Abstract
Purpose: :
This study was designed to evaluate the ability of both objective and subjective techniques to distinguish differences among multi–purpose solutions in patients who experience end of day discomfort.
Methods: :
367 soft contact lens wearers who reported end of day discomfort were enrolled at 22 sites in this double–masked, concurrently controlled study. Subjects were randomized to Regimen 1 (OPTI–FREE® RepleniSHTM Multi–Purpose Disinfecting Solution, Alcon Laboratories, Inc) or Regimen 2 (ReNu with MoistureLoc Multi–Purpose Solution, Bausch & Lomb). They were dispensed a new pair of their current FDA Group IV lens brand. Safety, including investigator–observed corneal staining, and efficacy were evaluated on Days 0, 14 and 28. At pre–selected sites, lenses were collected at the conclusion of the study for laboratory–measured lens lysozyme (HPLC) and ex vivo measurement of lens wettability after 14 hours of wear. Patients also rated specific product attributes using Likert style questions.
Results: :
Mean corneal staining was significantly lower in subjects using Regimen 1 compared to those using Regimen 2 at Days 14 (p=0.0189) and 28 (p=0.0046). Lenses cared for with Regimen 1 had significantly less residual lysozyme than lenses cared for with Regimen 2 (p<0.0001). The mean wetting angle of lenses was significantly lower, indicating better lens wettability, for the subjects using Regimen 1 (5.3°) than for those using Regimen 2 (91.3°, p<0.0001). In addition, the mean wetting angle correlated with the subjective response regarding a feeling of moisture while wearing the lens ("When I use this solution, my lenses feel moist", r=0.426).
Conclusions: :
Both objective and subjective measurements allowed for distinction among the two multi–purpose solutions. Significant differences in cleaning ability, wettability, and corneal staining were found between these two regimens. Compellingly, the wettability measurement was found to correlate with a feeling of moist lenses, thereby showing that the objective mean wetting angle measurement can be related to a subjective patient response. Doctors should consider these differences in product performance when recommending a lens care regimen.
Keywords: contact lens • cornea: clinical science