Cornea

By/Mohamed Ahmed El –ShafieMohamed Ahmed El –Shafie

Assistant Lecturer in ophthalmology department KafrELShiekh University

Anatomy of the Cornea

Anterior 1Anterior 1/6 of outer coat /6 of outer coat

Curved & Domshaped

Fibrous, Transparent & No BVsFibrous, Transparent & No BVs

Diameter : Horizontal 12mmDiameter : Horizontal 12mm Vertical 11mm Vertical 11mm Thickness: Central 0.5 - 0.6mm Thickness: Central 0.5 - 0.6mm Peripheral 0.8 – 1.0mmPeripheral 0.8 – 1.0mm Refractive Power : 42 D Refractive Power : 42 D

( What is The LIMBUS ?)( What is The LIMBUS ?)

5 Layers of the Corneaa.Epithelium: 5-6 layers of cellsb.Bowman’s membrane: clear acellular layerc.Stroma: 90% of corneal thickness

collagen fibrils that are parallel to each other

d.Descemet’s membrane: basal lamina of corneal endotheliume.Endothelium: single layer of cells which act as a “pump”

NERVE SUPPLY OF THE CORNEANERVE SUPPLY OF THE CORNEA

55THTH C.N C.N

OPHTH. division NASOCILIARY N 2 LongOPHTH. division NASOCILIARY N 2 Long CILIARY NCILIARY N

PAIN & COLD & SUPERFICIAL TOUCHPAIN & COLD & SUPERFICIAL TOUCH

Cornea gets its nutrition from:1. Limbal vessels2. Aqueous3. Tears

Transparency of the Cornea1. Uniform structure2. Avascularity3. Deturgescence

Clinical tests

Corneal senstion test = corneal reflex test

= Blinking reflex

• Aim

• Technique

• result

• Causes of lost corneal reflex

• Receprors:Keratitis: HSV,HZV, Keratomalacia,Corneal scarsHigh IOPTopical anaeathesiaCL

• Afferent:• Center :• Efferent:

5th n. lesion

Occipital cortex lesion

7thh n. lesion (facial palsy)

Corneal reflex

KERATITISKERATITIS

SUPERFICIAL KERATITISSUPERFICIAL KERATITIS

INTERSTITIAL KERATITIS:INTERSTITIAL KERATITIS: Non Suppurative iflammation of the Stroma - Syphilis, T.B., Leprosy DEEP KERATITISDEEP KERATITIS

SUPPURATIVE SUPERFICIALSUPPURATIVE SUPERFICIAL KERATITSKERATITS

(CORNEAL ULCERS) (CORNEAL ULCERS)DEFINITIONDEFINITION Localized Necrosis of Sup. Localized Necrosis of Sup.

StromaStroma with destruction of overlying with destruction of overlying

Epith.Epith.

ETIOLOGYETIOLOGY Predisposing FactorsPredisposing Factors

Causative OrganismsCausative Organisms

Predisposing Predisposing FactorsFactors

LocalLocal a) Traumaa) Trauma - Abrasion - Abrasion -- FB , Rubbing lashes , PTDs , CLFB , Rubbing lashes , PTDs , CL b) Loss of corneal sensationsb) Loss of corneal sensations c) Ocular causes c) Ocular causes ( ( xerosis, A deficiency, Lagoph.).) d) Prolonged use of Steroidsd) Prolonged use of Steroids

GeneralGeneral malnutrition Pregnancymalnutrition Pregnancy Diabetes Liver & Renal FailureDiabetes Liver & Renal Failure

CAUSATIVE ORGANISMSCAUSATIVE ORGANISMS

a) Bacterial e.g. Gono, Diphth., Pneumo, a) Bacterial e.g. Gono, Diphth., Pneumo, Staph, Staph, StreptStrept….….

b) Fungal ( not common )b) Fungal ( not common )

c) Viral e.g. Herpes Simplex and Zosterc) Viral e.g. Herpes Simplex and Zoster

d) Acanthamoeba (C.L.)d) Acanthamoeba (C.L.)

