Open the System Preferences and go to Accessibility.
Once there, click on Display in the left hand window.
Now, in the right hand window, move the Cursor Size slider toward the Large end until you have one that suits your eyesight.
Have to say that this was a new one for me, I didn't know this was there.
Hope it works for you, let us know
I bought an iMac in October but do not use it because I can not find a way to enlarge the pointer so that it is easily visible on the screen. I tried to download some pointers that would be easily seen but they were awful. Will someone tell me where to find pointer/cursor to download that are highly visible such as the ones for PCs at Debi's Cursors?
Thanks, old grrandma