IMI—Management and Investigation of High Myopia in Infants and Young Children

**Background:** High myopia (≤−6 diopters [D]) in infants and young children is a rare condition with a prevalence less than 1% in pre-school children. Unlike typical myopia that develops after age 5–6 years, early-onset high myopia often has a secondary cause, such as prematurity or monogenic/syndromic disorders. The clinical priority is to identify underlying medical diagnoses that may have greater overall health implications, including connective tissue disorders (e.g., Stickler syndrome, Marfan syndrome), inherited retinal dystrophies, and metabolic diseases. Optical correction is critical to prevent amblyopia and support normal visual development, but it can be challenging due to behavioral issues, anisometropia, or craniofacial abnormalities. Myopia control interventions lack evidence in this population and must be considered on a case-by-case basis.

**Methods:** This is a narrative review and expert consensus report from the International Myopia Institute (IMI). The authors synthesized epidemiological data, clinical guidelines, and published studies on the etiology, assessment, and management of high myopia in children under 10 years of age. Key sources included population surveys (e.g., from China, Singapore, US, UK), clinical trials (e.g., ETROP), and genetic studies. The paper provides structured recommendations for clinical evaluation, including history-taking, ocular examination, biometry, imaging, electrophysiology, and genetic testing. It also reviews optical and surgical correction options and myopia progression management.

**Key Results:** - **Prevalence:** High myopia is rare in young children: 0.03–0.2% before age 7 in China, 0.2% in Singapore under 6 years, and 0.6% at ages 5–7 in a US insurer report. Prevalence rises rapidly after age 10, especially in Asia (e.g., 15.1% in 16–18-year-olds in China). - **Etiology:** In hospital-based studies, 54% of highly myopic children under 10 years had prematurity, neurodevelopmental delay, or systemic disorders (e.g., Marfan, Stickler, Noonan, Down syndromes). 38% had associated ocular pathology. In a UK community study, 44% of children under 10 with myopia worse than −5.0 D had ocular (25%) or undiagnosed systemic conditions (18%). - **Myopia of Prematurity (MOP):** Premature infants, especially with retinopathy of prematurity (ROP), have high myopia rates. In the ETROP trial, 38% of treated high-risk pre-threshold ROP eyes were highly myopic (<−5.0 D) by age 4, vs. 19% with regressed ROP. MOP is non-axial, with mean refraction −12.4 D and axial length 23.36 mm, compared to full-term high myopes (−11.7 D, axial length 27.02 mm). Bevacizumab treatment results in less myopia (mean −0.98 D at 2 years) than laser or vitrectomy. - **Monogenic Forms:** Whole exome sequencing found causal mutations in 20% of high myopia cases, rising to 35% in those with syndromic features. Common syndromic forms include Stickler syndrome (incidence 1:7500–1:9000) and Marfan syndrome (1:5000–1:10000). Retinal dystrophies (e.g., RPGR, RPE65 mutations) and metabolic disorders (e.g., homocystinuria) also present with high myopia. - **Clinical Evaluation:** Recommended assessments include cycloplegic refraction, biometry (axial length, keratometry), fundoscopy, color vision testing (including tritan deficits), and screening for extraocular features (e.g., Beighton score for joint hypermobility). Genetic testing is indicated when syndromic features are present. - **Optical Correction:** Full correction is recommended for high myopia in young children to optimize visual development. For anisomyopia, contact lenses are preferred. Surgical options (e.g., PRK, LASEK, phakic IOLs) are used off-label in children with intolerance to spectacles/contact lenses, with reported mean visual acuity improvements of 1.6 lines. - **Myopia Progression:** Progression rates in syndromic myopia are often low (e.g., −0.32 D/year in preschool high myopes vs. −0.85 D/year in lower myopes). Axial elongation should be confirmed before initiating myopia control. Atropine use in infants with ROP is cautioned due to potential anterior segment effects. - **Complications:** Parapapillary diffuse choroidal atrophy in childhood may predict future myopic maculopathy. Posterior staphyloma was found in 12.7% of highly myopic children aged 6–19 years. Retinal detachment risk is elevated in syndromic myopia (e.g., Stickler syndrome), even in non-myopic eyes.

**Clinical Implications:** The primary goal in managing high myopia in infants and young children is to identify underlying systemic or ocular conditions that may have greater health consequences. A targeted history and examination can be performed in any clinical setting. Biometric evaluation is essential to distinguish axial from refractive myopia. Multidisciplinary care involving pediatricians, clinical geneticists, and inherited disease specialists is often warranted. Optical correction should be full to prevent amblyopia, with contact lenses or surgery considered in challenging cases. Myopia control interventions should only be used after confirming axial progression and considering potential adverse interactions with syndromic features. Due to the rarity and heterogeneity of early-onset high myopia, disease registries and pooled outcome data are needed to develop evidence-based management strategies.