Although US federal law entitles children enrolled in Medicaid to vision services, adults depend on rules set at the state level. That can lead to major disparities in service coverage, a state-by-state analysis in Health Affairs found.

The researchers analyzed data from each state's fee-for-service and managed care coverage of routine vision services for adults. Based on policies in place from 2022 to 2023, 12% of adult Medicaid enrollees, or 6.5 million people, lived in states that didn't cover routine eye examinations. About 27%, or approximately 15 million, lived in states without eyeglass coverage. In addition, nearly two-thirds of the states that did provide routine eye care required some kind of cost-sharing by enrollees.

Expanding access to routine eye examinations can increase the diagnosis and treatment of refractive errors, the leading cause of vision impairment, the researchers noted. Without insurance, an eye examination and glasses cost around $485. That's more than a third of the monthly income of a single adult at or below the federal poverty level, according to a press release from the National Institutes of Health, which sponsored the study.