In vivo wettability of high Dκ RGP materials

This study compared the in vivo wettability of four high Dk rigid gas permeable (RGP) materials (Aquila, Menicon, Super EX, Quantum 1 and Quantum 2). The study design was a double-masked right/left eye comparison of 6 months' duration where the lenses were worn on a daily-wear basis. It involved three experimental groups, each using Aquila in one eye and one of the other materials in the fellow eye. The main conclusions obtained are as follows: The in vivo intrinsic wettability, and its alteration during a 6-month period of wear, was similar for all four high Dk materials tested. The in vivo characteristics of these materials were not different from those of lower Dk materials, hence increasing Dk does not result in reduced wettability as suspected by some practitioners. In vivo wettability is highly patient dependent, and so its ongoing monitoring during routine practice is necessary for optimal patient management. In vivo wettability is affected by lens wear; after 6 months' wear the stability of the tear film at the front of the contact lens was significantly reduced and the level of surface contamination increased compared with dispensing. The notion of planned replacement should be extended to RGP contact lenses. Replacement frequencies of 6, or even 3 months would be of benefit for a significant number of patients.