Someone I once knew (and to this day consider to be one of the wisest people I've ever known) explained "love" to me as follows:
"Love is patient.
Love is kind.
Love does not envy.
Love does not boast.
Love is not proud.
Love is not rude.
Love is not self-seeking.
Love is not easily angered.
Love keeps no record of wrongs.
Love does not delight in evil, but rejoices in the truth.
Love always protects.
Love always trusts.
Love always hopes.
Love always perseveres.
When you can replace the word "Love" in the above sentences with your name, then you'll understand what true love is."
I have yet to fully accomplish this myself...and doubt I ever will.
Given the multitude of definitions for the word "love" ("I love my parents", "I love my car", "I love my job", I love my spouse", etc.), I'd say "love at first sight" is pretty much impossible.
The only "love at first sight" situation I can envision this to be applicable to is when a parent sees their child for the first time. It would seem to pretty much rule out "romantic" love.
FWIW