From the Guidelines
Keratitis is an inflammation of the cornea that requires prompt treatment to prevent corneal scarring and vision loss, and the most recent guidelines recommend empiric therapy with topical antibiotics for bacterial keratitis, with consideration of corticosteroids after 48 hours of antibiotic therapy 1.
Definition and Causes
Keratitis is an inflammation of the cornea, the clear dome-shaped tissue covering the front of the eye, and can be caused by infectious (bacterial, viral, fungal, or parasitic) or non-infectious factors.
Treatment
Treatment depends on the cause of keratitis, and the following options are recommended:
- Bacterial keratitis: antibiotic eye drops like fluoroquinolones (ciprofloxacin, moxifloxacin) or aminoglycosides, prescribed every 15-30 minutes initially, then tapered as symptoms improve 1
- Viral keratitis: antiviral medications such as trifluridine drops 9 times daily or oral acyclovir 400mg five times daily for 7-10 days
- Fungal keratitis: antifungal drops like natamycin 5% or voriconazole, applied hourly initially for several weeks
- Acanthamoeba keratitis: combination therapy with polyhexamethylene biguanide (PHMB) and propamidine isethionate drops
- Non-infectious keratitis: lubricating drops, topical steroids (used cautiously), or removal of the irritant
Considerations
- Corticosteroids may be considered after 48 hours of antibiotic therapy for bacterial keratitis, but should be avoided in cases of suspected Acanthamoeba, Nocardia, or fungus 1
- Patients should avoid contact lens wear during treatment, maintain good hygiene, and attend follow-up appointments to monitor healing
- Prompt treatment is essential to prevent corneal scarring and vision loss, and to reduce the risk of complications such as medication toxicity, intraocular infection, cataract, corneal perforation, and loss of vision due to corneal scarring 1
From the FDA Drug Label
ZIRGAN is a topical ophthalmic antiviral that is indicated for the treatment of acute herpetic keratitis (dendritic ulcers). NATACYN ® (natamycin ophthalmic suspension) 5% is indicated for the treatment of fungal blepharitis, conjunctivitis, and keratitis caused by susceptible organisms including Fusarium solanikeratitis.
The definition of keratitis is not explicitly provided in the drug labels, but it can be inferred that it refers to an inflammation of the cornea. The treatment for keratitis depends on the cause, with ganciclovir being used to treat herpetic keratitis (dendritic ulcers) 2 2, and natamycin being used to treat fungal keratitis 3.
- The recommended dosing regimen for ganciclovir is 1 drop in the affected eye 5 times per day until the corneal ulcer heals, and then 1 drop 3 times per day for 7 days 2.
- The treatment with natamycin should be determined by the clinical diagnosis, laboratory diagnosis, and drug response 3.
From the Research
Definition of Keratitis
Keratitis refers to the inflammation of the cornea, which can be caused by various factors including infections, injuries, or underlying medical conditions.
Causes of Keratitis
- Bacterial keratitis: caused by bacterial infections, often requiring intensive antimicrobial therapy 4
- Fungal keratitis: caused by fungal infections, which can be more challenging to treat than bacterial keratitis 5, 6
- Viral keratitis: caused by viral infections, often recurrent and common in developed countries 7
Treatment of Keratitis
- Bacterial keratitis: topical antibiotics such as fluoroquinolones or fortified aminoglycoside-cephalosporin combinations are commonly used 4, 8
- Fungal keratitis: topical antifungal agents such as voriconazole or natamycin are used, and in some cases, topical antibiotics like moxifloxacin may be effective 5, 6
- Viral keratitis: topical corticosteroids and oral antiviral medications like acyclovir are used to treat stromal keratitis and reduce the recurrence of herpes simplex virus keratitis 7
Treatment Outcomes
- Bacterial keratitis: treatment success, time to cure, and serious complications of infection are comparable among different antibiotic treatments 4, 8
- Fungal keratitis: treatment outcomes are often poor, with a lower cure rate compared to bacterial keratitis 5, 6
- Viral keratitis: treatment outcomes can be improved with the use of topical corticosteroids and oral antiviral medications 7