CLINICAL PICTURECLINICAL PICTURESymptomsSymptoms Pain Severe ( FB or pricking sensation )Pain Severe ( FB or pricking sensation ) Irritation of nerve endingsIrritation of nerve endings PhotophobiaPhotophobia LacrimationLacrimation BlepharospasmBlepharospasm Diminution of visionDiminution of visionSignsSigns Lids: OedemaLids: Oedema Conj.: Ciliary injectionConj.: Ciliary injection Cornea: Loss of luster, Grey infilt., Cornea: Loss of luster, Grey infilt.,

Oedema & +ve FTOedema & +ve FT Iris: Tender CB, Const. pupil & Iris: Tender CB, Const. pupil &

Aqueous flareAqueous flare

COMPLICATIONS OF CORNEAL COMPLICATIONS OF CORNEAL ULCERSULCERS

A) Non Perforated corneal ulcer Early Complications (1) (1) 2ry Iridocyclitis : ( Toxins )2ry Iridocyclitis : ( Toxins ) (2) 2ry Glaucoma(2) 2ry Glaucoma : Open angle glaucoma : Open angle glaucoma (3) Descematocele :

Late Complications (Healing abnormalities) (1) Corneal opacity ( Nebula, Macula or Leucoma non adherent

)

(2) Keratectasia:( weak corneal scar)

(3) Pseudoptregium

B) COMP. OF PERFORATED CORNEAL B) COMP. OF PERFORATED CORNEAL ULCERSULCERS

Early Complications

(1) Iris Prolapse (2) Anterior synechia ( Small periph. Perforation)(3) Corneal Fistula ( Small central perforation ) Lost AC IOP River Green Sign(4) Malposition of the Lens Sublaxation Ant. Dislocation Extrusion(5) Intra-ocular Hge Hyphema Vit., Ret. And choroidal hges(6) Macular and Optic Disc Oedema

(7) Endo or Panophthalmitis

Late complications

(1) Ant.Polar Cataract (Toxins )

(2) Leucoma Adherent ( Large Peripheral Perforation )

- AC irregular - Pupil pear shaped

(3) Ant. Staphyloma ( partial or total )(4) 2ry Glaucoma (closed angle by PAS )(5) Atrophia bulbi ( atrophy of the cil. processes )

B) COMP. OF PERFORATED CORNEAL ULCERS B) COMP. OF PERFORATED CORNEAL ULCERS (cont.)(cont.)

MANAGEMENT OF CORNEAL MANAGEMENT OF CORNEAL ULCERSULCERS

INVESTIGATIONS + TREATMENT

A) Corneal Scrapping ( Culture & Sensitivity ) Gram Stain for Bacteria Geimsa Stain for Trachoma & Acanthamoeba Silver Stain for Fungi

B) Local ttt (1) Atropine sulphate 1% (3) Bandage or Dark Glasses (4) Counter irritant (2) Dressings ( Antibiotic dps & oint )

C) Systemic ttt Antibiotics Analgesics Vitamins A & C

CORNEAL ULCERSCORNEAL ULCERSPrimary Corneal Ulcers - Infected Corneal ulcer Hypopyon Ulcers

(Bacterial) Herpetic Ulcers (Viral) Mycotic Ulcers (Fungal) Acanthamoeba K

(Protozoa) - Non-Infected Corneal ulcer Mooren’s Ulcer Keratomalacia Atheromatous Ulcer Ulcer with Lagophthalmos Neuroparalytic Ulcer Traumatic UlcerSecondary Corneal Ulcers

HYPOPYON ULCERHYPOPYON ULCER Predisposing Factors Causative Agents: Pneumococci ( 80% ) Clinical Picture

Symptoms Pain

Photophobia

Lacrimation

Blepharospasm Poor vision

Signs ( Acute Serpiginous ulcer )

- Ulcer Near the centre Central advancing Edge

Crescentic, undermined, preceded by dense infiltration

Peripheral Healing Edge Flat, Epithelialized, Vascularized

- Posterior Abscess : Dense infiltration in front of D M

- Hypopyon in the Anterior Chamber ( Sterile Pus )

Fungal UlcerFungal UlcerPredisposing Factors Trauma with green plant Use of Steroids Contact Lenses

Causative Agent Fusarium ( Filamentary fungi ) Candida ( Yeast forming fungi )

Acanthamoeba keratitisAcanthamoeba keratitis Aetiology

Protozoa ( Tap water and Swimming pools ) 70% of cases are C L wearers

Clinical Picture

Punctate or Dendritic K

Partial or Complete ring of Infiltration

Dendritic Corneal UlcerDendritic Corneal Ulcer

Herpes Simplex Virus ( Epitheliotropic ) 1ry infection in early childhood Dormant in 5th Ganglion Recurrence with body resistance

Predisposing factors Fevers (Influenza, Common cold and

Pneumonia) Menstruation Drugs ( Immunosuppressive drugs or Steroids)

Clinical Picture 1ry Ocular infection Dermato-blepharitis Follicular Conjunctivitis Epithelia Keratitis

Recurrent Ocular Infection (C/P of H. Keratitis)

(A) Blepharoconjunctivitis (B) Epithelial Keratitis: Dendretic Herpetic Corneal

Ulcer Dendritic appearance Long course with tendency to Recurrence Superficial ( never perforate except in … ) Never Vascularised Hypothesia Double Stain Test C) Amoeboid Ulcer due to immunity or local Steroids

Herpes Zoster OphthalmicusHerpes Zoster Ophthalmicus Varicella-Zoster (Neurotropic) Virus Old age - Immunity

Clinical Picture : Lids : Dermatoblepharitis ( pain and rash )

Keratitis : ( Hutchinson’s rule ) Epithelial Keratitis ( Punctate or dendritic ) Interstitial Keratitis

Ulcer with LagophthalmosUlcer with Lagophthalmos Bell’s phenomena

Symptoms as usual corneal ulcer ( of vision is not marked..why?)

