Acanthamoeba keratitis

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Acanthamoeba keratitis
Parasite140120-fig1 Acanthamoeba keratitis Figure 1B.png
Eye with Acanthamoeba keratitis
(fluorescein observation)
Classification and external resources
eMedicine med/10
MeSH D015823

Acanthamoeba keratitis is a rare disease in which amoebae invade the cornea of the eye. It may result in permanent visual impairment or blindness.[1][2][3]


Acanthamoeba trophozoite. Scale bar: 10 μm

In the United States, it is nearly always associated with contact lens use, as Acanthamoeba can survive in the space between the lens and the eye.[4][5][6][7] For this reason, contact lenses must be properly disinfected before wearing, and should be removed when swimming or surfing.

However, elsewhere in the world, there have been many cases of Acanthamoeba in those who don't wear contact lenses.[8][9]


To detect Acanthamoeba on a contact lens in a laboratory, the contact lens is placed on a non-nutrient agar saline plate seeded with a gram-negative bacteria such as E. coli. If Acanthamoeba are present, they will reproduce readily and become visible on the plate under 10-20X objective on an inverted microscope. Polymerase chain reaction can also be used to confirm a diagnosis of Acanthamoeba keratitis, especially when contact lenses are not involved. Acanthameoba is also characterized by a brawny edema and hazy view into the anterior chamber. Late stages of the disease also produces a ring shaped corneal ulcer.[10]


Signs and symptoms include severe pain, severe keratitis (similar to stromal herpetic disease), corneal perineuritis, and ring ulcer (late in the disease process).


One treatment used is PHMB.[11]

Propamidine isethionate has also shown some effectiveness.[12]

Another possible agent is chlorhexidine.[13]

Keratoplasty may sometimes be required.[12]

A combined regimen of propamidine, miconazole nitrate, and neomycin has also been suggested.[14][15]


  1. ^ Lorenzo-Morales, Jacob; Khan, Naveed A.; Walochnik, Julia (2015). "An update on Acanthamoeba keratitis: diagnosis, pathogenesis and treatment". Parasite 22: 10. doi:10.1051/parasite/2015010. ISSN 1776-1042. PMID 25687209.  open access publication - free to read
  2. ^ Anna Hodgekiss (2012-08-20). "I swam with my contact lenses in - now I'm blind in one eye | Mail Online". Retrieved 2013-08-02. 
  3. ^ "CDC - Acanthamoeba Infection - General Information - Acanthamoeba Keratitis FAQs". Retrieved 2013-08-02. 
  4. ^ Auran, JD; Starr MB; Jakobiec FA (1987). "Acanthamoeba keratitis. A review of the literature". Cornea 6 (1): 2–26. doi:10.1097/00003226-198706010-00002. PMID 3556011. 
  5. ^ JOHN D.T. (1993) Opportunistically pathogenic free-living amebae. In: J.P. Kreier and J.R. Baker (Eds.), Parasitic Protozoa. Vol. 3. Academic Press, New York, pp. 143–246.
  6. ^ Badenoch, PR; Adams M; Coster DJ (February 1995). "Corneal virulence, cytopathic effect on human keratocytes and genetic characterization of Acanthamoeba". International Journal for Parasitology 25 (2): 229–39. doi:10.1016/0020-7519(94)00075-Y. PMID 7622330. 
  7. ^ Niederkorn, JY; Alizadeh H; Leher H; McCulley JP (May 1999). "The pathogenesis of Acanthamoeba keratitis". Microbes and Infection 1 (6): 437–43. doi:10.1016/S1286-4579(99)80047-1. PMID 10602676. 
  8. ^ Sharma, S; Garg, P; Rao, GN (2000). "Patient characteristics, diagnosis, and treatment of non-contact lens related Acanthamoeba keratitis.". The British journal of ophthalmology 84 (10): 1103–8. doi:10.1136/bjo.84.10.1103. PMC 1723254. PMID 11004092. 
  9. ^ Bharathi JM, Srinivasan M, Ramakrishnan R, Meenakshi R, Padmavathy S, Lalitha PN; Srinivasan; Ramakrishnan; Meenakshi; Padmavathy; Lalitha (2007). "A study of the spectrum of Acanthamoeba keratitis: a three-year study at a tertiary eye care referral center in South India". Indian J Ophthalmol 55 (1): 37–42. doi:10.4103/0301-4738.29493. PMID 17189885. 
  10. ^ Pasricha, Gunisha; Savitri Sharma; Prashant Garg; Ramesh K. Aggarwal (July 2003). "Use of 18S rRNA Gene-Based PCR Assay for Diagnosis of Acanthamoeba Keratitis in Non-Contact Lens Wearers in India". Journal of Clinical Microbiology 41 (7): 3206–3211. doi:10.1128/JCM.41.7.3206-3211.2003. PMC 165372. PMID 12843065. 
  11. ^ Sharma S, Garg P, Rao GN; Garg; Rao (October 2000). "Patient characteristics, diagnosis, and treatment of non-contact lens related Acanthamoeba keratitis". Br J Ophthalmol 84 (10): 1103–8. doi:10.1136/bjo.84.10.1103. PMC 1723254. PMID 11004092. 
  12. ^ a b Lindsay RG, Watters G, Johnson R, Ormonde SE, Snibson GR; Watters; Johnson; Ormonde; Snibson (September 2007). "Acanthamoeba keratitis and contact lens wear". Clin Exp Optom 90 (5): 351–60. doi:10.1111/j.1444-0938.2007.00172.x. PMID 17697181. 
  13. ^ Hammersmith KM (August 2006). "Diagnosis and management of Acanthamoeba keratitis". Current Opinion in Ophthalmology 17 (4): 327–31. doi:10.1097/ PMID 16900022. 
  14. ^ "Acanthamoeba: Treatment & Medication - eMedicine Infectious Diseases". Retrieved 2009-02-27. 
  15. ^ S. Singh and M. P. Sachdeva (July 23, 1994). "Acanthamoeba keratitis". BMJ 309 (6949): 273. doi:10.1136/bmj.309.6949.273. PMC 2540756. PMID 7802782. Retrieved 2013-08-02. 

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