When patients new to soft contact lenses ask how many hours they can start wearing spherical hydrogels or silicone hydrogels each day, it may be well-founded to recommend wear for as long as they feel no discomfort, up to a clinician-set top hourly limit, according to an analysis of 74 participants introduced to monthly, reusable lenses. The study is published in Contact Lens and Anterior Eye, and follows a prior paper by the same researchers that evaluates daily disposable contacts.
After 2 weeks, few differences emerged between fast adaptation — worn for 10 hours starting the first day — and gradual adaptation beginning at 4 hours, with 2-hour daily increases until reaching 10 hours. “Neither a fast nor a gradual adaptation schedule had any major impact on the short-term ocular surface physiology or tear film stability with modern hydrogel or silicone hydrogel reusable contact lenses,” the investigation explains.
This prospective study was conducted at 4 university-affiliated centers in the UK, and included participants ages 18 to 28 years. Each was randomly assigned to fast or gradual adjustment. At each of three visits, patients underwent an ocular examination that included non-invasive tear break-up time (NIBUT), corneal staining, and other tests. Immediately after fitting and at subsequent visits, they completed a questionnaire — with a 0 to 100 scale — rating factors such as comfort, vision quality, lens awareness, and ease of lens application and removal.
In ocular examinations, no significant differences were found for either wear schedule or contact lens assignment, with one exception. After 4 to 6 days, participants assigned to gradual adjustment with silicone hydrogels had significantly decreased corneal staining scores compared with the fast adaptation group (P =.019). This difference, though, did not persist to 12 to 14 days.
Similarly, no significant differences appeared in subjective ratings until 12 to 14 days, when silicone hydrogel wearers who practiced gradual adjustment reported significantly better results for lens awareness (P =.02), the study explains. Conversely, this factor is counterbalanced by similar intergroup comfort scores during the two-week period. Visual quality was also comparable for either schedule in both lens groups.
Participants’ spherical equivalent refraction ranged from +.25 to -6.50 DS, and for inclusion, astigmatism was required to be ≤.75 DC. Care regimen consisted of nightly storage in a multi-purpose solution. All patients completed the protocol, and no adverse events were noted. A limitation of this analysis was that contact lenses were made by only 1 manufacturer.
These results are similar to the research group’s earlier paper examining daily disposable lenses, with a difference; gradually adapted daily silicone hydrogel wearers experienced a longer NIBUT after 12 to 14 days. Based on the new findings, rather than only using a fast adaptation strategy, “a sensible approach would be to instruct patients to wear them for as long as they are comfortable up to a suggested maximum,” the study suggests.
Wolffsohn JS, Ghorbani-Mojarrad N, Vianya-Estopa M, et.al. Fast versus gradual adaptation of soft monthly contact lenses in neophyte wearers. Cont Lens Anterior Eye. Published online May 22, 2021. doi:10.1016/j.clae.2021.101469