Lancaster | (603) 788-3561
St. Johnsbury | (802) 748-3536
Montpelier | (802) 223-7723
Littleton | (603) 444-2484
Shippee Family Eye Care, P.C.
Menu
  • Home
  • About Us
    • Meet Your Eye Care Team
  • Services
    • Eyeglasses
      • Choosing The Right Glasses
      • Eyeglasses FAQs
    • Emergency Eye Care
    • Common Eye Injuries
    • Family Eyecare
    • Contact Lens Exams
      • Contact Lenses for Astigimatism
      • Scleral Contact Lenses
      • Contact Lenses for Dry Eyes
    • Eye & Vision Exams
    • Eye Disease Management
      • Glaucoma
      • Senior Eye Exams
      • Glaucoma FAQs
      • Macular Degeneration
      • Cataracts
      • Cataracts FAQs
      • Blurry Vision
      • Low Vision
    • Pediatric Eye Care
      • Contact Lenses for Kids
    • Ortho-K
      • Ortho-K FAQ
    • Computer Vision
      • Computer Vision FAQs
    • Sports Vision Therapy
    • Sunglasses
    • Polarized Glasses
    • LASIK Co-Management
    • Dry Eye
      • Dry Eye FAQs
    • Lazy Eye Treatment
    • Vision Therapy
      • Vision Therapy FAQs
    • Specialty Contact Lenses
      • Hard to Fit Contacts
      • One Day Contact Lenses
    • MGD
    • Diabetic Eye Care
      • Diabetic Eye Care FAQs
    • Order Contacts Online
    • Pink Eye
  • Locations
    • Lancaster
      • Your Lancaster Staff
    • St. Johnsbury
      • Your St. Johnsbury Staff
    • Montpelier
      • Your Montpelier Staff
      • YourLens.com Online Contact Store
    • Littleton
      • Your Littleton Staff
  • Frames
    • Preferred Designers Frames & Designer Sunglasses
      • Bollé
      • Candie's
      • Coach
      • Dolce and Gabbana
      • Easy Clip
      • Elle
      • Espirit
      • Flexon
      • Flexon 600
      • Flexon Select
      • Fexon Magnetics
      • Flexon Suns
      • Flexon Kids
      • Autoflex
      • Fossil
      • GANT
      • Kate Spade
      • Lafont
      • Line Art
      • Nautica
      • Nike
      • Rampage
      • Rayban
      • Revlon
      • Safilo Elasta
      • Safilo Emozioni
      • Saks Fifth Avenue
      • Serengeti
      • Sigrid Olsen
      • Sofia Loren
      • Wiley X
    • Eye Wear
  • New Patients
    • Online Forms
    • Payment Options
  • Contact
  • Blog
  • Optometry Topics
    • Common Eye Conditions
      • Age-Related
      • Cognitive and Acquired
      • Vision Impairment
      • Injury & Irritation
      • Eye Lids
      • Changes in Appearance
    • Contact Lenses
    • Eye Diseases
    • Eyeglasses
      • Eyeglass Lenses
    • Eye Symptoms
    • Tips and Tricks
    • How the Eyes Work
      • Basic Visual Skills
    • Pediatric Vision
    • Protecting Your Eyes
    • Visual Rehabilitation
    • Vision Problems
    • What is Vision Therapy
    • Vision Therapy Programs
    • We Can Help With
      • Cataracts
      • Corneal Disorders
        • Disorders
      • Glaucoma
      • Refractive Disorders
      • Adult Strabismus
      • Retinal Disorders
    • Newsletters
      • Glasses & Frames
      • Contacts
      • Kid's Vision
      • Conditions That Affect Vision
      • Tips for Healthy Eyes
      • Amazing, Interesting Eyes
      • Medical Perspectives
  • Home >
  • Articles >
  • Newsletters >
  • What does 20/20 Vision Mean?

What does 20/20 Vision Mean?

  • Created in Newsletters
20/20 vision

Have you ever wondered what those numbers on your eyeglass prescription actually mean? Although reading an eye chart is a fairly simple test, it provides a very accurate way to measure your visual acuity or the sharpness of your vision. You'll also need a few other tests, in addition to the results of your eye chart reading, before your optometrist hands you your eyeglass prescription.

