Acanthamoeba keratitis

A survey to assess the degree of knowledge in Europe of this rare disease.

Acanthamoeba keratitis is a rare disease (Orphan Disease) of an infectious nature that affects the cornea and is caused by a family of protozoa of the Acanthamoeba family, found in soil, air and water.

Prevalence and characteristics

The vast majority of cases (approximately 85%) of Acanthamoeba keratitis present in contact lens wearersdue to incorrect use of the lenses, such as: inadequate cleaning and storage, night and prolonged use and other incorrect practices.

Infection, however, can also occur after corneal trauma, especially in rural settings.

This is a form of keratitis with a fairly low prevalence (7 cases per 1,000,000 in Europe), but it can have devastating effects on patients, as it can cause intense pain and, if not effectively treated, significant deterioration of vision, up to blindness, and perforation of the cornea.

Symptoms

The most common symptoms are pain, redness, blurred vision, hypersensitivity to light and excessive tearing. These manifestations are similar to those of other eye infections and may persist for several weeks.

The natural history of the disease is related to the specific characteristics of Acanthamoeba, whose life includes an active infectious stage and a 'dormant cyst' stage, during which the micro-organism manages to survive even under adverse environmental conditions.

Diagnosis

Early diagnosis is of utmost importance and is decisive in promoting the cure of the infection.

In case of clinical signs of AC, the ophthalmologist will perform some or all of the following examinations:

• molecular analysis of corneal scrapingsIt has a very high sensitivity and can give a result within 60 minutes. However, this test can have the disadvantage that even the presence of genetic material from the non-living micro-organism can give a positive result
• confocal microscopy in vivo: has a higher sensitivity than 90% when performed by experts; however, with this method only cysts of Acanthamoeba are well recognisable
• cultivation in vitro: has variable sensitivity and has the disadvantage of giving results after 3 weeks
• histopathological analysis: has a discrete sensitivity and corneal scrapings or excision or excised tissue from keratoplasty can be analysed.

Treatment

In order to eradicate Acanthamoeba keratitis, medical therapy must be based on drugs capable of suppressing the protozoan in both phases of its life cycle, both active and cystic, in order to completely eradicate the micro-organism.

There is currently no authorised drug in any country for the treatment of Acanthamoeba keratitis.

However, in recent years, the administration of 'off-label' (unauthorised) combinations of anti-amœbic agents, such as biguanides and diamidines, has greatly improved outcomes. The use of biguanides, in particular, has revolutionised the course of the disease, especially when treated in the early stages, as pain relief is rapid.

To achieve complete clinical resolution, however, therapy is prolonged for several months. Clinical resolution with medical therapy alone is possible in most patients (approximately 75%); in many cases, however, a corneal transplant is necessary during the course of the disease.

Survey on Acanthamoeba Keratitis

A survey to assess the level of knowledge in Europe about this rare disease.

Through the website dedicated to the ODAK Project, ophthalmologists throughout Europe are invited to fill out online a test to assess how widespread the knowledge of Acanthamoeba keratitis is and the off-label treatments currently used.

Contact

This is the address to access the test: http://www.odak-project.eu/resources/odak-ak-awareness-survey.

Questions

The questions mainly concern the degree of knowledge of this rare form of keratitis and its prevalence.

Purpose

The data collected through this survey will be used for a paper, edited by the ODAK Project, which will provide a current picture of the degree of knowledge of Acanthamoeba keratitis among European ophthalmologists.

We therefore invite you to contribute to this survey to spread awareness in Europe of the devastating effects of this rare eye disease.

See also:

• Acanthamoeba keratitis and medical therapy - Oculista Italiano
• Acanthamoeba keratitis and contact lens risks - Oculista Italiano