1. Something in your eyes
If small dust or foreign substance gets in your upper eyelid, your retina receive minuscule damage when you blink.
Source—“I’m experiencing roll-over”, published by Maruyama Ophthalmic Clinic in Toomi town, Takatsuki City, Osaka
2. Infection in ocular conjunctiva that contacts your eye surface and rear of the eyelid
There are several causes of conjunctivitis, and they can roughly be classified as infections(virus or contagion from microorganic contagion), allergies(pollenic, atopy, or direct cause from contact lenses) and exterior damage(scars to retina, dust, or chemicls).
3. Dry Eye
Dry Eye, or xerophthalmia refers to a condition in which one cannot produce enough tears to maintain healthy humidity of the eyes, or experience the unbalanced quality of substances in one’s tears. These conditions cause unbalanced distribution of tears to the surface of pupils and may damage the retina. Besides utilizing eye drops to moisturize the eyes(Drops containing Hyaluronic Acid), an insurance-covered treatment called “Tear Plug” is being carried out widely. The treatment will block lacrimal point using small silicone plug to block the outlet of tears and provide moisture.