Re: why would the color yellow suddenly flash into view? and not go away ?.

A common cause of sudden "yellow haze" in one's vision occurs from side-effects or toxicities of certain drugs (and yes, I do recommend that you see your doctor about this symptom). The medical term for this is xanthopsia. The most common drug causing the effect is digitalis, a heart drug that inhibits cell channels regulating the flow of calcium ions. However, other drugs including some of the newer anti-fungals can also cause yellow tinges to ones vision. Cataracts and other more chronic conditions can also produce a similar effect, though the xanthopsia generally develops slowly over time.

The exact mechanism of acute xanthopsia is not known, but probably involves effects of the given drugs on the retina of the eye, thus influencing the signals from the nerve cells responsible for sending color information to the brain.