Angela, if you are at all worried about this side effect and what might be causing it in your case then you should talk to you doctor and ask him to investigate or reassure you that there is no need to worry.
This side effect is very common when taking imatinib and other TKI's, but it has not proven to have any consequences other than the unsightliness of a red eye.
But this is obviously of great worry to you, so please talk to you doctor about it. It might be that when you are under stress and your blood pressure increases (as is normal when stressed) and this might put extra pressure on the very fine blood vessels in your eyes. You could ask if this would be a cause.
Best wishes,
Sandy