Simulating visual acuity. The purpose of this page is to give an idea of how blurry your vision is when you don't use your glasses or contact lenses, or when you use a prescription which doesn't match your eyes. This is illustrated by simulating the blurry perception of a Snellen eye chart, which is commonly used to make eye examinations.
A SCAI answered. Fasting for 9 to 12 hours before a cholesterol blood test ensures accuracy in the test. It helps make sure your body does not have extra sources of fat - say, from the ice cream you had for dessert - that could alter the test results.
The three hour test you need to fast for 12-14 hours prior because that test is fasting the lab needs a base fasting glucose to compare the rest of the blood after you drink the glucola.With that test you should still have nothing in between the blood draws, even though the taste is very bad.he three hour test you need to fast for 12-14 hours prior because that test is fasting the lab needs a base fasting glucose to compare the rest of the blood after you drink the glucola.