The Health Risk Every Contact Lens User Should Know About

Has your doctor warned you about this danger of prolonged contact lens wear?

True story: After an exhausting day, April dragged herself to the bathroom. Standing before the mirror, she began her nightly ritual of removing her contact lenses.

Her eyes began to sting and water. It wasn’t just the discomfort that alarmed April. When she looked around the room, everything was reduced to hazy, indistinct shapes. It was as if someone had placed a filter over her eyes. April knew how the world looked when she didn’t have her lenses on, but this fogginess was foreign and disturbing.

The next day, April booked the earliest appointment with an eye specialist. After a battery of tests, the doctor ruled out glaucoma and retinal detachment, and concluded that April had probably hurt her corneas — the clear, outer layer of the eyes — while removing the contact lenses. She was sent home with antibiotics, lubricating eye drops, and the assurance that her eyes should heal within a few days.

One week passed, and then two. April’s vision remained blurry. In fact, it took nearly three months for the ‘fog’ to lift. For a time, she wondered if she would ever see clearly again. It turned out that April’s corneas were unable to heal as quickly as healthy ones typically do. Years of prolonged contact lens wear had, in her doctor’s words, “starved” her eyes of oxygen.

The role of stem cells

April had a condition known as limbal stem cell deficiency (LSCD), which weakens the cornea’s ability to repair and renew itself. Limbal stem cells are what one might call “master cells” found in the cornea, which are responsible for producing new cells. April’s LSCD was not severe, so her eyes were eventually able to heal with treatment.

With LSCD, the recovery of the cornea may take three to six months. Even then, not all limbal stem cells can be restored fully. Some people may be left with residual areas of limbal stem cell deficiency for life. In more serious cases, people with LSCD may heal poorly or not at all, resulting in scarring and ultimately vision loss.

Contacts lens-induced LSCD

Most contact lens wearers would have heard about complications such as corneal ulcers and infections, but few are aware that contact lens wear can lead to limbal stem cell deficiency. What’s even more shocking is that LSCD accounts for up to a quarter of all contact lens-related eye problems.

“When we speak of limbal stem cell deficiency, it brings to mind the more harrowing causes such as acid burns, thermal injury, radiation or drug toxicity, and Stevens-Johnsons syndrome,” says Dr Claudine Pang, Consultant Ophthalmologist and Medical Director at Asia Retina Eye Surgery Centre.

“We don’t realise that the more prevalent issue of chronic contact lens overuse makes up 15 to 20 per cent of all LSCD cases.”

In fact, about five per cent of all contact lens wearers experience LSCD. To put that in perspective, out of the 125 million contact lens users worldwide, 6.25 million may develop LSCD. “That’s certainly significant enough for the need to raise awareness on this condition,” says Dr Pang.

Red flags of LSCD

Depending on the severity of the condition, you may experience symptoms such as eye discomfort, foreign body sensation, eye redness, sensitivity to light, contact lens intolerance, tearing, and blurring of vision. According to Dr Pang, milder cases of LSCD may not present symptoms at all until a sudden unforeseen corneal injury results in prolonged blurring of vision and poor healing of the cornea — as was the case for April.

If you experience these symptoms, consult an eye doctor. Your eye doctor will be able to spot signs such as an uneven corneal surface, abnormal blood vessels growing within the cornea, and other abnormalities.

Are you at risk?

If you are female, Asian, and wear contact lenses, your risk of developing LSCD is, unfortunately, higher. “Women are more prone to having dry eyes; while Asians have smaller, tighter orbits and lid apertures, making the contact lens surface area in contact with the eye much greater than our Caucasian counterparts,” explains Dr Pang. Other risk factors include:

• Prolonged or extended use of contact lens. People who wear contact lenses for 12 to 14 hours a day are more likely to develop LSCD. Every time we blink with the contact lens in our eyes, it creates microtrauma to the cornea. Over time, this will lead to cell injury.
• Sleeping with contact lens on. The lens acts as a barrier to oxygen getting to the cornea. Wearing a contact lens overnight creates prolonged hypoxia (oxygen deprivation) to the cornea.
• Poor fitting contact lens. Contact lenses should always be prescribed and fitted well by an eye-care professional. A contact lens that is too tight for the eye will produce much greater microtrauma and hypoxia.
• Prolonged exposure to preservatives in contact lens solutions. Harmful preservatives found in contact lens solutions inadvertently get trapped on the lens and consequently the eye. To avoid this, use daily disposable contact lenses.
• Dry and inflamed eyes. Contact lens wearers are already predisposed to dry eyes because the lens disrupts the normal functioning of the tear film. This is why contact lens wearers should take care to lubricate their eyes. Doing so replenishes oxygen supply to the cornea too. Also, other pre-existing conditions that contribute to eye dryness or inflammation, such as thyroid disease and other autoimmune disorders, should be treated as well.

Treatment of LSCD

So what happens if you have LSCD? First of all, stop wearing contact lenses. This gives the limbal stem cells a chance to regenerate. Dr Pang adds: “We must also treat dry eyes aggressively with preservative-free lubricating drops to restore the normal tear film. Since inflammation contributes significantly to LSCD, a course of preservative-free steroids and other anti-inflammatory eye drops are usually prescribed.”

Sometimes, more advanced treatments that promote corneal surface health may be needed. These include punctal plugs (tiny, biocompatible devices inserted into the tear ducts to block drainage), vitamin A ointment, and autologous serum eye drops (made from the patient’s blood serum, which is rich in healing factors).

Even after recovery, it’s a good idea to stop wearing contacts lens completely. “Any subsequent insult to the cornea may result in permanent vision loss,” explains Dr Pang. “If patients insist on wearing contact lenses, changes in contact lens type, regimen and care are essential. However, I would recommend seeking alternatives such as spectacles or refractive vision correction.”

If medical treatments do not work, surgical intervention in the form of autologous limbal stem cell transplant may be recommended. This involves harvesting stem cells from the patient’s healthy eye and transferring them to the damaged eye.

Prevention is key

Contact lens overuse or poor contact lens habits can unknowingly result in limbal stem cell deficiency without any prior signs or warning. The only way to know if you have early LSCD is to see your eye doctor regularly for evaluation. “It is always better to prevent its occurrence, then to ‘fight the fire’ after the cornea has been damaged,” says Dr Pang. “Often, the damage may be irreversible.”

Life after LSCD

Although April’s vision is mostly back to normal, it was a distressing experience she never wants to relive. Before this incident, she had been wearing bi-weekly lenses every day for more than 15 years. “I thought my eyes were healthy because I had never had an infection this whole time. I never expected to take so long to heal,” says April.

“It was awful seeing the world through a murky filter, and the prospect of being blind—even partially—was really frightening. I don’t think I will ever take my vision for granted again.”

Related links:

Making a Spectacle of Myself

Seeing Eye to Eye

More about Dr Claudine Pang: