"Omega-3 and -6 oil have been recommended for relieving dry eye for a long time."
I respectfully suggest that Mayo paper you cite provides little evidence to support that statement:
"... Fatty acids
Omega-3 and omega-6 fatty acids may help relieve dry eyes symptoms. These fatty acids, found in fish and vegetable oils, are thought to reduce inflammation in the body. In theory, increasing the amount of omega-3 fatty acids in your diet could reduce eye inflammation. More study is needed to prove this theory. But if you're interested in trying omega-3 fatty acids, discuss the benefits and risks with your doctor.
Omega-3 fatty acids are available in foods and in supplements. Some omega-3 fatty acid supplements can cause a fishy aftertaste and upset stomach. If this is a problem for you, look for pills that are odorless. Or, try adding foods that contain omega-3 fatty acids to your diet, such as:
Palm oil
Soybean oil
Flaxseed oil
Ground flaxseed
Walnuts
Salmon
Tuna
Mackerel
Sardines
Eggs from chickens fed with feed rich in omega-3 fatty acids
Caffeine
A recent study found that tear volume increased within hours after the use of caffeine. There's no specific research yet on caffeine and dry eyes, so it's not clear what effect, if any, caffeine might have on dry eyes symptoms...."
For years, my diet has included 20 grams of walnuts/day with breakfast cereal, 100-125 grams of salmon 3-4 times/week, tuna once/week, olive oil in cooking and salads, 10 grams each of almonds and hazelnuts per day, and a SBUX quad expresso on ice daily. Despite that diet, dry eye ensued in last 2 years. Vascepa seems to have negated it.
I am age 76 years with T1 diabetes since 1957.
Thank you for citation of the Mayo article which I found educational.
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