Patients
We included 75 children aged 8–12 years with myopia from the Second Affiliated Hospital of Dalian Medical University between June 2019 and September 2020. Before the experiment, we explained the expected benefifits and potential risks of using 0.01% atropine and OK lenses to the parents of children and also informed the detailed methods and precautions. This study was reviewed and approved by the Institutional Review Board of the Second Affifiliated Hospital of Dalian Medical University (Dalian, China) and adhered to the tenets of the Declaration of Helsinki. In addition, consent was obtained from the parents of patients. Explanation was provided to children using an easy-to-understand method before obtaining informed consent. Eight participants did not successfully complete the study during the follow-up visits: three because of difficulty in complying with the use of 0.01% atropine eyedrops, two because of keratitis, and three because of lost visits.
Inclusion and exclusion criteria
The inclusion criteria were as follows: (1) cycloplegic spherical equivalent refraction (SE) at least - 1.00 diopters (D) and diopter of spherical within - 1.00 to - 6.00 DS in both eyes; (2) myopic astigmatism ≤ - 1.00 DC and less than or equal to half the spherical diopter; (3) anisometropia of no more than 1.50 D.
The exclusion criteria were as follows: (1) wearing contact lenses within 3 days of the start of examination; (2) children with ocular disorders such as glaucoma, cataract, keratopathy, strabismus, and amblyopia and systemic disorders such as cardiac and respiratory illnesses; (3) intraocular pressure (IOP) of >21 mmHg and difference between the eyes of > 8 mmHg; (4) use of anticholinergic and cholinergic drugs that affect the evaluation of efficacy, such as atropine, pirenzepine, and pilocarpine, within the past 1 month; (5) use of other therapies that may affect the evaluation of efficacy within the past 3 months, such as wearing OK lenses and therapy of traditional Chinese medicine; (6) low birth weight (≤1500 g); and (7) history of hypersensitivity to atropine or anticholinergic drugs.
Methods
All subjects underwent comprehensive tests before treatment, including slit-lamp examination, visual acuity testing, autorefraction, intraocular pressure, AL, corneal topography and optical coherence tomography (OCT). We applied 1% atropine eye gel 3 times a day for 3 days for cycloplegic autorefraction. Cycloplegic spherical equivalent (SE) ≥ −1.00 D was considered to indicate myopia. Subjects were prescribed 0.01% atropine eye drops to be applied once per night before bedtime in both eyes in both the SA and OKA groups. Subjects were instructed to wear OK lens on both eyes every night for at least 8 consecutive hours in both the OK and OKA groups. Additionally, OK lenses
were worn 10 min after the use of 0.01% atropine in the OKA group. Some measurements, such as SE, AL, and SFChT, were taken after the use of tropicamide to induce sufficient mydriasis to induce the influence of accommodation. Further, 0.01% atropine is produced by Shenyang Xingqi pharmaceutical company (Shenyang, China), and there were no preservatives and the PH value between 3.5 and 4.0 in 0.01% atropine. The OK lens in this study are four-zone reverse-geometry lenses (Euclid Systems Ortho-K; Euclid System Corp., Herndon, USA) with BOSTON EQUALENS II (oprifocona) and a nominal Dk of 127 × 10-11 (cm2/s) (ml O2/ml_mmHg) (ISO/Fatt). Spectacles were rematched when the SE dropped by 0.5 D and the vision of wearing glasses decreased. OK lenses were rematched when the naked vision during the day reached < 0.5.
In this study, SE was measured using an autorefractor (KR-800, TOPCON, TOKYO, JAPAN). AL was measured using the non-contact Biometer (lenstar LS 900, HAAG-STREIT AG, KOENIZ, SWITZERLAND). SFChT was measured using the optical coherence tomography (CIRRUS HD-OCT, 5000, SINGAPORE). The average of five consecutive measurements by the same technician was used for analysis.
Statistical analysis
We applied SPSS 26.0 (IBM Corp., Armonk, NY) statistical analysis software for data analysis. All values were described by mean±standard deviation. The comparisons of baseline age, SE, AL and SFChT and changes in AL and SFChT were used independent sample one-way ANOVA analyses. The Pearson's chi-square test was used to analyze gender differences among groups. P < 0.05 was considered statistically significant. Stepwise multiple linear regression models were used to investigate the association between the change in SFChT at 12 month with the change in AL at 12 months. The standard β indicating the relative importance of each variable in comparable standardized units (z scores) was used to evaluate the importance of each variable in predicting weight. A two-tailed P value < 0.05 was considered to indicate statistical significance.