PurposeThis study sought to determine the prevalence of myopia in schoolchildren of a rural population in Mexico.MethodsA cross-sectional study was conducted in 317 children between 6 and 12 years old. A complete refractive examination was performed, including static retinoscopy without cycloplegic agents. All procedures were conducted according to the Declaration of Helsinki.ResultsIn total, 9.7% (95% CI: 13.07–6.52) of the examined children were myopic (spherical equivalent ≤ −0.50 D), 4.4% (95% CI: 6.66–2.14) presented astigmatism (cylinder ≤ −1.50 D), and 5.4% (95% CI: 7.89–2.91) presented hyperopia (spherical equivalent ≥ +0.50 D).ConclusionAdditional research is required to assess the prevalence of refractive errors in rural areas in Mexico, to analyze the associated risk factors, and to implement appropriate eye care plans for this population.

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We propose an alternative method to design diffractive lenses free of spherical aberration for monochromatic light. Our method allows us to design diffractive lenses with the diffraction structure recorded on the last surface; this surface can be flat or curved with rotation symmetry. The equations that we propose calculate the diffraction profiles for any substratum, for any f-number, and for any position of the object. We use the lens phase coefficients to compensate the spherical aberration. To calculate these coefficients, we use an analytic-numerical method. The calculations are exact, and the optimization process is not required.

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