Reading an Eye Chart Provides an Accurate Representation of Your Vision

Every eye exam includes a reading of the Snellen eye chart. The chart contains 11 lines of random letters, each line smaller than the preceding line. Patients were once required to stand exactly 20 feet away from the chart, but optometrists use mirrors today to approximate that distance.

The chart is read from the top to the bottom. Each line corresponds to a specific measurement, such as 20/20 or 20/80. If your vision is 20/60, you can read words clearly at 20 feet that people with normal vision can read at 60 feet. Although 20/20 is considered normal vision, some people can see even better than 20/20. If you can read the bottom line of the eye chart clearly, your vision is 20/10.

In addition to reading the Snellen eye chart, you may also be asked to read text on the small printed card that you'll hold in your hands. This test evaluates your near vision.

Other Eye Tests Augment Your Eye Chart Measurement

Your optometrist uses a variety of tests to determine your prescription, if needed, and assess the health of your eyes, including:

  • Refraction. Refraction helps your optometrist refine your prescription. You'll place your head against a phoropter, a device that contains multiple corrective lenses. While you look at a line on an eye chart, your optometrist will flip back and forth between two lenses and ask you to identify which lens provides the clearest image.
  • Autorefraction. Before your refraction, your optometrist or his staff may ask you to look into an autorefractor, a machine that does a very good job of estimating the prescription you'll need.
  • Cover Test. During this test, you'll cover one eye at a time and stare at a fixed point in the distance, then look at a near object. The test evaluates the ability of your eyes to work together to produce a single image. If you must move your eye in order to focus, you may have strabismus. Although the condition is commonly called "crossed eyes," it can still be an issue even if your eyes are only slightly misaligned. Strabismus is often detected during childhood and can be corrected with special eyeglasses, prism lenses, vision therapy or surgery if other treatment options aren't helpful.
  • Ocular Motility Test. The ocular motility test is a simple evaluation that assesses your ability to follow moving objects with your eyes. While you hold your head still, you'll use your eyes to follow a small beam of light that your optometrist moves in various directions.
  • Glaucoma Test. Glaucoma, a condition that occurs when the pressure inside your eyes rises to dangerous levels, can damage your optic nerve, resulting in vision loss. The test takes seconds and involves exposing each eye to a puff of air.
  • Color Blindness Test. Optometrists typically use the Ishihara Color Vision Test to determine if you can see colors normally. During the test, you'll look at a series of circles made up of colored dots. Each circle also contains a number in a lighter color. As you're shown the circles, you'll be asked to call out the numbers. If you can't see certain numbers, you may have color blindness.
  • Depth Perception Test: Eye exams also include a test of your depth perception. After you put on a pair of 3D glasses, you'll view a test booklet that contains several pages, each containing four circles. If your depth perception is normal, one of the circles will look as if it's closer to you than the others.
  • Slit Lamp Test. The slit lamp test takes advantage of the magnifying powers of a microscope to allow a thorough look at the individual structures that make up your eye. After you place your chin and forehead against the instrument, your optometrist will examine your corneas, whites of your eyes, eyelids, and irises. Your retinas can also be examined if dilating drops are used.

Is it time for your annual eye exam? Call us today to schedule your appointment.

Sources:

American Optometric Association: Visual Acuity: What is 20/20 Vision?

https://www.aoa.org/patients-and-public/eye-and-vision-problems/glossary-of-eye-and-vision-conditions/visual-acuity

All About Vision: Is 20/20 Vision Perfect Vision

http://www.allaboutvision.com/eye-exam/2020-vision.htm

American Academy of Ophthalmology: What Does 20/20 Vision Mean, 11/30/16

https://www.aao.org/eye-health/tips-prevention/what-does-20-20-vision-mean

All About Vision: What to Expect During a Comprehensive Eye Exam

http://www.allaboutvision.com/eye-exam/expect.htm

  • Common Eye Conditions
    • Age-Related
    • Cognitive and Acquired
    • Vision Impairment
    • Injury & Irritation
    • Eye Lids
    • Changes in Appearance
  • Contact Lenses
  • