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However, it is not common for people receiving Ortho-K to complain about blur in the clinic. Bad visual and optical quality may cause the perception of blur to some extent. (2013) reported that people using Ortho-K tend to complain about distortions from car headlights and bright lights at home. Previous studies have reported that Ortho-K inevitably increases higher-order aberrations (HOAs) and decreases contrast sensitivity ( Hiraoka et al., 2008a, b Gifford et al., 2013 Vincent et al., 2020). An increasing number of children have been using them in China ( Tay et al., 2017), Singapore ( Saw et al., 2019), etc., especially for the latter reason.Īlthough some studies ( Queiros et al., 2012 Zhao et al., 2018) have shown that myopic children’s quality of life partially improves with good acceptance of Ortho-K ( Wen et al., 2015 Li et al., 2016), visual and optical quality in children wearing Ortho-K lenses deteriorate because of the reshaped cornea and the affected tear film ( Li et al., 2018). Orthokeratology (Ortho-K) has been demonstrated to improve naked visual acuity during the day ( Swarbrick, 2006 Khan et al., 2016) by reshaping the corneal surface and to slow myopia progression ( Swarbrick, 2006 Le et al., 2010 Santodomingo-Rubido et al., 2015, 2017 Wen et al., 2015 Huang et al., 2016 Chen et al., 2018) by changing the peripheral defocusing state ( Queirós et al., 2010 Kang and Swarbrick, 2011 Santodomingo-Rubido et al., 2013).