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Acanthamoeba keratitis
Acanthamoeba keratitis, first recognized in 1973, is a rare, vision threatening, parasitic infection seen most often in contact lens wearers
Prevalence
1-2 / 1,000,000
Age of Onset
ICD-10
B60.1+
H19.2*
Inheritance
This condition does not appear to have a clear pattern of inheritance.
5 Facts you should know
FACT
A rare disease in which amoebae of the genus Acanthamoeba invade the cornea.
FACT
Acanthamoeba are protozoa found nearly ubiquitously in soil and water, and can cause infections of the skin, eyes, and central nervous system.
FACT
Infection of the cornea by Acanthamoeba is difficult to treat with conventional medications.
FACT
Acanthamoeba keratitis (AK) may cause permanent visual impairment or blindness, due to damage to the cornea or through damage to other eye structures.
FACT
In the United States, Acanthamoeba keratitis is nearly always associated with soft contact lens use.
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Common signs & symptoms
Acanthamoeba keratitis (AK) is an uncommon but severe corneal infection caused by a free-living amoeba. The signs and symptoms include:
Pain
Photophobia
Blurred vision
Epithelial defect
Epithelial edema
Stromal infiltration
Stromal necrosis
Corneal ulceration
Hypopyon formation
Keratic precipitates
Early and prompt diagnosis of AK is crucial for successful treatment, as the infection can quickly lead to corneal perforation and loss of vision. Diagnosis should be made based on clinical presentation, corneal scraping for direct microscopy and culture, and confocal microscopy.
References:
Seal, D., et al. "Acanthamoeba keratitis." The Lancet, vol. 387, no. 10027, 2016, pp. 1175-1185.
Jeng, B., et al. "Acanthamoeba keratitis: diagnosis, treatment, and management." Cornea, vol. 32, no. 2, 2013, pp. 123-129.
Current treatments
Acanthamoeba keratitis is a rare but potentially severe infection of the cornea caused by the microorganism Acanthamoeba. Treatment typically involves a combination of topical and oral medications, along with frequent monitoring by an ophthalmologist. Topical medications used to treat Acanthamoeba keratitis include:
Topical medication
Used to treat Acanthamoeba keratitis include polyhexamethylene biguanide (PHMB), chlorhexidine, propamidine isethionate, and neomycin. These medications are often used in combination, with PHMB being the most commonly used agent.
Oral medications
Used to treat Acanthamoeba keratitis include miltefosine, and diamidine compounds such as pentamidine and propamidine.
Surgical procedure
In some cases, a surgical procedure called debridement may also be necessary to remove infected tissue.
Prognosis for Acanthamoeba keratitis can be poor, especially if the infection is not diagnosed and treated early. It is crucial that patients receive prompt and aggressive treatment, as well as close follow-up care to prevent complications and ensure the best possible outcome.
References:
"Acanthamoeba Keratitis" by the American Academy of Ophthalmology.
"Acanthamoeba Keratitis" by the Centers for Disease Control and Prevention.
"Acanthamoeba Keratitis" by the World Health Organization.