How exposure damages the cornea
Every blink spreads a fresh layer of tears across the cornea (the clear front window of the eye), and closed lids protect it during sleep. When the eyelids can’t close fully, a condition called lagophthalmos, part of the cornea stays exposed to the air. The tear film evaporates, the surface dries out, and damage follows. Doctors call this exposure keratopathy.[1]
It usually starts as tiny dry spots on the lower third of the cornea. Caught early, that stage responds well to treatment. Left untreated, it can progress to larger patches of missing surface cells, wounds that won’t heal, melting of the cornea, new blood vessels, and infection, with a real risk to vision.[2] In severe cases the cornea can ulcerate or perforate.[1]
People describe pain, discomfort, constant watering, and blurred vision.[8]
What causes it. The most common cause of lagophthalmos is facial nerve paralysis, because the facial nerve controls the muscle that closes the eyelids.[1] Bell palsy is the most common form of facial paralysis, accounting for 38% to 83% of cases of facial weakness. Over 80% of people with Bell palsy recover on their own.[3] Other causes of facial paralysis include trauma, surgery, tumors, stroke, and conditions present from birth.[4] Surgery for acoustic neuroma, a tumor near the hearing nerve, is a well-known example.[9] Exposure can also come from eyelid surgery or scarring, from lids that sag outward, or from an eye that bulges forward.[2]
Some people also lose feeling in the cornea, for example after some brain tumor operations.[9] A cornea that is both exposed and numb needs particular care. Our page on neurotrophic keratitis covers that side.
How a scleral lens protects an exposed cornea
A scleral lens is a large rigid gas-permeable lens. It rests on the sclera (the white of the eye) and arches over the whole cornea without touching it. Before insertion it is filled with sterile, preservative-free saline, so a layer of fluid covers the cornea for as long as the lens is in.
For an exposed eye that means:
- The cornea stays wet whether or not the lids close. The lens holds the saline against the cornea, so moisture doesn’t depend on blinking.
- The surface is covered. The lens acts like a liquid bandage between the cornea and the air, and between the cornea and the eyelid.[4]
- Vision can improve. The smooth front of the lens and the fluid layer mask an uneven, damaged surface.
The limit is simple: the lens only protects while it’s in. The long-term published reports describe patients who were told not to sleep in their lenses.[9] Most people with exposure keratopathy still need a plan for the night, such as ointment, taping the lids, or a moisture chamber (a clear shield that seals around the eye). Your eye doctor sets that plan.
PROSE (prosthetic replacement of the ocular surface ecosystem) is a scleral lens treatment model used in much of the research below. Other studies used commercially available scleral lenses.
What the research shows
There are no randomized trials. The evidence comes from retrospective case series and case reports, mostly from specialist centers. They consistently describe better vision and a healthier surface, but they are small.
Vision and surface damage improved in a referred group. At the USC Eye Institute, 29 patients with exposure problems, lid retraction, or lids that turned outward were referred for PROSE after conventional treatment had failed. Eighteen completed fitting. In those 18, average vision improved from about 20/80 to about 20/35. Symptom scores and staining of the cornea, a sign of surface damage, also improved.[5] The study doesn’t say what happened to the 11 who didn’t complete fitting, so the results describe people who could be fitted.
Faster vision gains than standard care, in a non-randomized comparison. A Weill Cornell study looked at 45 patients (53 eyes) with exposure after eyelid or skull-base surgery. Twenty-two were treated with PROSE and 23 with standard care such as lubricants, plugs, taping, a moisture chamber, or surgery. The PROSE group started with worse vision and had tried more treatments before, an average of 8.3 compared with 2.1. Even so, they gained about 3 lines of vision within a month and kept that gain at 12 months. The standard-care group gained about 1 line at 12 months.[6] Because patients weren’t randomly assigned, the two groups aren’t directly comparable.
