Have Silicone Hydrogel Lenses Eliminated Hypoxia?

Objective: The purpose of this article is to review the literature to date to determine if silicone hydrogel lenses have eliminated corneal hypoxia. Methods: Results from clinical studies, including short-term laboratory studies and retrospective and prospective clinical trials that have assessed the cornea's response to silicone hydrogels, will be evaluated. Results: Silicone hydrogels have eliminated the physiologic signs associated with lens-induced hypoxia including ocular and limbal redness, neovascularization, epithelial microcysts, and endothelial responses. Responses to these markers are similar to those observed with nonlens wearers. Although, for most patients, the oxygen transmissibility of silicone hydrogels is enough to eliminate corneal edema, some patients with high oxygen needs and/or with high refractive errors will still demonstrate significant edema after overnight wear. Conclusions: The range of silicone hydrogels available today, regardless of wearing modality, have effectively eliminated hypoxia for most patients.