“…On average, counties with lower eye care provider availability per capita had fewer physicians per capita, lower population density, and a poorer, less urban, and older population than counties with greater eye care provider availability per capita. These characteristics may exacerbate or moderate the challenges for public health interventions in counties with limited eye care provider availability, although most of these characteristics increase the expected challenge (Gohdes et al, 2005;Layde et al, 2012;Prevent Blindness America and National Association of Chronic Disease Directors, 2005;Prevent Blindness America, 2004;Saadine et al, 2003;US Centers for Disease Control, 2009;Zhang et al, 2007). For example, older individuals are both more likely to need eye care services and to use eye care services (US Centers for Disease Control, 2009;Lee et al, 2009).…”