Susan - I was on Timoptic for several years when I suddenly seemed to develop an allergy to it. It's too bad, it worked well. When I was first treated they had me use Xalatan for a little while to get the pressure down, then switched to Timoptic to keep it down - but then the allergy problem developed and now I'm back on a low dose of Xalatan. My eye color hasn't changed yet! My corrected pressure stays between 15 and 19. I've been very lucky.