Anyone who sustains an injury to the eye or wears contact lenses can develop fungal keratitis, but the condition is most prevalent among:

• Agricultural workers who handle plant material, soil, or grain.
• Patients with compromised ocular surface defenses (e.g., chronic dry eye, prior ocular surgery).
• Individuals in warm, humid climates—especially Southeast Asia, Africa, and parts of South America.

According to the World Health Organization (WHO), fungal keratitis is responsible for up to 50 % of corneal blindness in some low‑income countries, highlighting its public‑health significance.[1] WHO, 2022

Symptoms

Fungal keratitis often begins slowly and may be mistaken for a bacterial infection. Typical symptoms include:

• Redness – diffuse or localized to the affected eye.
• Eye pain – ranging from mild discomfort to severe throbbing, often worsening with eye movement.
• Decreased vision – blurriness or a “shadow” over part of the visual field.
• Photophobia – heightened sensitivity to light.
• Tearing or watery discharge – sometimes accompanied by a thick, pus‑like secretion.
• Foreign‑body sensation – feeling as if something is stuck in the eye.
• Corneal opacity – a whitish or grayish spot that may enlarge over days.
• Satellite lesions – small, secondary spots radiating from the main ulcer (highly suggestive of fungal infection).
• Hypopyon – a layer of inflammatory cells settling in the lower anterior chamber, visible as a fluid line.

Causes and Risk Factors

Fungal organisms most often implicated

• Fusarium spp. – predominant in tropical agriculture.
• Aspergillus spp. – common in soil and decaying vegetation.
• Candida spp. – more frequent in patients with ocular surface disease or systemic immunosuppression.
• Rarely, Curvularia, Alternaria, and Exserohilum species.

Key risk factors

• Ocular trauma with vegetative matter (e.g., rice husks, wood splinters).
• Contact lens wear, especially when lenses are cleaned with tap water or stored improperly.
• Chronic ocular surface disease (dry eye, allergic keratoconjunctivitis, ocular rosacea).
• Prior corneal surgery or use of topical steroids without antifungal coverage.
• Systemic immunosuppression (diabetes, HIV/AIDS, chemotherapy).
• Environmental exposure to warm, humid climates where fungal spores are abundant.

Diagnosis

Prompt, accurate diagnosis is essential because fungal keratitis responds poorly to antibiotics and may progress to perforation if untreated.

Clinical examination

• Slit‑lamp biomicroscopy – reveals characteristic feathery or dry‑looking edges of the ulcer, satellite lesions, and sometimes a raised, “fluffy” infiltrate.
• Fluorescein staining – highlights the epithelial defect and ulcer size.

Laboratory tests

1. Corneal scraping – performed under aseptic conditions; material is examined by:
   • Potassium hydroxide (KOH) wet mount (rapid, detects fungal hyphae within minutes).
   • Gram stain (to rule out bacterial co‑infection).
   • Calcofluor white fluorescence microscopy (high sensitivity).
2. Culture – inoculation on Sabouraud dextrose agar, blood agar, and chocolate agar; results take 3–7 days.
3. Polymerase chain reaction (PCR) – increasingly used in specialized centers for rapid species identification.
4. In‑vivo confocal microscopy – non‑invasive, gives real‑time visualization of fungal filaments within the cornea (useful when scraping is difficult).

Imaging

• Anterior segment optical coherence tomography (AS‑OCT) – assesses depth of infiltration and stromal thinning.
• Ultrasound B‑scan – reserved for suspected perforation or when the view is obscured.

Treatment Options

Management involves a combination of antimicrobial therapy, supportive care, and, in severe cases, surgical intervention.

Topical antifungal agents

• Natamycin 5 % ophthalmic suspension – the first‑line medication for filamentous fungi (Fusarium, Aspergillus). Applied hourly for the first 48 h, then tapered based on response.[2] CDC, 2023
• Voriconazole 1 % eye drops – useful for deeper stromal infections and Candida species. Often combined with natamycin for mixed infections.
• Amphotericin B 0.15 % – alternative for Candida keratitis or when natamycin is unavailable.

Systemic therapy

Oral antifungals are added when the infection is deep, extensive, or unresponsive to topical therapy:

• Voriconazole 200 mg PO BID – excellent corneal penetration; monitor liver function.
• Itraconazole 200 mg PO BID – cheaper alternative for Candida.
• Duration generally 4–6 weeks, guided by clinical response.

Adjunctive measures

• Pain control – cycloplegics (e.g., homatropine) and oral analgesics.
• Frequent lubrication – preservative‑free artificial tears to reduce epithelial stress.
• De‑bridement – gentle removal of necrotic tissue to enhance drug penetration (performed by an ophthalmologist).

Surgical options

1. Therapeutic penetrating keratoplasty (PK) – full‑thickness corneal transplant for perforation or uncontrolled infection.
2. Lamellar keratoplasty – removes only the infected stromal layers, preserving healthier tissue.
3. Amniotic membrane graft – promotes healing in non‑perforating ulcers.

When to switch or combine therapies

If there is no improvement after 48–72 hours of intensive natamycin, clinicians often add or switch to voriconazole and consider systemic therapy. Persistent hypopyon, increasing ulcer size, or stromal melt warrants early surgical consultation.

Living with Keratophyton (fungal keratitis)

Daily management tips

• Medication adherence – set alarms; keep a dosing chart.
• Eye protection – wear protective goggles during household chores or outdoor activities.
• Hygiene – wash hands thoroughly before applying drops; use sterile pads.
• Avoid rubbing the eye – can worsen the ulcer.
• Follow‑up schedule – most patients need visits every 1–2 days initially, then weekly as the ulcer heals.
• Monitor vision changes – keep a simple log of any new blur or halos.
• Nutrition – maintain a balanced diet rich in vitamins A, C, and omega‑3 fatty acids, which support corneal health.

Impact on lifestyle

During the acute phase, avoid contact lens wear, swimming, and exposure to dusty or windy environments. Return to work or school usually occurs once the ulcer has epithelialized and vision stabilizes, often 4–6 weeks after infection onset.

Prevention

• Protective eyewear when gardening, farming, or handling organic material.
• Proper contact lens hygiene – use only sterile solutions, replace lenses as recommended, never rinse with tap water.
• Prompt treatment of ocular injuries – clean the eye with sterile saline and seek medical care within 24 hours.
• Control of systemic risk factors – maintain good diabetic control, avoid systemic steroids when possible.
• Limit use of topical steroids without antifungal coverage; always discuss with your eye doctor.

Complications

If fungal keratitis is not adequately controlled, the following serious outcomes may occur:

• Corneal perforation – may require emergency keratoplasty.
• Endophthalmitis – infection spreads to the interior of the eye, threatening vision.
• Scarring and visual loss – dense stromal opacities can cause permanent decreased acuity.
• Secondary glaucoma – due to inflammation or steroid use.
• Symblepharon or ankyloblepharon – adhesion of the eyelid to the globe in severe cases.

When to Seek Emergency Care

References (selected):

1. World Health Organization. Global estimates of visual impairment: 2022.
2. Centers for Disease Control and Prevention. Fungal Keratitis Fact Sheet. Updated 2023.
3. Mayo Clinic. Fungal Keratitis – Symptoms & Treatment. Accessed April 2024.
4. American Academy of Ophthalmology. Preferred Practice Pattern: Infectious Keratitis. 2023.
5. Cleveland Clinic. Management of Corneal Ulcers. 2022.