Refractive Errors and Amblyopia in Mexican Children Aged 6–12 Years: Clinical Prevalence and Visual Impact

Background: Refractive errors (REs) and amblyopia are the leading causes of visual impairment (VI) in children worldwide; however, national data for Mexico are scarce. Objective: We aim to estimate the clinical prevalence of RE, refractive amblyopia, and associated visual impairment (VI) in Mexican children aged 6–12 years. Methods: We analyzed 784,372 non-cycloplegic eye examinations from Salud Digna outpatient clinics across all 32 Mexican states (2021–2025). REs were classified as myopia (≤−0.50 D), hyperopia (≥+2.00 D), or astigmatism (≤ −1.00 D cylinder). Refractive amblyopia was defined as best-corrected visual acuity ≤ 20/30 in the most affected eye. The VI categories followed the WHO criteria. Results: Myopia was the most frequent (43.86%), followed by astigmatism (38.41%) and hyperopia (1.29%). Refractive amblyopia affected 4.94% of the children, predominantly due to astigmatic isoametropia (72.19%). VI related to refractive amblyopia occurred in 1.20% (mild), 0.37% (moderate), 0.01% (severe), and 0.01% (blindness) of children. Men showed a higher prevalence of RE and refractive amblyopia (p < 0.01). Geographic disparities were evident, with the central and southern states reporting the highest RA rates. Conclusions: Our outpatient-based study underscores REs, refractive amblyopia, and astigmatic ametropia as significant public health concerns in Mexican school-aged children. The high prevalence of uncorrected REs and refractive amblyopia highlights the need for nationwide school-based screening programs and early intervention strategies to mitigate long-term visual and developmental consequences.