CORNEACORNEA

Dr. Izar Aziz, dr., SpM(K)Dr. Izar Aziz, dr., SpM(K)

22

ANATOMY OF THE EYEANATOMY OF THE EYE

33

ANATOMY OF THE EYEANATOMY OF THE EYE

THE WALL OF THE EYE BALL IS COMPOSED OF A DENSE, THE WALL OF THE EYE BALL IS COMPOSED OF A DENSE, IMPERFECTLY ELASTIC SUPPORTING MEMBRANEIMPERFECTLY ELASTIC SUPPORTING MEMBRANE

THE ANTERIOR PART OF THE MEMBRANE IS THE ANTERIOR PART OF THE MEMBRANE IS TRANSPARENT TRANSPARENT THE THE CORNEACORNEA

THE ANTERIOR PART OF THE SCLERA IS COVERED BY THE ANTERIOR PART OF THE SCLERA IS COVERED BY MUCOUS MEMBRANE MUCOUS MEMBRANE THE THE CONJUNGTIVACONJUNGTIVA

44

THE CORNEA CONSIST OF FIVE LAYERS : - EPITHELIUMEPITHELIUM - - BOWMAN’S MEMBRANEBOWMAN’S MEMBRANE - - STROMA OR SUBSTANTIA PROPIASTROMA OR SUBSTANTIA PROPIA - - DESCEMET’S MEMBRANEDESCEMET’S MEMBRANE - - ENDOTHELIUMENDOTHELIUM

55

• THE EPITHELIUM REGARDED AS THE CONTINUATION OF THE CONJUNGTIVA OVER THE CORNEA

• THE SUBSTANTIA PROPIA REGARDED AS THE CONTINUATION FORWARD OF THE SCLERA

• THE STROMA FORMING 90 % OF THE TOTAL CORNEAL THICKNESS

66

• DESCEMET’S MEMBRANE IS A THIN ELASTIC MEMBRANE, COVERED ON ITS POSTERIOR BY ENDOTHELIUM

• THE PRIMARY MECHANISME CONTROLLING STROMAL HYDRATION IS A FUNCTION OF THE CORNEAL ENDOTHELIUM

• ENDOTHELIAL CELLS BECOME LESS IN NUMBER WITH AGE AND INDIVIDUAL CELL ENLARGE TO COMPENSATE

77

KERATITISKERATITIS

88

Function of the cornea :Function of the cornea :as as Window of the globe & refractive Window of the globe & refractive

mediamedia:: clear & transparent with power + clear & transparent with power +

42 D.42 D. as as microorganisms barriermicroorganisms barrier

99

Loss of transparency caused by:• endothelial damage• epithelial damage.

1010

KeratitisKeratitis : isinflammation of cornea ,caused bymicroorganism infectionantigen antibodies / allergic reaction.

1111

Epithelium covered by tear film :as a barrier Epithelium covered by tear film :as a barrier microorganisms infection . (except microorganisms infection . (except N. Gonorrhoea)N. Gonorrhoea)

Descemet’s membrane as barrier for Descemet’s membrane as barrier for bacterial infection to COA .(but not for bacterial infection to COA .(but not for fungus)fungus)

EtiologyEtiology of keratitis : of keratitis : Exogenous : bacteria ,fungus , virus, Exogenous : bacteria ,fungus , virus,

parasiteparasite Endogenous : allergic reaction.Endogenous : allergic reaction.

1212

Bacteria :Bacteria :--Pure PathogenPure Pathogen : Streptococcus : Streptococcus

pneumoniae, Pseudomonas aeroginosapneumoniae, Pseudomonas aeroginosa

--Opportunistic bacteriaOpportunistic bacteria : - : -Staphylococcus,Moraxella, Serratia(as Staphylococcus,Moraxella, Serratia(as flora at conjunctiva flora at conjunctiva

. Alcoholic/ B6 deficiency

.Topical steroid >>>

. Corneal abrasion

Pathogen bacteriaPathogen bacteria Corneal infection

1313

FungusFungus ( (usually opportunisticusually opportunistic))

Candida, Fusarium, AspergillusCandida, Fusarium, Aspergillus

VirusVirus VHSVHS VVZVVZ

Parasite Parasite : : AcanthamoebaAcanthamoeba

in in Contact lens userContact lens user

1414

Symptoms & SignsSymptoms & Signs SubjectiveSubjective ( (patient’s historypatient’s history ) )

painpain glare (photophobia)glare (photophobia) blur vision blur vision tearing (lacrimationtearing (lacrimation))

Objective Objective - - loupe or slit lamp examinationloupe or slit lamp examination blepharospasmeblepharospasme ciliary injection ciliary injection tearing (lacrimation)tearing (lacrimation) superficial infiltrate or corneal ulcersuperficial infiltrate or corneal ulcer hypopyon- hypopyon- in advanced cases.in advanced cases.

