Refractive errors are the leading cause of visual impairment and blindness, affecting more than 123.7 million individuals worldwide (1). Myopia, also known as nearsightedness, is a refractive error characterized by the inability of the eye to focus on distant objects clearly, resulting in blurred distance vision, whereas near vision remains unaffected. This is typically caused by excessive elongation of the axial length of the eye, which prevents light from being focused directly on the retina (2). Myopia is a major contributor to distance vision impairment across all age groups, particularly in children and young adults (3). However, its impact extends beyond mere visual impairment, affecting the educational, occupational, social, and psychological wellbeing of individuals. Studies have highlighted the associations between myopia and poorer academic or work performance, reduced social interaction, and a decline in the overall quality of life (4, 5).

Both genetic predisposition and environmental exposure substantially contribute to the onset and progression of myopia (6, 7). Among the environmental determinants, increased time spent indoors, prolonged engagement in near-vision tasks, and extensive use of electronic devices are recognized as leading risk factors (7). Furthermore, some studies have associated astigmatism, a refractive condition characterized by rays of light focusing on two orthogonal focal lines rather than a single focal point, resulting in blurred vision, as a potential factor contributing to the development of myopia (8–11). According to animal studies, uncorrected astigmatism blur may disrupt the normal emmetropization process, leading to excessive axial growth, thereby influencing the onset and progression of myopia (12–14).

In a meta-analysis by Hashemi et al. (15), myopia was estimated to affect 11.7% of children and 26.5% of the global adult population. With its prevalence increasing rapidly, particularly among younger age groups, myopia has become a significant global health concern (16). This is particularly evident in East and Southeast Asian countries, where the prevalence rates among younger populations exceed 80% (17–23). The growing burden of myopia is accompanied by a rise in high myopia, a higher degree form defined by a spherical equivalent refraction (SER) of less than −6.00 diopters (D) or an axial length greater than 26 mm, which significantly elevates the risk of developing sight-threatening ocular complications, such as cataracts, glaucoma, retinal detachment, and myopic macular degeneration, potentially leading to irreversible vision loss and blindness (24, 25). If current trends continue, by 2050, myopia and high myopia will affect approximately 4,800 million and 938 million individuals worldwide, respectively (26).

At present, several scattered studies have investigated the prevalence of refractive errors in Mexico, reporting myopia rates ranging from 4.6 to 45.21%, depending on the population and geographical region studied (27–35). Nonetheless, most of these studies were conducted prior to the COVID-19 pandemic, focused predominantly on school-based populations, and were limited to local or regional settings, reducing their applicability in understanding the broader national context. Moreover, data on the prevalence of high myopia in Mexico are scarce. Existing reports are based on localized findings, making it difficult to assess the broader magnitude and public health impact of high myopia at the national level (30, 31, 34, 35). Consequently, large-scale epidemiological investigations are needed to address the knowledge gaps regarding myopia prevalence and severity on a national scale.

In this regard, Salud Digna, a private, not-for-profit, and non-governmental primary healthcare institution with a nationwide presence in Mexico, offers a wide array of diagnostic services at the primary care level, including comprehensive optometry care for the general population. Its extensive network of clinics across the country improves access to eye care services and enables the collection of valuable eye health data, helping fill knowledge gaps and support public health initiatives to reduce visual impairment nationwide. Therefore, we conducted a large-scale, multicenter study aimed at estimating the prevalence and distribution of low myopia and high myopia in a nationally representative cohort of Mexican outpatients. The findings of this study represent a comprehensive and up-to-date resource for myopia epidemiology in Mexico, providing a theoretical basis for further research and direction for the development of myopia interventions to reduce the national burden of this condition.

