Sleeping in Contact Lenses

Jun 6, 2019
6 min read

It is estimated that 45 million people in the United States wear contact lenses.1 For many individuals, contact lenses have become the primary choice for vision correction, and for good reasons! Contact lenses offer to correct for a wide range of nearsighted, farsighted and astigmatic prescriptions and have become readily available in a variety of types and brands.

Contact lenses also provide us with improved aesthetics and greater versatility throughout the day, especially when we find ourselves in certain circumstances where spectacles do not seem to be as effective, for instance, while attending formal events or during certain types of physical activity.

With all the benefits that contact lenses bring, they certainly do not come without risks. It is true that the growing dependence on contact lenses as the preferred choice of vision correction has led to higher rates of misuse, especially when it comes to sleeping in contact lenses. Hence, it is important to have a thorough understanding of how these risks develop and how these risks affect the health of the eye overall. By evaluating lens wear habits and addressing common mistakes, new strategies can be discussed regarding how to prevent the issue of sleeping in contacts and thus, taking more optimal care of the eyes.

The recommended maximum number of hours for contact lenses approved for daily wear is anywhere from 10-14 hours per day. For proper eye health and function, it is vital that the eyes receive an appropriate amount of oxygen from the environment (Figure 1). Our corneas are what make this oxygen exchange possible.

While contact lenses permit for oxygen transfer to take place, it does so at a reduced rate in comparison to the eye when it is in its natural state (i.e. no contact lens on the eye) (Figure 2). Therefore, the longer that contacts are left in the eyes, the quicker the moisture from our natural tears evaporate, and the slower the rate of diffusion of oxygen into the eye. When an individual falls asleep while wearing their contact lenses, they are thereby increasing their chances of developing any or all of the following2:

  1. Keratoconjunctivitis Sicca: more commonly known as Dry Eye, a dehydrated, inflamed state of the cornea and/or conjunctiva caused by a deficiency in tear production or an altered tear film composition. This causes foreign body sensation, grittiness, redness, watering, pain and/or discomfort, vision fluctuation, and/or vision loss.
  2. Corneal & Conjunctival Infections: casually referred to as “pink eye.” This can be bacterial, viral, fungal, parasitic, or a combination of more than one microorganism. Symptoms can include severe pain, redness, discharge, and swollen eyelids. All of these infectious microbes have the potential for permanent vision loss if not treated appropriately or in a timely fashion.
    1. Acanthamoeba: a rare, but highly invasive parasitic microbe causing infectious keratitis of the cornea, conceivably the most dangerous and infectious threat to our sight caused by contact lens misuse. It is a result of contaminated contact lens use and has a high possibility of causing permanent visual impairment and/or blindness.
  3. Corneal Abrasions & Ulcers: injury to the cornea affecting one or more layers of the cornea, either by mechanical disturbance or infectious in nature. These can result in severe pain, redness, watering, and have the potential to cause permanent scarring and visual loss.

It is important to understand that each of the conditions mentioned above can be a direct result of sleeping in contact lenses and each condition discussed could result in permanent vision loss if left ignored or untreated.

Figure 1: Diffusion of oxygen into the eye, via the cornea, without contact lens on the eye.

Figure 2: Diffusion of oxygen into the eye, via the cornea, is reduced when contact lens is on the eye.

Contact Lenses Approved for Extended Wear /Overnight Use

The FDA has approved certain types of contact lenses for extended wear and/or overnight use. Most extended wear lenses are now made with a silicone hydrogel material which promotes a higher amount of oxygen flow through the lens into the eye. Nevertheless, it remains important to understand the increased level of risk associated with extended/continuous wear and the issues they can cause such as corneal hypoxia, inflammation, infection, etc. when compared to daily wear lenses.3

Prevention Strategies

Create and adhere to a solid nighttime routine. A healthy routine, when carried out for long enough, can turn into a habit, and a good habit can eventually lead to a better personal standard of care. One can consider their habitual evening routine as the “nightly triad”, which consists of the following three must-do tasks: Removing contact lenses, cleansing the face, and brushing teeth. This is will encourage self-discipline and force one to not want to miss any step before bedtime, if it is thought to be as part of a 3-step system.

It can also be helpful for many people to add daily reminders on their phones or other personal devices. For instance, adding a nightly reminder into one’s phone calendar to remove contact lenses or setting a nightly alarm to alert when it is time to be removing lenses are good tactics to reduce the chance of forgetting to remove them.

Finally, after having refreshed yourselves on the risks involved with sleeping in contact lenses and reading up on some tricks and tips to avoid falling asleep them, what are your thoughts? Do you have some suggestions of your own that other optometrists reading may be able to benefit from when they’re educating their patients on prevention? Feel free to leave your comments below!


  1. Centers for Disease Control and Prevention. Healthy Contact Lens Wear and Care. Retrieved from
  2. Churchill, J (Sept 2018). Why You Should Never Sleep in Your Contact Lenses. Retrieved from
  3. U.S Food and Drug Administration. Types of Contact Lenses. Retrieved from
  4. Air Optix. Contact Lenses. Retrieved from
  5. Hoffman, M (May 2018). ULTRA Contact Lenses Granted FDA Approval for Extended Wear. Retrieved from
  6. Cooper Vision. Biofinity. Retrieved from
  7. Ambrose A. et al (2018). Purevision. Retrieved from:
About Neety Kochar, OD

Neety Kochar, O.D. graduated from the Illinois College of Optometry in 2014, and now practices in Toronto, ON and San Francisco, CA. Neety's clinical interests lie in primary eye care, contact lenses, ocular disease and pre/post surgical management. She is …

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