Thank for the advice I will keep a watchful eye on him.Could be dust, dirt, or pollen just got in his eye.
It might also be because he's allergic to something.
Get a clean cloth, dampened with warm water and wipe his eyes and face if he'll let you. If there is something irritating him, that'll help get rid of it.
While you're doing that, give a quick check to see that there isn't any redness, swelling or any foreign substances in your cat's eyes. If you do find anything, call the vet but, if not, just keep an eye on him.
If this lasts for more than a day or so, call your vet and get professional advice.
Our cat, Casper, has allergies to dust and pollen. He sometimes gets watery eyes. Since he's all all-white cat, it stands out.
When his eyes get all "boogery" we wipe his face. He complains, at first, but he appreciates it, afterward.
We asked our vet about it and she doesn't think he's got conjunctivitis or anything like that so we don't worry. She also told us that, if his allergies get bad, she'll give us some allergy medicine for Casper but, since he doesn't like taking pills, we won't bother unless he gets too uncomfortable.