title: Role of the post-lens tear film in the mechanism of inferior arcuate staining with ultrathin hydrogel lenses.
abstract: We studied the depletion of the post-lens tear film as contributing to inferior arcuate staining with ultrathin high water content hydrogel lenses. We monitored the post-lens tear film specular reflection of hydrogel lenses (0.04 mm center thickness, 67% nominal water content), which caused inferior arcuate staining. A standard thickness (0.12 mm) lens was worn in the contralateral eye as a control condition. Lenses were worn for a 2 hour period by 20 subjects. Post-lens tear film appearances were categorized as amorphous, faint colored, or colored, where the colored patterns represented a relatively depleted post-lens tear film. We also measured lens dehydration, lens adherence, and pre-lens tear film stability in order to evaluate their role in inferior arcuate staining. The ultrathin and standard lenses caused staining in 100 and 75% of subjects, respectively; the severity of staining was much greater with the ultrathin lenses (Wilcoxon signed ranks test, P = 0.0004). The ultrathin lenses were associated with a higher incidence of post-lens tear film depletion (P = 0.018), had greater front surface dehydration (P = 0.0004), and were more adherent to the eye (paired t-test, P = 0.001). However, pre-lens tear thinning times were not significantly different between the two lens types (Wilcoxon signed ranks test, P > 0.05). These findings support the contention that post-lens tear film depletion is a component of a lens adherence or lens dehydration mediated mechanism of inferior arcuate staining.
authors.affiliation: Centre for Eye Research, School of Optometry, Queensland University of Technology, Australia.
authors.forename: S A
authors.initials: SA
authors.lastname: Little
authors.forename: A S
authors.initials: AS
authors.lastname: Bruce
mesh_terms: D000328:Adult; D003263:Contact Lenses, Hydrophilic / Q000009:adverse effects*; D003315:Cornea / Q000503:physiopathology; D003316:Corneal Diseases / Q000209:etiology / Q000503:physiopathology*; D003890:Desiccation; D005260:Female; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D008297:Male; D011092:Polyethylene Glycols; D013194:Staining and Labeling; D013666:Tears / Q000502:physiology*
chemical_list: D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011092:Polyethylene Glycols