I also have had dry eye for about 40 years. Restasis works better for me than Xiidra. For a while my insurance refused to cover Retasis, which I had been on for so many years. I found a different opthamologist who was able to write a valid reason for my need for Restasis versus Xiidra based on a specific diagnosis.I have secondary Sjogrens related to Hashimoto's and RA. Over the counter preservative free is the wat to go for additional help. I can't afford the Thera tears with flax but used one box and felt it was better than the regular Thera I always use and buy at Sam's Club.