Chen Minfeng, Zhang Ronghan, Zhu Chengwei, Peng Lulu, Zhao Sijun, Mao Xinjie
Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
Front Med (Lausanne). 2024 Oct 9;11:1421361. doi: 10.3389/fmed.2024.1421361. eCollection 2024.
This study analyzed the corneal surface shape following overnight orthokeratology with different optical zone diameters.
A total of 82 eyes belonging to 41 myopic children who completed 1 month of the orthokeratology (ortho-k) lens wear at the Eye Hospital of Wenzhou Medical University from January 2022 to January 2023 were retrospectively analyzed. According to the size of the base curve (BC) of ortho-k lens, patients were divided into BC 5.0 and BC 6.0 groups. The changes in decentration distance and corneal refraction of the two groups after the ortho-k lens wear were analyzed. Independent sample -tests were used to compare these two outcome measures between the two groups.
The decentration distance of BC 5.0 group (0.37 ± 0.19 mm) was significantly lower than that of BC 6.0 group (0.49 ± 0.25 mm, = -2.330, = 0.022). In the BC 5.0 group, the direction of decentration was superonasal in 3 cases, inferonasal in 2 cases, inferotemporal in 21 cases, and superotemporal in 6 cases. In the BC 6.0 group, the direction of decentration was superonasal in 2 cases, inferonasal in 2 cases, inferotemporal in 27 cases, and superotemporal in 19 cases. The optical zone area (8.19 ± 2.96 mm) and reverse curve zone area (30.05 ± 6.74 mm) in the BC 5.0 group were significantly lower than in the BC 6.0 group (10.42 ± 2.03 mm, = -4.043, < 0.001; 38.21 ± 4.77 mm, = -6.422, < 0.001). The change in the rate of refraction in the horizontal direction in BC 5.0 group were significant higher than in BC 6.0 group.
Base curve 5.0 mm ortho-k lens is better positioned than BC 6.0 mm lens. A small BC ortho-k forms a smaller optical zone and reverse curve area, which might get a greater aiameter of alignment curve to facilitate positioning better than the traditional BC lens. In addition, a small BC lens increases positive refraction in the peripheral area, resulting in a greater negative pressure than the traditional BC lens.
本研究分析了不同光学区直径的夜间角膜塑形术后角膜表面形状。
回顾性分析了2022年1月至2023年1月在温州医科大学附属眼视光医院完成1个月角膜塑形术（ortho-k）镜片佩戴的41名近视儿童的82只眼睛。根据ortho-k镜片的基弧（BC）大小，将患者分为BC 5.0组和BC 6.0组。分析两组佩戴ortho-k镜片后偏心距和角膜屈光的变化。采用独立样本t检验比较两组之间的这两个结果指标。
BC 5.0组的偏心距（0.37±0.19mm）显著低于BC 6.0组（0.49±0.25mm，t=-2.330，P=0.022）。在BC 5.0组中，偏心方向为鼻上3例，鼻下2例，颞下21例，颞上6例。在BC 6.0组中，偏心方向为鼻上2例，鼻下2例，颞下27例，颞上19例。BC 5.0组的光学区面积（8.19±2.96mm）和反转曲线区面积（30.05±6.74mm）显著低于BC 6.0组（10.42±2.03mm，t=-4.043，P<0.001；38.21±4.77mm，t=-6.422，P<0.001）。BC 5.0组水平方向屈光率的变化显著高于BC 6.0组。
5.0mm基弧的ortho-k镜片比6.0mm镜片定位更好。小基弧的ortho-k形成较小的光学区和反转曲线面积，可能比传统基弧镜片获得更大的配适弧直径，以利于更好地定位。此外，小基弧镜片增加了周边区域的正屈光，导致比传统基弧镜片更大的负压。
