optical stimulation of the brainwaves - help

[Danko]

I want to build a pair of flashing glasses (2 lamps-one for each eye 
flashing at frequency 1-30 Hz) which are used for optical stimulation of 
the brainwaves.
Now, I've been using pc-software for this (such as FLASHER), but glasses
would be more practical. 
Has anyone got any expierence in this? Are 2 light diodes strong enough as
a light source?