Tokyo, April 24 (Jiji Press)–A U.S. unit of major Japanese optical equipment maker Hoya Corp. <7741> has been hit by a cyberattack, and confidential information may have been leaked, it was learned Saturday.

The affected subsidiary is Texas-based Hoya Vision Care USA, which makes eyeglass lens and other products. A Hoya official said that the company has asked experts to investigate details of the cyberattack.

A hacker group called “Astro Team” claimed responsibility, saying in an online post in mid-April that it stole about 300 gigabytes of financial and customer data, as well as email data.

A system glitch occurred after the cyberattack, but the affected system has now mostly been restored, the official said.