If one is in complete darkness, what is the minimum optical power that the eye can "see" (let's say in 500-600 nm range).

I found that for 510 nm, 90 photons can be detected (http://en.wikipedia.org/wiki/Absolute_threshold).

Calculating the energy for these photons and considering 150 fs pulses with 80 Mhz repetition rate, results in an average power of 30 pW.

Does anyone has other sources of information about this ?

If one is in complete darkness, what is the minimum optical power that the eye can "see" (let's say in 500-600 nm range).

I found that for 510 nm, 90 photons can be detected (http://en.wikipedia.org/wiki/Absolute_threshold).

Calculating the energy for these photons and considering 150 fs pulses with 80 Mhz repetition rate, results in an average power of ~ 3 nW.

Does anyone has other sources of information about this ?