This document discusses diseases of the cornea. It provides details on the anatomy, layers, nerve supply, nutrition, and functions of the cornea. It describes pathological changes such as keratitis, corneal abrasions, ulcers, and opacities. It discusses infective keratitis in terms of pathogenesis, predisposing factors, common bacterial causes, symptoms, signs, and complications. The management of bacterial keratitis and treatment of uncomplicated versus perforated ulcers is also summarized.

1. DISEASES OF THE CORNEA

3. DIMENSIONS
 Ant surface
Elliptical
11-12 mm
10- 11 mm
 Posterior surface
circular
11.5mm
11.5mm
• Shape - Prolate

4.  Thickness centre 0.5-0.6 (thinner)
periphery 1.0-1.2mm
 Radius of ant.surface 7.8mm
curvature post surface 6.5mm (steeper)
 Refractive index 1.376
 Refractive power - + 45D (70% Of total
refractive power of the eye

5. LAYERS OF CORNEA

6.  Epithelial Layer – Regenerates
 Bowman’s Layer- Resistant to trauma and
infection
 Stroma – Collagen bundles with keratocytes
 Descemets layer- very tough
 Endothelium – hexagonal cells –
3000cells/mm2

7. Limbus
 1-1.5 mm
 anatomy
 Cells at limbus are unique – Limbal stem
cells
 Responsible for growth and regeneration of
epithelial cells

8. NERVE SUPPLY OF CORNEA
5th cranial nerve (Trigeminal)
Ophthalmic division
Nasociliary branch
Long ciliary nerves
Annular plexus around limbus
Subepithelialplexus Intraepithelial plexus
Cornea has body’s highest no. of nerve endings

9. NUTRITION METABOLISM
 Perilimbal capillaries
 Aqueous humour
(glucose diffussion)
 Atmospheric oxygen
(tear film)
 Epithelium &
endothelium
metabolically very
active
 Both aerobic &
anaerobic metabolism

10. CORNEAL TRANSPARENCY
 Avascularity
 Uniform refractive Index of the cornea
 Arrangement of corneal lamellae
 State of relative dehydration(78%)
Barrier effect Endothelial Osmotic
of epithelium pump gradient
& endothelium

11. FUNCTIONS OF CORNEA
 Transmission of light/Refractive medium
 Structural integrity of globe/Protects the eye

12. PATHOLOGICAL CHANGES IN
THE CORNEA
 Keratitis Superficial
Deep Stromal
Endothelial
 Corneal abrasion/erosion
 Corneal ulcer
 Corneal opacity Nebular, Macular, Leucomatous
 Corneal oedema
 Vascularisation

13. KERATITIS
MORPHOLOGICAL CLASSIFICATION
ULCERATIVE
 Suppurative/non
suppurative
 Superficial/deep/
perforated
NON
ULCERATIVE
Superficial
Diffuse sup. Keratitis
SPK
Deep
Non suppurating
Interstitial/disciform
Suppurating
Central/posterior corneal
abscess

14. KERATITIS
ETIOLOGICAL CLASSIFICATION
 Infective
 Allergic
 Trophic
 Asso. with skin &
mucous memb. ds
 Asso. with systemic
collagen vascular ds
 Traumatic
 Idiopathic
Moorens ulcer

15. INFECTIVE KERATITIS
PATHOGENESIS
Epithelial damage Infection
Corneal abrasion Exogenous
Epith. Drying Spread from ocular
tissue
Epith. Necrosis
Epith. desquamation Endogenous

16. PREDISPOSING FACTORS
 Ocular
- Trauma
- Contact lens
- lids and adenexal infections
- Topical medications
 Ocular surface diseases
- Dry eyes – Sjogrens syndrome,SJ synd. , Vit A def
- Prolonged Corneal Exposure - Proptosis, Lagophthalmos ,
ectropion
- Epi. Defect – Entropion , Trichiasis

17. PREDISPOSING FACTORS
 Systemic
- Diabetes mellitus
- Sjögren’s syndrome
- Steven johnsons syndrome
- Connective tissue disorders
- AIDS
- Measles malnutrition
 Occupational
- Farmers
- Animal handlers
- Gardeners

18. Bacterial corneal ulcers
 Agents :
Staphlococcus aureus/ albus
Streptococcus
Pseudomonas
Pneumococcus
N. gonorrhoeae
C. diphtheriae
E. coli

19. PATHOLOGY OF LOCALISED
CORNEAL ULCER
Stage of progressive infiltration-
progression of ulceration with leucocytes
infiltration and purulent suppuration
Stage of ulceration- desquamation of the
epithelium and tissue necrosis resulting in
saucer shaped ulceration
Stage of regression – characterized by
relatively smooth and transparent ulcer area
Cicatrization – Scar formation

