Given the high prevalence of myopia and its potential impact on vision, it is crucial to identify effective treatments that can slow down the progression of myopia in children.3 The present study investigated the effect of 0.01% atropine eye drops, orthokeratology, and their combination on the speed of axial length elongation and myopia progression in children with myopia. The study included 736 eyes of 736 myopic children, with a balanced distribution of gender, race, and baseline characteristics among the four groups (control, 0.01% atropine eye drops, orthokeratology, and combined 0.01% atropine eye drops and orthokeratology).
Our findings revealed that all three interventions (0.01% atropine eye drops, orthokeratology, and their combination) were effective in slowing down the speed of axial length elongation and myopia progression in children. The combined use of 0.01% atropine eye drops and orthokeratology showed the best control of axial length elongation and myopia progression. In comparison, 0.01% atropine eye drops alone worked better than orthokeratology alone in controlling both axial length elongation and myopia progression.
The effectiveness of atropine eye drops in slowing down myopia progression has been previously reported in several studies 6, 13, 14. Atropine works by inhibiting the muscarinic receptors in the eye, thereby reducing the accommodation and pupil constriction. This, in turn, reduces the axial length elongation and the progression of myopia. 15 Our findings support the effectiveness of 0.01% atropine eye drops in controlling myopia progression, with a reduction in the speed of axial length elongation by 0.20 ± 0.07 mm in one year.
Orthokeratology, on the other hand, involves the use of specially designed contact lenses to reshape the cornea temporarily. 16 The lenses are worn overnight, and the patient experiences clear vision during the day without the need for glasses or contact lenses. 17, 18 The effectiveness of orthokeratology in controlling myopia progression has been previously reported in several studies.18, 19 Our study also showed a significant reduction in the speed of axial length elongation in the orthokeratology group (0.23 ± 0.05 mm) compared to the control group.
The combination of 0.01% atropine eye drops with orthokeratology has been reported in only a few studies, with mixed results.20–22 Our study found that the combined treatment approach resulted in the slowest speed of axial length elongation (0.10 ± 0.04 mm), indicating its potential for effectively controlling myopia progression. The possible explanation for the enhanced efficacy of the combined treatment is that orthokeratology reduces peripheral hyperopic defocus, which is known to stimulate axial elongation and myopia progression, while atropine eye drops inhibit the muscarinic receptors in the eye, which is also implicated in myopia progression. 23 The combination of these two treatments may have a synergistic effect on controlling myopia progression, as both approaches target different aspects of the underlying mechanism of myopia.
Interestingly, our study also showed that 0.01% atropine eye drops alone were more effective than orthokeratology alone in controlling axial elongation and myopia progression. This finding is consistent with previous studies that have reported the efficacy of atropine eye drops in controlling myopia progression.24, 25 Atropine eye drops are thought to work by inhibiting the accommodative response and reducing the hyperopic defocus that drives axial elongation and myopia progression. However, atropine eye drops are associated with several side effects, including photophobia, blurred vision, and loss of near vision, which can limit their use in children. 6
It is noteworthy that the effectiveness of these treatments was consistent in both Chinese and Caucasian children. The findings of our study are consistent with previous studies that have reported a similar effect of atropine eye drops and orthokeratology in controlling myopia progression in both Asian and non-Asian populations. 20, 26, 27 This suggests that the underlying mechanism of myopia progression is similar across different ethnicities and that these treatments may be effective in controlling myopia progression in different populations.
The present study has some limitations that should be considered when interpreting the results. Firstly, the study was conducted over a one-year period, and longer-term follow-up is needed to assess the sustainability of the interventions' effects on axial length elongation and myopia progression. Secondly, the study did not investigate the mechanisms underlying the interventions' effects on axial length elongation and myopia progression, and future studies should explore these mechanisms. Thirdly, the study did not investigate the potential adverse effects of the interventions, and future studies should assess the safety of the interventions in children.