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sorry, this time am gonna write in english. The translation of this article will be available in some other time

Mycotickeratitis

The corneal epithelium is like our skin except that it is clear and smoother. Its transparency and structural integrity are critical for maintenance of vision. Corneal epithelium is tightly interdigitated and generally resistant to microbial invasion unless the surface of the cornea is damaged or compromised by disease or trauma such as abrasion or laceration. If transient fungal elements are present on the corneal or conjuctival surface at the time of injury, or are inoculated into the cornea by the instrument of trauma, then the cornea is susceptible to opportunistic fungal infection (mycotickeratitis). This probably explains why so many case reports of keratomycosis describe a previous injury of the cornea. Correspondingly, any chronic disruption of the epithelium by disease or toxic agents may facilitate invasion of the stroma by opportunistic fungi that alight on the corneal surface. The use of broad-spectrum topical antibiotics and steroids has been implicated in the development of keratomycosis. Local ocular surface abnormalities, dry eye, extended-wear contact lens use, exposure keratitis, and the previous herpes simplex keratitis are all predisposing factors to keratomycosis.
The first documented case of keratomycosis occurred in a farmer with a wheat chaff injury to the cornea, caused by Aspergillus glaucus. It was reported by Leber in 1879. for the next eight decades, mycotic keratitis was sufficiently uncommon to justify single case reports. In 1962, Gingrich noted an increasing frequency of keratomycosis in USA and summarized the more then 30 species of fungi reported as aetiopathic agents between 1930 and 1960 (Gingrich 1962).

Approximately 35-25.5 % of corneal ulcers are caused by fungi. Fusarium saloni (fig 1) is the most common agent and has been isolated in up to 65% of cases. Aspergillus and Candida (fig 2) are also commonly isolated. More rarely, Acremonium (fig 3) and Curvularia (fig 4) may be found.

Symptoms:

A stromal infiltrates surrounded by satellite lesions are suggestive of corneal fungal infection.
• Pain
• Discharge
• Tearing
• Photophobia
• Red eye
• Decreased vision
* may notice a white spot on cornea

Diagnosis:
– Clinical
– Culture

Treatment of mycotickeratitis:
• Topical antifungal agent q1h x 24-72 hrs then taper slowly as improvement noted.
o Natamycin 50 mg/mL or
o Amphotericin B 1.0 – 2.5 mg/mL or
o Miconazole 10 mg/mL
• For severe infection add systemic antifungal agent
o Ketoconazole 200-400 mg
o Amphotericin B 1 mg/Kg IV over 6 hours
• Topical cycloplegic agent
o scopolamine 0.25% or
o atropine 1 %
• Topical steroids are contraindicated in fungal keratitis
The following drugs are frequently used:
Carbonic anhydrase inhibitors: Oral and topical formulations reduce the amount of fluid produced inside the eye.
Miotics (parasympathomimetics): used on the eye, it helps to increase the outflow of fluid from the eye. It may cause a temporary redness, burning or stinging in the eye.
Beta adrenergic blockers: used on the eye, to reduce the amount of fluid produced inside the eye.

Other causative agents
Viral:
Herpes simplex & Herpes zoster viruses

Bacterial: (most common)
• Most common bacterial species causing corneal ulcers:
o Pseudomonas aeruginosa
o Staphylococcus aureus
o Staphylococcus epidermidis
o Sterptococcus pneumoniae
o Haemophilus influenzae
o Moraxella catarrhalis
• Bacterial species that can penetrate an intact corneal epithelium:
o Neisseria species
o Corynebacterium diphtheriae
o Haemophilus aegyptius
o Listeria species
* Streptococcus viridans causes crystalline keratopathy (central branching cracked glass appearance without epithelial defect; associated with chronic topical steroid use).

Parasitic: Acanthamoeba and Microsporidia