An update from me.
I used to massage my eyelids (with water-soaked cotton make-up-removal pads) to remove the muscle spasm from my eyes whenever needed (before computer usage, and after computer usage, as well as any time I feel the spasm).
Not just massaged them, but cleaned them (any part of them that felt "sandy" - mostly on the outer corner of my left eye) with the eye open.
This almost always removed the spasm. HOWEVER, one ophthalmologist has adviced that I don't do that, since it may cause Floppy eyelid syndrome. I still went on doing it, as I didn't have much choice.
Recently, I have felt that when my (closed) eyelids are under running water (e.g. in the shower), my left eyelid lets a little water in. I think that's because my eyelid has become a bit floppy (loose), like the ophthalmologist warned me. So I've stopped massaging my eyes, and so it's harder for me to remove the eye spasm now. Meaning I have to use screens even less than before.