From Awful Plastic Surgery:
ll I see in Audrina is lazy eyes, big teeth and a huge underbite. She should dye her hair blonde to match her ditzy personality And so on. What is wrong with Audrina’s eyes? Perhaps, she has strabismus, which is a condition in which the eyes are not properly aligned with each other; the eye muscles are uncoordinated and prevents that gaze of each eye to the same point in space. I believe that her eyes looks the way they do, because she is trying to focus her eyes and struggles with it.
Check out the subject on Wikipedia.
The condition can be treated with a combination of eyeglasses or prisms, vision therapy, and surgery, depending on the underlying reason for the misalignment. Suddenly, Audrina’s eyes look normal, so I feel that she may have opted for the surgery.
Here’s a photoshop of her eyes looking strange and then morphed into something more pleasing.

Here’s what she looked like previously and how she appeared at an event last week. There is remarkable change in her eyes; they look focused.


Audrina looks better now. I think she may have had her upper teeth filed down and her upper lip plumped up a bit (thanks commenters). There are also pesky drug rumors plaguing Audrina; maybe she has quit whatever she was using (supposedly Aderall to stay thin) and no longer looks dopey in public.
With her being thinner than ever now, I doubt she's stopped the pills.