This large-scale, nationwide, retrospective study provides one of the most comprehensive and current data on the prevalence, severity, and geographic distribution of myopia in the Mexican population, with specific attention to variations by age and sex. Based on data from over 3.50 million outpatients aged 6–100 years, our analyses provide five key observations: 1) the overall crude prevalence of myopia was 38.13%, with 37.13% classified as having low myopia and 1.00% as having high myopia; 2) children, adolescents, and young adults represented the most affected age strata; 3) low myopia predominated among males, whereas females exhibited a relatively higher prevalence of high myopia; 4) while myopia was prevalent across all states of Mexico, both forms of myopia were most concentrated in states within the Central region, specifically in Mexico City, State of Mexico, Puebla, and Tlaxcala; and 5) astigmatism significantly increased the risk of both low and high myopia in a severity-dependent manner.

These findings represent a significant update to the epidemiological understanding of myopia in Mexico, expanding the scope and relevance of previous studies, most of which are limited by demographic constraints and nearly all of which predate the COVID-19 pandemic (27–35). It is noteworthy that this study was framed within the post-COVID period to situate our results in the current epidemiological context. However, it was not designed to assess the changes attributable to the pandemic. Direct comparisons between pre- and post-pandemic myopia patterns were not feasible because of the absence of pre-pandemic baseline or longitudinal data in our dataset. Consequently, causal or temporal inferences regarding the pandemic-related changes in myopia cannot be made. Future longitudinal and population-based studies specifically designed to compare pre- and post-pandemic data are needed to quantify the long-term impact of the COVID-19 pandemic on myopia prevalence and severity in the Mexican population. Nevertheless, our findings provide valuable insights for informing both national eye health strategies and global efforts to control the growing myopia burden.

The variation in myopia prevalence across global regions is well-established, with East and Southeast Asian populations consistently reporting the highest myopia rates, often exceeding 80% among younger populations (15, 20, 39, 40). Although the available data from the Americas has indicated lower prevalence, recent projections suggest a steady increase through the region. According to Holden et al., the projected myopia prevalence for 2030 is estimated to be 48.5% in North America, 41.6% in Central Latin America, 40.7% in Southern America, and 35.9% in Tropical Latin America (26).

We estimated an overall age-standardized rate for total myopia of 44.44% (95% CI, 44.36–44.52%), placing Mexico within these projected trajectories, particularly aligning with trends observed in Central and North America. This estimation is also significantly higher than the 15.9% pooled rate reported in the most recent systematic review and meta-analysis of myopia in the Americas, which considered studies with varying age groups, methodologies, and prevalence rates (1.2–48%) (41). However, the representativeness of this pooled prevalence may be limited, as it only included data from the U.S. and Brazilian populations.

When subclassified by severity, we estimated age-standardized prevalence rates of 43.31% (95% CI, 43.24–43.39%) and 1.12% (95% CI, 1.11–1.14%) for low and high myopia, respectively. Although these estimates are lower than those reported in East and Southeast Asian countries, they still represent a significant public health burden, considering that two of five individuals face the potential risk of progressing to high myopia and its associated sight-threatening complications (42). This risk is particularly concerning among individuals aged ≤ 10, 11–20, 21–30, and 31–40 years, where the highest crude prevalences of total, low, and high myopia were consistently observed.

Several epidemiological studies have investigated the prevalence of refractive errors in the Mexican population, revealing considerable variability in reported myopia rates, ranging from 4.6 to 45.21%, depending on the region and the study population (27–35). However, it is important to highlight that most existing reports have focused predominantly on school-based populations, and nearly all were conducted at the local or regional level, thereby limiting their generalizability to the broader Mexican population. Only three studies have included broader age ranges beyond school-aged children, offering more inclusive, but still limited, perspectives on the national prevalence of this refractive condition (28, 31, 32).

Compared with these earlier reports, our overall estimate exceeded the previously reported rate by Gomez-Salazar et al., who found a myopia prevalence of 24.8% among outpatients aged 6–90 years old from 14 states across Mexico (28). Similarly, Barba-Gallardo et al. reported significantly lower rates: 7.1% in individuals under 18 years of age and 8.6% in adults over 18 years of age, based on data from Aguascalientes (32). In contrast, our estimate was slightly lower than that reported by Milán-Castilo et al. (31), who reported a prevalence of 45.21% in adults aged 21–89 years residing in Mexico City.

While the higher prevalence reported in our study may reflect recent increases in myopia rates compared to early findings, several factors should be considered. Demographic differences, including age distribution, sex, urban vs. rural residence, and geographic region, play significant roles. Moreover, methodological inconsistencies across studies, such as variations in sampling strategies, sample sizes, and types of ocular examinations performed, may also contribute to the discrepancies in the findings (43). For example, we reported age-adjusted prevalence estimates to reduce age-related biases, whereas previous studies did not apply age-standardization techniques. This lack of standardization can lead to potential biases because of differences in the age composition of the assessed population groups, making direct comparisons inappropriate and warranting cautious interpretation of the results.

In relation to age-specific prevalence, we observed a higher crude myopia prevalence of 38.6, 63.5, 66.4, and 55.65% among individuals aged ≤ 10, 11–20, 21–30, and 31–40 years, respectively. These prevalence rates exceed those reported by Gomez-Salazar et al. and Barba-Gallardo et al. within similar age strata (28, 32). However, all studies consistently showed that children, adolescents, and young adults were the groups most affected by myopia. This age-related burden can partly be attributed to environmental and behavioral factors, such as increased near work and reduced time spent outdoors due to schooling in children and adolescents, and occupational demands during the productive years of young adults (7, 44). Hence, to prevent academic performance declines among students and productivity losses among working-age individuals, it is essential to strengthen public health policies focused on prevention, education, and expanded access to vision care services across the country.

In a global context, the projected prevalence of high myopia by 2030 is estimated to be 6.1% (26). While the prevalence of high myopia remains low in European populations (0.8%) (45), other countries show much higher rates of high myopia. For example, in the United States (46), high myopia prevalence has reached approximately 8.3%, and in China, it ranges from 9.5 to 18.2% (40, 47). Data on the epidemiology of high myopia in Mexico are severely limited, and existing studies indicate a low prevalence.

We estimated an overall age-adjusted prevalence of high myopia at 1.12% (95% CI, 1.11–1.14%), offering one of the first large-scale national benchmarks for this vision-threatening condition. This estimate is significantly lower than the 5.79% reported by Milán-Castillo et al. (31). This difference was more evident when analyzed by age groups, since our prevalence estimates for individuals over 40 years ranged from 0.72 to 0.36%, decreasing in a linear manner. On the contrary, the prevalence of high myopia increased with age up to the fourth decade of life, with rates of 0.64, 1.49, 1.75, and 1.5% among individuals aged ≤ 10, 11–20, 21–30, and 31–40 years, respectively. These patterns were consistent with earlier findings of Teran et al. (30, 34, 35), who observed age-specific prevalence rates of 1.24% for elementary school children, 0.4% for middle school students, and 2.36% for high school students from Sinaloa.

Although our findings suggest that high myopia remains relatively uncommon in Mexico at the national level, the steady increase in prevalence from childhood to early adulthood highlights the need for close monitoring of myopia progression, especially in younger populations. Given the known risk of vision-threatening complications associated with high myopia, including cataracts, peripheral retinal degeneration and retinal detachment, myopic maculopathy, and open-angle glaucoma, even a modest prevalence at the population level may have significant public health implications over time (25). This underscores the importance of integrating high myopia surveillance into national vision screening programs and considering early intervention strategies to reduce disease progression in at-risk individuals with high myopia.

Most literature from other countries or regions suggests that myopia prevalence is higher among females (17–19, 30, 32, 33, 35, 46, 48–52). We found sex-specific differences in the prevalence of total myopia. Overall, males had a significantly higher rate of myopia (45.58%; 95% CI, 45.45–45.71%) compared to females (43.79%; 95% CI, 43.69–43.89%), a finding that aligns with previous studies conducted among Mexican schoolchildren and the general population (28, 34). However, adjusted multinomial logistic regression analysis indicated that males had lower risk of both low and high myopia.

While the sex-related pattern in the prevalence of low myopia was generally similar to that of total myopia, a subtle downward trend in prevalence among females emerged from the early 30s onward. Recently, it was observed that myopia progression tends to be faster among female individuals (53). In our study, females exhibited a relatively higher prevalence of high myopia than male regardless of age strata, a pattern consistent with earlier research (54).

