A woman holds a contact lense on her pointer finger.
Proper use of contact lenses includes close attention to storage and cleaning. (For Spectrum Health Beat)

People who wear contact lenses to bed may joke that they want to see better at night.

But Samantha Rosen, OD, doesn’t think it’s a good idea.

She light-heartedly uses this analogy: “Would you wear your underwear for a month without changing it? The obvious answer is ‘no,’ but people do that with their contacts all the time.”

Dr. Rosen, a pediatric optometrist at Spectrum Health Helen DeVos Children’s Hospital, purposely uses the exaggerated “underwear” comparison as a memorable warning.

The message is clear: If you have contact lenses, you generally should not wear them 24 hours a day.

Continuously wearing contacts can cause an infection that is harmful to the eyes, Dr. Rosen said. The resulting effect on a person’s vision can vary from temporary to permanent, with the damage being partial or severe—even leading to blindness.

Dr. Rosen said there are certainly other causes of infection besides wearing contacts to bed, “but this one is pretty high up there on the list.”

Swimming with your contacts in or failing to change the lenses—or the storage case—as prescribed can also cause infections, she said.

A person experiencing limited vision, redness, watery eyes or eye discharge may have an infection. It’s important to contact a doctor immediately, Dr. Rosen said.

“Most eye infections are vision threatening and need to be treated,” she said.

For those who fail to use their contacts as prescribed, there is but one small, insignificant comfort: You are not alone in your foibles.

A recent study by the Centers for Disease Control and Prevention found the vast majority of contact lens wearers are guilty of some misdeed when it comes to the use of their lenses. At least one contact lens hygiene risk behavior was reported by about 88 percent of older adults, 81 percent of young adults and 85 percent of adolescents.

The most common infractions: failing to visit an eye doctor annually, sleeping or napping in lenses, and swimming in lenses.

While misery may love company, it’s best to steer clear of that crowd’s behaviors.

“To avoid severe complications from the overuse of contact lenses, wear your contacts as prescribed by your provider,” Dr. Rosen said. “And generally, don’t wear them when you sleep.”

Dr. Rosen listed 5 things that can happen when you sleep while wearing contact lenses:

  1. It could change the shape of your eye. This affects the overall curvature of the cornea, thus altering how light is refracted. This change in light refraction can result in poorer vision.
  2. The eye could be deprived of oxygen. This will cause blood vessels to grow and it could ultimately interfere with a person’s vision.
  3. It could create cornea ulcers. This will cause pain and redness in the eyes and it may also interfere with vision.
  4. You could develop an intolerance to contact lenses. When people over-wear their contacts, the eyelids and eyes don’t handle contacts as well. Ultimately, the lenses can become too uncomfortable to wear.
  5. It could lead to permanent vision loss. Over-wearing the lenses can lead to an infection that penetrates the eye and results in permanent vision loss. The scarring from an infection can produce permanent partial vision loss or complete vision loss.