Sclera and Cornea Sclera and Cornea

cornea

Sclera

ScleraSclera

It forms the posterior portion of the globeIt forms the posterior portion of the globe It is perforated posteriorly by the optic nerve.It is perforated posteriorly by the optic nerve.

Parts of scleraParts of sclera

Episclera Episclera -- fibrous tissue containing fine fibrous tissue containing fine capillariescapillaries

Sclera properSclera proper -- collagen fibres of the stromacollagen fibres of the stroma Lamina fuscaLamina fusca -- located adjacent of the stromalocated adjacent of the stroma

Blood and nerve supplyBlood and nerve supply

Choroidal vessels is supplying blood to Episcleral part Anterior insertion of Recti muscles, the anterior ciliary

arteries form a dense episcleral plexes. These vessels becomes congestion of ciliary congestion.

Nerve supplyNerve supply

Short ciliary nerves posteriorly, Long ciliary nerves anteriorly provide sensory innervation.

Inflammation of episclera Simple Simple NodularNodular DiffuseDiffuse Necrotizing with inflammationNecrotizing with inflammation

without inflammationwithout inflammation

Types of scleritisTypes of scleritis Anterior scleritisAnterior scleritis Posterior scleritisPosterior scleritis

CorneaCornea

It is transparent part of the eye with circular wrist watch shapeIt is transparent part of the eye with circular wrist watch shape It is 10-11mm diameter It is 10-11mm diameter It is the most important refractive state of the eyeIt is the most important refractive state of the eye The junction of cornea and sclera is called limbus and also The junction of cornea and sclera is called limbus and also

important angle structure of the eye.important angle structure of the eye.

Part of corneaPart of cornea It has 5 layers in the anatomic structureIt has 5 layers in the anatomic structure

EpitheliumEpithelium -- corneal epithelium rests on a basement of membrane secreted by the basal cells.

Bowman’s membrane - Bowman’s membrane - condensation of substania propria

Stroma - collagen fibrils arranged inset of lamellae, lying parallel to the surface..

Decemet’s membrane - homogenous, very resistant membrane

Endothelium - single layer of flattened polygonal endothelial cells

Blood supply and nerve supply

Blood supply :Blood supply :Cornea is Cornea is avascularavascular structure. structure.

Nerve Supply :Nerve Supply : The cornea nerve, are derived from The cornea nerve, are derived from the long the long and short ciliary nerves of the and short ciliary nerves of the ophthalmic ophthalmic division of division of trigeminal trigeminal nerve.nerve.

Types of ulcersTypes of ulcers

Bacterial ulcerBacterial ulcer Fungal ulcerFungal ulcer Viral ulcerViral ulcer Parasitic ulcerParasitic ulcer

Degenerative conditionDegenerative condition Corneal dystrophiesCorneal dystrophies

Bacterial ulcerBacterial ulcer

It is defined as a break in the corneal It is defined as a break in the corneal epithelium with added infectionepithelium with added infection

InvestigationsInvestigations

Lacrimal sac syringingLacrimal sac syringing Diabetic statusDiabetic status Corneal scrappingCorneal scrapping

Gram and Giemsa stains for bacteriaGram and Giemsa stains for bacteria Culture on blood agar for aerobic organismsCulture on blood agar for aerobic organisms 10% KOH wet preparation for fungus10% KOH wet preparation for fungus Culture on Sabouraud’s dextrose agar for fungusCulture on Sabouraud’s dextrose agar for fungus

Viral Viral

Ulcer with a branched appearance caused by herpies Ulcer with a branched appearance caused by herpies simplex virus.simplex virus.

InvestigationsInvestigations

Sensation of corneaSensation of cornea Fluorescent stainFluorescent stain Enlarged and tender pre auricular lymph nodesEnlarged and tender pre auricular lymph nodes

KeratoconusKeratoconus

Bilateral conical protrusion of central part of the Bilateral conical protrusion of central part of the cornea due to thinning is called cornea due to thinning is called KeratoconusKeratoconus

In this condition we have to check keratometry to In this condition we have to check keratometry to know the astigmatismknow the astigmatism

Corneal dystrophiesCorneal dystrophies

Cornea loses its clarity due to deposition of materials Cornea loses its clarity due to deposition of materials in various layers of the cornea in various layers of the cornea it can be seen by it can be seen by ChildhoodChildhood

Types ofTypes of dystrophiesdystrophies

Epithelial dystrophyEpithelial dystrophy -- Map dot finger printMap dot finger print

Stromal dystrophyStromal dystrophy -- Granular or macular or Granular or macular or latticelattice

Endothelial dystrophyEndothelial dystrophy -- Fuch’s Fuch’s

Don’ts in a case of corneal ulcerDon’ts in a case of corneal ulcer

No BandageNo Bandage No steroid drop ( except viral)No steroid drop ( except viral) No schiotz tonometerNo schiotz tonometer