If you believe that (romantic) love is a pure and beautiful thing, then it's impossible to believe in love at first sight. This claim rests on two assumptions:
1)Blind people are denied love at first sight.
2)If love is good and pure, it won't immediately exclude someone simply because they are handicapped.
If you accept these two statements, Reason demands that one of the following suppositions is true:
A. Love is beautiful and pure, and is thus available to everyone, despite their handicaps. The discriminatory nature of love at first sight thus renders it an oxymoron.
B. Love is not beautiful and pure; it's a primal Darwinian instinct, and thus excludes people with handicaps. Being a capricious, arbitrary emotion, love is possible at first sight.
Personally, I'm not sure which of those two views I believe in.