cornea for undergraduate
TRANSCRIPT
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Cornea
By/Mohamed Ahmed El –ShafieMohamed Ahmed El –Shafie
Assistant Lecturer in ophthalmology department KafrELShiekh University
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Anatomy of the Cornea
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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 ?)
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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”
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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
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Cornea gets its nutrition from:1. Limbal vessels2. Aqueous3. Tears
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Transparency of the Cornea1. Uniform structure2. Avascularity3. Deturgescence
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Clinical tests
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Corneal senstion test = corneal reflex test
= Blinking reflex
• Aim
• Technique
• result
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• 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
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KERATITISKERATITIS
SUPERFICIAL KERATITISSUPERFICIAL KERATITIS
INTERSTITIAL KERATITIS:INTERSTITIAL KERATITIS: Non Suppurative iflammation of the Stroma - Syphilis, T.B., Leprosy DEEP KERATITISDEEP KERATITIS
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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
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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
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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.)
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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
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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
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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
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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.)
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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
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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
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HYPOPYON ULCERHYPOPYON ULCER Predisposing Factors Causative Agents: Pneumococci ( 80% ) Clinical Picture
Symptoms Pain
Photophobia
Lacrimation
Blepharospasm Poor vision
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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 )
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Fungal UlcerFungal UlcerPredisposing Factors Trauma with green plant Use of Steroids Contact Lenses
Causative Agent Fusarium ( Filamentary fungi ) Candida ( Yeast forming fungi )
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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
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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
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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
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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
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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
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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
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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 )
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Traumatic Corneal ulcerTraumatic Corneal ulcer
Trauma + 2ry Infection
Trauma External: wounds, chemicals, burn & FB
Local: Lash, PTD & PTC
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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
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Band Shaped keratopathy Band Shaped keratopathy
Horizonal opacity ( in the interpalpebral area )
Hyaline degeneration + Ca deposition
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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)
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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 )
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KERATOGLOBUSKERATOGLOBUS Congenital enlargement of the Anterior
SegmentSigns Cornea: Large in diameter and curvature AC : Deep Iris : Tremulous Lens : Sublaxation
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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
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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-$100
B-Anterior staphyloma
C-Arcus senilis
D-Decematocele
A-Nebula
C-Arcus senilis
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15-$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-$100
Examination of cornea reveals:A-Nebula
B-Leucoma
C-Decematocele
D-keratoconus
B-Leucoma
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Examination of cornea reveals:A-Nebula
B-Leucoma adherent
C-Leucoma non-adherent
D-Keratectasia
15-$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
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Leucoma adherent
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Keratoconus ‘Munson sign’
ccorneaccornea