This results in a lens that is about 4 in (10.2 cm) in diameter and 1-1.5 in (2.4-3.8 cm) thick. Our eyes are seldom precisely matched, so to accommodate the difference between our two eyes, binoculars also have a diopter adjustment near the optical lens on. Exophoric shifts were greater with aspheric lenses (1.8 ± 2.4Δ Biofinity, 1.7 ± 1.7Δ NaturalVue) than with the concentric MiSight (0.5 ± 1.3Δ). The lens material is poured into a lens mold, which has a spherical curved bottom. Negative relative accommodation reduced with the aspheric lenses (p = 0.001): by 0.9 ± 0.5D with Biofinity and 0.5 ± 0.7D with NaturalVue. The MFCLs altered the autorefraction measure at distance and near (p = 0.001) the accommodation response was less with aspheric lenses. Near acuity was affected less than distance acuity the reduction was greatest with the NaturalVue (0.05 ± 0.07 logMAR reduction). Compared with the single vision lens, the Biofinity aspheric had the greatest visual impact: 0.19 ± 0.14 logMAR distance acuity reduction, 0.22 ± 0.15 log contrast sensitivity reduction. The four lenses differed in distance (p = 0.001) and near visual acuity (p = 0.011), and contrast sensitivity (p = 0.001). Testing included visual acuity, contrast sensitivity (Pelli-Robson), stereoacuity, accommodation response, negative and positive relative accommodation, horizontal phorias, horizontal fusional vergence and AC/A ratio, and a visual quality questionnaire. In random order, participants wore four MFCLs: Proclear single vision distance, MiSight concentric dual focus (+2.00D), distance center aspheric (Biofinity, +2.50D) (CooperVision lenses), and NaturalVue aspheric (Visioneering Technologies). So as light passes through a thick medium like glass or water, it slows down. Pupil sizes were 4.4 ± 0.9 mm during distance viewing and 3.7 ± 0.8 mm at near. Fundamentally how binoculars work and magnify a view is by using lenses that causes light to do something known as refraction: Through the vacuum of space, light travels in a straight line, but as it passes through different materials it changes speed. Participants were twenty-six myopes (19-25 years, spherical equivalent -0.50 to -5.75D), with normal binocular vision and no past myopia control. This allows for a greater magnification, shorter tube length and a wider separation of the objective lenses which increases the stereoscopic effect. The light passes through the large lens (objective lens) it then passes through the prisms and shows a far greater path length. The effects of MFCLs on visual quality, accommodation and vergence in young-adult myopes were evaluated. As their name implies, prismatic binoculars work by using a set of prisms in each tube. Multifocal soft contact lenses (MFCLs) are prescribed to inhibit myopia progression these include aspheric and concentric designs.