The tear film has 3 layers: mucous (from cells on the white part of your eye), aqueous (watery tears made by your lacrimal gland and accessory glands), and oil layer (created by glands inside your eyelids called meibomian glands).
These 3 layers contribute to overall health of the tear film. Other things that contribute are:
1.) How much inflammation is seen in your eyes?
2.) Do you have an underlying systemic (bodily) condition that affects one of these layers?
3.) What lifestyle do you lead? Are you a professional cook who deals with steam and frying pan grease? Do you live in the desert or in a more humid environment?
The best thing to do is get a comprehensive dry eye eye evaluation from your optometrist or ophthalmologist. We will look at all these factors and come up with the best treatment options that are best for you.
Check out this article I wrote for MeMD.me for even more information! https://www.memd.me/why-are-my-eyes-so-dry/