These sex-specific differences may reflect underlying biological and hormonal factors, such as higher levels of sex hormones, specifically follicle stimulating hormone and luteinizing hormone, which could influence myopia onset and progression in females (55). Additionally, extracellular matrix remodeling and collagen fiber synthesis in highly myopic corneas are more active among females, suggesting a greater susceptibility to myopia progression and severity (56). Behavioral and environmental factors also play a role, as females may spend more time on near work activities such as reading, writing, and using electronic devices, while spending less time outdoors, increasing their risk of myopia development (7, 44). However, these factors could not be directly evaluated in the present analysis because of the dependance on routinely collected clinical data. This highlights the importance of adapting myopia management strategies accounting for sex-specific biological, behavioral, environmental, and lifestyle factors into a comprehensive framework to enhance the effectiveness of current interventions.

Regarding geographic distribution, our results showed that both low and high myopia are widespread nationally. However, there was a notable concentration in the Central region, specifically in Mexico City, State of Mexico, Puebla, and Tlaxcala, where age-standardized prevalence estimates for low myopia were the highest: 52.38% (95% CI, 52.12–52.64%), 51.35% (95% CI, 51.14–51.56%), 51.05% (95% CI, 50.64–51.47%), and 49.16% (95% CI, 47.66–50.7%), respectively. In the case of high myopia, the highest prevalence was similarly concentrated in Tlaxcala (2.73%; 95% CI, 2.39–3.12%), State of Mexico (1.77%; 95% CI, 1.73–1.81%), Mexico City (1.74%; 95% CI, 1.69–1.78%), and Puebla (1.55%; 95% CI, 1.48–1.62%).

These prevalence estimates are significantly higher than those previously reported by Gomez-Salazar et al. (28), who reported overall myopia prevalence of 36% in Mexico City, 35.6% in Puebla, and 31% in the State of Mexico. Such differences may suggest a potential increase in the burden of myopia over time in these densely populated areas, likely influenced by urban-related risk factors, such as reduced time spent outdoors, increased exposure to near work, and lifestyle changes associated with urbanization. Likewise, improved access to diagnostic services in these states may partially explain the higher detection rates; however, this does not entirely account for the magnitude of the observed differences.

Furthermore, the results above were further supported by multinomial logistic regression analysis, which indicated that these states were significantly associated with an increased risk of developing both forms of myopia after confounding adjustment. Individuals from Mexico City and Puebla had 8 and 9% higher risks, respectively, of developing low myopia compared to those in the State of Mexico, which had the highest overall prevalence, whereas the risk for high myopia was 10% higher in Mexico City and markedly 50% higher in Tlaxcala. However, because information enabling stratification by urban–rural setting and socioeconomic status was not systematically collected, the assessment of potential geographic and social disparities was limited in this study. Despite this limitation, these findings highlight the importance of strengthening regional strategies into urban populations and particularly, the elevated risk observed in Tlaxcala for high myopia warrants targeted investigations into possible contributing factors, including genetic predisposition, environmental exposures, socioeconomic conditions, and disparities in healthcare access.

Analogously, our findings also highlight the strong and severity-dependent association between astigmatism and both forms of myopia. To our knowledge, this is the first study to describe the interrelationship between these variables in a Mexican cohort. Multinomial logistic regression indicated that the presence of astigmatism significantly increased the risk of developing both low and high myopia, with the risk rising according to astigmatism severity. Individuals with mild, moderate, and severe astigmatism had a 3-, 8-, and 11-fold increased risk of developing low myopia, respectively, relative to those without astigmatism, whereas the risk for high myopia considerably increased by 5-, 33-, and 100-fold, respectively.

