I see flashes at night when im tired. sometimes i would see orange&black strips of flashes by looking around, and sometimes it would be white. it seems to worsen when im really tired. is this a sign of eye cancer?

The condition you are describing is called 'photopsia' or the appearance of sparks or flashes. It is very common in people over 60 as age related changes occur inside the eye. However, anyone who is extremely nearsighted is also susceptible, even in childhood. It should be assumed that anyone with photopsia has a retinal tear and requires a thorough, dilated exam of the peripheral retina.

Photopsias are an indication that the vitreous gel is pulling on the retina. Usually if it has been stable for 3+ weeks the risk of a retinal detachment is low. If it gets noticeably worse or is associated with a lot of floaters or changes in peripheral vision, it should be evaluated by an ophthalmologist. It is very, very unlikely cancer.

A proper eye examination is needed for diagnosis, more likely ocular migraine than malignancy.