An increase in HOAs also causes a decrease in visual quality, noted as a decrease in contrast sensitivity or contrast visual acuity (CVA), which may influence the daily life of children. Several previous studies found a significant increase in spherical aberration (SA), coma, and total HOAs. Peripheral defocus and other optical changes caused by post-OK or wearing MSCL also cause changes in the corneal and retinal higher-order aberrations (HOAs). BSCLs and MSCLs also produce different magnitudes of peripheral myopic defocus with different additions. They found that the lenses turned peripheral hyperopic defocus to myopic defocus and sustained it during the wearing period. Previous studies of children with low to moderate myopia measured horizontal and vertical peripheral defocus after wearing OK lenses. This method has been applied in children for myopia control, as peripheral defocus is proposed to be one of the mechanisms by which OK lenses, BSCLs, and MSCLs slow myopia progression. Previous animal studies found that relative peripheral hyperopia induced by a negative lens produces central axial elongation, whereas peripheral myopic defocus produces axial hyperopia. These are commonly designed for central distance correction and peripheral additions. Another efficient method that is widely recognized is bifocal (BSCL) or multifocal soft contact lenses (MSCL). A meta-analysis showed OK lenses could slow myopia progression by approximately 30% to 60%. OK lens is a common clinical myopia control approach. Orthokeratology (OK) lenses are rigid gas permeable contact lenses with a reverse-geometry design and are intended to be worn at night. Thus, controlling myopia in children of primary school age is important and necessary. The incidence of high myopia is increasing year by year, and some cases are sufficiently serious to cause blindness due to pathological myopia, such as retinal detachment, glaucoma, and myopic choroidal neovascularization. Myopia can develop quickly during primary school ages, and some individuals will develop high myopia in adulthood. Myopia has become a global pandemic in recent decades. Registered 25 September 2018 retrospectively registered, The high addition of this MSCL did not result in better myopia control efficacy Trial registrationĬhinese Clinical Trial Registry: ChiCTR1800018564. MSCL produced larger myopic defocus at the periphery, increased less HOAs and had worse CVA than OK lens. HOAs increased more in the OK group (all p < 0.05). All HOAs increased after wearing the lenses except the trefoil in the MSCL group (all p < 0.05). ResultsĪfter wearing the lenses, subjects in the MSCL group had RPCD and RPR values similar to the OK group at the paracentral (within 2 mm of the cornea or 20° of the retina, all p > 0.05) but larger than the OK group at the periphery (all p < 0.05). Axial length (AL) was measured before and after wearing the lenses for 1 year. HOAs including spherical aberration (SA), coma, trefoil, and total HOAs, and high (100%) and low (10%) CVA were compared between the groups. Relative peripheral corneal defocus (RPCD) and relative peripheral refraction (RPR) were measured before and after wearing lenses. Subjects at 8 to 13 years of age with spherical equivalent refraction from − 1.00 to − 5.00 dioptres (D) were included in the OK group ( n = 30) and MSCL group ( n = 23). This is a prospective, nonrandomized, controlled study. To compare peripheral defocus, higher-order aberrations (HOAs), and contrast visual acuity (CVA) in myopic children wearing orthokeratology (OK) lenses and multifocal soft contact lenses (MSCLs) designed with highly addition.
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