It lists ingredients carboxymethylcellulose sodium, glycerine, polysorbate 80. why is flax oil not listed?

Flaxseed oil is considered an inactive ingredient in the US so is listed elsewhere on the carton. In the US, some eyedrop ingredients are considered as "active" based on FDA Monograph rules. Many useful and protective ingredients are included in eyedrops, but those not classified as "active" will be listed separately on the carton.

are they preservative free

Yes they are preservative free, but that’s not necessarily a good thing. The manufacturer says you should only open a vial, use 1-2 drops per eye and then DISCARD the vial and all remaining lubricant. The reason is that because there is no preservative, any bacteria that gets into the opened vial will multiply like crazy and within a short period of time could become enough bacteria to create an eye infection after repeated use of a vial. These drops are far better than most others on the OTC market, but they are very expensive, especially if you need to use more than one vial a day for blepharitis, etc. At $24 a box (retail price) you are purchasing just 1/5 of an ounce (!) of lubricant in 30 delivery vials — that would be a bit more than a teaspoonful of lubricant total.

Do these eyedrops have flaxseed oil?

Yes, but as the fifth Inactive Ingredients. Active Ingredients, eye lubricants, are carboxymethylcellulous sodium, glycerin and polysorbate. BF has severely dry eyes and so far Retaine MGD has proven to be her go to drops. Nano Tears work but are only single use.

can they be used during the day, to drive, will they blur vision?

They do blur my vision for a few (2-3 ) minutes. I usually relax with my head tilted back to really get the benefit from the drop because the drop relieves the burning immediately to my irritated dry eye.