Upon activation the Rogen's wounds will slowly start healing. Also once eagle eye is activated Rogen can activate a Technique that only he can perform which is Riryoku which physically drains rogen's opponent. the Mandeku Shūgan is the second transformation of the eagle eye and upon activation rogen becomes able to see opponents chakra only. His healing rate increases dramatically and Riryoku's power increases.
One of the techniques that the eagle eye is capable of is Shūgan: Shattered Souls
The other technique that the eagle eye is capable of is Shūgan: Death from Four Sides