Wondering if you have an infection from your contact lens? The spooky answer to this question is that sometimes you don’t know you’ve got an infection from your contact lens. That’s the stuff of campfire tales, isn’t it? “It was only then that the man found out his eye had been infected the whole time. And on the car door handle, was the hook!”
Our eyes have exquisite sensitivity to irritation. But, as is often the case in life, sensitivity doesn’t always correlate with specificity. Scratch on your eye? Feels like sand. Infection on your eye? Feels like sand. Sand in your eye? Feels like sand. Hey! Look at that one! Sometimes it gets it right.
Contact lens tolerance is on a real Negative Nancy type of continuum. At the top of the spectrum, winning best tolerance possible, is an eye that feels the same with a contact as without. At the other end of the spectrum is an eye that feels and reacts to contacts as if you put a piece of mulch in the eye. Some people can’t have a contact in for four seconds without promising to never sin again if they can make it ‘til it’s out. The majority of people are somewhere in the middle of this tolerance continuum. Their eyes feel normal to mild irritation depending on the time of day or environment they’re in.
The problem with infections isn’t that they’re so rare that it is catastrophic when an eye has one. It’s that they’re rather common. So it is possible to “get used” to what it feels like to have a mild infection and ignore the warning from your eye. The warning signals usually feel like—you guessed it—sand in your eye.
Sometimes there’s redness to go along with the sand-in-eye warning signal. When this happens for the first time, people take their contacts out ASAP. Then they wait until everything feels alright a day or two later and resume with contacts as normal. Sometimes all that happened to cause it was a little scratch on the eye that heals in a few hours, none worse for the wear. Other times that scratch is under a contact of someone who’s had the sand-in-eye feeling before. They leave the contact in a bit longer and it gets a little infected. It has become an ulcer. This feels a lot worse and there aren’t many people who try to keep wearing a contact when the eye feels that terrible. But eyes are resilient. Eye doctor visit or not, most of the time the ulcer heals into a tiny, insignificant scar and life goes on as normal.
The way we know that this happens a lot is the scars are visible for decades after the ulcer heals. There is rarely a day in clinic that I don’t examine one eye with a scar and the patient has no memory of a past eye infection. After all, who remembers one time a couple decades ago when their eye was a little red and irritated for a day or two? The fact that it’s so common can make us think infections don’t matter very much. It is true, they don’t matter most of the time. It’s when they do matter, though, that it’s a very big deal.
The reason I got LASIK the week I did was because of a corneal ulcer. Not mine. It was a patient’s I saw while on an ophthalmology rotation in medical school. He was my exact age and was getting a corneal transplant because of a big, white scar in the center of his cornea. I read the past ocular history section of his chart. All that it said was “central corneal scar from contact lens induced corneal ulcer.” I got LASIK five days later.
That medical school experience made a point to me very real, which still comes up almost daily. Those little ulcers that never get identified because they went away don’t matter much. It’s not the infections you don’t know about, where you’d ask how to know you have an infection, that impact your life. But it’s that one infection. It’s the one that starts as indistinguishable as the rest but ends as subtle as a sledgehammer. It can change everything.
Like any scary campfire story, there’s a helpful warning in there about being cautious. “Beware the irritation indicating a corneal ulcer from your contacts, because the phone call was coming from inside the house!”