Fungal keratitis is difficult to diagnose and treat. Common causative fungi include Aspergillus, Candida, and Fusarium. Diagnosis involves potassium hydroxide wet mount, stains like Gram or Grocott's, and culture. Topical natamycin is first-line treatment but systemic antifungals like voriconazole may be needed for severe cases. Management also includes frequent debridement and potentially therapeutic penetrating keratoplasty for non-responsive or advanced cases. Prognosis depends on factors like ulcer size and presence of hypopyon.

2. 
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Fungal Keratitis is one of the most difficult forms of
microbial keratitis to diagnose & to treat successfully.
Fungus are eukaryotic heterotrophic organisms &
typically forms reproductive spores.
Fugus may be a part of normal external ocular flora. (
3-28% of normal eyes)
Most commonly seen are:
Aspergillus
Rhodotorula
Candida
Penicillium
Cladosporium
Alternaria

3. Filamentous Septate Fungi
(Non Pigmented):
Fusarium, Aspergillus
 Filamentous Septate
Fungi(Pigmented):
Alternaria, Curvularia
 Filamentous Non Septate:
Mucor
 Yeasts: Candida


4. Overall incidence is low- 6-20%
 Aspergillus most common organism
worldwide.
 Incidence varies geographically:
Northern US: Candida, Aspergillus
Southern US: Fusarium
 In India: Aspergillus (27-64%)
Fusarium (6-32%)
Penicilliun (2-29%)


5. Fungi gain entry into stroma through a defect
in epithelial barrier.
 In stroma, cause tissue necrosis & host
inflammatory reaction.
 Fungus can penetrate deep into stroma &
through intact descemet’s membrane.
 Blood borne growth inhibiting factors may not
reach avascular structures of eye like cornea
so fungi continues to grow & persists i.e. why
conjunctival flap help in control of fungal
infection.
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6. 
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Trauma (M/C)
Contact lens use.
Cosmetic Lens- filamentous
Therapeutic Lens- Yeasts
Overall Bacterial infection more common
with
contact lens users
Topical Medications- Corticosteroids
Anaesthetic Abuse
Broad Spectrum Antibiotics
Corneal Sx- Penetrating Keratoplasty, LASIK.
Chronic Keratitis- Herpes Simplex, Herpes
Zoster,Vernal/allergic keratitis
Immunocompromised State- HIV, Leprosy

7. 
Symptoms:
Foreign body Sensation
Slow onset increasing Pain
Clinical signs are more severe than symptoms.

Signs:
Nonspecific: Conjunctival injection
Epithelial defect
Anterior chamber reaction
Specific:
Infiltrate
Feathery Margins
Elevated edges
Rough Textured
Satellite lesions
Endothelial Plaque
Gray/Brown Pigmentation( s/o Dematiceous
Fungi like Curvularia)
Hypopyon ( Non Sterile, thick & immobile)
Yellow line of demarcation
Immune Ring (Wesseley)

9. Gram Stain
Giemsa Stain
Grocott’s Methamine Silver
PAS Stain
lectins
 Fluoroscent Microscopy
Acridine Orange
Calcoflour white
 Smear: Potassium Hydroxide Wet Mount
(10-20%)
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Stains:

10. 
Culture Media:
Should include same media for general infectious
keratitis work up.
 Sheep Blood Agar
 Chocolate Agar
 Sabouraud’s dextrose Agar
 Thioglycollate Broth
 Brain Heart Infusion Broth / Solid Media
Positive culture expected in 90% cases,
within 72 hrs in 83% cases
within 1 week in 97% cases
Increasing Humidity of medium by placing inoculated
agar plates in Plastic bags enhance fungal growth.

