My eyes! Parasites in....my contact lenses?!

Photo courtesy of Stacey Peoples

     Now there is not a doubt in my mind that after reading that title you are wondering what fresh hell I'm presenting you this week. Sometimes, while reading about and studying diseases it seems nothing is safe but rest assured that the human body is by far the best security system on the market with defenses in place to keep little nasties like parasites out of it. But every now and again, little buggers manage to slip through undetected. When this happens, our body explodes with defense mechanisms all striking at the same time because it isn't sure to how to properly defend itself agains the invader.

     Our eyes are a prime example of a location where invaders can work their magic and bypass our bodies natural security system and sometimes, we unintentionally help them out in their efforts. Take one of the 45 million people in the USA alone who wear contact lenses. Now these lenses themselves aren't the problem per se, but it's how we handle them that can sometimes be a detriment to our lives. This is because of those 45 million people, about 40-90% of them do not properly follow the instructions of their optometrists for the care of their lenses and as a result have an increased risk of not only eye disease but increased risk of a parasite residing in their eyes.

     Take the case of Nick Humphreys in the UK who wore contacts throughout the day. Where things went wrong was when he showered with his contacts still in his eyes and a few days later, Humphreys was blind in one of his eye. This blindness was the result of an infection called Acanthamoeba keratitis (AK) which is a protozoan parasite commonly found in soil and in water and isn't usually known to cause much damage except for when it gets in a hosts' eyes.

      Humphreys isn't the only one who has suffered from AK, in fact 85% of the AK cases occur in people who actively wear contact lenses throughout the day. In the case of AK, lenses can become contaminated by exposure through swimming, using a hot tub, or not properly caring for your contact lenses. This usually results in the growth of bacteria on the lenses onto which the amoebas attach and begin to eat. Once they eat through the lens they inevitably end up in the hosts eyeball where they begin their normal parasite processes. Once they're in, the symptoms include redness, blurred vision, light sensitivity and a general feeling of something in one's eye.

Acanthamoeba keratitis

     So what is the moral of the story? Please protect your contact lenses and as a result your eyeballs. There are very clear instructions laid out not only by your optometrists but also on the boxes and instructions for contact lenses and contact lens solution. Don't shower or swim in contacts and definitely don't clean contacts using tap water or anything else but the good, strong lens cleaning solution. It should also be noted that there are other parasites that can make it into the eye and do even more damage than AK. These include toxoplasmosis (another protozoan parasite), loiasis (caused by a helminth parasite), and onchocercaiasis (another helminth parasite carried by black flies).

     There are also ectoparasites (parasites that live on the surface of the body) that can do some damage around the eyes. These include pubic lice which can get lost and make their way up to the eyelashes and eyebrows. These cause some gross buildups of excrement and other debris in the eyelashes and can result in a loss of hair around the eyes. There is also the Demodex parasite which causes the loss of eyelashes, conjunctivitis and potentially decreased vision.

 As always, be safe and make good choices while living life. There are things out there that are trying their best to break in but luckily we have methods for combatting these creepy crawlies. Make sure you follow the directions and practice safe practices with contacts, this is one less creeper you have to worry about.