Updates in Acanthamoeba keratitis.
OBJECTIVE
Acanthamoeba keratitis is a potentially blinding microbial disease that has been increasing in incidence during the past two decades. Prognosis of this serious disease had been dismal, but improvement in diagnosis, a better understanding of the natural course of the disease, and recent introduction of multiple and effective therapeutic agents have resulted in improvement of visual outcomes.


METHODS
A review of literature pertaining to Acanthamoeba keratitis.


RESULTS
Contact lens wear and exposure to contaminated water sources remain the most important risk factors; however, in vivo confocal microscopy and improved biomicroscopic screening have proven instrumental in accurate early diagnosis. Complications of Acanthamoeba keratitis include dacryoadenitis, corneal melting and scarring, severe secondary glaucoma, cataract, and chronic anterior segment inflammation that can rarely lead to reactive blinding retinal ischemia. Combination chemotherapeutic agents have been shown to be more effective than monotherapy, whereas rehabilitative surgery such as penetrating keratoplasty is best performed on a quiet eye free of ocular inflammation and with no residual amoebae.


CONCLUSIONS
Increased suspicion by clinicians for Acanthamoeba and confocal microscopy have allowed more rapid and accurate diagnosis; treatment with multiple antiamoeba drugs is essential to disease resolution. Provided there are no residual amoebae after treatment, penetrating keratoplasty has been successful in visual rehabilitation. Secondary glaucoma occurs frequently and may require drainage procedures for control of intraocular pressure. Posterior complications are rare but may lead to ischemic retinitis.
Awwad
Shady T
ST
Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9057, USA.
Petroll
W Matthew
WM
McCulley
James P
JP
Cavanagh
H Dwight
HD
D000048:Acanthamoeba / Q000302:isolation & purification; D015823:Acanthamoeba Keratitis / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D000563:Amebicides / Q000627:therapeutic use; D000818:Animals; D003315:Cornea / Q000469:parasitology / Q000473:pathology; D006801:Humans; D033401:Microscopy, Acoustic; D018613:Microscopy, Confocal; D011379:Prognosis
D000563:Amebicides