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Abstract:
Acanthamoeba species are an important cause of microbial keratitis that may cause severe ocular inflammation and visual loss. The first cases were recognized in 1973, but the disease remained very rare until the 1980s, when an increase in incidence mainly associated with contact lens wear was reported. There is an increased risk when contact lens rinsing and soaking solutions are prepared with nonsterile water and salt tablets. The clinical picture is often characterized by severe pain with an early superficial keratitis that is often treated as herpes simplex infection. Subsequently a characteristic radial perineural infiltration may be seen, and ring infiltration is common. Limbitis and scleritis are frequent. Laboratory diagnosis is primarily by culture of epithelial samples inoculated onto agar plates spread with bacteria. Direct microscopy of samples using stains for the cyst wall or immunostaining may also be employed. A variety of topically applied therapeutic agents are thought to be effective, including propamidine isethionate, clotrimazole, polyhexamethylene biguanide, and chlorhexidine. Various combinations of these and other agents have been employed, often resulting in medical cure, especially if treatment is commenced early in the course of the disease. Penetrating keratoplasty is preferably avoided in inflamed eyes, but may be necessary in severe cases to preserve the globe or, when the infection has resolved, to restore corneal clarity for optical reasons.
Insights
Acanthamoeba keratitis, a severe eye infection linked to contact lens use, causes inflammation and vision loss. Early diagnosis and treatment with specific agents are crucial for successful outcomes.
Area of Science:
- Ophthalmology
- Infectious Diseases
- Microbiology
Background:
- Acanthamoeba species are a significant cause of microbial keratitis, leading to severe ocular inflammation and potential vision loss.
- The incidence of Acanthamoeba keratitis increased notably in the 1980s, primarily associated with contact lens wear, especially when using non-sterile solutions.
- Risk factors include improper contact lens hygiene, such as using tap water or homemade saline solutions.
Purpose of the Study:
- To review the etiology, clinical presentation, diagnosis, and management of Acanthamoeba keratitis.
- To highlight the association between contact lens wear and the increased incidence of this infection.
- To discuss current therapeutic strategies and their effectiveness.
Main Methods:
- Review of existing literature on Acanthamoeba keratitis.
- Analysis of clinical case reports and epidemiological data.
- Summary of diagnostic techniques, including culture and microscopy.
- Evaluation of various topical therapeutic agents and treatment outcomes.
Main Results:
- Acanthamoeba keratitis presents with severe pain and characteristic corneal infiltrates, often initially misdiagnosed.
- Diagnostic methods include culture on bacterial-infused agar plates and direct microscopy with specific stains or immunostaining.
- Effective treatments involve topical agents like propamidine isethionate, clotrimazole, polyhexamethylene biguanide, and chlorhexidine.
- Early treatment initiation significantly improves the chances of medical cure.
Conclusions:
- Prompt diagnosis and early intervention are critical for managing Acanthamoeba keratitis and preventing vision loss.
- Contact lens hygiene practices are paramount in reducing the risk of this infection.
- While medical management is often successful, penetrating keratoplasty may be required in severe or refractory cases.