Postmarket surveillance of Menicon Z rigid gas-permeable contact lenses for up to 30 days continuous wear in the United States

Objectives: To evaluate the incidence of microbial keratitis associated with the use of the Menicon Z rigid gas-permeable (RGP) contact lenses (CLs) for up to 30 days continuous wear (CW). For this study, CW was defined as wearing CLs in an extended-wear modality with an average wearing time of 22 days or more. Microbial keratitis was the sole endpoint of the study safety evaluation. Methods: Subjects who were interested in RGP lens CW were recruited for the study through 33 investigational practices. To be eligible for the study, subjects must have worn the Menicon Z lens for CW for at least 1.5 months with an average CW time of 22 days or more. Eligible wearers were then contacted at 6-month intervals for up to 24 months after enrollment to determine their typical wearing schedules and continuance of wear and to detect any problems that would be indicative of microbial keratitis. Discontinuation from the study was defined as a discontinuation of contact with or CL wear by the study participants. Study volunteers could be discontinued from the study at 6, 12, 18, or 24 months if they could not be contacted (lost to follow-up); if they were not wearing their CL for CW; or at their own request. Wearing time data collected for individuals discontinued from the study was included in the wearing time analysis. Results: The study population included 507 participants, of whom 173 had discontinued by the end of study at 24 months. Lack of 22 days or more of CW was the most frequently cited reason for discontinuation and accounted for 121 of the 173 subject discontinuations. Lost to follow-up, study participant choice, and other reasons accounted for the remaining 52 subject discontinuations. Of the reported wearing times over the duration of the study, 1,275 of the 1,527 contacts resulted in reported wearing times of 22 days or more of CW. There were no findings of microbial keratitis during the study. Overall, there was a low reported rate of complications for the enrolled study participants. Conclusions: On the basis of this study, CW of the Menicon Z hyper-Dk/t RGP lens provides a safe and full-time vision correction alternative for patients who can adapt to RGP lens wear.