The abstract below suggests a noticeable rise n intraocular pressure during scleral lens wear, in both smaller and larger sizes. This is interesting though not necessarily anything to hit the panic button over.

Optometrist Greg DeNaeyer, in “THE SCLERAL LENS VAULT: SCLERAL LENSES AND INTRAOCULAR PRESSURE” . (Contact Lens Spectrum, Sept 1) does a great job putting this study in context. His take-home points seem to be that:

There are accuracy concerns with measuring IOP while wearing sclerals
If IOP really does rise during scleral lens use, where are all the IOP related complications that ought to be happening? Scleral lenses have been fitted for decades now.
The possibility of IOP increase does probably mean some re-thinking might be in order when considering fitting sclerals on patients at risk of glaucoma,.

Intra-ocular pressure variation associated with the wear of scleral lenses of different diameters.

Cont Lens Anterior Eye. 2018 Jul 24. pii: S1367-0484(18)30782-3. doi: 10.1016/j.clae.2018.07.004. [Epub ahead of print]

Michaud L, Samaha D, Giasson CJ.

Abstract

PURPOSE:

To evaluate the variation of intra-ocular pressure during scleral lens wear, and the influence of the lens diameter on the results.

METHODS:

This is a prospective, randomized study performed on Caucasian subjects (16 F; 5 M), aged 24.7 + 4.1 y.o. A diurnal variation pattern (IOPg) was established, then, transpalpebral IOP (IOPt) was taken before and during SL wear. One eye, randomly fitted with a 15.8 diameter SL (L1), was compared to the fellow eye, fitted with an 18 mm SL of the same design, thickness and material (L2). Anterior segment tomography was taken pre-and after lens removal.

RESULTS:

Baseline IOPg (L1:15.2 + 3.1 mm HG; L2: 15.1 +/- 2.8 mm) did not reveal significant diurnal variations. Wearing L1, IOPt rose from 10.1 + 1.9 mm HG to 14.4 + 5.5 mm HG after 4.5 + 0.3 hrs, while with L2, it rose from 9.2 + 2.1 mm HG to 14.4 + 4.8 mm Hg. This difference is statistically significant based on time but not on lenses. Anterior segment parameters did not vary except for the anterior chamber volume (L1: -1.53 + 7.61 mm3; L2: -3.47 + 6.4 mm3), and for the corneal thickness (+2.1% with L1 and L2).

CONCLUSION:

These results suggest that, as evaluated with a non-standard transpalpebral methodology, IOP during scleral lens wear may be increased in average by 5 mm Hg, regardless of the lens diameter. More work is needed to confirm if practitioners should be warned when using SL on populations at risk for glaucoma.