Infection of the Cornea of Eye. Presentation by Dr. Haseeb Ahmed Bhatti during his years of MBBS study at Ziauddin University .

1. Microbial
Keratitis
By
Haseeb Ahmed Bhatti
Ziauddin Medical College

2. CORNEA
The cornea is a round, convex, transparent,
avascular structure that forms the anterior one-
sixth of the outer coat of eyeball

3. •Vertical diameter is 10.6mm
•Horizontal diameter is11.7mm
•Cornea is thinnest at its center and
thicker at periphery
•Is avascular and devoid of lymphatic
drainage
•Nerve supply is from long ciliary
nerves, a branch of the ophthalmic
division of trigeminal nerve.
•Refractory power = +43diopter

4. Histologically
consists of five
layers
• The epithelium
• The bowman’s
membrane
• The stroma
• The
descement’s
membrane
• The
endothelium

5. Microbial/Infective Keratitis
Inflammation of the cornea,
resulting from the menace of
micro-organisms.
The keratitis may be :
1. Bacterial
2. Fungal
3. Viral
4. Protozoal

6. Bacterial Keratitis
Most common-Suppurative corneal ulceration
Etiology
 Staphylococcus aureus
 Streptococcus pneumoniae
 Niesseria gonorrhea
 Hemophilus influenza
 Pseudomonas aerogenosa
 Moraxella
 Other gram –ve bacilli

7. Predisposing Factors
1. Corneal epithelial trauma
2. Contact lens Wearers
3. Aqueous tear deficiency
4. Chronic use of Steroids
5. Hypovitaminosis A

8. Pathogenesis of Corneal ulcer
Occurs through four stages:
1) Infiltrative stage: Injury to epithelium causes
inflammation, with PMN cell infiltrates and
edema, giving rise to a yellow/white corneal
opacity
2) Active stage: Necrosis and sloughing off of
epithelium causing ulcer formation.
3) Regressive stage: A line of demarcation
develops around the ulcer consisting of
leucocytes while the surrounding cornea
becomes clear. This is induced by treatment or
natural host mechanisms.
4) Cicatrization stage: Healing by

9. Symptoms
 Sudden/Rapid onset
 Pain
 Foreign body sensation
 Photophobia
 Blurred vision
 Redness of eye
 Muco-purulent Discharge

10. Bacterial
corneal
Ulceration
with
Accumulation
of
Pus inside
the
Eye –Anterior
chamber
(hypopyon).

11. Signs
 Upper eyelid Edema and discharge
 Cunjuctival hyperemia
 Surrounding corneal inflammation (focal
or difffuse) - Haziness
 Ulceration of epithelium
 Corneal Stain positive
 Hypopyon/Sterile pus
 Raised IOP

12. Acute
painful red
eye with
White spot
on Corneal
surface.

13.  Strep-
pneumonia
Corneal ulcer

14. Management
 Admission if Necessary
 Proper History & Examination
 Investigations
Baseline
Microbiological - C/S
 Treatment

15. Treatment
1. Infection Control – Antibiotics
 Dual therapy (Aminoglycoside+cephalosporin)
 Mono therapy (Flouroquinolones)
 Systemic (Ciprofloxacin 750mg bd)
2. Atropine 1%
 Pain relief
 Prevent posterior synechie formation
 Decrease exudation by decreasing capillary
permeability

16. 3. Antigluacoma drugs
 Decrease IOP
4. Prevention of perforation
 Pressure bandage
 Conjuctival flap
 Therapeutic corneal graft
Treatment

17. Complications
 Toxic Iridocyclitis
 Secondary Glaucoma
 Descemetocele
 Perforation of corneal ulcer
 Corneal scarring

18. Fungal keratitis
 Aspergillus
 Fusarium
Filamentous
Most common in Tropical climates
 Candida
Non-filamentous/Yeast
Most common in temperate climate

19. Predisposing Factors
 Trauma-organic matter (wood+plants)
 Chronic use of topical steroids
 Ocular surface disease
 Compromised immune system

20. Symptoms
 Gradual onset - slow progress
 Foreign body sensation
 Photophobia
 Blurred vision
 Discharge - Purulent

21. Signs
 Greyish white ulcer that has delicate fine
feathery edges
 Elevated surface & irregular contour
 Endothelial plaque may be present
 Progressive infiltration, may be
surrounded by stellate lesions
 Immune ring
 Ciliary congestion
 Yeast: Yellow white ulcer with dense
suupuration

23. Management
 History & Examination
 Investigation
Baseline
Giemsa , KOH and methamine silver stain
Culture
 Treatment

24. Treatment
 Topical Antifungal therapy
Natamycin 5% suspension
Fluconazole 2% suspension
Amphotericin B 0.15% solution
 Systemic Antifungal therapy
Ketoconazole 200-600mg od
Fluconazloe 200-400mg od
 Mechanical debridement
 Therapeutic keratoplasty

25. Protozoal keratitis
 Acanthamoeba spp.
 Microsporidea
o Acanthamoeba is free living ubiquitous
protozoa found in fresh water and soil
o Active trophozoite or dormant cyst

26. Risk factors
Contact lens
Ocular trauma – Corneal
abrasion
Herpetic keratitis

27. Clinical features
Symptoms: Blurred vision, Severe pain &
Photophobia
Signs:
 Diffuse punctate Epitheliopathy
 Epithelial pseudodentrites
 Limbitis-diffuse or focal anterior stromal
infiltrates
 Ring Abcess
 Perineural infiltrates (radial keratoneuritis)
– enlargement of corneal nerves

