congestion is best treated either with antibiotics or anti-inflammatory as the case may be.

Pigmentation of conjunctiva

Commonest pigmentation of conjunctiva seen in children is staining of conjunctiva and sclera by bile pigment in various types of jaundice including neonatal jaundice. Pigmentation of jaundice is bilateral and most marked in the fornix. It does not require any ocular treatment.

Other types of pigmentations are deposits of melanin in conjunctiva as a part of congenital melanosis, melanotic tumours of conjunctiva, Addisons disease. Sometimes it is seen in keratomalacia, vernal catarrh and trachoma.

External pigments may be deposited in the fornices following prolonged use of local drugs like : Argyrosis following use of sliver containing drops. Adrenaline and many other drugs taken systemically can also cause pigmentation of the conjunctiva. Staining of dry conjunctiva by Kajal or Surma is very common in children in Indian subcontinent.

Chemosis of conjunctiva. Chemosis of conjunctiva is a very common feature of conjunctival disorder. It may be caused by— (1) Local conjunctival disease, (2) Intraocular disease, (3) Orbital disorder, or (4) Systemic disorder. There is either an increased permeability of arterial blood supply or stasis of venous flow. Impaired lymphatic drainage may also manifest as edema of conjunctiva. Chemosis of conjunctiva is unilateral in case of ocular or orbital causes. It is bilateral when the causative factor is systemic. Chemosis of conjunctiva may be mild giving a glossy appearance to the conjunctiva, moderate when the conjunctiva is lifted from the sclera and has a translucent fluid laden appearance or it may be severe enough to protrude the conjunctiva through the inter palpebral fissure. It may be congested when the causative factor is inflammatory. Chemosis is least marked in tarsal conjunctiva due to the firm attachment of the conjunctiva to the tarsal plate. The fornices may accumulate fluid without being noticed on the conjunctival surface presenting as puffiness of the lid. The lower lid chemosis of bulbar conjunctiva is most marked and obvious. It develops round the cornea like a crater. In severe chemosis the cornea may be hidden in the over hanging chemosed conjunctiva. If the conjunctiva remains exposed for sufficient time it may develop ulcers.

Causes of conjunctival chemosis are : 1. Allergy

(a) Exogenous allergy—As seen in seasonal allergic conjunctivitis.

(b) Endogenous allergen may produce picture similar to angio neurotic oedema. 2. Inflammation

(a) Hyper acute conjunctivitis—Ophthalmia neonatorum,

(b) Panophthalmitis,