Two very different ways to fix the same problem
When the cornea, the clear front window of the eye, is badly misshapen, light can’t focus properly and glasses stop helping. There are two broad ways to deal with that.
A scleral lens leaves the cornea alone and puts a new optical surface in front of it. The lens rests on the white of the eye, arches over the cornea, and holds a layer of saline against it. The fluid fills in the irregular shape, and the smooth lens surface does the focusing.
A corneal transplant (keratoplasty) replaces diseased corneal tissue with donor tissue. In a penetrating keratoplasty, the full thickness of the central cornea is replaced. In a deep anterior lamellar keratoplasty (DALK), the front layers are replaced and your own innermost layer is kept.
Side by side
| Scleral lens | Corneal transplant | |
|---|---|---|
| Rests on / acts on | Rests on the white of the eye (sclera) | Replaces part or all of the central cornea |
| Touches the cornea | No. Vaults it over a layer of saline | Yes. It is surgery on the cornea |
| Irregular corneas | Corrects irregular shape optically. Can’t clear a cloudy or scarred cornea | Replaces irregular or scarred tissue, though the graft itself often heals irregularly |
| Dry eye | Keeps the cornea bathed in saline while worn | Not a treatment for dry eye |
| Comfort | Often comfortable once fitted | Recovery is gradual, with drops and follow-up visits |
| Handling | Daily insertion, removal, and cleaning | Nothing to handle, but many grafted eyes still need contact lenses for best vision |
| Cost drivers | Custom fitting, number of lenses and visits, replacements, care products | Surgery, donor tissue, long-term follow-up, and often lenses afterward |
| Who it suits | Irregular corneas that are still clear enough to see through, in people who can wear and handle a lens | Scarring or clouding a lens can’t overcome, or when lenses fail or can’t be worn |
When scleral lenses can delay or avoid a transplant
Severe keratoconus. A university hospital clinic in Belgium studied 75 eyes with very advanced keratoconus, the kind usually referred for transplant. Scleral lenses were prescribed for 51 of them. After an average follow-up of about two and a half years, 40 of those 51 eyes were still wearing their lenses, 4 had stopped because they couldn’t handle them, and 7 were lost to follow-up. The authors concluded that scleral lenses more than halved the need for transplant in their keratoconus clinic.[1]
That study also shows the limits. Of the 75 eyes, 8 went on to have a transplant because vision with lenses wasn’t good enough, the lenses couldn’t be tolerated, or they couldn’t be handled. Another 12 weren’t fitted, either because the other eye saw well or because lens wear wasn’t advisable.[1]
Cross-linking also plays a part. After cross-linking was introduced across the Netherlands, about 25% fewer transplants were performed for keratoconus.[9] See scleral lenses vs cross-linking.
When surgery is the answer
A scleral lens changes the shape of the surface light passes through. It doesn’t clear tissue that light can’t pass through. Situations where a transplant becomes the better option include:
- Scarring or clouding in the center of the cornea that limits vision even with a well-fitted lens.
- Vision that stays too poor in the best lens your fitter can design.
- Lenses that can’t be tolerated or handled, even after refits and support.
In the CLEK study of 1,065 people with keratoconus followed for eight years, 12% had a transplant in at least one eye. The factors linked to a higher chance of transplant included younger age, a steeper cornea, worse vision, corneal scarring, and poorer contact lens comfort.[2]
Transplants for keratoconus can do well over the long term. One specialist center reviewed 502 keratoconus eyes that had either a full-thickness or a lamellar transplant. Graft survival was 96.7% at 10 years and 95.6% at 20 years, and average vision improved from about 20/378 before surgery to 20/32 at 30 months.[3] Those are results from one experienced specialist center. The cell layer that keeps the graft clear also thinned over time: average cell density fell from 2,494 to 1,521 cells per square millimeter at 10 years.[3]
A transplant doesn’t always end lens wear
A graft rarely heals into a perfectly regular curve. Small amounts of astigmatism after a transplant can be managed with glasses, while larger amounts may need contact lenses or further surgery.[4]
Contact lenses, especially scleral lenses, are widely used after transplants. A 2025 systematic review of 15 studies covering 464 grafted eyes found that scleral lenses were the most frequently fitted lens, used in 61% of eyes, and every study reported a significant improvement in vision with lenses.[5] At one US academic center, 44 of 48 grafted eyes fitted with scleral lenses (91.7%) reached 20/40 or better.[6]
Grafted eyes need extra care under a scleral lens:
- Swelling. In a small study of 9 grafted eyes, short-term scleral lens wear caused about three times as much corneal swelling as in healthy eyes.[8]
- Rejection. In a long-term study of grafted eyes wearing scleral lenses, 30% had at least one graft rejection episode over an average of about five years.[7] In another, 6 of 48 eyes (12.5%) developed rejection, and 3 of them were able to go back to lens wear.[6] These studies don’t show that the lenses caused the rejections, which can happen in any graft.
Questions to ask your surgeon and fitter
- Is my cornea clear enough that a lens could give me good vision?
- Have I had a proper trial of scleral lenses, fitted by someone experienced with corneas like mine?
- If I need a transplant, which type do you recommend and why?
- Will I likely need contact lenses afterward? Who will fit them?
- If I already have a graft, how often should it be checked while I wear scleral lenses?
Common questions
Can scleral lenses help me avoid a corneal transplant?
For many people, yes, at least for a long time. In a Belgian study of severe keratoconus, 40 of 51 eyes that would otherwise have gone to transplant surgery were still wearing scleral lenses at their last visit. Whether that applies to you depends on your cornea, especially whether it is scarred, and on whether you can wear and handle the lenses.
Will I still need contact lenses after a corneal transplant?
Possibly. A graft rarely heals into a perfectly regular shape, and the astigmatism it leaves can be more than glasses can correct. Contact lenses, often scleral lenses, are a common way to get the best vision from a healthy graft.
Is it safe to wear a scleral lens on a corneal graft?
Many grafted eyes wear scleral lenses successfully, but they need closer monitoring. A graft can swell more under a lens than a healthy cornea does, and rejection episodes can occur. Your surgeon and fitter should work together, and you should know the warning signs to watch for.
What's the difference between a full and a partial transplant?
A full-thickness (penetrating) transplant replaces all layers of the central cornea. A deep anterior lamellar transplant replaces the front layers and keeps your own inner layer. Which one a surgeon recommends depends on your cornea.