1515

1616

Special examinationsSpecial examinations : : Flourescein test for corneal ulcerFlourescein test for corneal ulcer Seidel test for perforating corneaSeidel test for perforating cornea

1717

Laboratory Studies Etiologic diagnosis.Scraping from:

infiltrate / edge of the ulcerfornices of conyunctiva

Slide Staining :Gram ( for bacteria)Giemsa (for fungus )

1818

Clinical courseClinical course

Subepithelial /epithelial keratitis

Recover without scar

Become corneal ulcer

Recover with scar

NebulaMakula

Leukoma

Perforating cornea, accompanied bulging of the cornea & iris prolaps

Recover with scar :Leukoma adherentstaphyloma cornea

Corneal blindness

Advanced inflamation

-endophtalmitis-panophtalmitis

recover Extirpation of the globe

Abulbi

Phtysis bulbi

Permanent blindness

1919

Clinical appearance of corneal Clinical appearance of corneal ulcersulcers

Serpeginous corneal ulcerSerpeginous corneal ulcer.. Etiology : PneumococcusEtiology : Pneumococcus acute, well circumscribed acute, well circumscribed gray ulcer, tends to spread to center of corneagray ulcer, tends to spread to center of cornea hypopyon is common (sterile)hypopyon is common (sterile)

2020

•Pseudomonas ulcer.• Etiology : Pseudomonas aerg. (present in Flourescein

sol.)• bluish-green exudate • very acute ,spread rapidly to all direction ,because proteolytic enzyme destroy the corneal stroma

descemetocele

2121

Marginal Ulcer Marginal Ulcer Etiology : StaphylococcusEtiology : Staphylococcus affect limbal area affect limbal area

Fungal ulcerFungal ulcer history: agriculture trauma history: agriculture trauma topical steroid usage >>>>topical steroid usage >>>>

gray Infiltrategray Infiltrate thick hypopyon & irregular surfacethick hypopyon & irregular surface satellite lesions - in endotheliumsatellite lesions - in endothelium

2222

Herpes Simplex keratitis.Etiology : VHS type Icorneal sensibility <<<lesion : filament, punctate, dendritic, disciform

2323

Mooren’s UlcerMooren’s Ulcer Etiology : antigen antibodies reactionEtiology : antigen antibodies reaction Progressive excavation of the limbus.Progressive excavation of the limbus.

2424

• KeratomalaciaEtiology : Vitamin A deficiencyadvance stage of xerosis conjunctiva & corneaNo ciliary injection

2525

TreatmenTreatmentt atropineatropine eye drops eye drops Anti microorganismsAnti microorganisms depend on depend on

laboratory finding (scraping & culture) laboratory finding (scraping & culture) Antibiotic for bacteriaAntibiotic for bacteria Anti fungus for fungal infectionAnti fungus for fungal infection Antiviral for viral infectionAntiviral for viral infection

High dose Vit. A for keratomalaciaHigh dose Vit. A for keratomalacia Steroid for Mooren’s ulcerSteroid for Mooren’s ulcer eye bandageeye bandage

2626

Prognosis Prognosis depends on :depends on : depth & width of the ulcerdepth & width of the ulcer

Corneal Corneal scarscar

2727

NebulaMakulaLeukomaLeukoma adherent

Central ,-->corneal

blindness-Periphery (No visual disturbance )

2828

PreventionPrevention

Avoid corneal traumaAvoid corneal trauma Avoid over use of topical steroid Avoid over use of topical steroid Cure external eye infection as Cure external eye infection as

soon as possible.soon as possible. Avoid trigger factor for relapsing Avoid trigger factor for relapsing

H.simplex keratitis. H.simplex keratitis.

2929

Have a nice Have a nice day !day !

3030

Reference BooksReference Books

Vaughn D, Asbury T; Vaughn D, Asbury T; General General Ophthalmology,Ophthalmology, 15th edition, 15th edition, Appleton & LangeAppleton & Lange

Miller S; Miller S; Parson’s Diseases of the Parson’s Diseases of the eye,eye, 17 th Edition, Churcill 17 th Edition, Churcill Livingstone, 1984Livingstone, 1984

Kanski JJ, Kanski JJ, Clinical Ophthalmology,Clinical Ophthalmology, 4th 4th edition,Oxford Butter Worth edition,Oxford Butter Worth Heineman Ltd, 1999Heineman Ltd, 1999