The short answer is no, it is never safe to sleep in contact lenses. In general, contact lenses are a wonderful way to treat myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and even presbyopia (difficulty seeing up close). Whether it is for an active lifestyle, or simply cosmetic, contact lenses may offer many patients an additional way to improve their vision other than just with glasses. With proper fitting, a little training, and some simple lens care, most patients can successfully wear contact lenses. However, contact lenses should be used with care and caution so as to avoid potentially serious complications.

Some of the more common issues contact lens wearers face include dry eyes and allergies. Mild dry eyes and allergies are frequently managed with artificial tears, while more advanced cases may benefit from prescription eye drops, and/or in-clinic treatments. Contact lens wear can exacerbate these common conditions and may end up limiting their use. As a corneal surgeon, the most serious complication from contact lenses that I see is a corneal ulcer (infection of the front layer of the eye). This condition, if caught early enough, can usually be treated with antibiotic eye drops. Sometimes, more serious infections may require corneal transplantation (transplanting the clear window at the front of the eye) in order to restore vision. One of the most common causes of corneal ulcers is sleeping in contact lenses. Why does this happen? When we wear contact lenses we limit or block the amount of oxygen that reaches the cornea. During sleep, when our eyes are closed we lose the natural protective immune effect that tear turnover and blinking affords us. This is a perfect storm for many organisms — bacteria, fungi, and parasites to invade the weakened corneal defenses.

So what can we do as patients to prevent this? First, make sure your contact lens fit is checked annually. Second, never sleep in your contact lenses. Some patients do better with daily disposable contact lenses, rather than extended wear contacts that need to be stored. Patients can simply discard their contacts each night, and place a new pair the following morning. Third, refractive surgery, such as LASIK, PRK, and ICL (implantable lenses) can offer many, if not all, of the same benefits of contacts without the daily hassle. Prior to any surgery, it is imperative to have a detailed exam and discussion to confirm whether someone is an ideal candidate, and to ensure safety. Until then, whenever you think it is OK to sleep in your contacts, please think again.

[heichel] 

Chris W.D. Heichel, MD, ophthalmologist specializing in cornea, cataract and refractive surgery

https://health.ucsd.edu/news/features/Pages/2019-01-07-corner-clinic-workout-injuries-ideal-weight-sleeping-with-contacts.aspx