Symbols of this story are color and the light from the window. I noticed that everything was colored after the man fell in love with the woman. So color could be the symbol of happiness. Every time he opens the window, the light shines upon him. This might be the symbol of bright future.
Irony in this story is that though the title of this story is Love at First "Sight", the woman was blind and actually had no sight.
The theme of this story is that love does not have to be visible.