Department of Ophthalmology, Children's Hospital of Fudan University, Shanghai, China.
BMC Ophthalmol. 2022 Jun 3;22(1):243. doi: 10.1186/s12886-022-02461-4.
To determine the pattern of axial variation in subjects with initial shortened axial length during the entire period of orthokeratology and to discuss the possibility of shortened AL after one month of orthokeratology becoming a predictor of myopia control.
This study retrospectively included 106 children with myopia aged 8 to 14 wearing OK lenses. Fifty-four eyes with shortened axial length (AL) at the first-month visit were enrolled in the axial length shortening (ALS) group, and fifty-two eyes without shortened AL were enrolled in the no axial length shortening (NALS) group. Axial length and refractive error at baseline and within the entire period of orthokeratology (20 months), including fitting, washout period and re-wear, were measured. Eighty-five children who started wearing single vision spectacle were also included as a control group.
In the ALS group, AL became longer after shortening and slowly exceeded baseline; afterward, AL experienced a rebound during the washout period and shortened again if OK lenses were re-worn. After washout period, significant difference in AL (ALS:0.28 ± 0.19 mm, NALS: 0.52 ± 0.17 mm) and spherical equivalent (ALS:-0.43 ± 0.44D, NALS:-0.91 ± 0.40D) between the two groups were found(P<0.05). The changes in AL and SE were both significantly correlated with the changes in AL at the first-month visit (P<0.05).
After AL is shortened in the initial stage of orthokeratology, it will experience a rapid rebound during the washout period, and the shortening can reappear when re-wearing OK lenses. Hence, the evaluation of orthokeratology will be more objective and accurate after the wash-out period. In addition, the existence and degree of axial shortening can be used as a predictor of long-term myopia development.
确定在整个角膜塑形术期间，初始轴向长度缩短的患者轴向变化的模式，并探讨角膜塑形术后一个月轴向长度缩短是否可以作为近视控制的预测指标。
本研究回顾性纳入了 106 名年龄在 8 至 14 岁之间、佩戴角膜塑形镜的近视儿童。将首次就诊时轴向长度缩短的 54 只眼纳入轴向长度缩短（ALS）组，而无轴向长度缩短的 52 只眼纳入无轴向长度缩短（NALS）组。测量基线和整个角膜塑形术（20 个月）期间的眼轴长度和屈光不正，包括适配期、洗脱期和重新佩戴期。还纳入了 85 名开始佩戴单焦眼镜的儿童作为对照组。
在 ALS 组中，眼轴在缩短后变长，并且缓慢超过基线；之后，在洗脱期眼轴会反弹，如果重新佩戴角膜塑形镜，眼轴又会缩短。洗脱期后，两组间眼轴（ALS：0.28±0.19mm，NALS：0.52±0.17mm）和等效球镜（ALS：-0.43±0.44D，NALS：-0.91±0.40D）差异有统计学意义（P<0.05）。眼轴和 SE 的变化均与首次就诊时眼轴的变化显著相关（P<0.05）。
在角膜塑形术的初始阶段眼轴缩短后，在洗脱期会经历快速反弹，重新佩戴角膜塑形镜时缩短会再次出现。因此，洗脱期后对角膜塑形术的评估将更加客观和准确。此外，轴向缩短的存在和程度可作为长期近视发展的预测指标。
