Acanthamoeba are naturally occurring amoeba (one-celled organisms) commonly found in water sources, such as tap water, well water, hot tubs and sewage systems. These common parasites can enter the eye and cause acanthamoeba keratitis, a very serious eye infection that can result in permanent scarring of the cornea and vision loss.
Contact lens wearers are at increased risk of encountering acanthoamoeba infection if proper contact lens care is not followed. One should not wear contact lenses while swimming or using a hot tub.
Another common parasite is microsporidia, a spore-forming unicellular parasite found in soil. Microsporidial infection can occur when mud enters the eye during sporting activities such as football or rugby in muddy fields. This can cause keratoconjunctivitis, which may cause eye pain, redness or blurry vision as early as two days to a couple of weeks after exposure.
Managing Corneal Ulcers and Corneal Infections
Most corneal ulcers and infections can be effectively treated with intensive antibiotics, antifungal, antiviral and antiparasitic eyedrops and medication.
When infections are more severe, the treatment will be prolonged and visual outcome can be more unpredictable. There may be a need for surgical management such as a cornea biopsy to establish the diagnosis or a therapeutic cornea transplant.
Keratoconus / Keratoectasia
Keratoconus is due to progressive irregularity and distortion of the cornea from the weakness of the cornea stroma. It is an eye disease in which the regularly shaped cornea thins and begins to bulge into an irregular cone-like shape. This irregular shape results in irregular light refraction as it enters the eye on its way to the light-sensitive retina, causing distorted vision.
Keratoconus can occur in one or both eyes and often begins during the teenage years or in the early 20s. This condition causes increased irregular astigmatism and poor vision that cannot be corrected by spectacles or contact lenses. The progressive thinning of the cornea also results in scarring and discomfort of the eye.
Most causes of keratoconus are inherent weakness of the cornea stroma and worsened by rubbing of the eye. Some are due to post-refractive surgical procedures and other cornea procedures.