Signs Incomplete lid closure Ciliary injection & +ve flurorescein Ulcer in lower 1/3 with straight upper border

Treatment Usual ttt Methyl cellulose drops 0.5% several times/day

KeratomalaciaKeratomalacia

Non infective ulceration and melting of the cornea Vitamin A (malnourished infants or malabsorption in adults)

Clinical Picture Loss of corneal luster Melting of the cornea Corneal hypothesia Conjunctiva: dry with Bitot’s spots

Treatment Vit. A injection (200,000 IU/day) Topical vit. A in early cases Surgical ttt in late cases : Conj. Flap Therapeutic CL PK

Neurotrophic (Neuroparalytic) Neurotrophic (Neuroparalytic) KeratitisKeratitis

Corneal Sensation

Aetiology Herpes Zoster

Clinical Picture Symptoms No pain vision (central ulcer) Signs Large deep ulcer

perforation

Treatment Usual ttt of corneal ulcer Long term Bandage Tarsorraphy ( median )

Traumatic Corneal ulcerTraumatic Corneal ulcer

Trauma + 2ry Infection

Trauma External: wounds, chemicals, burn & FB

Local: Lash, PTD & PTC

Degenerative ConditionsDegenerative Conditions

ARCUS SENELIS Bilateral peripheral Fatty degeneration Common in old age

Symptoms nonSignsClear zone between the opacity and Limbus (Lucid interval of

vogt)

NB ARCUS JUVENILIS may occur in hyperlipidemia or juv. DM

Band Shaped keratopathy Band Shaped keratopathy

Horizonal opacity ( in the interpalpebral area )

Hyaline degeneration + Ca deposition

KERATOCONUSKERATOCONUS Definition Progressive conical protrusion of the cornea Starts at Puberty Weakness of central part Incidence Bilateral +ve family history Symptoms Gradual of vision - Myopia ( Curvature & Axial ) - irregular Astigmatism - Opacity at the apex of the

cone Sudden of vision (Acute Hydrops i.e. acute edema

due to rupture of DM)

Signs of Keratoconus

A) Early

Retinoscopy ( RR is spinning or scissoring ) placido disc: ring distortion Keratometer

B) Late

- Cone shaped central cornea Notching of the L.L. on looking down Manson’ Slit Lamp Thin apex and deep A.C.

- Fleisher ring: brown ring the cone base ( hemosidren deposition )

KERATOGLOBUSKERATOGLOBUS Congenital enlargement of the Anterior

SegmentSigns Cornea: Large in diameter and curvature AC : Deep Iris : Tremulous Lens : Sublaxation

KERATOPLASTYKERATOPLASTY Aim: Replacing the opaque part by a clear

cadaveric cornea Types: - Lamellar ( Superficial ) - Deep ( Penetrating ) NB: Both of them may be partial or total

Indications: - Optical a) Central corneal opacities b) Keratoconus - Therapeutic a) Resistant corneal ulcer b) Corneal fistula

Examination of cornea reveals: 15-$1 Million

14-$500,00013-$250,00012-$125,00011-$64,00010-$32,0009-$16,0008-$8,0007-$4,0006-$2,0005-$1,0004-$5003-$3002-$2001-$100

B-Anterior staphyloma

C-Arcus senilis

D-Decematocele

A-Nebula

C-Arcus senilis

15-$million

14-$500,000

13-$250,000

12-$125,000

11-$64,000

10-$32,000

9-$16,000

8-$8,000

7-$4,000

6-$2,000

5-$1,000

4-$500

3-$300

2-$200

1-$100

Examination of cornea reveals:A-Nebula

B-Leucoma

C-Decematocele

D-keratoconus

B-Leucoma

Examination of cornea reveals:A-Nebula

B-Leucoma adherent

C-Leucoma non-adherent

D-Keratectasia

15-$million

14-$500,000

13-$250,000

12-$125,000

11-$64,000

10-$32,000

9-$16,000

8-$8,000

7-$4,000

6-$2,000

5-$1,000

4-$500

3-$300

2-$200

1-$100

A-Nebula

Leucoma adherent

Keratoconus ‘Munson sign’

ccorneaccornea