Methodological design of the eye health module in the 2025 Continuous National Health and Nutrition Survey

The objective of this article is to describe the methodological design, instruments, and scope of the eye health module of the 2025 Continuous National Health and Nutrition Survey (Ensanut). The 2025 Continuous Ensanut will include an eye health module, with questionnaires for different age groups covering contact with eye health services, use of glasses, history of diagnosis, treatment, and institution providing care for cataract, diabetic retinopathy, glaucoma, macular degeneration, and dry eye. Distance and near visual acuity will be assessed, with and without correction, using standardized digital optotypes, in addition to assessing corneal transparency, media opacity, and fundus reflex and taking fundus photographs. The module will provide evidence on prevalence, care cascades, and access barriers in Mexico, revealing gaps in access, diagnosis, and treatment in eye health, generating key information for public policy and health equity.