Transcript THE CORNEA

THE CORNEA
By
EMAD M. ELHADY MD
PROF. OF OPHTHALMOLOGY
FACULTY OF MEDICINE
ZAKKAZEEKK UNIVERSITY
THE CORNEA
GROSS ANATOMY
Anterior 1/6 of outer coat
Curved & Domshaped
Fibrous, Transparent & No BVs
Diameter : Horizontal 12mm
Vertical
11mm
Thickness: Central 0.5 - 0.6mm
Peripheral 0.8 – 1.0mm
Radius of Curvature : Anterior 8 mm
Posterior 7 mm
Refractive Index
: 1.37 ?
Refractive Power : 42 D ( what is Diopeter?)
( What is The LIMBUS ?)
MINUTE ANATOMY
5 LAYERS
(1) Epithelium
St. Squamous Nonkeratinised (5-6 layers)
Surface Flat cells (2-3 layers)
Intermed. Polyhedral cells (2-3 layers)
Basal Columnar cells (one layer)
(2) Bowman’s layer
Structure less (Acellular) condensation
Never regenerate
Ends as a round border
(3) THE STROMA (Substantia Propria)
- 90% of corneal thickness
- C T Bundles ( Regular arrangement )
- Bundles of each layer \\ to each other
perpendicular to next layer
- Cells ( present in Lacunae )
Corneal corpuscles ( Keratoblasts )
Corneal metabolism & Healing
Leucocytes
Inflammation
(4) DESCEMET’S MEMBRANE
Homogenous, Structureless & Highly Elastic
Resistant & Easily Regenerate
CORNEAL ENDOTHELIUM
One Layer of Polyhedral cells
Partial dehydration of the cornea
Continuous with the Endothelium of T M
NERVE SUPPLY OF THE CORNEA
5TH C.N
OPHTH. division
NASOCILIARY N
PAIN & COLD & SUPERFICIAL TOUCH
2 Long CILIARY N
CORNEAL PHYSIOLOGY
NUTRITION ( cornea is avascular )
By diffusion
Tear Film
Aqueous humour
Limbal capillaries
CORNEAL TRANSPARENCY ( WHY ? )
Anatomical Factors :
Cornea is avascular
Epithelium is nonkeratinized
Stromal lamellae are regular
Nerves are nonmyelinated
Precorneal tear film
Physiological Factors :
Corneal dehydration
Uniform refractive indices of corneal tissue
FUNCTIONS OF THE CORNEA
Refractive 42 D
Protective ( corneal reflex )
THE LIMBUS ( The Corneo-Scleral Junction )

