目的：对比分析缩小CRT与VST设计的角膜塑形镜光学区后表面直径(BOZD)对控制儿童青少年近视进展的有效性及安全性。

方法：回顾性研究。研究对象为2019-06/2022-05就诊于我院角膜塑形镜验配中心的8-16岁近视患者400例400眼(纳入右眼数据分析)。按验配角膜塑形镜品牌以及BOZD分组：CRT-S组(BOZD<6.0 mm)，CRT组(BOZD=6.0 mm)，VST-S组(BOZD<6.2 mm)，VST组(BOZD=6.2 mm)，每组各100例100眼。分别戴镜1 d，1 wk，1、6 mo，1、2 a时收集分析各组配戴前后裸眼视力(UCVA)、角膜平坦K值、眼轴、屈光度数以及角膜损伤发生率有无差异。

结果：戴镜1 d时，VST-S组的UCVA提升最快，但1 wk后，各组均达到较好的UCVA，组间无显著差异。戴镜6 mo，CRT-S组的角膜平坦K值降幅最大，戴镜1 a后，各组的角膜平坦K值降幅无显著差异。在各时间点，缩小同品牌的角膜塑形镜BOZD后，眼轴增长均显著降低。戴镜6 mo时，CRT-S组与VST-S组的眼轴增长量及离焦环直径无显著差异，但在1、2 a时，VST-S组的眼轴增长量及离焦环直径显著低于CRT-S组。随访2 a时，缩小同品牌的角膜塑形镜BOZD后，球镜度数及等效球镜度数(SE)的增长均显著降低。VST-S组球镜度数及SE变化最小，近视控制效果最好。四组的柱镜度数变化值以及角膜损伤发生率无显著差异。

结论：缩小角膜塑形镜光BOZD可有效控制眼轴增长及近视度数的进展； VST设计原理的镜片缩小BOZD后近视控制效果优于CRT设计原理镜片； 缩小BOZD不会增加额外的角膜损伤风险。

METHODS:Retrospective study. The study subjects were 400 myopia patients aged 8-16 years who were admitted to the orthokeratology fitting center of our hospital from June 2019 to May 2022, with 400 eyes(including right eye data analysis). The subjects were divided into CRT-S group(BOZD<6.0 mm), CRT group(BOZD=6.0 mm), VST-S group(BOZD<6.2 mm), VST group(BOZD=6.2 mm)according to the brand of orthokeratology lens and BOZD group, with 100 cases in each group. Uncorrected visual acuity(UCVA), corneal flat K value, axial length, spherical equivalent, and incidence of corneal injury were collected and analyzed at 1 d, 1 wk, 1 and 6 mo, 1 and 2 a, respectively.

RESULTS:After wearing lenses for 1 d, the UCVA of the VST-S group improved the fastest, but after 1 wk, all groups reached a good UCVA, and there was no significant difference between groups. The corneal flat K value of the CRT-S group decreased the most after wearing lenses for 6 mo, and there was no significant difference in the corneal flat K value of all groups after 1 year of lens wearing. At each time point, the axial length growth decreased significantly after reducing the BOZD of the same brand of orthokeratology lens. At 6 mo, there was no significant difference in the axial length growth and defocus ring diameter between the CRT-S group and the VST-S group, but at 1 and 2 a, the VST-S group had significantly lower axial length growth and defocus ring diameter than the CRT-S group. The growth of the diopter sphere and spherical equivalent(SE)was significantly reduced when the BOZD of the same brand of orthokeratology lens was reduced at 2 a follow-up. The VST-S group had the smallest changes in the degree of SE and had the best myopia control effect. There was no significant difference in the change value of the diopter cylinder and the incidence of corneal injury among the four groups.

CONCLUSION:Reducing the BOZD of the orthokeratology lens can effectively control the growth of the axial length and the progression of myopia degree. The myopia control effect of the VST lens is better than that of the CRT lens after reducing the BOZD. Reducing the BOZD of the orthokeratology lens does not increase the risk of additional corneal injury.