Hypoxic effects on the anterior eye of high-Dk soft contact lens wearers are negligible

To determine whether the eyes of high-Dk soft contact lens wearing subjects can be discriminated from non-contact lens wearing subjects. This study was a prospective masked assessment of 32 subjects, 16 of whom wore experimental high-Dk soft contact lenses and 16 of whom did not wear contact lenses. Subjects wore high-Dk lenses on a 30-night replacement schedule for an average of 9 months. Tear film characteristics, staining and vascularization of the cornea, conjunctival staining, and the presence of microcysts in the corneal epithelium were assessed using slitlamp microscopy. The endothelium was examined for polymegethism. No differences were found between the two groups in any of the variables that were examined (p > 0.05) except that the high-Dk lens wearing group had about twofold more tear film debris and 2.5-fold more severe conjunctival staining (p < 0.05). Hypoxia-associated effects were not apparent in the eyes of subjects wearing experimental high-Dk soft contact lenses. Conjunctival staining can generally distinguish lens wearers from non-lens wearers and can be used to discriminate between high-Dk lens wearing subjects and non-lens wearing subjects.