Variation of Distance Visual Acuity and the Distribution of Monocular Visual Impairment in Examinees Aged 12 Years or Older

Abstract

Background: Distance visual acuity integrates optical image formation, retinal sampling and neural visual processing. Aggregate visual acuity frequencies allow transparent descriptive analysis, but not person-level or survey-representative inference.

Objective: To describe the distribution of presenting distance visual acuity in each eye among participants with recorded outcomes in the National Health and Nutrition Examination Survey (NHANES) 2005–2006 vision component.

Methods: We extracted the nine publicly reported response-frequency categories for right-eye (VIDRVA) and left-eye (VIDLVA) presenting visual acuity from the CDC codebook. The primary measure was the proportion of nonmissing eye observations with presenting acuity worse than 20/40. All estimates were unweighted, eye-specific and descriptive. No inferential comparisons or population estimates were attempted.

Results: The published vision file included 6,980 participant records. Presenting acuity was available for 6,486 right eyes and 6,478 left eyes. Acuity worse than 20/40 was recorded for 1,067/6,486 right eyes (16.45%) and 1,050/6,478 left eyes (16.21%). Acuity of 20/20 was recorded for 2,885 right eyes (44.48%) and 2,930 left eyes (45.23%).

Conclusions: The publicly reported frequencies document a substantial unweighted proportion of eyes with acuity below 20/40 among recorded examinations. These findings are not prevalence estimates for U.S. residents, do not identify binocular impairment or the mechanism of loss, and require individual-level survey-weighted validation before population-level claims.