Yutong Song1, Shenlin Zhu1, Bi Yang1, Xue Wang1, Wei Ma1, Guangjing Dong1, Longqian Liu2. 1. Department of Optometry and Visual Science, West China Hospital, Sichuan University, No. 37, Guoxuexiang, Wuhou District, Chengdu, 610041, Sichuan, China. 2. Department of Optometry and Visual Science, West China Hospital, Sichuan University, No. 37, Guoxuexiang, Wuhou District, Chengdu, 610041, Sichuan, China. b.q15651@hotmail.com.
Abstract
PURPOSE: The study aimed to observe and analyze the dynamic accommodation and binocular vision changes in myopic children after they switched from spectacles to orthokeratology (ortho-k) lenses. METHODS: Thirty-six myopic children aged 8-14 years were enrolled in this prospective, self-controlled study from West China Hospital. General information was gathered, and examinations were performed at baseline and at 1, 3, 6, and 12 months after switching to ortho-k lenses. The examination included assessments of distance/near visual acuity, distance/near horizontal and vertical ocular alignment, distance/near horizontal vergence range, accommodative amplitude, monocular/binocular accommodative facility, accommodative response, positive and negative relative accommodation (PRA/NRA), accommodation convergence/accommodation (AC/A), stereopsis, and reading ability. RESULTS: After the children switched to ortho-k lenses, distance and near ocular alignment showed an exophoric shift (distance: p = 0.001, near: p = 0.002), and the horizontal vergence range decreased by different degrees (convergence: distance blur point (p = 0.002), distance break point (p = 0.005), near blur point (p = 0.011), near break point (p = 0.043); divergence: distance break point (p < 0.001), distance recover point (p < 0.001), near recover point (p = 0.005)). The stereopsis ability (p < 0.001), monocular/binocular accommodative facility (p < 0.001), and PRA (p = 0.010) increased. The accommodative lag (p < 0.001), accommodative amplitude (p < 0.001), and calculated and gradient AC/A (calculated: p = 0.001, gradient: p = 0.025) decreased. The adjusted horizontal and vertical reading times and their ratio decreased (all p < 0.001). CONCLUSION: The subjects showed distance and near exophoric shifts after switching to ortho-k lenses; improvements in accommodative function, stereopsis, and ocular motility; and a decrease in the binocular horizontal vergence range. The relationships between these changes and the ortho-k myopic control effects require further investigation.
PURPOSE: The study aimed to observe and analyze the dynamic accommodation and binocular vision changes in myopic children after they switched from spectacles to orthokeratology (ortho-k) lenses. METHODS: Thirty-six myopic children aged 8-14 years were enrolled in this prospective, self-controlled study from West China Hospital. General information was gathered, and examinations were performed at baseline and at 1, 3, 6, and 12 months after switching to ortho-k lenses. The examination included assessments of distance/near visual acuity, distance/near horizontal and vertical ocular alignment, distance/near horizontal vergence range, accommodative amplitude, monocular/binocular accommodative facility, accommodative response, positive and negative relative accommodation (PRA/NRA), accommodation convergence/accommodation (AC/A), stereopsis, and reading ability. RESULTS: After the children switched to ortho-k lenses, distance and near ocular alignment showed an exophoric shift (distance: p = 0.001, near: p = 0.002), and the horizontal vergence range decreased by different degrees (convergence: distance blur point (p = 0.002), distance break point (p = 0.005), near blur point (p = 0.011), near break point (p = 0.043); divergence: distance break point (p < 0.001), distance recover point (p < 0.001), near recover point (p = 0.005)). The stereopsis ability (p < 0.001), monocular/binocular accommodative facility (p < 0.001), and PRA (p = 0.010) increased. The accommodative lag (p < 0.001), accommodative amplitude (p < 0.001), and calculated and gradient AC/A (calculated: p = 0.001, gradient: p = 0.025) decreased. The adjusted horizontal and vertical reading times and their ratio decreased (all p < 0.001). CONCLUSION: The subjects showed distance and near exophoric shifts after switching to ortho-k lenses; improvements in accommodative function, stereopsis, and ocular motility; and a decrease in the binocular horizontal vergence range. The relationships between these changes and the ortho-k myopic control effects require further investigation.
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