As an alternative to Kinect One (which requires Windows 8) the PS4 eye camera has some interesting features/functions although it is lower res and does not have an Infra Red (IR) blaster..
And can cost $85 AUD or cheaper online or via JB hifi…

How does it compare to Microsoft’s Kinect One camera?
Review in 2013:http://au.ign.com/blogs/finalverdict/2013/11/02/xbox-one-vs-playstation-4-kinect-20-vs-playstation-4-camera
Review in 2014: http://www.techradar.com/au/news/gaming/consoles/ps4-vs-xbox-720-which-is-better-1127315/5#articleContent
A not so positive review: http://www.techradar.com/au/reviews/gaming/gaming-accessories/playstation-4-camera-1202008/review

One possible future use for PS4 eye camera, the VR Project Morpheus: http://www.techradar.com/au/reviews/gaming/project-morpheus-1235379/review

http://www.psdevwiki.com/ps4/PlayStation_4_Camera

Available functions

• photo, video
• voice commands (available as well with an earset with microphone)
• depth calculation/imaging
• pad, move, face, head and hand recognition/tracking
• one of the cameras can be used for generating the video image, with the other used for motion tracking.

http://www.psdevwiki.com/ps4/Talk:PlayStation_4_Camera

Features (Could be used for eye tracking..)

• automatic black level calibration (ABLC) support 2×2 binning
• programmable controls for frame rate, mirror and flip, standard serial SCCB interface cropping and windowing
• image quality controls: lens correction and defective pixel canceling two-lane MIPI/LVDS serial output interface
• embedded 256 bits one-time programmable (OTP)
• memory for part identification, etc.
• supports output formats: 8/10/12-bit RAW RGB on-chip phase lock loop (PLL)(MIPI/LVDS)
• supports horizontal and vertical sub-sampling programmable I/O drive capability
• supports images sizes: 1280×800, 640×400, and 320×200
• built-in 1.5V regulator for core
• support alternate frame HDR / line HDR
• fast mode switching

What can you do with it?
http://ps4eye.tumblr.com/
“Bigboss (@psxdev) has successfully streamed video data from the PS4 camera to OS X!”
Picture at https://twitter.com/psxdev/status/439787015606136833

Drivers for PS4
http://bigboss-eyetoy.blogspot.co.uk/2014/09/ps4eyecam-released.html
Links to https://github.com/bigboss-ps3dev/PS4EYECam/
“It is the first public driver for PlayStation 4 Camera licensed under gpl.”

Historical
PS3Eye for Mac: http://webcam-osx.sourceforge.net/