University of Iowa Health Care

Ophthalmology and Visual Sciences

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Acanthamoeba keratitis

Acanthamoeba keratitis is a rare parasitic infection of the cornea that primarily occurs in contact lens wearers.  The infection may be limited to the epithelium in its early stages, resulting in epithelial dendrites and punctate epitheliopathy. Later stromal involvement classically results in a partial or complete paracentral ring infiltrate, radial perineuritis, and pain out of proportion to the appearance on exam.  Scleritis and uveitis may also be present.

Figure 1: Corneal ring infiltrate in a patient with Acanthamoeba keratitis.  The diagnosis was confirmed by confocal microscopy (Figure 3).

Contributor: Jesse Vislisel, MD
Photographer: Brice Critser, CRA

Acanthamoeba keratitis

Acanthamoeba keratitis, slit lamp


Figure 2: Concentric ring infiltrate in a contact lens wearer with early Acanthamoeba keratitis.

Contributor: Jesse Vislisel, MD
Photographer: Stefani Karakas, CRA

Concentric ring infiltrate in a contact lens wearer with early Acanthamoeba keratitis

Concentric ring infiltrate in a contact lens wearer with early Acanthamoeba keratitis

Concentric ring infiltrate in a contact lens wearer with early Acanthamoeba keratitis


Figure 3: Confocal microscropy of the patient in Figure 1 demonstrating high-contrast round objects consistent with Acanthamoeba cysts and irregular forms suggestive of Acanthamoeba trophozoites

Contributor: Jesse Vislisel, MD

Acanthamoeba keratitis, confocal


Figure 4: Epitheliitis with marked radial perineuritis secondary to Acanthamoeba infection.

Contributor: Jesse Vislisel, MD
Photographer: Stefani Karakas, CRA

Epitheliitis with marked radial perineuritis secondary to Acanthamoeba infection.

Epitheliitis with marked radial perineuritis secondary to Acanthamoeba infection.


Figure 5: 300x magnification of the corneal epithelium in a patient with Acanthamoeba keratitis.  H&E stain demonstrates a classic example of the double-walled cyst structure of Acanthamoeba.

Contributor: Jordan Graff, MD
Photographer: Nasreen Syed, MD

H&E stain demonstrates a classic example of the double-walled cyst structure of Acanthamoeba.


Figure 6: Intra-stromal Acanthamoeba cysts and trophozoites visible on H&E stain.

Contributor and Photographer:  Meagan Seay, DO

Acanthamoeba keratitis
(higher resolution, not available)


Figure 7: Protozoa visible on Wright-Giemsa stain.

Contributor and Photographer: Meagan Seay, DO

Acanthamoeba keratitis
(higher resolution, not available)

Reference

Krachmer, Jay H., Mark J. Mannis, Edward J. Holland. Cornea. St. Louis: Mosby, 2011.


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last updated: 09/11/2015
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