Anatomy of Conjunctiva& Classification of

Conjunctivitis1

Contents

I. Anatomy of conjunctiva Parts of conjunctiva Structure of conjunctiva Glands of conjunctiva Blood supply Nerve supply

II. Types of conjunctivitis

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Parts of ConjunctivaI. Palpebral Conjunctiva

Marginal Conjunctiva extends from the lid margin to about 2mm on the back of the lid up to a shallow groove, the sulcus subtarsalis.

Tarsal Conjunctiva• Thin, transparent and highly

vascular.• In the upper lid – firmly

adherent to whole tarsal plate.• In the lower lid – adherent only

to half width of tarsus.• Tarsal glands seen through it as

yellow streaks.

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Orbital part, lies loose between the tarsal plate and fornix.

II.Bulbar Conjunctiva Thin, transparent Separated from the anterior sclera by episcleral

tissue and tenon’s capsule 3mm ridge around cornea – Limbal Conjunctiva In the area of the limbus, the conjunctiva, tenon’s

capsule and episcleral tissue are fused into a dense tissue, adherent to corneoscleral junction

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III. Conjunctival Fornix Joins the bulbar conjunctiva with the palpebral

conjunctiva Subdivided into superior, inferior, medial and lateral

fornices.

Plica Semilunaris : Pinkish crescentic fold of conjunctiva, persent in the medial canthus. It is a vestigeal structure in humans and represents the nictitating membrane of lower animals.

Caruncle : Small, ovoid, pinkish mass, in the inner canthus, just medial to the plica semilunaris. It is a piece of modified skin and hence is covered with stratified squamous epithelium, sebacious glands, etc.

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Structure of ConjunctivaI. Epithelium 2-5 layered, non-keratinized epithelium. Also

contains goblet cells. The layer of epithelial cells varies from region to

region• Marginal conjunctiva has 5 layered stratified

squamous type epithelium.• Tarsal conjunctiva has 2 layered epithelium:

superficial cylinderical and deep cuboidal cells.• Fornix & bulbar conjunctiva have 3

layered epithelium: superficial cylinderical, middle polyhedral and deep cuboidal cells.

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• Limbal Conjunctiva has again many layered (5 to 6) stratified squamous epithelium.

II. Adenoid Layer Also called lymphoid layer Consists of fine connective tissue reticulum in the

meshes of which lie lymphocytes. It is not present since birth but develops after 3-4

months of life. For this reason conjunctival inflammation in an infant does not produce follicular reaction.

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III. Fibrous Layer Consists of a meshwork of collagenous and

elastic fibres. This layer contains vessels and nerves of

conjunctiva It blends with the underlying Tenon’s capsule in

the region of the bulbar conjunctiva

Glands of Conjunctiva9

I. Mucin secretory glands These glands secrete mucus which is essential for wetting the cornea and conjunctiva.

Goblet cells: unicellular glands located within epithelium

Crypts of Henle: in tarsal conjunctiva Glands of Manz: in limbal conjunctiva

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II. Accessory lacrimal glands Glands of Krause: present in subconjunctival

connective tissue of fornices, about 42 in the upper and 8 in the lower fornix

Glands of Wolfring: present along the upper border of superior tarsus and along the lower border of inferior tarsus.

Blood Supply11

Arteries : that supply the conjunctiva are derived from three sources (1) peripheral arterial arcade of the eyelid (2) marginal arcade of the eyelid (3) anterior ciliary arteries• Palpebral conjunctiva and fornices are supplied by

branches from the peripheral and marginal arterial arcades of the eyelids.

• Bulbar conjunctiva is supplied by two sets of vessels: the posterior conjunctival arteries (branches from arterial arcade of eyelids) and the anterior conjunctival arteries (branches of anterior ciliary arteries) Terminal branches of the posterior and anterior conjunctival arteries anastomose to form pericorneal plexus.

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Veins : from the conjunctiva drain into the venous plexus of eyelids and some around the cornea into the anterior ciliary veins.

Lymphatics : are arranged in two layers – superficial and deep Lymphatics from the lateral side drain into pre auricular lymph nodes and those from medial side into the submandibular lymph nodes.

Nerve Supply14

A circumcorneal zone of conjunctiva is supplied by branches from long ciliary nerves, which supply the cornea.

Rest of the conjunctiva is supplied by the branches from lacrimal, infratrochlear, supratrochlear, supraorbital and frontal nerves.

Types of Conjunctivitis15

Inflammations of the conjunctiva (conjunctivitis) is defined as conjunctival hyperaemia, associated with a discharge, which maybe watery, mucoid, mucopurulent or purulent.

Types: Common types includeA. Infective Conjunctivitis

Bacterial Conjunctivitis• Acute bacterial conjunctivitis• Hyperacute bacterial conjunctivitis• Chronic bacterial conjunctivitis• Angular bacterial conjunctivitis

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Chlamydial Conjunctivitis• Trachoma• Adult inclusion conjunctivitis• Neonatal chlamydial conjunctivitis Viral Conjunctivitis• Adenovirus conjunctivitis• Enterovirus conjunctivitis• Molluscum contagiosum conjunctivitis• Herpes Simplex conjunctivitis Ophthalmia neonatorum Granulomatous conjunctivitis

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B. Allergic conjunctivitis Simple allergic conjunctivitis• Hay fever conjunctivitis• Seasonal allergic conjunctivitis• Perennial allergic conjunctivitis Vernal keratoconjunctivitis (VKC) Atopic Keratoconjunctivitis Giant papillary conjunctivitis Phlyctenular conjunctivitis Contact dermo conjunctivtis

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C. Cicatricial conjunctivitis Ocular mucous membrane pemphigoid (OMMP) Stevens Johnson syndrome Toxic epidermal necrolysis (TeN) Secondary cicatricial conjunctivitis

D. Toxic Conjunctivitis

Thank You

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