My girlfriend has cataracts in both eyes. Is there anything I can do to help her condition?

Surgery. Help her to get them removed if they are visually significant and affecting daily activities -- otherwise might not have to worry about them.
Maybe. Depending upon the density of the cataracts and level of visual loss, polarized sunglasses with an amber tint and careful refraction are good temporizing measures. Unfortunately surgery is often the only recourse for cataracts. You could best support her by helping her to understand her condition and if she decides upon surgery, helping out with the logistics. She is lucky you are there to help.