Drops are mostly for symptom relief. If you feel like your eyes are dry and you need a drop, go ahead and put one in. To answer you question, with contact lenses if you are having dryness problems first look at switching your solutions. I recommend the hydrogen peroxide based solution. Either Clear Care or Proxy Clear are two good solutions for that. Be careful not to get it into your eye because it is peroxide! Then, if you don’t want to switch solutions, switch to Dailies. That is the lens that you put right in when you wake up and throw it away at the end the day. So you get nice fresh lens every day.
For contact lenses though, I usually give my patients Retain CMC. The Retain you are referring to is MGD, but Retain CMC is the one I use with my patients for contact lenses. It is a little lighter, it does not have preservatives. It is not approved for contact lenses but it is still a great drop for contacts. Retain MGD might cause a little clouding but otherwise it still should be okay, but I say go with Retain CMC.
Dr. Travis Zigler