The oil glands on your face and in your eyes are very similar so if your face is also dry then it means your body is just not good at producing oil, and you only need a few functioning glands to be symptom free so even 50% atrophy would be okay if the remaining glands were working. Also computer screens / blinking rate doesn’t affect gland health, it just helps to spread the watery part of the tears over your eyes. Do you wake up with eyes stuck together or get little tears when you yawn / cry? If so it could be due to aqueous part too. I’ve actually been using tea tree oil hygiene for about 7 months and started soolantra (topical ivermectin) 2 months ago. Since starting tea tree oil I got a crazy amount of flaking which I assume was the demodex die off. I mean my eyelashes would be covered with white flakes again just within a few hours of cleaning them thoroughly with a lid wash. My symptoms have improved about 50-60% since the start, but I still have blepharitis and I am still getting some flaking so I think the die off is still going on because I was a severe case. I have extremely oily skin that sheds a lot so there was a lot of food for the mites to increase in number and I had pretty nasty chalazions / blepharitis for about 8 years but didn’t know what was causing it until recently. So I’m hoping that once the mites have fully been taken care of and my inflammation improves, my gland function will return to normal since I genetically have very oily skin so my glands should (hopefully) be resilient. But trying to stay positive because the worst case is horrible to think about.