Many people jump at the chance to wear contact lenses, sometimes to improve appearance. Not having to hunt for the spot where they put down their glasses is appealing, but contact lens wearers who fail to take proper care of their contact lenses are putting their eyesight at risk. 
A report released this year by the CDC reveals some of the most common – and dangerous – mistakes of contact lens wearers:
- 1. 50 and 87% of wearers sleep or nap in their contacts, respectively
- 2. 50% never replace their contacts, and 82% don’t replace them often enough
- 3. 85% shower with their lenses in, which can allow bacteria from water to get onto the lenses
- 4. 85% admit to keeping old contact lens solution in the case, which loses its disinfecting power
- 5. 55% top off old contact lens solution with new solution
“Individuals are likely doing at least one, if not more, of these behaviors,” said Dr. Jennifer R. Cope, medical epidemiologist at the CDC and lead author of the report.
Contact wearers who commit one or more of these optical sins are putting themselves at risk of infections so serious they could lose their eyesight.
“We think that there’s an event where maybe you seed the contact lens or your case with one of the microorganisms that can cause infection and then subsequent behavior can allow that to amplify so it’s causing an infection,” Cope said. She added that showering in lenses or not replacing contact lens solution could seed bacteria. Wearing the lenses for too long after that may give the contaminants the opportunity to swell in number.
According to the report, one-third of contact lens wearers have had to visit a doctor due to pain or redness in their eyes. 
The story of Chad Groeschen is a cautionary tale. When his left eye started to itch, he assumed it was allergies. After the eye got goopy and he lost sight in it, he thought it was just a sinus infection. The Cincinnati-based builder and sculptor was shocked when doctors at Cincinnati Eye Institute told him his contact lens had caused a bacterial infection in his eye that was rapidly destroying his cornea.
Groeschen had been using extended-wear contacts, which are approved by the FDA for overnight wear. He believed he was doing himself a favor by choosing extended-wear lenses over regular ones because he wouldn’t have to handle them as often. Instead, Groeschen wound up with Pseudomonas, which is one of the most serious types of bacterial infections in the eye. The American Academy of Ophthalmology warns that sleeping with contact lenses in the eyes increases the risk of infection.
The infection was so bad that some of the cells in Groeschen’s cornea started to die. Though the infection has healed, he was left with a scar that obscures his vision, and he may need a cornea transplant.
Cope said many contact lens wearers are not aware they’re even doing anything wrong.
Dr. William J. Faulkner, director of urgent services at Cincinnati Eye Institute – one of the doctors treating Groeschen – says contact lens wearers should see an eye doctor immediately if they experience pain, redness, or pus in the eye.
Julie Fidler is a freelance writer, legal blogger, and the author of Adventures in Holy Matrimony: For Better or the Absolute Worst. She lives in Pennsylvania with her husband and two ridiculously spoiled cats. She occasionally pontificates on her blog.