Gifford Kate L, Gifford Paul, Hendicott Peter L, Schmid Katrina L
School of Optometry and Vision Science, and Institute of Health and Biomedical Innovation, Faculty of Health, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove QLD 4059 Australia.
School of Optometry and Vision Science, Faculty of Science, University of New South Wales, Rupert Myers Building, Barker Street, Kensington NSW 2033 Australia.
Cont Lens Anterior Eye. 2020 Feb;43(1):44-53. doi: 10.1016/j.clae.2019.11.008. Epub 2019 Nov 30.
Orthokeratology (OK) is known to alter relative peripheral refraction (RPR) with this presumed to be its key myopia control mechanism. A prospective, longitudinal study was performed to examine stability of OK-induced RPR changes in myopic children and young adults.
RPR of twelve children (C)(8-16 years) and eight adults (A)(18-29 years) with spherical equivalent refraction of -0.75 to -5.00D were measured unaided and while wearing single vision soft contact lenses (SCL). Measurements were repeated after 1, 6 and 12 months of OK wear. RPR was measured using an open-field Shin Nippon SRW-5000 autorefractor at 10, 20 and 30 degrees nasally (N) and temporally (T), converted into power vectors M, J0 and J45. On-axis refractions and axial lengths (IOL Master) were also measured.
Compared to the unaided state, 1-month of OK wear shifted the RPR in the myopic direction at 30 T (C: p = 0.023; A:, p = 0.002) and 30 N (C&A, p = 0.003) and was stable thereafter, with similar changes compared to SCL wear. J0 showed a myopic shift in comparison to both unaided and SCL correction in children but not adults, and J45 did not change in either group. The on-axis OK correction was predictive of the RPR shift in both children and adults at 30 T (C: r=-0.58, p = 0.029; A: r=-0.92, p < 0.001) and 30 N (C: r=-0.60, p = 0.024; A: r=-0.74, p = 0.013) with symmetry of RPR shifts (C: r = 0.67, p = 0.008; A: r = 0.85, p = 0.004). No relationships between changes in RPR and axial length were found after twelve months of OK wear; level of myopia was stable in both groups.
Relative to both unaided and single vision SCL correction, OK shifted the RPR in the myopic direction; the RPR was stable from 1 to 12 months. The RPR shift in OK wear varied with the degree of myopia but was not correlated with myopia progression.
角膜塑形术（OK）已知会改变相对周边屈光（RPR），推测这是其控制近视的关键机制。进行了一项前瞻性纵向研究，以检查OK引起的近视儿童和年轻成年人RPR变化的稳定性。
测量了12名儿童（C组，8 - 16岁）和8名成年人（A组，18 - 29岁）的RPR，等效球镜度为-0.75至-5.00D，测量时分别处于裸眼状态以及佩戴单焦点软性接触镜（SCL）时。在佩戴OK镜1、6和12个月后重复测量。使用开放式日本新日本SRW - 5000自动验光仪在鼻侧（N）和颞侧（T）的10°、20°和30°测量RPR，并转换为屈光力矢量M、J0和J45。还测量了轴上屈光和眼轴长度（IOL Master）。
与裸眼状态相比，佩戴OK镜1个月后，在30°颞侧（C组：p = 0.023；A组：p = 0.002）和30°鼻侧（C组和A组，p = 0.003）的RPR向近视方向偏移，此后保持稳定，与佩戴SCL时的变化相似。与裸眼和SCL矫正相比，儿童的J0向近视方向偏移，而成年人则不然，两组的J45均无变化。在30°颞侧（C组：r = -0.58，p = 0.029；A组：r = -0.92，p < 0.001）和30°鼻侧（C组：r = -0.60，p = 0.024；A组：r = -0.74，p = 0.013），轴上OK矫正可预测儿童和成年人的RPR偏移，且RPR偏移具有对称性（C组：r = 0.67，p = 0.008；A组：r = 0.85，p = 0.004）。佩戴OK镜12个月后，未发现RPR变化与眼轴长度之间的关系；两组近视程度均保持稳定。
相对于裸眼和单焦点SCL矫正，OK使RPR向近视方向偏移；RPR在1至12个月内保持稳定。OK佩戴时的RPR偏移随近视程度而变化，但与近视进展无关。
