A Walmart eye doctor may offer more affordable eye exams, but that doesn’t mean you’ll be shortchanged in the optometry department.

Optometrists, no matter where they work, are all doctors licensed to treat vision problems and diagnose eye conditions. The official name for an optometrist is doctor of optometry, or OD for short.

A Walmart optometrist is often — but not always — independent. An independent doctor of optometry works with Walmart, but not for Walmart, meaning they largely set their own prices, instead of Walmart setting a chain-wide rate.

In Walmart’s case, independent optometrists are always located on-site, either inside the vision center or in a small office outside of the store’s entrance or exit.