Corneal epithelium
Conjuctival epithelium

Bowman’s membrane ends as a rounded border

Substantia propria

Descemet’s membrane

Endothelium
Sclera (irregular lamellae)
Trabecular meshwork
Endothelium of the angle of AC
KERATITIS
KERATOS
iTiS
CORNEA
INFLAMMATION
SUPERFICIAL KERATITIS
Suppurative (Corneal Ulcer)
NonSuppurative (Pannus)
INTERSTITIAL KERATITIS
Suppurative (Central Abscess)
NonSuppurative (Diffuse or Local)
DEEP KERATITIS
Suppurative (Post Abscess or Ulcer)
NonSuppurative (Keratitis Profunda)
SUPPURATIVE SUPERFICIAL
KERATITS
(CORNEAL ULCERS)
DEFINITION
Localized Necrosis of Sup. Stroma
with destruction of overlying Epith.
ETIOLOGY
Predisposing Factors
Precipitating Factors
Causative Organisms
Predisposing Factors
Local
a) Trauma
- Abrasion ( Gono & Diph can invade normal epithelium )
- FB , Rubbing lashes , PTDs , CL
b) Loss of corneal sensations
c) Ocular causes ( xerosis, A deficiency, Lagoph.)
d) Prolonged use of Steroids
General
malnutrition
Diabetes
Pregnancy
Liver & Renal Failure
PRECIPITATING FACTORS
Infection of nearby structures
CAUSATIVE ORGANISMS
a) Bacterial e.g. Gono, Diphth., Pneumo, Staph, Strept….
b) Fungal ( not common )
c) Viral e.g. Herpes Simplex and Zoster
d) Acanthamoeba (C.L.)
PATHOLOGY OF CORNEAL ULCERS
Stage of Infiltration
Inflammatory reaction PNLs
Grey disc shaped area - Oedema - Ciliary injection
Stage of ulceration
A) Progressive unclean Stage
Necrotic area
ulcer with irregular Edge
Necrotic Floor
Surrounded by Dense reaction
B) Regressive Clean Stage
Large ulcer with regular Edge
Deep, Clear, Transparent Floor
Less infiltration
Stage of Healing
A) Vascularization
Limbal cap.
Sup. Vasc.
AB & Fibroblasts
B) Fibrous tissue formation
NB :
Epith.
B.M.
Mitosis & Migration
Never regenerate
Permanent scar
Stroma
Irregular F.T.
D.M.
Regenerates as an elastic membrane
Endothelium
Nebula or Leucoma
Enlargement and Widening of cells
CLINICAL PICTURE
Symptoms
Pain
Severe ( FB or pricking sensation )
Irritation of nerve endings
Photophobia
Lacrimation
Blepharospasm
Diminution of vision
Signs
Lids: Oedema
Conj.: Ciliary injection
Cornea: Loss of luster, Grey infilt., Oedema & +ve FT
Iris:
Tender CB, Const. pupil & Aqueous flare
COMPLICATIONS OF CORNEAL ULCERS
A) Non Perforated corneal ulcer
Early Complications
(1) 2ry Iridocyclitis : ( Toxins )
(2) 2ry Glaucoma : Open angle glaucoma
(3) Descematocele : Small translucent bleb
Not seen in children or T hypopyon ulcer
Late Complications (Healing abnormalities)
(1) Corneal opacity ( Nebula, Macula or Leucoma non adherent )
(2) Corneal Facet : rapid healing of the epith.
(3) Keratectasia : ( weak corneal scar &
(4) Pseudoptregium
IOP )
B) COMP. OF PERFORATED CORNEAL ULCERS
Early Complications
(1) Iris Prolapse ( Big Para central or periph. Perforation )
(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
B) COMP. OF PERFORATED CORNEAL ULCERS (cont.)
Late complications
(1) Ant.Polar Cataract (Toxins )
(2) Leucoma Adherent ( Large Peripheral Perforation )
- AC
irregular
- Pupil pear shaped
- IOP may be high
- may be pigmented
(3) Ant. Staphyloma ( partial or total )
(4) 2ry Glaucoma (closed angle by PAS )
(5) Atrophia bulbi ( atrophy of the cil. processes )
MANAGEMENT OF CORNEAL ULCERS
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
Vitamins A & C
Analgesics
D) Treatment of Complications
(1) 2ry Glaucoma
Usual ttt
Antiglaucoma ttt
paracentesis
(2) Descematocele
Bilateral Bandage or C L
Avoid Straining
Antiglaucoma ttt
Hood Flap
PKP
(3) Perforation
Small
Large
CyanoacrylateTissue Adhesive
Hood Flap or PKP
E) Treatment of Corneal Opacity
Central Nebula
Glasses or CL
Eximer Laser
Lamellar KP
Leucoma
PKP
In blind eye
CCL
Tattoo
Treatment of Resistant CU
Scrapping for Culture & Sensitivity
Debridement
Cautery
Chemical
Physical
S.C. injection of AB
Conjunctivoplasty
Therapeutic KP (Lamellar or Penetrating)
CORNEAL ULCERS
Primary 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 Ulcer
Secondary Corneal Ulcers
HYPOPYON ULCER
Predisposing Factors
Causative Agents:
Pneumococci ( 80% ) Typical HU
Morax Axenfield Bacillus (10%)
Streptococci, Staphylococci, Pseudomonas and Fungi
Clinical Picture
Symptoms Pain
Photophobia
Lacrimation
Blepharospasm
Poor vision
Signs
( Acute Serpiginous ulcer )
- Haziness of the cornea ( loss of luster )
- Ciliary injection
- 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
- Flourescein Test is +ve
- Hypopyon in the Anterior Chamber
( Steril Pus ) PNL +Fibrin +Iris Pigment
NB
Perforation is common…why?
Desematocele is Rare
Treatment of Hypopyon Ulcer



