IMPORTANCE During the outbreak of COVID-19, outdoor activities were limited and digital learning increased. Concerns have arisen regarding the impact of these environmental changes on the development of myopia.OBJECTIVE To investigate changes in the development of myopia in young Chinese schoolchildren during the outbreak of COVID-19. DESIGN, SETTING, AND PARTICIPANTSIn this observational study, 2 groups of students from 12 primary schools in Guangzhou, China, were prospectively enrolled and monitored from grade 2 to grade 3. Comparisons between the exposure and nonexposure groups were made to evaluate any association between environmental changes during the COVID-19 outbreak period and development of myopia. The exposure group

Purpose: To investigate changes in subfoveal choroidal thickness (SFChT) during orthokeratology (Ortho-K) lens wear and after its cessation and the association of short-term change in SFChT with the long-term eye elongation in Ortho-K subjects. Design: A prospective clinical trial. Methods: Fifty myopic children aged between 9 and 14 years were enrolled. Twenty-nine subjects continuously wore Ortho-K lens for 12 months and discontinued for 1 month. Twenty-one subjects wearing single vision distance spectacles for 12 months were included as the control group. SFChT was assessed using optical coherence tomography. Ocular parameters, including axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT) and apical corneal power (ACP), were also measured. Results: After 12 months of follow-up, AL elongation was larger and SFChT change was smaller in the control group compared to the Ortho-K group (both p < 0.001). In the Ortho-K group, SFChT increased by 16 lm from baseline at the 1-month visit (p < 0.001), and the magnitude of choroidal thickening remained unchanged at the 6-and 12-month visit (p = 0.289). One month after discontinuation of Ortho-K lens, SFChT and ocular parameters of the anterior segment, including ACP, CCT and ACD recovered to baseline level (All p > 0.05), and AL increased by 0.23 AE 0.18 mm compared to baseline (p = 0.018). SFChT change at 1-month was negatively associated with AL change at 13-month (standard b, À0.581, p = 0.001) after adjusting for other influencing factors, including baseline age and the ocular parameters. Conclusion: Subfoveal ChT (SFChT) significantly increased after short-term Ortho-K lens treatment and the increase maintained throughout the period of treatment. One month after Ortho-K lens cessation, SFChT, ACP, CCT and ACD returned to baseline. Short-term response in SFChT is associated with long-term change in AL in children undergoing Ortho-K lens and may be a predictor for the effectiveness of the treatment.

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BackgroundThe myopia control effect of orthokeratology (OK) varies among individuals. The variation might relate to the proposed ‘areal summation effect’ of lens-induced visual signals. The current study evaluated the areal summed corneal power shift (ASCPS) in myopic children treated with OK lenses and assessed whether the ASCPS achieved at early post-OK visit can predict the lens long-term effect on the axial length (AL) elongation.MethodsStudy participants were 130 myopic children treated with OK lenses (age range, 8 to 15 years) in a prospective study. Corneal topography and AL were measured at baseline and 1, 3, 6, 9 and 12 months after OK lens wear. The ASCPS was derived from corneal topographic measurements and defined as the change in the areal summed corneal relative refraction at the follow-up visit from baseline. The impact of the ASCPS achieved at the 1 month post-OK visit on the 12 months AL elongation was examined using multivariate linear regression analysis.ResultsBaseline age of the study participants was 11.8 ± 1.8 years and their mean spherical equivalent was −3.00±0.92 D. The ASCPS was 6.90±6.09 D*mm at the 1 month visit and remained stable throughout the follow-up period (p=0.5508, repeated-measures analysis of variance). Greater 1 month ASCPS was associated with slower AL elongation at the 12 months visit (β=−0.007, p=0.001).ConclusionsThe ASCPS achieved at early post-OK visit is predictive for the lens long-term effect on the myopic AL elongation. The parameter is potential in guiding the OK lens practice to slow down axial growth in myopic children.