Authorities say a bug zapper that had the wrong kind of light bulb has caused vision problems for five people at a veterans medical facility in North Carolina. The News & Observer reports that Durham VA Health Care System said the bulb emitted light that was too strong and impacted the vision of three employees, a resident and a contractor who had a meeting near the device. System spokesperson Yves-Marie Daley says the vision of those affected is improving. She didn’t specify the date of the incident or the severity of the vision loss. The center opened an internal investigation.