The effect of silicone-hydrogel and conventional hydrogel contact lenses wear on the tear film: a comparison between de lenses

Purpose: The aim of this study was to evaluate the effect of one conventional hydrogel and four silicone-hydrogel contact lenses of 6-months daily wear on the quantity and stability of the tear film. The tests were performed with a group of patients with no previous contact lenses experience before and after wear on 96 eyes. Methods: The contact lenses tested were: 19 Galyfilcon A (Acuvue® Advance™), 15 Balafilcon A (PureVision™), 20 Lotrafilcon A (Focus® Night & Day™), 14 Lotrafilcon B (O2Optix™) and 28 Etalfilcon A (Acuvue®). Each silicone-hydrogel contact lens was used for 1 month and the conventional hydrogel for 15 days. Every patient used a different lens in each eye. Tear film stability was monitored by tear Break-up-time (BUT) and Non Invasive Break Up Time (NiBUT) and tear volume was measured by the Total Tear Meniscus Height and the Red Phenol Test. Results: The following tables summarize the difference between the measurements obtained in the first and in the last day of wear of each contact lens brand and the results were analyzed comparing the conventional hydrogel and the siliconehydrogel contact lenses (Table 1, 2, and 3), the lenses belonging to the first generation of silicone-hydrogel contact lenses (table 4) and the lenses belonging to the second generation of silicone-hydrogel (Table 5). The significance (p value) of 0.05 is considered statistically significant. Conclusions: Although there are some differences between the lenses, there are no statistically significant differences between the lenses and measurements obtained before and after contact lenses wear on the tear film tests.