Why the question comes up
Fluid inside the eye drains out through tiny channels near the edge of the cornea and then into veins on the surface of the eye. A scleral lens rests on the white of the eye in roughly that area. One theory, proposed in 2016, is that the lens could press on those surface veins and slow drainage, raising eye pressure. A 2026 review argues that the structural changes seen with scleral lens wear point toward a modest pressure rise.[9]
The theory makes sense, but proving it is hard. Eye pressure is normally measured on the cornea, and a scleral lens covers it. Studies have measured pressure before insertion and after removal, through the eyelid, on the white of the eye, or indirectly by watching the optic nerve. Each method has drawbacks, and that explains part of why results conflict.[10]
What the studies found during wear
These studies were short, and nearly all were in healthy young adults:
- Randomized crossover, 8 hours. Thirty-one healthy adults wore a 16.5 mm scleral lens on one eye and a soft lens on the other for 8 hours, then switched. In the scleral lens eye, measured pressure rose from an average of 11 to 16 mmHg right after insertion, stayed there during wear, and returned to 11 after removal. The soft lens eye didn’t change. A layer of the optic nerve also thinned slightly and recovered after removal.[1] The authors note an important limitation: pressure during wear was measured through the eyelid with one instrument, and before and after with another, and the two agreed poorly. That makes the exact size of the rise uncertain.[1]
- One eye vs the other, 6 hours. In 26 healthy adults, pressure rose by about 2 mmHg with one instrument and didn’t change with another. The optic nerve rim thinned slightly in both the lens-wearing and the control eye, with no significant difference between them. The authors concluded the effect on pressure in normal eyes was minimal.[2]
- Lens size, 5 hours. In healthy adults, pressure measured on the white of the eye rose by a little over 1 mmHg with both a 15.6 mm and an 18.0 mm lens, with no difference between sizes. Pressure measured on the cornea after removal was unchanged.[3]
What the studies found after removal
- Meta-analysis. Pooling studies that measured pressure after the lens came out, a 2026 meta-analysis found no significant change, though the studies varied widely.[4]
- Habitual wearers. In 25 people with keratoconus who had worn scleral lenses for about 4 years on average, pressure was essentially identical before and after 4 hours of wear.[6]
- Three months of wear. In 60 people in China, average pressure changed by less than 0.3 mmHg over three months. But 10% of eyes showed a rise of 2 mmHg or more at two consecutive visits.[5] In 17 people with keratoconus, average pressure didn’t change significantly over three months, though it rose slightly in those with severe keratoconus.[8]
- Ocular surface disease. In a retrospective review of 46 eyes, pressure measured after removal didn’t change significantly from before lens wear.[7]
What this means for you
Putting it together: a modest rise in pressure while the lens is on is possible, the evidence is mixed, and pressure after removal looks stable on average. No study so far shows that scleral lenses cause glaucoma, but no long-term study has tested that in people with glaucoma or at high risk.
That gap matters because scleral lenses are often worn by people who already have eye disease. At one center, patients fitted with PROSE devices had a higher rate of glaucoma than the general population, and fitting was harder in eyes that had had glaucoma surgery: 2 of 5 such eyes couldn’t be fitted successfully.[11]
A 2023 review recommends ongoing checks of optic nerve structure and function for people at risk of glaucoma who need scleral lenses.[10] If you have glaucoma, high eye pressure, a family history of glaucoma, or have had glaucoma surgery, tell your fitter, make sure your glaucoma doctor knows you wear scleral lenses, and keep up with your optic nerve and visual field tests. Don’t stop glaucoma treatment or change your lens schedule without talking to them.
Common questions
I have glaucoma. Can I still wear scleral lenses?
Many people with glaucoma need scleral lenses for another eye condition, and the decision is a balance between the benefit to your vision and the uncertainty about pressure. Make sure your glaucoma doctor and your scleral lens fitter both know about each other, and keep up with optic nerve and visual field checks.
Can I use my glaucoma drops while wearing scleral lenses?
Ask your eye doctor how to time your drops around lens wear. Don't put drops into the lens bowl or change your schedule without their guidance.
Will my eye doctor be able to check my pressure while I wear the lens?
Not easily. The lens covers the cornea, where pressure is normally measured. Most checks are done before you insert the lens or after you remove it, and some clinics use instruments that measure through the eyelid or on the white of the eye, which are less precise. That's why doctors also look at the optic nerve directly.