Treatment of the cause ( Dacryocystectomy)
Usual ttt of corneal ulcer ABCD
Subconjunctival Injection of AB
Cephazoline ( 100mg in 0.5 ml )
Tobramycin or Amikacine ( 20mg in o.5 ml )

Fortified Eye Drops
Gentamycine or Tobramycine 15mg/ml.


Treatment of 2ry Glaucoma
Cautery in Resistant Cases ( Pure Carbolic A )
Atypical Hypopyon Ulcer
Pyogenic organisms other than Pneumococci (20%)
Common in children with increased resistance
The Ulcer :
Anywhere in the cornea
Not Serpiginous, spreads in all directions
Perforation is less common
Desematocele may occur
Fungal Ulcer
Predisposing Factors
Trauma with green plant
Use of Steroids
Contact Lenses
Causative Agent
Fusarium ( Filamentary fungi )
Candida ( Yeast forming fungi )
Aspergillus
Clinical Picture
Little or no ciliary Injection
Raised, dry, grey white lesion with feathery margins
Satellite lesions
Stromal deep infiltrate
Endothelial plaques
Hypopyon
Treatment




Usual ttt
Topical Antifungal ttt
Natamycine 5%
Miconazole 1%
Amphotericin B o.3%
Systemic Antifungal ttt
Ketoconazole 400mg/day
Fluconazole 400mg/day
( In cases of deep Keratitis or failure of topical ttt )
Surgical ttt (PKP)
Acanthamoeba keratitis



Aetiology
Protozoa ( Tap water and Swimming pools )
70% of cases are C L wearers
Clinical Picture
Punctate or Dendritic K
Superficial Stromal K
Partial or Complete ring of Infiltration
Limbitis and Scleritis
Treatment
Debridment
Topical ttt
Diamidines (Propamidine)
Biguanides (Chlorohexidine 0.02%)
Aminoglycosides (Neomycin)
Antifungal (Miconazole and Ketoconazole)
Dendritic 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 (as 1ry infection)
(B) Epithelial Keratitis
Symptoms : as those of corneal ulcer
Signs :
A) SPK
B) (Characters of 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
C) Stromal Keratitis (cell mediated immune reaction)



Interstitial Keratitis (unifocal or multifocal)
Disciform Keratitis (stromal inf. and epithelial odema +kps)
Necrotizing Keratitis Severe and rapidly progressive
Overlying ulceration eccentric to infiltration
-ve double stain
Vascularisations
D) Herpetic Iridocyclitis
Complications
Toxic punctate epithelial erosions (Antiviral drugs)
Keratitis Metaherpetica
Neurotrophic Keratitis
Treatment of Herpetic Epithelial Keratitis
Local Antiviral Drugs
Acyclovir ( Zovirax ) 3% eye ointment 5 times/day
TFT ( Tri-Fluro-Thimidine ) eye drops
Ara-A ( Vidarabine ) eye ointment
IDU ( Iodo-deoxy-uridine ) eye drops
NB Corticosteroids are contraindicated
Treatment of Stromal H Keratitis
Topical Corticosteroids
Prophylactic Antiviral drugs
Treatment of resistant cases
Debridement ( to remove infected cells )
Cautery by Tinct. Iodine 7% in alcohol (kill the virus)
Therapeutic L K
Herpes Zoster Ophthalmicus
Varicella-Zoster Virus
Neurotropic Virus
Old age Immunity
Clinical Picture :
Lids
: Dermatoblepharitis ( pain and rash )
Keratitis : ( Hutchinson’s rule )
Epithelial Keratitis ( Punctate or dendritic )
Interstitial Keratitis
Scleritis
Iris
: 2ry iridocyclitis
IOP
: 2ry glaucoma
Choroid : Focal choroiditis
Clinical Picture of H Z Ophthalmicus
Retina
: retinal vasculitis,detachment and necrosis
Optic Nerve: Papillitis or Retrobulbar neuritis
Orbit
: Orbital oedema and Proptosis
EOM
: Paralytic Squint (3rd N. palsy)
Treatment:
Acyclovir tab. 800mg 5 times/ day for 7 days
Steroids + Antibiotic skin oint.
Steroids + Antibiotic eye drops
Analgesics
Ulcer with Lagophthalmos
A primary ulcer in the lower 1/3 of the cornea
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
ttt of the cause
Keratomalacia

