Well, theres the problem: The wiki seems outdated. 4+ hours do not equalate to 2400 turns, since 1 turn is a second. And the flaming eye inflicts teleglow for 80 minutes (= 4800 seconds/turns), according to the source code.
And the cooldown on this attack for the monster seems to be 12 turns, if I see that right.
I’ve yet to check the effects for teleglow.
It seems to have a one in 72000 minus time left on teleglow chance to cause blindness for 1 to 2 minutes if the duration of the effect left is higher than 4 hours.
I also created a test world and spawned in 9 flaming eyes and let them stare at me.
It took some time until I’ve turned blind, but after almost two minutes I was able to see and did not turn blind again, so it might not even have been the flaming eye causing the blindness.
Or it just bugged out one time.
Did you use any mods? What version did/do you play on? Could you make a backup of your world and let them stare at you again to see if you turn blind?