Exposure is a common reason for therapeutic scleral lenses. At the Mayo Clinic, exposure keratopathy was one of the three most common reasons for fitting scleral lenses for ocular surface disease. Of 115 patients who completed fitting, all but 2 met their treatment goals, such as better comfort, surface protection, or healing.[7]
Lenses can help when lid surgery hasn’t been enough. A small report described three people (four eyes) with facial palsy after acoustic neuroma surgery, whose corneas stayed exposed despite an eyelid weight and a partial lid closure. With mini-scleral lenses, vision in the two people with one affected eye improved to 20/30, and the surface damage in the third person cleared within a week. All three were followed for two years.[8]
Long-term use is possible. A Belgian report described three people with eyelids that didn’t close fully and numb corneas after brain tumor surgery. They wore scleral lenses for 3, 17, and 18 years as an alternative to having their eyelids partly sewn shut. Two of the three eyes still needed a corneal transplant during that time, and lens wear resumed 4 to 6 weeks afterward.[9]
Other options, compared
Treatment depends on the cause, how long the exposure is expected to last, and how damaged the cornea is. Options are often combined.[1][4]
| Option | What it does | Typically suited to |
|---|---|---|
| Lubricating drops, gels, and ointment | Replace moisture lost to evaporation | Every stage, often heavier at night |
| Taping the lids or a moisture chamber | Keeps the eye covered or humid during sleep | Night-time protection, temporary palsy |
| Botulinum toxin to the upper lid | Temporarily lowers the lid to cover the cornea | Short-term protection while recovery is awaited |
| Scleral lens | Keeps a saline layer over the cornea while worn | Ongoing exposure, or failure of drops and taping, especially when vision matters |
| Eyelid weight or spring | Helps the upper lid close | Lasting facial palsy |
| Tarsorrhaphy | Partly sews the lids together | Severe or threatened corneal damage |
| Eyelid repositioning surgery | Corrects lids that sag outward or are pulled back | Lid retraction, ectropion, scarring |
Questions to ask a scleral lens fitter
- How many patients with exposure keratopathy or facial palsy do you fit?
- Will you work with the eye doctor or surgeon who manages my eyelids?
- How should I protect my eye at night and whenever the lens is out?
- Is my cornea’s sensation reduced, and does that change how you’ll monitor me?
- How many visits does a fit usually take, and what do the fees cover?
- If my facial nerve recovers, will I still need the lens?
- What should I do if the lens fogs, or if my eye becomes red or painful?
Common questions
Can I wear a scleral lens at night when my eye doesn't close?
Usually not. In the long-term published reports, patients were told not to sleep in their lenses. Night-time protection, such as ointment, taping, or a moisture chamber, is usually still needed. Your eye doctor will tell you what to use and whether overnight wear is ever appropriate in your case.
Is a scleral lens an alternative to eyelid surgery?
For some people it can be. Small studies describe scleral lenses used as a long-term alternative to partly sewing the eyelids closed, and researchers have suggested them as an alternative to lid surgery for some patients. For others, surgery to help the lids close is still the better long-term answer. The choice depends on the cause, whether recovery is expected, and what you want for your appearance and vision.
My Bell palsy may recover. Should I still consider a scleral lens?
Most people with Bell palsy recover on their own, so a scleral lens is more often considered when exposure lasts or doesn't respond to drops, ointment, and taping. If your cornea is being damaged now, ask your eye doctor whether a lens could protect it while you wait.
What if my eye is also numb?
A numb cornea makes exposure more dangerous because it may not hurt when something is wrong. It can also make the lens harder to learn to handle. Regular checks with your doctor matter more than how the eye feels. See our page on neurotrophic keratitis for more.
Are scleral lenses covered by insurance for exposure keratopathy?
Sometimes. Some medical plans cover scleral lenses when they are medically necessary for a disease of the eye surface. Coverage depends on your plan and on whether the practice is in network, so ask for the codes and a written estimate.
Why is the white of my eye red outside the lens by the end of the day?
The lens covers the cornea and part of the white of the eye, but the area outside it can still dry out when the lids don't close well. Tell your fitter where the redness is and when it starts. A change in lens size or shape, extra lubrication, or moisture chamber glasses sometimes helps.
Why are some days so much better than others?
Wearers with exposure often notice that wind, fans, air conditioning, heating, and low humidity make a big difference. Moisture chamber glasses and avoiding direct air flow can help on bad days. If a bad day comes with pain, redness, or blurrier vision that doesn't settle, remove the lens and call your eye doctor today.
I use ointment at night. Does that affect my lens in the morning?
It can, because ointment left on the lids or lashes can smear onto the lens and blur your vision. Wearers often clean their lids gently before putting the lens in. Ask your eye doctor which night ointment or gel to use and how to time it around your lens.
The lens protects my eye. Can I wear it in the shower or pool?
No. Keep scleral lenses away from water, including showers, pools, lakes, and hot tubs, because water can carry organisms that cause serious eye infections. Put the lens in after you shower, and take it out before swimming. If water gets on a lens, remove it and clean and disinfect it before wearing it again.