Non infective ulceration and melting of the cornea
Vitamin A (malnourished infants or malabsorption in adults)

Clinical Picture
Loss of corneal luster
Appearance of yellow dots (deg. Epithelium)
Melting of the cornea
No inflammatory reaction (quite eye)
Corneal hypothesia
Conjunctiva: dry with Bitot’s spots
2ry infection
Endophthalmitis

Treatment
Vit. A injection (200,000 IU/day)
ttt of hypoproteinemia ( fresh plasma)
Topical vit. A in early cases
Surgical ttt in late cases : Conj. Flap
Therapeutic CL
PK
Neurotrophic (Neuroparalytic) Keratitis
Corneal Sensation
Aetiology
Herpes Zoster
Radical ttt of 5th Neuralgia ( Alcohol inj.)
Damage of Orbital Ns (SOF & OA syndromes)
Clinical Picture
Symptoms
Signs
No pain
vision (central ulcer)
Epithelial exfoliation starts at the center
Large deep ulcer
perforation
Treatment
Usual ttt of corneal ulcer
Long term Bandage
Tarsorraphy ( median )
Traumatic Corneal ulcer
Trauma + 2ry Infection
Trauma
External: wounds, chemicals, burn & FB
Local: Lash, PTD & PTC
Treatment
Usual ttt + ttt of the cause
Mooren’s Ulcer ( chronic serpeginous ulcer )
1ry non infective corneal ulcer
Rare
Common in old age
Aetiology
( unknown )
Limbal vasculitis
Autoimmune disease
Symptoms
Signs
Proteolytic enzymes
necrosis of sup. layers
12345
Marginal grey infiltration
Crescentic Ulcer
Advanced edge ( undermined and creeps toward the center )
Healed edge ( Peripheral and vascularised )
Thin cornea
Extension is slow and perforation is rare
Treatment
Usual ttt + Topical Steroids
Topical Cyclosporine
Conj. Excision // to the ulcer
Lamellar keratoplasty
Systemic Steroids & Immunosuppressive drugs
Atheromatous Corneal Ulcer
Occurs on top of an old Leucoma
Hyaline degeneration with desquamation and 2ry infection
Resistant with bad healing
Commonly perforates due to 2ry infection
Treatment
Usual ttt
Conjunctival flap
Keratoplasty
Secondary Corneal Ulcers

Ulcers 2ry to MPC
Marginal, Crescentic and Superficial ( Rare )
Rapid healing

Ulcers 2ry to Gonococcal Conjunctivitis
Marginal ulcer : Most common
Ring ulcer : Multiple marginal ulcers
Central and paracentral ulcers : usually perforate

Trachomatous Ulcers
A) Typical Shape Horizontal
Site In front of pannus
Superficial
Secondary infection is common
Scarred by facet ( Healing )
B) Marginal, Central and Paracentral: not related to Pannus
C) Mechanical: PTDs or Rubbing lashes
2ry Corneal Ulcers

