Skip to content
My WebMD Sign In, Sign Up

Eye Health Center

Font Size

Eye Tests and Exams

Non-Contact Tonometry

This eye test is used to help diagnose glaucoma. An instrument known as a tonometer measures the pressure in the eye. The "air puff" tonometer measures the eye pressure indirectly by the eye's resistance to a puff of air.

Applanation instruments can also be used to measure pressure. They are the most accurate, but they require local anesthetic.

Ultrasound

An ultrasound eye test uses sound waves to provide a picture of the eye's internal structure. It is useful in evaluating ocular tumors, as well as the retina when it is being obscured by cataracts or a hemorrhage. Measuring the length of the eye by ultrasound or other means is part of preoperative evaluation for cataract surgery and determination of the optimal cataract implant power.

 

Visual Acuity Testing

This is a test of visual acuity, your ability to see sharply and clearly at near and far distances. For children who cannot yet read, there is the Random E's Visual Acuity Test. The child is asked to identify the direction that the letter "E" opens to by holding out three or four fingers to mimic the letter. You can practice this at home with your child before the test. This eye test is safe, there are no risks involved, and it works just as well as most other eye tests.

Visual Field Test

This is an eye test used to measure peripheral (side) vision. When taking this test, you will be asked to stare at on object in the center of your line of vision (either the doctor's eyes or a computer screen). As you look at the target, you will be asked to note when you see an object moving into your peripheral vision. This test is done to measure loss of vision from conditions such as stroke or glaucoma.


 

1|2

WebMD Medical Reference

Reviewed by Alan Kozarsky, MD on August 01, 2014

Today on WebMD

Woman holding tissue to reddened eye
Learn about causes, symptoms, and treatments.
eye
Simple annoyance or the sign of a problem?
 
red eyes
Symptoms, triggers, and treatments.
blue eye with contact lens
Tips for wearing and caring.
 
Understanding Stye
Article
human eye
Article
 
eye
Video
eye exam timing
Video
 
vision test
Tool
is vision correction surgery for you
Article
 
high tech contacts
Article
eye drop
Article
 

Special Sections