High School Earth Science/Geologic Time Scale - Lesson Summary. 1  The Earth is very old, and the study of Earth's past requires us to think about times that were millions or even billions of years ago. Scientists use the geologic time scale to illustrate the order in which events on Earth have happened.
Medical Definition of intraocular pressure. : the pressure within the eyeball that gives it a round firm shape and is caused by the aqueous humor and vitreous body.
What is an intravenous pyelogram (IVP)? An IVP is an imaging test used to look at the kidneys and ureters. The ureters are the narrow tubes that carry urine from the kidneys to the bladder. During the test, the radiologist injects a contrast dye into one of your veins.