More than 1,400 people in Somerset have been issued with penalty notices after falsely claiming an exemption from prescription charges.
NHS Somerset said it had been randomly checking prescriptions across the county during the past year as part of anti-fraud measures.
An NHS spokesman said the operation had recovered £22,712.
Those caught were ordered to pay the original cost (£7.40) plus a £37 penalty.
Anyone not paying within 28 days faced further charges.
The operation found 59% of ophthalmic patients wrongly claimed for sight tests and glasses, 21% falsely said they were exempt from NHS dental charges and 11% had claimed for medicine they were not entitled to receive without payment.