i farmed more than 10 pika with no compund eyes in viridan, and no ball. Then got a compound eye pokemon with thief (butterfree) and killed more than 30 pikachu with thief, and still not a light ball, always in Viridan.
In the power plant i just got 3 or 4 berry.
Then i was pissed off and bought 1 light ball for 20k.
A guy on the forum said that static should work (imho is not working [artificial difficulty yay])
Imho Compound eye don't work either, but not sure about that.