Acanthamoeba and understating of risk factors between contact lens wearers

Mehdi Noorisadeghi,1,*

1. Shahid beheshti university of medical science



Acanthamoeba is free living protozoa that cause serious infection in the eye named acanthamoeba keratitis(ak). this infection could lead to ulceration and with late diagnosis maybe blindness. nowadays ak is more common rather than past. ak in more common in contact lens users due to poor hygiene and its growing among contact lens users. acanthamoeba is very challenging in control and disinfect. it has two walls cyst. five species of these free-living amoebae have been reported to cause keratitis. these are: a. polyphaga, a.castellani, a. hatchetti, a. culbertsoni and a. rhysodes. acanthamoebae are present in freshwater, brackish water and seawater bodies. nearly 85% of acanthamoeba cases occur in contact lens wearers, and a primary risk factor for developing ak is exposing contact lenses to water. unfortunately most of the laboratory tests informed that non of the contact lens disinfection solutions in iranian market have strong effect on acanthamoeba cysts, according to my research in fact not just in iran but all famous solutions such as renu, opti free and light, dont have sufficient effects on killing cysts of acanthamoeba except those with h2o2 and they are not common and famous between contact lens wearers due to harder handling and two step neutralizing. avoiding tap water exposure when wearing contact lenses is important. this brings me to exam contact lens wearers awareness about these serious issues. i exam it with questionnaire between 100 patents. with 5 questions:_ if they ever expose the contact lens to water by rinsing or storing in water, wearing contact lens while showering and swimming and how they behave with contact lens storage case. the purpose of this study is to determine how dangerous acanthamoeba is and prevalence of risky behaviors among contact lens wearers.


100 participants who were my patients were asked about exposing their lenses to water and their understanding of risks that associated with these behaviors. searching in articles about contact lens disinfection solutions. about acanthamoeba keratitis and water exposure behaviors among contact lens users.


With questionnaires it appears 86 percent of 100 contact lens wearers do at least one of the 5 risky behavior and exposing their contact lens to water by showering, swimming or rinsing it. and 65 of 100 didnt know that tap water contaminated with such resilient microorganisms like acanthamoeba. 83 percent rinse and wash their lens storage case with water. 97 percent didnt know their solutions is not capable of killing some microorganisms like acanthamoeba and 96 of them said if they know more about the risk of acanthamoeba keratitis they do better hygiene.


We as optometrists or eye doctors should aware every patients about acanthamoeba and this concept that tap water has microorganisms could infect their eye. although we have a lot of microbial keratitis between contact lens wearers but we dont have good understanding between contact lens wearers about risk factors. i think we should also aware people about their contact lens solutions efficacy. most of the contact lens wearers know a little about such a resilient and dangerous microorganisms like acanthamoeba in their environment and they said if they do know about it they will do better contact lens care.


Acanthamoeba keratitis, water exposure, contact lens solutions