Different myopia control interventions have certain effects on ocular asthenopia in children and adolescents. As children and adolescents are in a critical period of visual development, the presence of asthenopia may lead to an earlier onset and increased prevalence of a range of chronic eye diseases and retinal disorders, thereby affecting their physical and mental health as well as future development. However, existing studies have mostly focused on single interventions, lacking a systematic comparison of the effects of multiple myopia control approaches on asthenopia. Therefore, the present study aims to investigate, through a cross-sectional survey, the impact of various myopia control interventions-including conventional spectacles, defocus-inducing spectacles, orthokeratology, low-concentration atropine, red-light therapy, and combined multi-intervention strategies-on asthenopia, to assess the prevalence and severity of asthenopia among users of different interventions, and to compare the differences in their effects on asthenopia. This will provide evidence-based support for the selection of individualised correction strategies in clinical practice and contribute to advancing clinical research on asthenopia in children and adolescents.

Myopia, as a global visual health issue, has seen a rising incidence in recent years, with a trend toward younger age of onset. It is projected that by 2050, nearly five billion people worldwide will be affected by myopia, of whom approximately one billion will be at risk of high myopia. Due to increasing academic demands, prolonged reading or use of electronic devices, and a marked lack of outdoor activity time, the prevalence of myopia among children and adolescents in China has been escalating. Children and adolescents are in a critical period of visual development; the presence and progression of myopia may lead to an earlier onset and increased prevalence of a range of chronic eye diseases and retinal disorders, seriously affecting their physical and mental health as well as future development.

In response to this major public health concern, professionals in the field of ophthalmology have focused on myopia control research and practice, establishing a comprehensive management system based on three major approaches: behavioural intervention, optical correction, and pharmacological therapy. Various myopia control interventions have been rapidly adopted in daily life, ranging from conventional spectacles to defocus-inducing spectacles with myopia control functions, orthokeratology (OK) lenses, and low-concentration atropine ophthalmic preparations. Conventional spectacles, as the most widely used refractive correction method, offer high safety and affordability but lack a significant myopia control effect. Defocus-inducing spectacles create a special non-focused optical zone in front of the retina, producing myopic defocus that signals the brain to slow axial elongation; they also affect choroidal thickness and choroidal blood flow, thereby controlling ocular growth and myopia progression. However, the visual system's adaptation to the defocus design can cause peripheral blurring. OK lenses are rigid gas-permeable contact lenses with reverse-geometry design that correct myopia and astigmatism; during the correction process, they alter corneal morphology and tear film stability, thereby affecting visual quality. 0.01% atropine sulfate eye drops are a commonly used ophthalmic medication that slows myopia progression and inhibits axial elongation, but they also suppress ciliary muscle accommodation, leading to reduced accommodative amplitude and blurred near vision. Repeated low-level red-light (RLRL) therapy is a non-pharmacological intervention based on photobiomodulation (PBM) and has demonstrated good efficacy in controlling axial elongation and refractive error progression.

In clinical practice, it has been observed that during myopia control, children and adolescents may experience symptoms of asthenopia such as blurred vision, eye soreness, tearing, and inability to sustain reading, and may even exhibit adherence issues such as refusing to wear spectacles or discontinuing atropine without instruction. Asthenopia is a syndrome of visual disturbances and ocular discomfort, with or without systemic symptoms, caused by various factors that overload the visual system beyond its functional capacity. Over the past decade, especially since the outbreak of the COVID-19 pandemic in 2019, online teaching and video conferencing have become routine, and modern reading habits, learning styles, and leisure activities have increasingly relied on video terminals. Consequently, asthenopia has shown a trend toward younger age, with the prevalence in children rising from 10%-20% before the pandemic to 50%-65%. International studies have reported that approximately 89.9% of Malaysian students and 80.3% of Indian students suffer from computer vision syndrome, a subtype of asthenopia. During the COVID-19 pandemic, a survey of 1,825 adolescents in Hunan, Guizhou, Anhui, Shanghai and other regions of China found that about 51.1% of junior and senior high school students had asthenopia, indicating a concerning situation. The mechanisms underlying asthenopia involve multi-system interactions: when improper correction or suppressed accommodative function leads to a mismatch between accommodative demand and convergence, or when tear film instability causes dry eye symptoms, and when degraded retinal image quality increases neural load, all can precipitate asthenopia.

The Chinese Expert Consensus on the Diagnosis and Treatment of Asthenopia (2024) clearly states that myopia control interventions can also trigger or exacerbate asthenopia. In children with myopia, accommodative function declines and asthenopia symptoms worsen after three months of using 0.01% low-concentration atropine eye drops. Compared with conventional spectacles, wearing defocus-incorporated multiple segments (DIMS) spectacles can reduce asthenopia during visual search tasks in adolescents and adults. Acupuncture cycle therapy combined with atropine eye drops can effectively alleviate asthenopia while controlling myopia progression in school-aged children. In summary, different myopia control interventions have certain effects on asthenopia in children and adolescents. However, existing studies have mostly focused on the impact of single interventions on myopia and asthenopia, with a lack of systematic comparisons among conventional spectacles, defocus-inducing spectacles, OK lenses, low-concentration atropine, and multi-intervention combinations regarding their effects on asthenopia. Based on the above findings, we plan to investigate the influence of these myopia control interventions on asthenopia, assess the prevalence and severity of asthenopia among users of different correction modalities, and compare the differences in their effects on asthenopia, so as to provide evidence-based support for individualised clinical decision-making.

Inclusion Criteria:

• ① Children and adolescents with myopia attending the Optometry Centre of Tianjin Medical University Eye Hospital;

  • Age range 6-18 years, grouped by chronological age at 12 and 13 years into a children's group (6-12 years) and an adolescent group (13-18 years), irrespective of sex; ③ Current use of one or a combination of the following interventions: a. conventional single-vision spectacle lenses; b. defocus-inducing spectacles (multifocal or peripheral defocus design); c. orthokeratology (OK) lenses; d. low-concentration atropine eye drops (0.01%); e. red-light therapy; f. no myopia control intervention; ④ Best-corrected visual acuity (BCVA) ≥ 0.8 on the standard logarithmic visual acuity chart; ⑤ Written informed consent obtained from guardians, and assent obtained from children aged 8 years and older.

Exclusion Criteria:

• ① Individuals residing in plateau or high-wind areas;

  • Individuals with a history of any ophthalmic surgery;

    • Individuals diagnosed with psychiatric disorders such as anxiety disorder, depressive disorder, bipolar disorder, or somatic symptom disorder by a psychiatrist, or those who have taken psychoactive medications (e.g., anxiolytics, antidepressants, sedative-hypnotics) within the past 3 months; ④ Individuals with ocular diseases or conditions including keratoconus, strabismus, conjunctivitis, amblyopia, high myopia, glaucoma, cataract, retinal nerve defects, or systemic diseases such as diabetes, hypertension, arthritis, osteoporosis, thyroid disease, chronic migraine, or chronic headache, or those taking medications known to potentially induce asthenopia; ⑤ Others: inability to cooperate with subjective questionnaire completion or objective examinations; or other conditions deemed unsuitable for inclusion by the investigators.

Children and adolescents with myopia attending the Optometry Centre of Tianjin Medical University Eye Hospital