29. Diagnosis
 Soft contact leans wear
 Severe persistant pain
 Radial keratoneuritis
 Identification of Amoebis cyst in
smear & culture
 Calcoflour white (flourescent dye)
 Laminar corneal biopsy

30. Treatment
 Debridement – infected epithelium
 Topical Amoebicides as dual therapy
a. Propamidine isethionate 0.1% (broline) +
Polyhexamethyl biguanide 0.02%
b. Neomycin + Broline + Chlorhexadine 0.02%
 Therapeutic keratoplasty
Avoid in Inflammed eyes

31. Viral Keratitis
 Herpes simplex
 Herpes zoster
 Adenovirus
 Measles
 Paramyxovirus parotitis
 CMV
 EBV

32. Herpes Simplex keratitis
 DNA virus of he Herpesviridae Family
 Infection is extremely common
 Major cause ofunilateral corneal scarring
worldwide
 TYPE 1
 Predominantly causes infection above the waist.
 Droplet infection or close contact with infected
individual
 TYPE 2
 Below the Waist (genital herpes)
 STD
 Genital secretions - Birth

33. Primary infection
 Infection in early life
 Uncommon during first six months
 Subclinical causing mild fever and malaise
 Virus eventually travels up the axon of sensory
nerves into its ganglions.
 Type 1 remains dormant in trigeminal ganglion
 Type 2 in spinal ganglia.
Ocular involvement
 Blepharitis
 Acute Follicular Conjunctivitis
 Epithelial Punctuate Keratitis
Pathogenesis

34. Recurrent keratitis
 Poor health
 Exposure to ultraviolet rays
 Fever
 Psychatric disturbance
 Use of steroids.
 Lesions
 Acute/Active Epithelieal Keratitis
 Stromal Keratitis
 Kerato uveitis.

35. Clinical Features of HSV keratitis
Symptoms
 Foreign Body Sensation
 Lacrimation – Watery discharge
 Photophobia
 Pain (mild to moderate)
 Reduced Vision
Signs
 Ciliary congestion
 Diminished corneal Sensitivity

36. Active epithelial keratitis: Dendritic ulcer
 Most characteristic lesion, occurs in corneal
epithelium
 Typical branching, linear pattern with
feathery edges and terminal bulbs at ends.
 Visualized by fluorescein staining
HSV dendritic ulcer stained
with fluorescein

38. Geographic/Amoeboid ulceration
Delicate dendritic lesions take
a broader form.

39. Diagnosis
 Morphological appearance of corneal ulcer
 Diminished corneal Sensitivity
Differential diagnosis
 Herpes zoster Keratitis
 Acanthomebia Keratitis
 Healing Corneal ulcer
 Toxic drug Keratopathy

40. Treatment
 Topical Anti-viral drugs
I. Acycloguanosine - Acyclovir
II. Trifluorothymidine
III.Adenine Arabinoside
IV.Idoxuridine
 Debridement
 Topical antibiotics
 Cycloplegics

41. o Active viral invasion and destruction of Endothelium
of cornea
Signs
 Stroma appears cheesy and necrotic.
 Keratic precipitates or KP bodies (Anterior Uveitis)
 Features of AEK may be present.
Stomal Necrotic Keratitis
Treatment
Topical Antivirals
Topical Antibiotics
Topical Cycloplegics
Lubricants/Pressure patching Bandage contact lens

44. Disiform Keratits
 Definition: It is viral endothelitis in
which there is disc shaped grey area
of stromal edema with localised
keratic precipitates
o Reactivated viral infection of
keratocytesand Endothelium
o Hypersensitivity reaction to viral
antigen

45. Clinical Features
 Central zone of epithelial
edema
 Stromal thickening - edema
 Folds in descemet;s
membrane
 Mild to moderate anterior
uveitis
 Keratic precipitates
 Reduced corneal sensitivity

48. Treatment
 Topical Antiviral
 Topical antibiotics
 Topical weak steroids
 Cycloplegics

49. • Caused by HHV3 (VZV)
• Primary infection as Chicken pox
• Virus may travel into sensory ganglia of dorsal
root ganglion and trigeminal nerve ganglion
• Reactivation of virus causes Herpes Zoster or
Herpes Zoster opthalmicus
Mechanism of damage.
Cellular infiltration
Ischemic vasculitis
Inflamatory granulomatous reaction
Herpes Zoster Ophthalmicus (HZO)

51. Pain
Rashes
Edema
Post Herpetic Neuralgia
Corneal lesions
 Acute epithelial keratitis
 Microdendritic ulcer
 Nummular keratitis
 Diciform keratitis
 Reduced corneal sensation
Other Ocular Features
 Conjunctivitis
 Episcleritis
 Secondary glaucoma
 Anterior Uveitis
Clinical Features

53. Neurologic complications
o Cranial nerve palsy
Mostly 3rd nerve
o Optic neuritis
1:400

54. Treatment
Systemic
 Acyclovir – 800mg 5/day
 Analgesics
 Antibiotics
 Systemic steroids - prednisolone 40-
60mg

55. References
 Jack J. Kanski's Clinical
Ophthalmoscopy a Systemic
Approach fifth edition
 Infective keratitis lecture by Dr.
Shabbir Hussain, Department of
Ophthalmology
Edward S. Harkness institute,
columbia university college of
physicians and surgeons
 Clinical Opthalmology; Shafi M.
Jatoi

56. EnjoIX