Physical Activity in Functionally Monocular Persons in the United States, 2003–2006

PURPOSE: Real-world physical activity patterns in monocular persons have not been previously characterized. This study uses a nationally representative sample to compare the physical activity levels of functionally monocular to binocularly sighted persons in the United States. METHODS: This cross-sectional study uses data from the 2003–2004 and 2005–2006 National Health and Nutrition Examination Survey (NHANES) to compare differences in physical activity between functionally monocular and binocular participants. The main outcome measures were accelerometer-measured mean steps per day and mean daily minutes of moderate or vigorous physical activity (MVPA). Statistical analysis was conducted using multivariable negative binomial regression models adjusted for age. RESULTS: In total, 7967 NHANES participants had complete visual acuity and accelerometer data. The mean age at baseline was 44.5 years, and a majority were Caucasian (73%) and female (51%). In models adjusted for age only, functionally monocular participants (n = 172) took fewer steps (9277 with 95% confidence interval [CI], 8800–9753 vs. 10,057 with 95% CI, 9832–10,281) and engaged in similar minutes of MVPA (26.75 with 95% CI, 22.0–31.5 vs. 26.70 with 95% CI, 25.6–27.7) per day compared to binocularly sighted participants (n = 7758). In our final model, functionally monocular participants took 16% fewer steps per day (P < 0.01) and engaged in 26% fewer minutes per day of MVPA (P = 0.01). Poorer visual acuity, older age, female gender, obesity, congestive heart failure, and arthritis were also associated with a statistically significant decrease in physical activity in both models. CONCLUSIONS: Functionally monocular persons have lower physical activity levels compared to those with binocular eyesight in the United States, even after adjusting for better-eye visual acuity. TRANSLATIONAL RELEVANCE: Our translational study provides insight into the epidemiology of physical activity and its impact on population health. We quantify real-world physical activity in two at-risk populations, monocular and blind individuals.