Panasonic have developed a biometric (retina scanner) Camera which doubles as a webcam.

"Camera includes Private IDâ„¢ Client Software for stand-alone PC protection software-PC Log-On, Folder & File locking, and more.

Multi-Function Dual Channel Camera -Authenticamâ„¢ can provide increased security measures. Using the Authenticam obviates the need for conventional passwords and will pay for itself by eliminating the need for password maintenance....."

Full details here for PC Model

And different model here Standalone Model