Most people with keratoconus can tell you the moment their glasses stopped being enough. Night driving got harder. Headlights started to streak and smear. A new prescription helped for a few months and then did not. Soft contacts felt fine but did not make anything sharper.
That pattern is not a sign that you are getting a bad prescription. It is what keratoconus does, and it is the exact problem scleral lenses were designed for.
Why Glasses Stop Working
The cornea is the clear front window of the eye, and it does most of the eye’s focusing. In a healthy eye it is smooth and evenly curved. In keratoconus it thins and bulges forward into a cone, and the cone is rarely symmetric.
Glasses can correct regular astigmatism, where the eye is curved more in one direction than the other in a predictable way. They cannot correct the uneven, lumpy distortion of a keratoconic cornea, which we call irregular astigmatism. A soft contact lens does not help much either, because a soft lens drapes over the cornea and takes on the same irregular shape.
To see clearly, the eye needs a new, smooth front surface. That is what a rigid lens provides.
What a Scleral Lens Actually Does
A scleral lens is a large rigid gas permeable lens, about the size of a dime. It does not touch the cornea at all. It vaults over it and rests on the sclera, the white of the eye.
Before you put it on, you fill the bowl of the lens with sterile, preservative-free saline. When the lens goes on, that saline is trapped between the lens and the cornea. Light now passes through the smooth front of the lens and the layer of fluid, and the irregular cornea underneath is effectively hidden from the optics of the eye.
Two things make this different from the small hard lenses many keratoconus patients have tried:
Nothing rubs on the cone. A small corneal lens often rests right on the tip of the cone. For some people that is fine. For others it is uncomfortable, it pops out, or it slides off center. A scleral lens lands on the much less sensitive white of the eye instead.
The cornea sits in fluid all day. That saline layer keeps the surface of the cornea wet for as long as the lens is in, which is a big part of why many patients find sclerals comfortable for long days.
What the Research Shows
Keratoconus is the most common reason scleral lenses are prescribed. In the SCOPE survey of scleral lens practitioners worldwide, 74 percent of scleral lenses were prescribed for corneal irregularity, 16 percent for ocular surface disease and 10 percent for ordinary prescriptions (Nau et al., Eye & Contact Lens, 2018).
The vision results are why. In a study of 157 keratoconic eyes followed for at least a year at the Southern College of Optometry, average best-corrected vision improved from roughly 20/63 in glasses to roughly 20/24 in scleral lenses. Serious complications were uncommon: inflammatory events occurred in under 10 percent of eyes and infection in under 1 percent (Fuller and Wang, Optometry and Vision Science, 2020).
The same paper cites earlier work in which scleral lenses spared about 80 percent of patients with severe keratoconus from needing a corneal transplant. That number will not apply to every eye, but it explains why so many specialists now reach for a scleral before they reach for surgery.
Use is growing fast. At one academic eye center, scleral lenses went from zero keratoconus patients in 2010 to about one in five in 2020, mostly among people with more advanced disease (Contact lens prescribing trends for keratoconus, 2022).
Who Is a Good Candidate
I tend to think about scleral lenses for keratoconus patients who:
- No longer see well enough in glasses for driving, work or school
- Have tried soft or small hard lenses and found them uncomfortable, unstable or not sharp enough
- Have moderate to advanced keratoconus, or scarring at the tip of the cone
- Have keratoconus plus dry or irritated eyes
They are not the only answer. Early keratoconus is often managed perfectly well with glasses or soft specialty lenses, and some people do great in a small rigid lens or a hybrid lens. I wrote a separate comparison of scleral, hard, soft and hybrid lenses if you want to see how they stack up.
Scleral Lenses Do Not Stop Keratoconus
This is the part I always make sure patients hear. A scleral lens corrects how you see. It does not change the cornea or slow the disease.
If your keratoconus is still progressing, which is most common in teenagers and young adults, the treatment that slows it is corneal cross-linking. That is a procedure done by corneal surgeons. When I see signs that a cornea is still changing, I talk with you about a referral at the same time we work on your lenses. The two are not either-or. Many patients have cross-linking and then wear scleral lenses for vision.
What the Fitting Looks Like
A scleral lens is fitted on the eye, not ordered from a prescription. The process usually looks like this:
- Evaluation. We measure the shape of the cornea and check the health of the eye to confirm a scleral lens makes sense for you.
- Diagnostic lens. A trial lens goes on the eye so we can see how it vaults the cone and where it lands on the white of the eye.
- Custom design. The lens is designed for your eye and ordered. A highly irregular cornea often needs a refinement or two.
- Training. You learn to fill, insert, remove and clean the lenses before they go home with you.
- Follow-up. We check the fit again after you have worn them in real life, then keep monitoring the eye over time.
If you want to know what daily life with these lenses is like, I put together a guide to your first weeks with scleral lenses. For cost and insurance, see how much scleral lenses cost.
Where to Get Scleral Lenses Near You
We fit scleral lenses at all three Everyday Eye Care offices. Our Pasco office on Road 68 is about 13 minutes from Richland and 14 from Kennewick, so it is the closest option for most of the Tri-Cities. In Eastern Oregon, our Hermiston office serves Umatilla, Boardman and Pendleton, and we also fit in Sunnyside for the Yakima Valley.
Scleral evaluations are booked by phone because they need a longer appointment than a routine exam. Call Pasco at (509) 543-7953, Sunnyside at (509) 839-4575 or Hermiston at (541) 567-5283 and ask for a scleral lens evaluation.
This article is general information, not medical advice. Whether a scleral lens is right for your eyes is decided at an examination.