Biometric and refractive changes following the monocular application of peripheral myopic defocus using a novel augmented-reality optical system in adults.

The prevalence of myopia is growing at an alarming rate and is associated with axial elongation of the eye. The cause of this undesirable physiological change involves multiple factors. When the magnitude of myopia approaches high levels, this accompanying mechanical effect increases the risk of developing other clinical conditions associated with permanent vision loss. Prior work has investigated how we may halt or reverse this process of axial elongation associated with myopic progression when we expose the eye to a peripheral myopic defocus stimulus. Specifically, the known, short-term response to myopic defocus stimulation is promising and demonstrates the possibility of establishing more permanent effects by regulating the axial length of the eye with specific defocus stimulation. However, how to directly convert these known, short-term effects into more long-term, permanent changes to effectively prevent these unfavourable physiological and refractive changes over time is yet to be understood. Here, we show for the first time that we can produce sustained, long-term reductions in axial length and refractive endpoints with cumulative short-term exposure to specific myopic defocus stimuli using a novel optical design that incorporates an augmented reality optical system. We believe that this technology will have the potential to improve the quality of vision in mankind.

Effect of short-term peripheral myopic defocus on ocular biometrics using Fresnel "press-on" lenses in humans.

This study assessed axial length and choroidal thickness changes following short-term peripheral myopic defocus in normal adult subjects. Twenty subjects underwent defocus sessions by viewing a full-field projected movie 4 m away for 4 h in the morning, while wearing spectacle lenses, corrected for distance vision in both eyes. The right eye, serving as the test eye, was peripherally defocused using a Fresnel lens overlay of + 3.50 D with a central clear aperture of 11.5 mm (correlating to a clear central visual field of approximately 23°), while the left eye served as the control (with no Fresnel lens overlay). A subset of 10 subjects from the same cohort also underwent additional defocus sessions with + 5.00 D of peripheral defocus. Axial length was measured and radial sub-foveal choroidal scans were obtained before and after the defocus sessions. The increase in axial length of the test eyes were significantly less than the control eyes under both peripheral defocus conditions (p < 0.05). The difference in mean change for choroidal thickness between test and control eyes was not significant for either dioptric condition. Our results demonstrated that short-term peripheral myopic defocus significantly inhibited axial elongation in adult humans, without significant changes in choroidal thickness.

Visual Performance as a Function of Clear Central Aperture Diameter with a Defocused Myopic Periphery.

SIGNIFICANCE: Visual performance is affected least by a 15° radial aperture surrounded by peripheral myopic defocus. This finding has important applications for spectacle and contact lens designs and myopia control optimization. PURPOSE: The purpose of this study was to assess the effect of clear central apertures of different diameters with a defocused retinal periphery, using a range of visual performance tasks. METHODS: Thirty visually normal subjects (mean age, 24.4 ± 3.3 years; 20 females; mean spherical equivalent of -1.28 D) were enrolled. Subjects wore five different spectacles during testing, all corrected for distance refraction, in random order: three single-vision spectacles with clear central apertures of 10, 12.5, and 15° radii with the periphery defocused using Fresnel "press-on" lenses (+3.5 D sphere), progressive addition lens (PAL) spectacles with a +3.5 D addition, and single-vision lens (SVL) spectacles with no peripheral defocus. Static and kinetic visual field sensitivities, reading rate and comprehension, head movements, global saccadic tracking, and saccadic visual search were evaluated. RESULTS: Reading rate and comprehension did not differ across the five test conditions; however, increased head movement was found with the smallest aperture compared with the PAL condition with adjusted P < .05. Static visual field sensitivity was reduced for all three apertures in eccentric regions when compared with the SVL and PAL conditions with adjusted P < .05, whereas kinetic sensitivity did not differ for any lens condition. The 15° aperture was superior to the 10 and 12.5° apertures based on its similarity to the SVL and PAL spectacle conditions in head movement during reading, the Michigan Tracking Test, and the vertical results of the Developmental Eye Movement Test. CONCLUSIONS: Visual performance is least affected adversely by a 15° aperture surrounded by a peripheral myopic defocus. This finding has important applications for spectacle and contact lens designs to optimize myopia treatment with minimal impact on visual performance.