Illustrated By Sandy Ley.
A 23-year-old Taiwanese student has gone blind and lost an eye after wearing the same temporary contact lenses for six months — never once removing them, not even while swimming, bathing, or sleeping. Lian Xao developed a condition called bacterial keratitis when an amoeba called acanthamoeba, commonly found in water and soil, came into contact with bacteria on her lenses. After this parasitic cell ate the lens bacteria, it infected the young woman’s cornea (the clear external layer of the eye) and burrowed through to her retina. While a cornea can often be replaced, once an amoeba has progressed beyond this layer, the damage is permanent.
This gory outcome is the consequence of a fairly common condition among contact-lens wearers. It may sound unbelievable that this woman didn’t realize a parasite was destroying her eyes, but the symptoms of corneal infection can be relatively minor: red eyes, slight pain, tearing, sensitivity to light, and reduced vision. Plus, sufferers may not experience all of these and may interpret any of them as allergies or standard irritation. Once an infection like this spreads from the cornea to the inner eye, however, the pain intensifies, and eyesight loss is guaranteed.
This news comes in the wake of yet another amoeba tragedy: Last week, a nine-year-old Kansas girl died after being infected by a brain-eating amoeba called Naegleria fowleri, which the girl likely contracted while engaging in water sports. Naegleria fowleri is found especially in still, warm water and so is more prevalent during the summer months; it enters the body through the nasal cavity and then progresses to the brain, killing its victims within about five days. It’s incredibly rare (as of 2012, only 200 cases have ever been published in English) but also extremely lethal (only 12 of these 200 victims survived). Nose clips offer effective protection if you’re planning to submerge yourself in warm freshwater this summer.
To prevent corneal infection, meanwhile, contact hygiene is a must. Generally, lenses should be worn no more than eight hours per day and should be removed before swimming. It’s also vital to properly clean lenses with fresh solution, store them in a dedicated case that you replace every three months, and swap out lenses on the schedule recommended by your eye doctor. Sticking to a hygiene routine will protect your contacts and, more importantly, your eyesight.