Medical Parasitology Assignment: Acanthamoeba Keratitis and Use of Contact Lens Solution


Acanthamoeba spp. have been found in soil, sea water, sewage, swimming pools, contact lens equipment, medicinal pools, dental treatment units, dialysis machines, heating, ventilating and air conditioning systems. The microorganism can enter human body through the eye, the nasal passages to the lower respiratory tract, ulcerated or broken skin. When Acanthamoeba spp. enters the eye, it can cause severe keratitis in otherwise healthy individuals, particularly contact lens users. Acanthamoeba Keratitis develops from the entry of the amoebic cyst through abrasions on the cornea. The large majority of such cases have been associated with the use of contact lenses.


In multivariate analyses, case-patients had significantly greater odds of having used Advanced Medical Optics Complete Moisture Plus (AMOCMP) solution. From the finding, it suggest that the solution was not intrinsically contaminated and that its anti-Acanthomoeba efficacy was likely insufficient.

Case-patients method had been given a diagnosis of AK by an Ophthalmogolist; had symptom onset and had Acanthamoeba spp. identified from cultures of corneal specimens. Data collection and laboratory investigation, standardized questionnaires were used to interview case-patients by phone to obtain demographic characteristics, information regarding to the illness, contact lens-related product use and hygiene practices and behavior during the month before symptom onset.

Epidemiology of the case-patients, more than half (88%) from 105 patients wore contact lenses used soft contact lenses, 94% reported using some type of cleaning or disinfecting solution used a multipurpose solution. The most frequently reported symptoms among case-patients were pain, redness, sensitivity to light and sensation of a foreign body.

The investigation of national AK (Acanthamoeba Keratitis) outbreak identified use of single contact lens solution as the primary risk factor for infection. The AMOCMP is a multipurpose solution use for disinfecting, rinsing, cleaning, and storing lenses.

From the result, there are wide range of behaviors that can result in exposure of contact lenses to water (example such as rinse lenses or cases with tap water and showering with lenses in).

The study of the problem had several limitations. Firstly, because AK culture is a highly specific, but insensitive, diagnostic tool and because preferred diagnostic methods vary by medical center, inclusion of only patients with culture-confirmed cases may have introduced regional testing bias and underestimated the scope of the outbreak. Second, the response rate among persons approached for control interview was low; therefore, demographic differences between cases and controls may have been due to selection bias among control. Thirdly, recall bias may have been introduced as we asked participants to report on contact lens product use and behavior during the previous 2 years. Forth, misclassification bias may have been introduced because at least 2 case-patient appeared to not differentiate between use of saline and cleaning or disinfecting solutions. Fifth, because more than 40 percent of case-patients and all controls were interviewed after AMOCMP was recalled.

There are certain ways in which Acanthamoeba keratitis can be diagnosed. The diagnosis may include detecting ameba in laboratory settings, wherein blood agar plate is treated with E.Coli layer. Then a portion of the contact lenses will be placed on the prepared agar place. In case there are Acanthamoeba spp. on the lenses then a patch will be visible on the area of the lenses. In other cases wherein contact lenses are not the source of infection, then polymerase chain reaction technique can be utilized to diagnose the infection. Sometime diagnosis can be done by looking at the corneal ulcer developed during progressed stage of the infection.

Treatment that can be used for the problem such as follow doctor’s directions for the care and cleaning of your contact lenses then never use tap water to clean your contact lenses. For contact lens user, if they want to swim, do not swim, shower or hot tub while wearing contact lenses or without goggles. Before sleep, soak contact lenses in fresh disinfecting each night. Before handle and want to wear contact lens, wash hands before handling contact lenses. After that, always clean contact lenses immediately upon removal.

Treatment for corneal ulcers and infections depends on the cause. Treatment should be started as soon as possible to prevent scarring of the cornea. If the exact cause is not known, patients may start treatment with antibiotic drops that work against many kinds of bacteria. Once the exact cause is known, drops that treat bacteria, herpes, other viruses, or a fungus are prescribed. Corticosteroid eye drops may be used to reduce swelling and inflammation in certain conditions. Doctor may also recommend that you to avoid eye makeup, don't wear contact lenses at all, or don't wear them at night. After that, take pain medications, wear an eye patch to keep light out and help with symptoms and also wear protective glasses.


As conclusion, to avoid from the infection of Acanthamoeba Keratitis, contact lens users should follow precaution and follow the instruction that mentioned as in the summary. Avoid wearing contact lens more than 24 hours. Always remember that, never use tap water to clean your contact lenses. If the contact lens users want to swim, do not swim, shower or hot tub while wearing contact lenses or without goggles. It will prevent water from enter the yes while wearing contact lens. Before go to sleep, soak contact lenses in fresh disinfecting each night and put in the contact lens case that not contaminated with any unwanted materials. Before handle and want to wear contact lens, wash hands before handling contact lenses. After that, always clean contact lenses immediately upon removal. Make sure the cap of the contact lenses solution always close tightly and do not mix the solution with any solution especially tap water. It may contaminated the solution and if unfortunately, the tap water may contain unwanted microorganism such as stated above; Acanthamoeba spp. The goal of the research is to prevent any infection of the microorganism to the contact lenses users. As the researcher, they want to ensure that the microorganism not infect the users. Any prevention must be follow by the user to prevent infection to their eyes such as ulceration that may lead to blind.


Dorland’s Pocket Medical Dictionary 27th Edition, Saunders, pp 4

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