Clinical performances of two disposable soft contact lenses of different materials on Hong Kong-Chinese

Abstract

Dryness due to contact lens wear and poor wetting of contact lenses among contact lens wearers is a common observation and contact lens manufacturers have introduced new, better quality soft lens materials that are claimed to be more deposit resistant, and/or dehydration resistant. The purpose of this study was to evaluate and compare the clinical performance of Hydron ActiSoft 60§, made of a new material (HyGMA™) which is claimed to be dehydration resistant with excellent wettability, with ActiFresh 400, made of conventional non-ionic hydrogel material. The experiment was conducted as a double-masked, randomised, cross-over study. Clinical assessment included pre-lens non-invasive tear break up time (PL-NITBUT), logMar visual acuity and contrast sensitivity (CS). Corneal staining, if any, was recorded at each visit. Subjective ratings in regard to dryness, grittiness, lens awareness, vision, comfort, handling (removal), handling (cleaning) and the overall preference of each lens type were obtained at the end of 3 (Phase A) and 6 months' (Phase B) wear. Twenty-eight subjects successfully completed the study. In Phase A, no significant differences were found in both baseline PL-NITBUT and PL-NITBUT after wearing the same lenses for 1 month between the two lens types. In phase B, baseline PL-NITBUT for ActiFresh 400 was significantly shorter than that for ActiSoft 60. However, after 1 month of wear, the difference in PL-NITBUT between the two lens types was no longer significant. PL-NITBUT was significantly reduced after 1 month's wear for both ActiSoft 60 and Actifresh 400, and in both Phase A and Phase B. The two lens types provided comparable logMAR visual acuity, and there was no significant differences in CS (Pelli Robson) between spectacle lens correction (equivalent spheres) and either lens type. The incidence of corneal epithelial staining was significantly higher and more severe with ActiFresh 400 than with ActiSoft 60, both in Phase A and Phase B. Statistically, there were no significant differences in the scores to the set of questions listed in the questionnaire between the two lens types, except for lens awareness and lens handling. Of the subjects having a preference for one lens, more subjects preferred ActiSoft 60 than ActiFresh 400. In terms of overall preference of the two lens types, at the end of Phase A, 50% of the subjects preferred ActiSoft 60 while only 30% preferred ActiFresh 400, the remaining 20% had no preference. However, by the end of Phase B, preferences for ActiSoft 60 and ActiFresh 400 were comparable. This appeared to be due mainly to the ease of lens handling of the latter.