In the course of fitting and following 31 eyes with corneal contact lenses, an increase in corneal curvature of one or both principal meridians of greater than 0.5 diopters was noted in 53% of the eyes. The study further established a significant correlation between this increased corneal curvature and an increase in central corneal thickness associated with epithelial edema. Finally, it was shown that an increase in central corneal thickness was strongly linked to the presence of epithelial edema.
Miller D. Contact Lens-Induced Corneal Curvature and Thickness Changes. Arch Ophthalmol. 1968;80(4):430-432. doi:10.1001/archopht.1968.00980050432004