Nitrates widen blood vessels, and Viagra increases that effect. Mixing the two can cause your blood pressure to drop drastically. A sudden drop in blood pressure can make you pass out, and you may die if your blood pressure stays too low for too long.
3 doctors agreed: 1  Allergic dhiners: She has what's known as allergic shiners. It it caused by blood shimmering through her fine skin. 2  Cold compress: Purple or blue marks under eyes may be due to blood vessels under eyes. Cold ice packs might help marks decrease by contracting the vessels. What causes : rapid appearance of brown spots on nose, under eyes, forehead. Feet cold and turn purple, sore breasts, acid reflux, popping joints? Dr. Jan Lei Iwata Dr. Iwata
For example, when the red and blue cones are simulated in a certain way you will see the colour purple. The exact physical causes of colour blindness are still being researched but it is believed that colour blindness is usually caused by faulty cones but sometimes by a fault in the pathway from the cone to the brain.