Early Intervention for Premyopic Children

With more popularity of screen-based digital devices in the post-pandemic era, childhood myopia prevention and control has encountered a tough challenge on a global scale. Though the protective effect of spending more time outdoors has been well proven, the optimal practice for preventing or delaying the early onset of childhood myopia still needs further investigations, particularly in pre-myopic children around the school entrance age. It has been reported that there is a double-digit increase in myopia prevalence before and after elementary school entry, and young children with early-onset myopia are at great risk of rapid progression to high myopia later in life. Most recently, nightly use of 0.05% atropine eye drops is effective in reducing the incidence of childhood myopia. However, photophobia is a common adverse effect of higher concentration atropine, which may hinder children from daytime outdoor activities. Besides, little is known about the optical approach for myopia prevention in the existing literature. These unmet demands in clinical practice motivate us to propose a randomized controlled trial on myopia prevention with optical (Defocus Incorporated Multiple Segments [DIMS] spectacle lenses) or pharmacological (0.01% atropine eye drops) modalities among pre-myopic preschoolers aged 5-6 years. To explore the adaptability and feasibility of DIMS spectacle lenses for pre-myopic children with normal visual acuity, we have conducted a pilot study and revealed that all 24 subjects can tolerate daily full-time wearing of DIMS spectacle lenses without significant visual complaints. In this proposal, we plan to recruit a total of 234 eligible participants who have been identified as pre-myopic and asymptomatic in a population-based eye care program in Yilan County. Eligible subjects will be randomly assigned to the DIMS spectacles (n=78), 0.01% atropine (n=78), and usual care (n=78) groups. Less environmental pressure is hypothesized in preschool compared with elementary school. Hence, pre-myopic children will be asked to wear DIMS spectacle lenses in a stepwise pattern: at-home wearing in the preschool stage and full-time in the elementary school stage. Cycloplegic spherical equivalent (SE) refraction and axial length will be measured every 3 months over the 18-month follow-up period. The primary outcome is the changes in mean cycloplegic SE over the study period in each group. The secondary outcomes include the cumulative percentage of incident myopia, the cumulative percentage of a fast myopic shift of SE, and the changes in mean axial length over the study period in each group. This proposed project may offer insight into the intervention strategy for myopia prevention and evoke the possibility of a reinvented eye care policy that may focus on early identification and intervention for pre-myopic preschoolers.

Inclusion criteria

• Age at enrollment: 5-6 years old (the senior grade of kindergarten)
• Cycloplegic SE of the eye with less SE (less positive or more negative refractive error): < +1.00 D and > -0.50 D
• Astigmatism: 1.0 D or less in both eyes
• Anisometropia: 1.50 D or less
• Monocular uncorrected visual acuity: 6/7.5 or better in both eyes
• Either of the parents with moderate myopia
• Acceptance of random group allocation
• Submission of complete informed consent.

Exclusion criteria

• Strabismus or any ocular motility disorder
• Any ophthalmic and systemic disorders that might affect visual functions or refractive development
• Previous treatment of atropine or other myopia control intervention