The prevalence of myopia has increased worldwide. One of the effective ways to control myopia progression is specially designed spectacles. However, the optical performance of the eye wearing such spectacle lenses were rarely reported. This study presents a spectacle lens design for myopia control along with optical performance analysis. The spectacle lens has an optical zone of 9 mm in diameter, surrounded by lenslets located in a circular zone from radial distance of 4.5 mm to 17 mm. The lenslets are arranged in the form of a Fibonacci spiral. The optical structure of the spectacle lens was built in the design software Zemax. The peripheral refraction (M, J0, J45) of the eye wearing designed spectacle lens was calculated and compared with results from the eye wearing spectacle lens with lenslets arranged in the same way as the two commercially available spectacle lenses. Additionally, the MTF (Modulation Transfer Function) of the eye with rotation was calculated as well. The results show that the myopic defocus within the ±40° field of view as well as MTF during eye rotation are higher than these of the other two types of lenslet arrangements, demonstrating that the new spectacle lens may control myopia progression more effectively and provides a better visual quality when the line of sight deviates from the center of the lens.
The fast development of IOLs has provided patients with optical performance that more closely resembles that of the healthy human eye, however such optical performance experience is achieved only for on-axis (0 degrees) optical performance, leaving the peripheral vision inferior to the health human eyes.. Recently, studies have demonstrated the importance of peripheral vision to patients' daily life. To solve this problem, an IOL with improved peripheral vision has been proposed. The IOL is designed to optimize peripheral vision in a 40-degree field of view (FOV) under 3 mm pupil diameter, while maintaining on-axis optical performance. The design results shows that the designed IOL provide the same level of central field optical performance compared to healthy human eyes and traditional IOLs as well as the improving peripheral vision. This IOL design may help to reduce the risks related to peripheral vision loss in daily life.
This paper presents a design of multizone soft contact lens (SCL) to correct myopia and slow its progression in children and young adults. The SCL anterior surface was a multizone spherical surface, being divided into five concentric zones with diameters of 3.5, 4.5, 6, 8.6, and 14.2 mm respectively. The first zone is for distance correction surrounded by alternating plus power treatment zone and distance correction zone. The outmost zone was a connecting carrier for fixing the SCL. Based on an established myopic model eye, the multizone SCL was designed employing Zemax software. The relative peripheral myopic shift of the designed SCL was analyzed by the mean sphere M at eight peripheral positions from 0° to 35° in steps of 5° under 3 and 6 mm pupil diameters. A -3 diopter (D) multizone SCL with a central thickness of 0.0659 mm and a diameter of 14.2 mm was obtained. The refractive error at 0° field of view (FOV) is fully corrected for 3 mm pupil. The mean sphere M of the myopic model eye fitted with the designed SCL is up to -5.45 D at 20° under 3 mm pupil (photopic vision), and nearly -6 D at 35° under 6 mm pupil (scotopic vision), showing significant peripheral myopic shift. Besides, the modulation transfer function (MTF) values remain above 0.56 at 50 c/mm for distance vision under 3 mm pupil for the full ±15° FOV. The above shows that the designed multizone SCL is able to correct myopic refractive error in photopic vision. In addition, it produces a large peripheral myopic defocus in both photopic and scotopic conditions, exhibiting excellent potential to slow the myopia progression.
Due to the loss of the flexibility of the crystalline lens, presbyopia is the most common vision dysfunction for adults after 40. To correct presbyopia, this paper presents a design of a MIOL, which can give extended clear vision range both in photopic vision(3mm pupil diameter) and in the mesopic vision(4.5mm pupil diameter). With a pseudophakic eye model, a multi-configuration with object distance covering a full range of normal visual from 8m to 0.4m was applied. The surfaces of MIOL were aspherical diffractive surface. MIOL was divided into two regions: the inner zone was optimized when the pupil diameter was 3mm and the outer zone was optimized when the pupil diameter was 4.5mm. Finally, we got a 22 diopters (D) MIOL with a central thickness of 0.652mm and an optical diameter of 4.5mm. By evaluating the modulation transfer function, we got optical performance of the pseudophakic eye with this MIOL. When the pupil diameter of pseudophakic eye was 3mm, MTF at 50c/mm and 100c/mm was respectively above 0.4 and 0.15 for the object distance from 8m to 0.4m. When the pupil diameter of pseudophakic eye was 4.5mm, MTF at 50c/mm and 100c/mm was respectively above 0.25 and 0.09 for the object distance from 8m to 0.4m.The visual acuity was above 0.9 for the whole visual range at both of two pupil diameters. Therefore it is safe to say that the new MIOL design provides good optical performance for whole visual range under both of the photopic vision and the mesopic vision.
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