The prescription belongs in your hands

FTC guidance says prescribers must automatically provide the eyeglass prescription after a refractive exam and before offering to sell glasses. They cannot charge an extra prescription-release fee or condition the exam on buying eyewear.

Sources[1] FTC

Know what may still be missing

The FTC explains that only some states require pupillary distance on the prescription. Do not assume the federal rule guarantees every fitting measurement. Ask what information is included and whether a separate measurement service is needed.

Sources[2] FTC

Use the choice you have

Keep the prescription and compare written quotes for the same lens specification and services. If a US prescriber refuses to release it, retain the correspondence and use the FTC's complaint guidance. A cheaper quote still needs to meet your prescription and fitting requirements.

Sources[1] FTC