If I'm in the dark for a while, my right eye seems to take a longer time to get used to the light. What might be causing this and how to aid?

Variety of reason. There can be a variety of reasons for this. It could be abnormality of your iris and your pupils. There can be some blockage in light due to cataracts or capsule opacification if you had surgery already... It could also be an abnormality of your retina. It would be helpful to know your age and other diseases, like diabetes, macular degeneration..Best thing is to see your eye doctor.
Myotonic pupils. You may have myotonic pupils( also known as holmes - adies pupils) if this is the case , one pupil (in your case the right one) is larger than the left and is slow in reaction to light and darkness. Generally speaking it is an innocent condition.