Phlyctenular Ulcers
A) Limbal ulcer: ( ulcer of limbal phlycten )
Deep, when perforate
peripheral Leucoma Adherent
B) Ring ulcer: multiple phylectens
C) Fascicular ulcer: Superficial
Starts near the limbus
Creeps to the center followed by leash of B.V.
INTERSTITIAL KERATITIS
Non Suppurative iflammation of the Stroma + Uveitis
Aetiology
Delayed hypersensitivity to infectious organism
- Syphilis, T.B., Leprosy
- Herpes Simplex and Zoster, Measles and EBV (infectious M.)
Types
(1) Diffuse I.K.
(2) Dsciform Keratitis
Syphilitic Interstitial Keratitis

Congenital Syphilis ( 95% )
5 – 15 Years
Bilateral
Hutchinson’s triad ( I.K., Hutchinson’s teeth and Deafness )

Acquired Syphilis ( 5% )
10 years after 1ry infection
Unilateral
Uveitis and Retinitis
Symptoms
Pain, photophobia, lacrimation, redness and
vision
Signs of Syphilitic I.K.
( 1 ) Progressive Stage ( 2 weeks )
Severe infiltration ( haze ) + Vascularization
Salmon patches ( reddish pink )
Ciliary injection
( 2 ) Florid stage ( 2 months )
Marked symptoms and signs
vision up to HM
( 3 ) Regressive stage ( 2 years )
Residual interstitial corneal opacity
Obliterated BV
fine opaque lines
Uveitis
Investigations
+ve Wassermann reaction
Treatment of Syphilitic I.K.
-
-
Antisyphilitic ttt ( Penicillin )
Atropine
Steroids
Keratoplasty for residual opacity
DISCIFORM KERATITIS
Antigen antibody reaction ( viral antigen )
H.S. & H.Z.
Grey disc-shaped dense opacity
Loss of corneal sensation
Drop of vision
Treatment
Corticosteroids + Antiviral drugs
Tarsorraphy
Keratitis profunda
Localised non suppurative deep Keratitis
Aetiology
Allergic reaction to chronic infections e.g. TB
Herpes Simplex or Zoster
Trauma
Idiopathic
Clinical Picture
Diffuse deep Keratitis
Iridocyclitis
Posterior Abscess and Ulcer
Diffuse suppurative deep Keratitis
Congenital, HU, Trauma, IK and endogenous with TB and S.
Degenerative Conditions
ARCUS SENELIS
Bilateral peripheral Fatty degeneration
Common in old age
Symptoms non
Signs
Arc shaped opacity in the upper ½ of cornea then lower ½
Clear zone between the opacity and Limbus (Lucid interval of vogt)
Outer border is sharp and well defined
Inner border is diffuse and illdefined
NB ARCUS JUVENILIS may occur in hyperlipidemia or juv. DM
Band Shaped keratopathy
Horizonal opacity ( in the interpalpebral area )
Old degenerated eyes
Hyaline degeneration + Ca deposition
KERATOCONUS

Definition
Progressive conical protrusion of the cornea
Starts at Puberty
Weakness of central part

Incidence
Females _ Atopy
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 seen by
Profile view
Notching of the L.L. on looking down
Manson’
Slit Lamp
Thin apex and deep A.C.
- Deep opacity at the apex of the cone
Rupture of BM
Folds of DM
- Fleisher ring: brown ring the cone base ( hemosidren deposition )
DD
Ant. Staph. -
Keratectasia
-
Keratoglobus
Treatment
- Early casrs : Glasses or hard CL
Corneal Collagen Cross linking with Riboflavin
- Late cases : PKP
KERATOGLOBUS
Congenital enlargement of the Anterior Segment
Signs
Cornea: Large in diameter and curvature
AC : Deep
Iris : Tremulous
Lens : Sublaxation
Refraction: Stationary myopia
DD
: Buphthalmos
Treatment: Glasses
KERATOPLASTY

Aim: Replacing the opaque part by a clear cadaveric cornea

Types:
- Lamellar ( Superficial )
- Deep ( Penetrating )
NB: Both of them may be partial or total
- Tectonic : Has a specific shape according to site and indication

Indications:
- Optical
a) Central corneal opacities
b) Keratoconus
- Therapeutic a) Resistant corneal ulcer
b) Corneal fistula