20. STAGE OF PROGRESSIVE
INFILTRATION & ULCERATION
 Saucer shaped ulcer
 Walls project above normal surface
 Grey zone of infiltration
 Hypopyon
 Progress laterally or deeper

21. Stage of regression
 Line of demarcation
 Necrotic material shed off
 Begins to heal
 Vascularisation

22. Stage of cicatrisation
 If epithelium only-no scar
 NEBULAR- bowman’s membrane & superficial
stroma
 MACULAR- upto half of stroma
 LEUCOMATOUS-more than half of stroma
 Corneal facets

24. BACTERIAL CORNEAL ULCER
SYMPTOMS
Pain/ FB sensation
Redness
Watering
Photophobia
Blurred vision

25. SIGNS
#Lid oedema
#Blepharospasm
#Conjunctiva-Chemosis,Hyperaemia,Ciliary congestion
#Corneal ulcer-
Margins-swollen,over hanging
Floor-necrotic material
Stromal oedema around
#AC-hypopyon-mobile
#Iris-slightly muddy
#Pupil-small
#IOP-may be raised

27.  Symptoms are acute
 Severe clinical signs
 Rapid progression
 Wet looking ulcer area
 Purulent discharge

28.  Staphylococcus
aureus,Streptococcus pneumoniae-
oval, yellowish white densely opaque
ulcer which is surrounded by relatively
clear cornea

29.  Enterobacteriae (E. coli, Proteus species,
and Klebsiella species)- shallow ulcer with
greyish white pleomorphic suppuration and
diffuse stromal opalescence.
 The endotoxins may produce ring-shaped
corneal infiltrate.

30.  Pseudomonas - produce an irregular sharp
ulcer with thick greenish mucopurulent
exudate.
Diffuse liquefactive necrosis and
semiopaque (ground glass) surrounding
cornea.

31. Hypopyon corneal ulcer
 Cause- pneumococcus
 Source of infection-Chronic dacryocystitis
 Predisposing factors-virulence of organism
-resistance of the tissue
 Common in old debilitated or alcoholics

32. Dev.of hypopyon
 Iritis due to bacterial toxins
 Outpouring of leucocytes from vessels
 Leucocytes gravitate to bottom of AC
 Hypopyon (sterile & mobile )

33. Signs
 Ulcer serpens –greyish
white/yellowish disc shaped ulcer
near centre of cornea
 Starts at periphery & spreads towards
centre
 Tendency to creep over the cornea in
serpiginous fashion
 Iridocyclitis
 Hypopyon
 Perforation tendency +

34. COMPLICATIONS
 Toxic iridocyclitis
 Secondary glaucoma
 Descemetocele
 Perforation
Iris prolapse
Ant. Capsular cataract
Corneal fistula
Spontaneous expulsion of lens & vitreous
Intraocular haemorrhage Expulsive hmg.
Purulent uveitis Endophthalmitis/
Panophthalmitis
 Corneal scarring/ opacification

35. Descemetocoele

36. Perforated corneal ulcer with iris
prolapse

37. Management of corneal ulcer
 Clinical evaluation
 Lab investigations
 Treatment

38. Clinical evaluation
1.)History-mode of onset
2.)General physical exam.-
Anaemia ,nourishment,immunocompromising
disease
3.)Ocular examination

39. Lab investigations
 Routine
-Hb
-DLC
-ESR
-Blood sugar
-Urine & stool
examination
 Microbiological
-gram’s & giemsa smear
-10%KOH
-culture-blood agar
-SDA
-calcofluor white stain

40. TREATMENT
OF BACTERIAL KERATITIS
UNCOMPLICATED ULCER
 Identify & treat the cause
Corneal scraping
staining/culture
topical Antibiotics-ciprofloxacin 0.3%
-Ofloxacin 0.3%
-gatifloxacin 0.3%
 Rest to eye Cycloplegics- 1% atrophine
 Antiglaucoma medications
 Systemic antibiotics and analgesics
 Hot fomentation,dark googles

41. Treatment of Non-healing ulcer
of uncomplicated type
 Removal of any known cause of non-
healing corneal ulcer-local,systemic
 Mechanical debridement of ulcer
 Cauterisation of ulcer
 Bandage soft contact lens
 Peritomy

42. PERFORATED ULCER
Small < 3mm (impending perforation)
 IOP lowering drugs
 Pressure bandage
 Bandage contact lens
 Tissue adhesives
 Conj. flap
Large >3mm
 Therapeutic PK

43. COURSE OF CORNEAL
ULCER
Healing Deep penetration Sloughing
Descemetocele Pseudocornea
Perforation Ant. Staphyloma
Adherent Leucoma

44. THANK YOU!