You can test your webcam online or using programs that come with Windows 10 or your Mac. You don't have to wait for a video call to find out there's a problem with your webcam — test it ahead of time.

Flash photography can sometimes show a ‘white glow’ in the eyes, which may indicate the presence of a condition, such as eye cancer or cataracts. Retinoblastoma is an eye cancer that begins in the ...