l do not know whats wrong with my eyes, they're fine during the day, but as soon as early afternoon comes around they get all red. l use moisturing eye drops without preservatives and it does not help. l tried switching mascara and that has not helped either!

talk to a doctor about this, but it could be an allergic reaction to something in the air (such as scents from a plant or animal) or maybe you should check if your a/c filters need replacement (dirt)

Sounds like u could be allergic to something that u have for lunch. Are u working in an air-conditioned office? Sometimes air-borne (chemical) particles can cause irritations.
Are u getting enough sleep at night?
Do u work on a computer all day? Do u take a 5-10 min break from the screen every hour or so?
Mascara. Even though u changed, could be that u may have an allergy to both. Chemical based foundation & eye make up can cause irritations to u eyes as the day passes.
Are u straining ur eyes to see what u r doing? If so, it would pay u to visit an optometrist. They should do a thorough eye examination, which includes checking the health of ur eyes.
Good luck. Red.

Stop smoking pot at 5.