A fair question
If you’ve cried in a fitter’s chair, chased a lens across the bathroom floor, or squinted through blur for years, being told “try this one” can feel like more of the same. Skepticism is reasonable. The honest answer is that scleral lenses are built on a different principle from the lenses most people have failed with, which is why they often work when others haven’t, and also why they come with a different set of problems.
What’s actually different
They don’t sit on the cornea. Soft lenses, corneal rigid gas permeable (RGP) lenses, and hybrid lenses all rest on the cornea, the clear front window of the eye. A scleral lens is larger and rests on the white of the eye (the sclera) instead.
They arch over the cornea. The lens vaults over the cornea without touching it. A steep cone or a scarred, irregular surface doesn’t press against the lens edge or decide where the lens sits, so how irregular your cornea is matters much less for fit and comfort.
They hold a layer of saline against the eye. The space under the lens is filled with saline before it goes in. That fluid fills in the irregular surface of the cornea, so light passes through the smooth front of the lens instead of the bumpy cornea. It also keeps the cornea bathed, which is why sclerals are used for severe dry eye too.
They move very little. Because the lens is tucked under both eyelids and rests on the white of the eye, it doesn’t slide with every blink the way a corneal RGP does.
For a deeper side-by-side, see scleral vs RGP lenses, scleral vs soft lenses, scleral vs hybrid lenses, and scleral vs piggyback lenses.
What the research shows for people like you
Much of the scleral lens research is in people who had already run out of other options.
- After other optical corrections failed. An Israeli clinic reviewed 97 people (155 eyes) fitted with scleral lenses for irregular astigmatism after other optical corrections had failed. Their best vision with scleral lenses was significantly better than their best vision before, across keratoconus, corneal transplants, and other causes. Over an average follow-up of about 35 months, 27% stopped wearing them.[1]
- After conventional therapies failed. A US prospective study of 101 patients with corneal ectasia, irregular astigmatism, or ocular surface disease who had failed conventional therapies found significant gains in vision, and their average score on a vision-related quality-of-life questionnaire rose from 57.0 to 77.8 out of 100 at six months.[2]
- Compared with corneal RGPs, by wearers. In a survey of people with keratoconus, 76 scleral wearers rated their vision and comfort higher than 75 corneal RGP wearers did, and reported fewer problems with lenses moving or being lost. But they reported more trouble with halos and with handling.[4]
These are mostly single-clinic studies, and some only counted people who completed fitting. They show what’s possible, not a promise.
Where sclerals can still fail
This is the part the fear gets right.
- Handling is harder. Scleral lenses are bigger and must be filled with saline every time. In the keratoconus survey, more scleral wearers than RGP wearers reported handling difficulty (63% vs 40%).[4] Handling is also the most common reason people stop.[5]
- They work better for some eyes than others. In a year-long study of 95 wearers, 77% of people with irregular corneas completed the year, compared with 58% of people whose corneas were regular.[5]
- Not everyone gets through fitting. At one US referral center, 115 of 212 people evaluated for scleral lenses for ocular surface disease completed the fitting process.[6]
- If your old lens was working, the gain may be small. In a randomized trial of 30 people already wearing corneal RGPs successfully, scleral lenses were more comfortable on average, but vision and quality-of-life scores were no different, and 47% preferred the scleral lens while 53% preferred their corneal lens.[3]
- Some problems are new. Midday fogging, halos, and a slower morning routine are scleral-specific issues many wearers describe. See my vision still isn’t perfect.
Questions to ask your fitter
- Given why my other lenses failed, why do you think a scleral lens will work better?
- Are there problems I had before that a scleral lens won’t fix?
- What results do you realistically expect for my vision and comfort?
- How many visits and lens changes should I expect?
- What happens if it doesn’t work: what would we try next?
If sclerals do turn out not to be right for you, that isn’t the end of the road. See what if scleral lenses don’t work for me? for the other options.
Common questions
My RGP lenses kept popping out. Will a scleral lens?
It's much less likely. A corneal RGP is small and moves on the cornea with every blink, while a scleral lens is larger and rests on the white of the eye, tucked under both lids. In a survey of people with keratoconus, scleral wearers reported fewer problems with lens movement or loss than corneal RGP wearers. A scleral lens can still pop out now and then; if it happens, tell your fitter so they can look at why.
Soft lenses dried my eyes out. Will sclerals be worse?
Not necessarily. A scleral lens holds a reservoir of saline against the cornea, which is why it's also used for severe dry eye. But some wearers still get dryness or midday fogging, and dryness of the lid surface and tear film still matters. Tell your fitter what happened with soft lenses so they can plan for it.
If I'm doing fine in RGPs, should I switch?
Maybe not. In a randomized trial of people already wearing corneal RGPs successfully, scleral lenses were rated more comfortable, but vision and vision-related quality of life were about the same, and preferences were split almost evenly. If your current lenses work, talk through the trade-offs with your fitter.
I tried sclerals years ago and they didn't work. Is it worth trying again?
It can be. Lens designs, measuring methods, and fitters vary a lot. Many wearers describe succeeding on a second attempt with a different design or a more experienced fitter. Bring your old lens details and notes on what went wrong.
How many lens types do I have to fail before trying sclerals?
There's no fixed rule. Scleral lenses are increasingly considered as a first lens for keratoconus, rather than only a last resort, and some insurance plans have their own criteria. Ask your fitter which option they'd try first for your eyes and why.