Many people choose to wear contact lenses to help them to see clearly day-to-day, and while they are extremely safe in the majority of cases, there are some hidden dangers. One of these is known as corneal hypoxia.

All of our cells need oxygen to survive. Inside the body, this oxygen is delivered via the bloodstream, when oxygenated blood travels around the body to all of the cells and tissues. However, since the cornea doesn’t have enough blood vessels to supply all of the oxygen that it needs to be healthy, it primarily relies on receiving oxygen through its exposure to the air.

Hypoxia is the term used to describe a lack of oxygen. Corneal hypoxia occurs when the cornea doesn’t get enough oxygen, and the primary reason why this happens is because of prolonged wear of standard contact lenses.

Standard contact lenses cover the entire surface of the cornea, essentially cutting off the oxygen supply to the cornea completely for the whole time that you are wearing them. While this is fine for a number of hours during the day, if you wear your contact lenses for too long, the lack of oxygen can cause the cornea to start to swell. This happens because the cornea starts to accumulate lactic acid, and this pulls water to it, causing edema.

​​​​​​​While the initial symptoms of corneal hypoxia may seem more of an annoyance than a concern, there is also the potential for much more serious problems, including the development of corneal cysts and death of the epithelial cells, both of which can compromise our vision.

While extended contact lens wear is the most common cause of corneal hypoxia, it can also be caused by infections, trauma to the eye, chemical burns, immune system diseases and other eye conditions, such as glaucoma and uveitis.

There are a number of signs of oxygen deprivation affecting the eyes. These include, but aren’t limited to:

• Blurred vision
• Burning pain in the eyes
• Scratchiness or general irritation of the eyes
• Excessive tearing
• Visible swelling in the epithelial (outer) layer of the cornea

If you notice any of these symptoms, particularly if you are a contact lens wearer, you should get checked out by our eye doctor right away.

The good news is that it is possible to avoid corneal hypoxia altogether by ensuring that you don’t wear standard contact lenses for longer than you should, or overnight. If you start to notice any of the signs of the condition after wearing your contact lenses for a long period during the day, removing your lenses should enable the issue to resolve itself.

Another option is to switch from standard contact lenses to a gas-permeable variety. As their name suggests, this type of contact lens is made from a material that enables oxygen to pass through them and reach the surface of the eyes, keeping the cornea oxygenated and comfortable.

If your corneal hypoxia is severe, more significant treatment may be needed to bring your condition under control. Corticosteroids have been shown to be effective at reducing the edema associated with corneal hypoxia.

If you suffer from ongoing episodes of corneal hypoxia, our eye doctor may recommend that you undergo laser vision correction surgery, such as LASIK, to reduce or eliminate your reliance on contact lenses in the future.

​​​​​​​If you have any questions about corneal hypoxia, or if you have concerns about your vision, please don’t hesitate to contact our knowledgeable eye care team at 718-565-2020.