If you suffer from extremely dry eyes, you may want to talk to your eye doctor about scleral contact lenses.

Older versions of these lenses were more difficult to fit and uncomfortable to wear for any length of time (they didn’t allow enough oxygen to pass through to the eye).

But thanks to new materials and manufacturing techniques over the past few years, newer versions are safe, fit well, and can offer blessed relief from chronic dry eyes.

You might be thinking, don’t contact lenses tend to make eyes drier? Most do—but not these.

And if you need your vision corrected, they can do that, too. Here’s how they work…

WHY BIGGER IS BETTER

The edge of a typical soft contact lens rests just a smidge outside the colored part of the eye, on the beginning of the sclera, the white part of the eye. A soft lens hugs the cornea (the eye surface that covers the colored part of the eye)—so there’s only a very thin layer of tears between the lens and the surface.

A scleral lens is much larger—up to 24 millimeters (mm) in diameter in comparison to the 14.5 mm of a typical soft lens—so its edge sits much further into the sclera, the white part of the eye. The main advantage of a scleral lens is that it doesn’t touch the cornea—it arcs over it, leaving a space between the scleral lens and the eye surface.

Now, what could you do with that space if you had dry eyes? You could fill it with sterile saline solution that bathes the surface of the eyes all day long—and that’s exactly what dry-eye patients are doing. You put the scleral lenses in each morning and take them out each night, as you would with most regular contact lenses.

PRACTICE MAKES PERFECT

When I spoke with Peter A. Russo, OD, an optometrist who specializes in scleral lens fittings at Loyola University Medical Center in Maywood, Illinois, he was careful to point out that scleral lenses can be tricky to use—it’s hard to get the lens into your eye without spilling the saline. But after some instruction from your doctor and some practice, you get the hang of it.

The biggest downside is cost, which varies widely and is usually many times the cost of typical contact lenses, said Dr. Russo. In fact, the price can be roughly $1,200 to $2,500 or even higher for both the pair and the fitting, according to Glenda Secor, OD, FAAO, an optometrist and communications chair for the American Academy of Optometry. Replacement lenses are usually needed anywhere from one to 10 years later—whenever the pair is scratched or warps or if your medical condition changes—and the cost of the replacement lenses isn’t as steep (typically hundreds, not thousands), according to Deborah S. Jacobs, MD, an ophthalmologist with the Boston Foundation for Sight and a member of the American Academy of Ophthalmology. (The lenses may be covered by insurance if they are considered a medical necessity by the insurer). Why such a huge expense? It’s because each pair of scleral lenses is customized to each patient’s particular set of eyes, so it may take multiple office visits with a specially trained eye practitioner to get an exact fit. “The design of these scleral lenses is complicated—for example, there are five distinct curvatures on the back of each scleral lens that need to be specified by the doctor,” said Dr. Russo. In addition, the doctor must spend extra time training the patient in how to use the lens.

Chronic dry eyes can literally be debilitating—Dr. Russo often sees patients who are using prescription eye drops every 30 minutes and still can’t get relief. If you’ve tried other treatments and are still suffering, scleral lenses are worth considering. Talk to your eye doctor, and ask for a referral to an eye doctor who specializes in fitting scleral lenses.