Slughorn's party and Alan Rickman's eyes

[Carol]

Good news! They're filming Slughorn's Christmas party, which means we
may get to hear Luna's Rotfang Conspiracy line and overhear Snape's
and Draco's conversation along with Harry. Oh, I hope, I hope!

http://www.the-leaky-cauldron.org/2008/1/10/emma-watson-updates-about-filming-slughorn-s-party-scene-in-half-blood-prince

Hermione will be there, at least, presumbly escaping the clutches of
Cormac McLaggen, who has been cast.

Unrelated question: I was looking at the "Sweeney Todd" premiere
photos posted on Leaky and noticed that Alan Rickman's eyes are a much
lighter brown than they are in the films, where they appear almost
black. Does anyone know whether he wears contacts to make his eyes
resemble Snape's? In the HP films, his eyes look very much as I always
picture Snape's eyes when I read his description in the books.

Carol, hoping to see every single Snape scene from both HBP and DH
traslated to film