The records of roughly 500,000 patients of an eye clinic with locations throughout Iowa may have been stolen as part of a ransomware attack on the business earlier this year.

Wolfe Eye Clinic said Tuesday (6/22) its computer network was attacked on Feb. 8 by hackers who demanded a ransom to unlock access to its systems, but the company didn’t pay the hackers. The company plans to notify affected patients that their information may have been stolen and offer them a year of credit monitoring and identity theft protection services.

Wolfe Eye Clinic’s Chief Financial Officer Luke Bland said a team of specialists was hired to investigate after the hacking, and that revealed last month that patient records may have been compromised.

“Unfortunately, these types of cyber incidents have become all-too-common for health care providers of all sizes nationwide,” Bland said.

The company has set up a website and call center to respond to the hacking. Affected patients can call 1-833-909-3906 to get more information.

Wolfe Eye Clinic is based in Marshalltown, Iowa and it has locations in 40 cities across the state.