Yes, my question is, I have dry eyes also. Will these drops help w/the dryness?

I suffer from both chronic dry eye and allergies. I apply the drops in the morning. Then I use Systane or Genteal gel and rub them around the water line and outer lid to seal in moisture, while not obstructing my vision during the day. At night I apply the gel in the eye since I will be sleeping, but if my eyes still itch, I will apply the drops first, then wait about 10-15 minutes and apply the gel to the inside of the eye lid and it's helped tremendously.

Can I use these drops with contacts or before I put my contact lenses in?

You have to wait 10 to 15 minutes after putting in the drops before putting in contact lenses.

Are there preservatives in these drops?

I really don't know. Like with any eye drops, don't touch the surface of the eye and keep in a cool dry place.

Once the bottle open, how long it will expired? I have pollen allergy which it happened every summer, am I able to reuse for next summer time?

My bottle says it is good till 2022. I would refrigerate it if I wanted to keep it a longer time then 6 months. I have allergies about year round with eye irritation and swelling. I use this once a day /as needed. My Opthamologist recommended this product. It use to be prescription. I use it instead of orally taking a decongestant all the time. They recommended discarding it if it becomes cloudy ..Hope this is helpful. It works well for me...