The FDA sent a warning letter to Japanese ophthalmic laser maker Nidek Co. after finding quality control violations during a May inspection of a plant in Aichi, Japan.

The federal watchdog agency issued a Form 483 to Nidek after the inspection, but the company did not respond within the required 15-day window, according to the warning letter. The letter flagged 6 violations found during the inspection held May 20-23.