Clinical Science
Effect of peripheral plus ring diameter and its relationship with pupil diameter on axial elongation in myopic patients after wearing orthokeratology lenses
Yu Jia, Zhang Jing, Zhou Yuehua, Yuan Xiaohui, Zhou Qiliang, Li Chen
Published 2023-08-10
Cite as Chin J Exp Ophthalmol, 2023, 41(8): 776-781. DOI: 10.3760/cma.j.cn115989-20211214-00686
Abstract
ObjectiveTo investigate the effect of peripheral plus ring size and its potential associations with pupil diameter (PD) on axial length (AL) elongation in myopic patients after wearing orthokeratology lenses.
MethodsA case-control study was conducted.One hundred eyes from 100 myopic patients who underwent orthokeratolokgy lenses fitting were enrolled at Beijing Ming Vision and Ophthalmology from January to June 2020.AL and central corneal thickness (CCT) measurements were obtained using Lenstar LS900 ocular biometry, and steep keratometry (Ks), flat keratometry (Kf) were assessed using the TMS-4 corneal topographer.The patients were divided into larger peripheral plus ring diameter (LPPRD) group consisting of 55 eyes with PD<PPRD-0.9 mm and smaller PPRD (SPPRD) group consisting of 45 eyes with PPRD-0.9 mm <PD<PPRD+ 0.9 mm based on PPRD and PD sizes in the tangential difference map.Differences in the above parameters before and after wearing orthokeratology lenses were compared between the two groups.The study followed the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Ineye Hospital of Chengdu University of Traditional Chinese Medicine (No.2021yh-008). All the subjects and their guardians understood the purpose and method of the study and signed the informed consent voluntarily.
ResultsThe PPRD of LPPRD group was (5.15±0.37)mm 12 months after wearing orthokeratology lenses, which was significantly higher than (4.75±0.32)mm of SPPRD group (t=0.214, P<0.01). The elongation of AL at 3, 6, 9 and 12 months after wearing orthokeratology lenses were (0.13±0.07), (0.23±0.11), (0.31±0.13) and (0.36±0.41)mm in LPPRD group, and (0.06±0.05), (0.11±0.06), (0.14±0.07) and (0.17±0.08)mm in SPPRD group, respectively.There were significant differences in AL elongation at different time points after wearing orthokeratology lenses between the two groups (Fgroup=30.527, P<0.01; Ftime=16.528, P<0.01), and the AL elongation at different time points was smaller in SPPRD group than in LPPRD group, showing statistically significant differences (all at P<0.01). Compared to before wearing orthokeratology lenses, Ks and Kf were significantly smaller and CCT was thinner 3, 6, 9, and 12 months after wearing orthokeratology lenses in both groups (all at P<0.01). There was no significant difference in Ks, Kf, and CCT between the two groups (all at P>0.05). There was no significant difference in PD at different time points before and after wearing orthokeratology lenses between the two groups (Fgroup=1.133, P=0.293; Ftime=231.427, P=0.112).
ConclusionsThe size of peripheral plus ring and its relationship with PD are key factors influencing the AL elongation rate in myopic patients after wearing orthokeratology lenses.With smaller PPRD, patients have slower AL elongation and better myopia control.
Key words:
Myopia; Therapy; Orthokeratologic procedures; Peripheral plus ring; Axial length; Myopia defocus
Contributor Information
Yu Jia
Eye School, Chengdu University of Traditional Chinese Medicine, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
Zhang Jing
Eye School, Chengdu University of Traditional Chinese Medicine, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
Beijing Ming Vision and Ophthalmology, Beijing 100062, China
Zhou Yuehua
Eye School, Chengdu University of Traditional Chinese Medicine, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
Beijing Ming Vision and Ophthalmology, Beijing 100062, China
Yuan Xiaohui
Eye School, Chengdu University of Traditional Chinese Medicine, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
Zhou Qiliang
Eye School, Chengdu University of Traditional Chinese Medicine, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China
Li Chen
Eye School, Chengdu University of Traditional Chinese Medicine, Ineye Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China