Abstract: Hydrogel vs. silicone hydrogel contacts and dry eye

Hm. Refitting patients with si-hy lenses cut dry eye issues in half. Yup, that's noticeable.

Improving contact-lens related dryness symptoms with silicone hydrogel lenses.
Optom Vis Sci. 2008 Aug;85(8):778-84.
Chalmers R, Long B, Dillehay S, Begley C.

PURPOSE.: To determine dryness symptoms attributable to hydrogel contact lens (HCL) wear by comparing symptoms from age-matched HCL wearers and non-wearers in a cross-sectional study, and to compare that difference to the change in proportion of subjects reporting frequent dryness among HCL wearers after refitting with lotrafilcon A or B silicone hydrogels (SHCLs).

METHODS.: Prevalence of frequent dryness symptoms was compared between HCL and non-wearers from a cross-sectional, historical dataset of Dry Eye/Contact Lens Dry Eye Questionnaires using an age-matched subset of 259 HCL and 246 non-wearers. Prospective change in prevalence of frequent dryness from non-randomized studies (n = 1036), in which daily wear (DW) HCL wearers were refit with lotrafilcon A or B SHCLs, was then compared to the cross-sectional difference between HCL wearers and non-wearers.

RESULTS.: In the Dry Eye/Contact Lens Dry Eye Questionnaires dataset, 47% fewer non-wearers reported frequent dryness than HCL wearers (p = 0.0001). In the lotrafilcon A DW refitting trials, frequent dryness was reported by 67 and 62% fewer subjects for during the day (DD) and end of the day (EOD) dryness (p = 0.0001, both) after refitting. In continuous wear lotrafilcon A trials, there were 63 and 41% reductions in the proportion reporting frequent DD and EOD dryness (p = 0.014 and p = 0.02). Refitting to DW lotrafilcon B yielded a 48 and 46% reduction in the number of subjects reporting frequent DD and EOD dryness (p < 0.0001, both).

CONCLUSIONS.: After refitting DW HCL wearers with either lotrafilcon A or B SHCLs, the proportion of symptomatic wearers was approximately half; an amount similar to the difference in proportion between HCL and non-wearers. This raises the possibility that refitting HCL wearers with SHCLs eliminates the component of dryness that is induced by HCL wear. Further research with more robust experimental design is recommended to test this hypothesis.