Relevant Links

Lens Calculations:

https://www.physicsclassroom.com/class/refrn/Lesson-5/The-Mathematics-of-Lenses

Iris Center Corneal Reflection Method:

https://ieeexplore.ieee.org/document/5601753

https://www.ncbi.nlm.nih.gov/pubmed/20952326

Tobii Eye Tracking method:

https://www.tobiipro.com/learn-and-support/learn/eye-tracking-essentials/how-do-tobii-eye-trackers-work/

Google AIY Vision Kit:

https://aiyprojects.withgoogle.com/vision/#meet-your-kit