For example:
After many years of struggling, I can finally see a horizon in distance.
or
After many years of struggling, I can finally see a horizon in the distance.
I'm having trouble to determine when to use the article "the" and when it's ok to drop it...
At the time of posting this question, it didn't occur to me there is a third option:
"...I can finally see a horizon in a distance."
So would indefinite article be possibly the best option here - because the exact distance is not known? Someone in my proximity strongly opposes the use of definite article in this case, precisely for the reason that exact distance is not known (defined).