Short-term changes in IOP from scleral contact lens wear

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Spanish researchers observed slight increases in intraocular pressure (IOP) and small changes in the parameters of the iridocorneal angle (ICA) and Schlemm’s canal (SC) in the short term in patients who wear scleral lenses, although it did not seem to be clinically relevant in healthy subjects,¹ according to Juan Queiruga-Piñeiro, MD, first author from the Instituto Universitario Fernández-Vega, Fundación de Investigación Oftalmológica, Universidad de Oviedo, and the

Instituto de Investigación Sanitaria del Principado de Asturias, both in Oviedo, Spain.

The changes produced by SLs have been assessed previously in the different anterior segment structures or in the IOP. In contrast this study under discussion evaluated in a comprehensive and combined way, the short-term changes produced by SLs in the cornea, ICA, and SC structures and by measurements with AS-OCT, and in the IOP, including the structural parameters of the optic nerve head with OCT.

In their study, the investigators evaluated 30 healthy subjects who were fitted with 2 scleral lenses of different sizes; the first lens was 15.8 mm and the second 16.8 mm. The participants wore the lenses for 2 hours in both eyes and the left eye served as the control.

The parameters measured were the central corneal thickness (CCT) and the parameters of the ICA, SC, and the optic nerve head were measured before and after wearing the SLs. The IOP was measured before and after lens removal and with a transpalpebral tonometer before insertion of the lenses; during lens wear at 0, 1, and 2 hours; and after lens wear.

The results showed that the CCT increased significantly after wearing lens 1 by a mean of 8.10 µm and after lens 2 by a mean of 9.17 µm (p < 0.01 for both comparisons).

When lens 1 was removed, the ICA parameters decreased significantly, and when lens 2 was removed, the nasal and temporal SC area and length decreased (p < 0.05 for both comparisons).

Regarding the IOP, transpalpebral tonometry showed that the IOP increased after wearing lens 1 for 2 hours by a mean of 2.55 mmHg and after wearing lens 2 for 2 hours by a mean of 2.53 mmHg (p < 0.01 for both comparisons). as well An increase in the IOP also was seen when measured using Perkins applanation tonometry after wearing lens 1 for 2 hours by a mean of 0.43 mmHg (p = 0.02).

In the future, the clinicians noted the importance of establishing a standard method for measuring the IOP with SLs and of assessing the changes produced by these types of contact lenses in ICA and SC in subjects with different angle widths, higher IOPs, and/or susceptibility to developing glaucomatous disease, as well as optic nerve head monitoring.

The investigators concluded, “In the short term, the SL resulted in a slight increase in IOP in addition to small changes in the ICA and SC parameters, although it did not seem to be clinically relevant in healthy subjects.”

Reference:

1. Queiruga-Piñeiro J, Barros A, Lozano-Sanroma J, et al. Assessment by optical coherence tomography of short-term changes in IOP-related structures caused by wearing scleral lenses. J Clin Med.2023;12:4792;https://doi.org/10.3390/jcm12144792