Comparative clinical performance of two silicone hydrogel contact lenses for continuous wear

Silicone hydrogel soft contact lenses are now available for use on a 30-day continuous wear basis. The aim of this study was to compare the clinical performance of two such lenses.

In a single-centre, randomised, subject-masked, two-period crossover study, 30 subjects wore a pair of PureVision lenses (Bausch & Lomb) and a pair of Focus Night & Day lenses (CIBA Vision), alternately, for successive eight-week periods. Assessment was made of lens fit and surface characteristics, logMAR visual acuity, ocular response and subjective reaction.

Lens fit, deposition and post-lens debris were similar for the two lens types. High contrast visual acuity was statistically significantly better for the PureVision lens, as was the subject-reported quality of vision, although these differences were not considered clinically significant. For both lenses, limbal and conjunctival redness reduced throughout the duration of the study, whereas there was a slight increase in the overall amount of corneal staining. The incidence of mucin balls peaked four weeks after commencing lens wear and began to decline thereafter; more mucin balls were noticed in subjects wearing Focus Night & Day lenses. No differences between the lenses were observed for any other biomicroscopic signs.

This study demonstrates similar clinical performance with the two silicone hydrogel lenses evaluated. We believe that, with careful monitoring, both of these new-generation lenses can be prescribed for continuous wear.