11. 
Newer Methods
Electron Microscopy
Polymerase Chain Reaction
SCRAPING
Advantage:
Provide initial debridement of organisms
Improve penetration of drugs
Methods:
 Surgical Blade
 Diamond tipped motorized burr
 Diagnostic Superficial Keratectomy/Corneal
Biopsy

12. Done in Minor OT with Topical Anaesthesia
2-3 mm dermatologic trephine on anterior
corneal stroma incorporating both clinically
infected & adjacent clear cornea.(Avoiding
Visual Axis)
 Femtosecond Laser
 27 guage hypodermic needle
 6-0 silk suture

Anterior Chamber Tap:
Hypopyon or Endothelial Plaque

13. ANTIFUNGALS

POLYENES:
Amphotericin B, Natamycin
Binds to ergosterol in fungal cell membrane &
cause the membrane to become leaky.
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AZOLES:
Ketoconazole, Fluconazole,
Voriconazole
Inhibits CYP P450 14 a-demethylase enzyme
involved in conversion of lanosterol to
ergosterol

14. 
PYRIMIDINES:
Flucytosine
Causes Faulty RNA Synthesis & non competitive
inhibitor of Thymidylate Synthesis
ALLYLAMINES:
Terbinafine
Ergosterol Biosynthesis inhibitor
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ECHINOCANDINS: Capsofungin, Micafungin
Cell wall Synthesis inhibitors, D-glucan
synthesis inhibitor

16. Topical Natamycin 5% is Initial drug of choice.
 Topical Amphotericin B 0.15% added in c/o
worsening, candida & aspergillus.
 Oral or Topical Azole added in c/o Fusarium.
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Indication for Systemic antifungals:
( voriconazole 1st choice)
Severe deep keratitis
Scleritis
Endophthalmitis
Prophylactic t/t after Penetrating Keratoplasty
for Fungal Keratitis
Virulent Fungus

17. Length of treatment is based on clinical
response of individual.
 If toxicity is suspected and if adequate t/t has
been given for 4-6 weeks treatment should be
discontinued & patient is observed for
reccurence in follow up.
 Intrastromal injections: given if infiltrate is
recalcitrant to topical t/t & depth of lesion in
cornea.
 Subconjunctival injections: reserved in cases
of scleritis, severe keratitis, endophthalmitis.
Miconazole (preferred) as is least toxic
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18. 
Synergism:
Amphotericin B & flucytosine
Natamycin & Ketoconazole
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Antagonism:
Amphotericin B & Imidazoles
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Antibiotics with Antifungal Property:
Chloramphenicol- fusarium, Aspergillus
Moxifloxacin & tobramycin- Fusarium
Chlorhexidine
Povidone Iodine.

19. 1.
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Debridement
Therapeutic Penetrating Keratoplasty
Conjunctival Flap
Flap + Keratectomy
Flap + Penetrating Graft
Lamellar Graft
Cryotherapy ( In Keratoscleritis)

20. Debridement:
Done every 24-48 hrs under topical anaesthesia

Debulks necrotic material & organisms
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Enhances penetration of topical drugs
Penetrating Keratoplasty
Indication:
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Infectious process progress to limbus or sclera
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Failure of medical t/t
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Recurrence of infection
To delay or prevent the need for corneal transplant with
severe thinning or perforation is managed with
TISSUE ADHESIVE(N-BUTYL CYANOACRYLATE)
BANDAGE CONTACT LENS

21. Technique for Penetrating Keratoplasty:
 Size of trephination should leave 1-1.5 mm
clear zone of clinically uninvolved cornea to
reduce residual fungus.
 Interrupted sutures with slight longer bites
Should be used to avoid cheese wiring
 Irrigation of Anterior chamber with
antifungals
 Affected intraocular structures like iris, lens,&
vitreous should be excised
 Surgical instruments should be changed to
sterile ones once infected tissue removed to
avoid recontamination.

25. If endophthalmitis is suspected:
Intraocular Antifungal injected at the time of
keratoplasty. ( Preferably Amphotericin B)
 After PK:
Topical antifungals continued to prevent recurrence.
If pathology reports are negative for organism at
edge of corneal specimen STOP antifungals after 2
weeks and follow up patient for recurrence.
If Pathology reports are positive t/t continued for 6-8
weeks.
 CICLOSPORIN A: Antifungal that also prevent
immune response so can be used in place of steroids
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26. Factors associated with Treatment Failure:
 Large ulcer size (greater than 14mm square)
 Presence of Hypopyon
 Aspergillus as causative organism