目的：观察和分析配戴CRT与VST设计角膜塑形镜对低E值角膜形态控制青少年近视发展的有效性及安全性的对比研究。

方法：前瞻性研究，选取2020-01/2021-12于我院视光门诊就诊配戴角膜塑形镜的青少年近视患者100例100眼，取右眼数据用于研究。按等效球镜分低度近视组(-1.00--3.00 D)和中度近视组(-3.25--5.00 D)，各50例。组内采用随机数字表法分为CRT组和VST组，各25例。测量各组配戴前后裸眼视力、屈光度、眼轴(AL)、泪膜破裂时间(BUT)、角膜内皮细胞密度、角膜点染分级、镜片偏位情况、MRT 15°-30°处视网膜近视离焦量。随访1.5 a。

结果：低度近视中，CRT组和VST组配戴角膜塑形镜后裸眼视力各时间点无差异，中度近视数组塑形后裸眼视力CRT组优于VST组，两组1 d，1 wk的视力有差异(t=-9.474、-12.067，均P<0.01)，其他时间点两组均无差异。戴镜后6 mo，1.5 a，低度近视、中度近视中CRT组和VST组AL增加量均无差异，但CRT组比VST组增长少。两组戴镜后6 mo，1.5 a的双眼BUT及角膜内皮细胞密度均无差异。从两组的角膜损伤来看CRT组角膜损伤低于VST组，但无差异(Z=-1.803，P=0.071)，CRT组镜片偏位情况优于VST组(Z=-4.629，P<0.001)； MRT 15°-30°处视网膜近视离焦量，低度近视中两组无差异，中度近视中1、3、6 mo离焦量有差异(t=-3.949，P=0.008； t=-5.833，P<0.001； t=-6.231，P<0.001)，CRT组能产生更多的近视性离焦量。

结论：对于对低E值角膜形态的患者，CRT采用角膜8 mm处的矢高值来验配，不局限于角膜E值，塑形更快，塑形后裸眼视力更好，特别对于中度近视能获得更好的白天视力，从控制近视来看，CRT验配中抬高反转区(RZD)，产生小的中央光学区能产生更大的周边近视性离焦，但两组控制眼轴增长之间无明显差异。两组的角膜损伤少，对近视控制安全性一致。

METHODS: This prospective study involved 100 cases(100 eyes)of adolescent myopia patients fitted with orthokeratology at our optometry clinic from January 2020 to December 2021. The data of right eye were collected for research, and they were divided into low myopia group(-1.00 to -3.00 D)and moderate myopia group(-3.25 to -5.00 D)according to spherical equivalent, with 50 cases in each group. Each group of patients was further randomly divided into the CRT group and the VST group, with 25 cases in each group. Uncorrected visual acuity, refractive error, axial length(AL), tear film break-up time(BUT), corneal endothelial cell density, corneal staining grading, lens decentration, and refractive power at 15°-30° were measured before and after wearing orthokeratology, with a follow-up duration of 1.5 a.

RESULTS: The uncorrected visual acuity of CRT and VST subgroups in the low myopia group showed no statistical significance at any time point after wearing orthokeratology. However, in the moderate myopia group, CRT subgroup showed better uncorrected visual acuity than the VST subgroup, with significant differences at 1 d and 1 wk(t=-9.474, -12.067, both P<0.01); no significant differences were noted at other time points. After wearing lens for 6 mo and 1.5 a, the AL growth for the CRT subgroup in low and moderate myopia was less than the VST subgroup, with no statistically significant differences. There were no statistically significant differences in binocular BUT and corneal endothelial cell density after wearing lens for 6 mo and 1.5 a. Corneal injury was lower in the CRT subgroup than that in the VST subgroup, but the difference was not statistically significant(Z=-1.803, P=0.071). Lens decentration was significantly better in the CRT subgroup than in the VST subgroup(Z=-4.629, P<0.001). In the periphery of the retina at 15°-30°, there were no significant differences in the amount of myopic defocus between the two groups, while it was statistically significant at 1, 3, and 6 mo in the moderate myopia subgroup(t=-3.949, P=0.008; t=-5.833, P<0.001; t=-6.231, P<0.001), indicating that CRT subgroup could produce a greater amount of myopic defocus.

CONCLUSION: For patients with low E-value corneal morphology, CRT, using the vector height at 8 mm on the cornea for fitting, is not limited to the corneal E-value. It shapes faster and improves uncorrected visual acuity after shaping, especially for moderate myopia, achieving better daytime vision. In terms of controlling myopia, CRT fitting elevates return zone depth(RZD), creating a small central optical zone to produce more peripheral myopic defocus. However, there was no significant difference between the two groups in controlling AL growth. Both groups showed minimal corneal damage, indicating consistent safety in myopia control.