Abstract
Purpose: :
Corneal staining has been identified as a significant risk factor for soft contact lens-related corneal infiltrative events. The purpose of this study is to do preliminary analyses of the association between corneal staining and other clinical variables. Knowing these associations, if they exist, is important to determine if other clinical variables may be confounding the associations previously detected between corneal staining and infiltrative events.
Methods: :
Data from 72 eyes of 36 patients in the Longitudinal Analysis of Silicone Hydrogel (LASH) Contact Lens Study were used for this analysis. The LASH study monitors patients wearing lotrafilcon A contact lenses for up to 30 days of continuous wear. Univariate logistic regression and chi-square analyses were performed to detect associations between corneal staining and other clinical signs detected during extended wear including: epithelial microcysts, corneal edema, corneal neovascularization, blepharitis, meibomian gland dysfunction, limbal redness, bulbar redness, and conjunctival staining. Global scores were created for corneal staining, conjunctival staining, limbal redness, and bulbar redness from regional data. Variables found to be significant in the univariate associations were entered into a multivariable logistic regression model.
Results: :
Twelve percent of right eyes and 9% of left eyes had clinically significant, but asymptomatic, corneal staining. Twenty-two percent of right eyes, and 19.4% of left eyes had significant conjunctival staining. 16.7% of all eyes had at least one quadrant with grade 2, or two quadrants with grade 1, bulbar redness and limbal redness.In right eyes, no univariate associations were found between corneal staining and any of the other clinical variables. In left eyes, univariate associations were detected between corneal staining and limbal or bulbar redness (both p=0.055). However, in a multivariable model, these associations were not significant.
Conclusions: :
There does not appear to be an association between asymptomatic corneal staining and other clinical slit lamp signs during silicone hydrogel extended wear. Limbal or bulbar redness may confound associations with corneal staining, and should be controlled for in analyses of corneal staining with other outcomes.