Annual. Monthly. Biweekly. Daily. Soft. Hard. Hybrid. Customized. Today there are ample contact lens designs made to fit the different lifestyles of the 40.9 million contact lens wearers in the United States. Contacts are proven to be a safe and effective when used as designed, but what happens when the wearer wears a contact lens contrary to how it’s designed?
It’s no secret that contact lenses aren’t always worn as recommended by their eye care provider. Maybe it’s to try to extend the life of their contacts to save a couple bucks. Maybe it’s dropping a contact lens on the ground and washing it with tap water because they forget their solution at home. Maybe it’s as simple as forgetting to take the lenses out before that 20 minute power nap after the morning coffee wore off. In fact, a 2014 survey by the Center for Disease Control revealed that 99% of all contact lens wearers reported at least one behavior that put them at risk for an eye infection or inflammation. We can write about every one of those risky behaviors, but today we are just going to focus on sleeping with your contacts.
What happens to your eye when you sleep?
It’s common knowledge that you need oxygen to survive, but have you ever thought about how this gets to your eye? Your eye has many blood vessels and if you’ve ever seen someone with allergies or pink eye, you probably noticed this yourself, but there is actually a part of your eye that does not contain any blood vessels at all: your cornea. The cornea is a dynamic, clear, dome-shaped structure at the center of the eye, spanning across your iris and pupil. The clarity and shape of the cornea is essential to maintaining visual acuity. Because there are not any blood vessels in the cornea, the cells rely on the diffusion of oxygen through the front part of the eye. When your eyes close, this diffusion is limited and causes the cornea to swell while sleeping.
The problem with sleeping with soft contact lenses
When your eyes are closed with contacts on, the oxygen exchange to your eye is inhibited even more than normal. This results in increased swelling of the cornea (edema) and can cause the contact lens to fit improperly, which can lead to acute red eye irritation. If the cornea is repeatedly deprived of oxygen (hypoxia), the eye may form new blood vessels (corneal neovascularization) or improperly formed cells that may rupture (corneal microcysts). Complications can change the surface and shape of the cornea, ultimately making it unsafe to wear contact lenses.
To counter this, contact lens manufacturers have created extended wear contact lenses which increase the oxygen permeability of contact lenses. These contacts are approved for up to 30 days continuous wear, but these claims must be taken with caution. In the manufacturer’s own literature, only 80% of patients are expected to be able to achieve 30 days of continuous wear and 3-5% of wearers developed corneal inflammation accompanied with mild to severe pain.
Contact lenses may also scratch the surface of the eye causing a corneal abrasion. The Center for Disease Control identifies corneal abrasions as a likely pathway for parasites to invade the eye. This may lead to sight-threatening microscopic organisms like Acanthamoeba to enter the eye and eat the cells of your cornea. Coupled with poor hygiene, cleaning or storage, your eye may be exposed to bacteria and amoeba for longer periods of time, increasing your risk for infection. Even a short nap with your contact lenses on will increase your risk of developing a corneal ulcer, that is a painful, open sore on the clear part of your eye. If left untreated, ulcers may develop scarring.
Orthokeratology Lenses Should be Worn Overnight Not Soft Contact Lenses
So then, can sleeping with contact lenses make your vision better? Optometrists can now custom design contact lenses that will reshape your eye while you sleep allowing you to see 20/20 during the day without glasses or surgery. This is called orthokeratology. These retainer lenses are made of material that allows those vital gasses to reach your eye and prevent irritation that may cause edema. At Insight Vision Center Optometry, our orthokeratology program has been developed to seamlessly integrate into your life and guarantee that you love the way you see.
Bottom line, always wear contact lenses as recommended by an eyecare professional and be sure to exercise proper handling, cleaning, storage and wear. Contact lens manufacturers always have a specific amount of time a contact lens is approved for wear. Anytime that period is exceeded, you may put your eye’s health at risk.