The eyes are the keys

I I am learning very exciting stuff about the psychosomatic link between the eyes and one's moods. Apparently the eye muscles that surround the eyes called orbicularis oculi impact happiness centers in your brain. ( Refer The Science of Happiness by Stefan Klein ).
That made me curious about trataka. .the fifth stage of yoga.
Here are some powers that according Swami Niranjanananda come from regular practice of the eye exercises.
*  One could get rid of all fears.
* The special powers of yoga called siddhis are achieved through it.
* Develops mental focus.
* Improve memory
* Develops self confidence