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Visual Acuity, Color, Depth, and Eye Pressure Exams

4/4/2020

Nearly everyone has done a visual acuity test and probably do so on a yearly basis; however, you may not be familiar with a color vision, depth perception or an eye pressure exam.

Visual Acuity Test
A visual acuity test is done utilizing the Snellen Eye Chart. Typically, you will read the letters of the smallest line you can read. First, by utilizing one eye at a time then both eyes together. When doing this exam for monitoring of eye changes and not prescription lenses, there are no additional testing of how it does with specific corrections.

Color Vision Test
Color vision will typically be tested using a book to look at images. In each of the images there is either a number or a design in which the number is to be read off and the design is to be traced with your finger. There are usually a transformative design, which means that only color blind people will see a design; whereas those with normal color vision won't see anything.

Depth Perception Test
The depth perception test is typically used using a book to look at images which are referred to as targets. The patient is to identify the target that has a disparity and looks closer than the others. Often, the distance in which the book is held is controlled or measured to be able to determine what is called sterioacuity, or the ability to detect differences in distance.

Eye Pressure Exam
The eye pressure exam is called tonopathy. In the past, you may had received a puff of air to test your pressure, but now there is a more accurate method that measures pressure by touching the eye. You will receive eye drops to numb the eye (anesthetic eye drops) then a few minutes later, a device with a blue light touches the outside of your eye in order to measure the pressure. Since you have received anesthetic eye drops, you won't feel anything. A normal pressure ranges from 10 - 21 mmHg. Typically, this test is done to monitor for glaucoma, which is due to high pressure (typically > 21 mmHg) in the eye