Amoebic keratitis

What it is

From: Orphanet

A rare corneal infection due to the protozoan Acanthamoeba that generally occurs in contact lens wearers and that is characterized by severe ocular pain, blepharospasm, photophobia, eye tearing, blurred vision and foreign body sensation. It can lead to impaired visual acuity if not treated promptly.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormal cornea morphology · Very frequent (99-80%)

Any abnormality of the cornea, which is the transparent tissue at the front of the eye that covers the iris, pupil, and anterior chamber.

Abnormal corneal epithelium morphology · Very frequent (99-80%)

Abnormality of the corneal epithelium, that is of the epithelial tissue that covers the front of the cornea.

Ocular pain · Very frequent (99-80%)

An unpleasant sensation characterized by physical discomfort (such as pricking, throbbing, or aching) localized to the eye.

Photophobia · Very frequent (99-80%)

Excessive sensitivity to light with the sensation of discomfort or pain in the eyes due to exposure to bright light.

Punctate opacification of the cornea · Very frequent (99-80%)

Punctate opacification (reduced transparency) of the corneal stroma.

Anterior uveitis · Frequent (79-30%)

Inflammation of the uveal tract in which the primary site of inflammation is the anterior chamber.

Cataract · Frequent (79-30%)

A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.

Corneal perforation · Frequent (79-30%)

A rupture of the cornea through which a portion of the iris protrudes.

Decreased corneal sensation · Frequent (79-30%)

Reduced ability of the cornea to respond to stimulation.

Iris atrophy · Frequent (79-30%)

Loss of iris tissue (atrophy)

Scleritis · Frequent (79-30%)

Inflammation of the sclera.

Abnormality of the posterior segment of the globe · Frequent (79-30%)

Abnormal anterior chamber morphology · Occasional (29-5%)

Abnormality of the anterior chamber, which is the space in the eye that is behind the cornea and in front of the iris.

Corneal stromal edema · Occasional (29-5%)

Abnormal accumulation of fluid and swelling of the stroma of cornea.

Other findings in the same source

From: Orphanet

Additional reported features include Corneal ulceration (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

All ages

Inheritance in the source

From: Orphanet

Not applicable

Frequency and the population described

From: Orphanet

Point prevalence: 1-9 / 100 000; Europe; Value and class.

Which doctor should you see?

The suggested department for discussing Amoebic keratitis is Infectious Diseases, with a general physician / infectious disease specialist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which exposure or organism is suspected, and what evidence would confirm it?
• Are precautions, vaccination or advice for close contacts relevant to this infection?
• What should happen if symptoms worsen or do not improve as expected?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.