Sofia Cláudia Peixoto-De-Matos

SIGNIFICANCE: Results of this randomized, double‐masked clinical trial demonstrate the effectiveness of the MiSight soft contact lens in slowing myopia progression over multiple years. PURPOSE: The purpose of this study was to quantify the effectiveness of MiSight daily disposable soft contact lens in slowing the progression of juvenile‐onset myopia. METHODS: Myopic children (spherical equivalent refraction, −0.75 to −4.00 D; astigmatism, P <. 001). Mean change in axial length was 0.32 mm (52%) less in the test group than in the control group (0.30 ± 0.27 vs. 0.62 ± 0.30 mm, P <. 001). Changes in spherical equivalent refraction and axial length were highly correlated ( r = −0.90, P <. 001). Over the course of the study, there were no cases of serious ocular adverse events reported. Four asymptomatic corneal infiltrative (one test, three control) events were observed at scheduled study visits. CONCLUSIONS: Results of this clinical trial demonstrate the effectiveness of the MiSight daily disposable soft contact lens in slowing change in spherical equivalent refraction and axial length.

To evaluate neophyte contact lens wearers' fitting to rigid gas permeable (RGP) contact lenses in terms of wearing time, tear volume, stability, corneal staining, and subjective ratings, over a 1-month period of time. Twenty-two young healthy subjects were enrolled for wearing RGP on a daily wear basis. The participants included in this study never wore contact lenses and showed a value under 10 in McMonnies Questionnaire. Contact Lens Dry Eye Questionnaire, Visual Analog Scales, Schirmer test, tear film break-up time (BUT), and corneal staining grading were performed. Follow-up visits were scheduled at 1, 7, 15, and 28 days. Six subjects dropped out due to discomfort from the study before 1 month (27% of discontinuation rate). Successful RGP wearers (16 participants) achieved high levels of subjective vision and reported comfort scores of approximately 9 of 10 between 10 and 15 days. They reported wearing their lenses for an average of 10.12±2.43 hr after 1 month of wear. Conversely, unsuccessful wearers discontinued wearing the lenses after the first 10 to 15 days, showing comfort scores and wearing time significantly lower compared with the first day of wear. Schirmer test showed a significant increase at 10 days (P<0.001), and the BUT trends decreased after the first week of wear in unsuccessful group. Symptomatology related with dryness and discomfort, detected during the first 10 days of the adaptation, may help the clinician to predict those participants who will potentially fail to adapt to RGP lens wear.

Higher myopic refractive errors are associated with serious ocular complications that can put visual function at risk. There is respective interest in slowing and if possible stopping myopia progression before it reaches a level associated with increased risk of secondary pathology. The purpose of this report was to review our understanding of the rationale(s) and success of contact lenses (CLs) used to reduce myopia progression. A review commenced by searching the PubMed database. The inclusion criteria stipulated publications of clinical trials evaluating the efficacy of CLs in regulating myopia progression based on the primary endpoint of changes in axial length measurements and published in peer-reviewed journals. Other publications from conference proceedings or patents were exceptionally considered when no peer-review articles were available. The mechanisms that presently support myopia regulation with CLs are based on the change of relative peripheral defocus and changing the foveal image quality signal to potentially interfere with the accommodative system. Ten clinical trials addressing myopia regulation with CLs were reviewed, including corneal refractive therapy (orthokeratology), peripheral gradient lenses, and bifocal (dual-focus) and multifocal lenses. CLs were reported to be well accepted, consistent, and safe methods to address myopia regulation in children. Corneal refractive therapy (orthokeratology) is so far the method with the largest demonstrated efficacy in myopia regulation across different ethnic groups. However, factors such as patient convenience, the degree of initial myopia, and non-CL treatments may also be considered. The combination of different strategies (i.e., central defocus, peripheral defocus, spectral filters, pharmaceutical delivery, and active lens-borne illumination) in a single device will present further testable hypotheses exploring how different mechanisms can reinforce or compete with each other to improve or reduce myopia regulation with CLs.

Purpose. We defined the theoretical oxygen tension behind modern scleral contact lenses (CLs) made of different rigid gas permeable (RGP) materials, assuming different thickness of the tear layer behind the lens. A second goal was to show clinically the effect of the postlens tear film on corneal swelling. Methods. We simulated the partial pressure of oxygen across the cornea behind scleral CLs made of different lens materials (oxygen permeability Dk, 75–200 barrer) and different thickness (T_av, 100–300 μm). Postlens tear film thicknesses (T_post-tear) ranging from 150 to 350 μm were considered. Eight healthy subjects were fitted randomly with a scleral lens with a thin and a thick postlens tear layer in two different sessions for a period of 3 hours under open-eye conditions. Results. The CLs with less than 125 barrer of Dk and a thickness over 200 μm depleted the oxygen availability at the lens–cornea interface below 55 mm Hg for a postlens tear film of 150 μm. For a postlens tear film thickness of 350 μm, no combination of material or lens thickness will meet the criteria of 55 mm Hg. Our clinical measures of corneal edema showed that this was significantly higher (P < 0.001, Wilcoxon signed ranks test) with the thicker compared to the thinner T_post-tear (mean ± SD, 1.66 ± 1.12 vs. 4.27 ± 1.19%). Conclusions. Scleral RGP CLs must be comprised of at least 125 barrer of oxygen permeability and up to 200 μm thick to avoid hypoxic effects even under open eye conditions. Postlens tear film layer should be below 150 μm to avoid clinically significant edema.