These findings suggest that astigmatism may not only coexist with myopia but may also contribute to its onset or progression, particularly in more severe cases. A recent longitudinal study by Liang et al. explored the influence of astigmatism and its axis orientation on axial elongation in Chinese schoolchildren. The study found that high-magnitude astigmatism, particularly with against-the-rule (ATR) or oblique orientation, exerted the fastest rates of axial length growth in both myopic compound and emmetropic eyes, possibly caused by horizontally or diagonally oriented hyperopic retinal defocus, which may serve as a visual signal that triggers ocular growth and contributes to myopia development (57).

This underscores the critical role of astigmatism in influencing ocular growth and impairing normal refractive development towards myopia. Early detection, timely correction, and close monitoring of moderate to high astigmatism, particularly ATR and oblique orientations, may help identify children at greater risk and diminish myopia progression, allowing for more proactive management. Furthermore, longitudinal prospective research in the Mexican population is needed to confirm these associations and explore the underlying mechanisms using ocular biometric data, such as axial length, corneal curvature, and anterior segment parameters. Understanding whether these biomechanical interactions are consistent across different demographic and environmental contexts in the country will be key to developing enhanced population-specific interventions.

Our study has several strengths. First, the large sample size of over 3.50 million individuals aged 6–100 years across all Mexican states provided robust statistical power and nationwide representation, which allowed us to perform in-depth age- and sex-specific prevalence estimations of myopia and high myopia in Mexico. Second, the use of age-standardized prevalence rates accounted for potential biases related to the population’s age structure, strengthens the validity of the findings. Third, by analyzing data from 2023, this study represents a significant update to the epidemiological understanding of myopia in Mexico, generating the most recent and valuable resource within a post-pandemic context.

However, several limitations should be acknowledged. First, the use of non-cycloplegic refraction data may have overestimated the prevalence of myopia, particularly in younger individuals owing to active accommodative effects. Because of the nationwide multicenter setting, it is difficult to apply cycloplegic refraction in each captured individual and therefore our findings should be interpreted with caution, particularly when comparing prevalence estimates with studies employing cycloplegic protocols. However, given the large sample size, the trend of increased prevalence in younger age strata remains a valuable indicator of the underlying epidemiological patterns.

Second, the retrospective and cross-sectional design cannot establish causal relationships between the prevalence of low and high myopia and sex-specific differences, as well as the observed association between astigmatism severity and both forms of myopia. Therefore, further longitudinal prospective studies are needed, especially those incorporating ocular biometric data, to determine the temporal and mechanistic relationships between astigmatism and myopia development and progression.

Third, the exclusive use of electronic clinic-based data introduces potential selection bias, limiting the generalizability of the findings to a broader population sample. Finally, data on key behavioral and environmental factors, such as socioeconomic status, educational attainment, city-level urban–rural classification, outdoor exposure, and screen time, were not available in routine clinical documentation. The absence of these variables prevented a more detailed assessment of the lifestyle and environmental determinants of myopia, highlighting the need for future studies incorporating these measures.

Despite these limitations, this study underscores the growing burden of myopia in Mexico, establishes the first national epidemiological precedent of high myopia, and provides valuable insights to inform public health planning and lays the foundation for future clinical and epidemiological research in the field of visual care.

This retrospective cross-sectional study found a moderate overall prevalence of total myopia among the Mexican outpatient cohort, with children, adolescents, and young adults being the most affected groups by both low and high myopia. Regardless of age strata, low myopia was more prevalent among males, whereas females exhibited a relatively higher prevalence of high myopia. Astigmatism was a risk factor for myopia, and increasing severity grades increased the risk of developing and progressing of both low and high myopia. Although our findings suggest that high myopia remains relatively uncommon in Mexico at the national level, the steady increase in its prevalence from childhood to early adulthood highlights the need for close monitoring of myopia progression, especially in younger populations.

A coordinated action from the public and private healthcare sectors is needed to strengthen the early detection and longitudinal surveillance of myopia progression, as well as to promote timely therapeutic engagement nationwide. Expanding the accessibility and affordability of proven optical interventions for myopia management, such as peripheral defocus-based lenses or diffusion optics technology eyeglasses, will be essential to curb progression and reduce future visual impairment in at-risk populations, namely, children and adolescents.