A 52-year-old male farmer from Maharashtra presents with a 5-day history of left eye pain, photophobia, and blurred vision. He reports a thorn prick injury to the cornea while working in the field 2 weeks ago. On examination, visual acuity is 6/60. Slit-lamp examination reveals a central corneal ulcer with raised, indurated edges, satellite lesions, and a hypopyon. KOH mount of corneal scrapings shows broad, aseptate hyphae with right-angle branching. What is the most appropriate next step in management?

Question

Accepted Answer

A. Topical natamycin 5% hourly and oral itraconazole 200 mg twice daily. ## Clinical Diagnosis

**Key Point:** The KOH mount finding of broad, aseptate hyphae with right-angle branching is pathognomonic for *Aspergillus* species, the most common fungal cause of corneal ulcer in India.

**High-Yield:** Fungal corneal ulcers classically present with:
- Indolent course (slow progression over days to weeks)
- Raised, indurated edges with satellite lesions
- Hypopyon (sterile inflammatory exudate)
- History of vegetative matter or agricultural trauma

## Organism Identification

| Feature | Aspergillus | Candida | Fusarium |
| --- | --- | --- | --- |
| Hyphae | Broad, aseptate, 5–10 μm | Pseudohyphae, budding yeast | Septate, narrow, 2–4 μm |
| Branching | Right-angle (45°) | Acute angle | Acute angle |
| Growth rate | Slow | Slow | Rapid |
| Clinical course | Indolent | Indolent | Aggressive |
| Geography | Tropical/subtropical | Immunocompromised | Tropical |

## Treatment Algorithm

```mermaid
flowchart TD
  A[Fungal corneal ulcer confirmed]:::outcome --> B{Organism identified?}:::decision
  B -->|Aspergillus| C[Natamycin 5% topical]:::action
  B -->|Candida| D[Fluconazole or voriconazole]:::action
  B -->|Fusarium| E[Voriconazole preferred]:::action
  C --> F[Oral itraconazole 200 mg BD]:::action
  D --> G[Oral fluconazole 400 mg OD]:::action
  E --> H[Oral voriconazole 200 mg BD]:::action
  F --> I[Monitor for perforation risk]:::outcome
```

**Key Point:** Natamycin is the **gold standard topical antifungal** for *Aspergillus* corneal ulcer because:
1. It is a polyene antibiotic with broad-spectrum fungicidal activity
2. It does not penetrate the cornea well systemically, so topical application is essential
3. Oral itraconazole provides systemic coverage and improves outcomes

**Clinical Pearl:** Voriconazole is reserved for *Fusarium* (which is resistant to natamycin) or when *Aspergillus* shows poor response to natamycin. Fluconazole is preferred for *Candida* but is less effective against *Aspergillus*.

**Warning:** Do NOT use topical steroids in fungal ulcers — they promote deeper invasion and perforation. Avoid systemic antifungals alone without topical therapy in corneal disease.

![Corneal Ulcer — Bacterial and Fungal diagram](https://mmcphlazjonnzmdysowq.supabase.co/storage/v1/object/public/blog-images/explanation/3571.webp)

Answer

B. Topical voriconazole 1% hourly and oral fluconazole 400 mg once daily

Answer

C. Topical moxifloxacin 0.5% hourly and oral acyclovir 800 mg five times daily

Answer

D. Topical chloramphenicol 1% hourly and systemic ceftriaxone 1 g IV twice daily

Explanation

Clinical Diagnosis

Organism Identification

Treatment Algorithm

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Feature	Aspergillus	Candida	Fusarium
Hyphae	Broad, aseptate, 5–10 μm	Pseudohyphae, budding yeast	Septate, narrow, 2–4 μm
Branching	Right-angle (45°)	Acute angle	Acute angle
Growth rate	Slow	Slow	Rapid
Clinical course	Indolent	Indolent	Aggressive
Geography	Tropical/subtropical	Immunocompromised	Tropical