Study design
This was a retrospective study. We collected 117 cases of subjects with myopia based on the inclusion and exclusion criteria for this study attending the outpatient ophthalmology clinic of Beijing Children's Hospital. The subjects groups included SVS group, OK lenses group, SVS-LLRL group, and OK-LLRL group. All subject examinations were completed between December 12, 2022 and June 10, 2023.
The study adhered to the Declaration of Helsinki principles. The subjects and guardians of the subjects provided written consent. The Ethics Committee of Beijing Children's Hospital approved the study(2022-E-137-Y).
Inclusion and exclusion criteria
Inclusion criteria: (1) Subjects aged 6 to 12 years; (2) No organic lesions found during ocular examination; (3) Best-corrected visual acuity of at least 1.0; (4) Cycloplegic SER of -0.5 D to -3.00 D, DC ≤ 1.50D in both eyes; (5) Intraocular pressure ranges from 10 to 21 mmHg; (6) Willingness to participate in the study and sign the informed consent form.
Exclusion criteria: (1)Strabismus, amblyopia and anisometropia (difference in spherical lens of both eyes > 1.50 D). (2) History of ocular trauma, fundus disorders, or surgery. (3) Received other interventions for myopia during the period, including but not limited to atropine eye drops and myopic optical defocusing spectacles.
Ophthalmic examination
Routine examinations, including cycloplegic refraction, AL, intraocular pressure, anterior segment, and fundus photography, were conducted on all subjects by a specialized technician. Tear secretion, corneal topography, and corneal endothelial count were also assessed for those wearing OK lenses, while OCT was added for individuals with red light exposure.
Optical correction
All subjects were required to have their refraction determined by retinoscopy after full paralysis of the ciliary muscle (Compound Tolpicamide; Shenyang Xingqi Ophthalmic Pharmaceutical Co. Ltd, Shenyang, China), and the prescription was determined for them by subjective optometry after the accommodative function and pupil were restored.The SVS group and the SVS-LLRL group were both fitted with single-vision spectacle following subjective optometry without any special treatment, and were instructed to wear the lenses throughout the day. Meanwhile, the OK lenses group and the OK-LLRL group were fitted with custom lenses (CRT; Paragon Vision Sciences Inc., U.S.) based on the subjects' examination results, trial wear evaluation, fluorescein sodium staining, and observation of the configuration using a slit lamp microscope. These lenses are designed with high permeability, and high oxygen and safety factors. The lenses were worn for less than 10 hours at night. Regular assessments were conducted to assess the lenses' fit.
LLRL intervention
SVS-LLRL and OK-LLRL groups received low-level red light supplementation based on optical correction, utilizing 650mm red light (A head mounted device) for 3 minutes, twice daily, with at least a 4-hour interval between each session. This kind of light source is safe for the eyes and has been certified by the State Administration for Market Regulation of China. This device connects to the internet and uploads treatment parameters, including the date, time, and level of participation, to the background automatically. If the frequency of use is less than eleven times per week, or if uncooperative behaviors such as closing the eyes occur for an extended period during usage, the monitoring staff will send a text message reminder to the subject's guardian to improve cooperation and compliance. The instrument's utilization rate is automatically recorded by the system, and if it falls below 80%, it will be excluded from the study.
Observation Outcomes
The initial refraction, AL, and AL after three months of treatment were collected, and the difference in the amount of change in AL at three months was compared between the groups. The refraction was expressed as cycloplegic SER, that calculated as sphere + 1/2 cylinder, and the AL was measured in both eyes of the study subjects using the IOL Master optical biometer (IOLMaster-500; Carl Zeiss AG, Germany), and the mean value was taken for five measurements. AL changes of less than 0.1 mm were considered effective in controlling myopic progression, and the myopia control effective rate was calculated for the four groups[12].
Statistical analysis
SPSS 26.0 statistical software was utilized for analyzing data. Normally distributed data were presented as mean values ± standard deviation, and non-normally distributed data were presented as median values and interquartile ranges. The study utilized the χ2 test to analyze qualitative data and the Wilcoxon signed rank test for within-group comparisons of quantitative data. The Kruskal-Wallis test was employed for between-group comparisons, with multiple comparisons between groups conducted using the Bonferroni-corrected normal approximation to determine significant differences between the two groups. Results were considered statistically significant at p < 0.05.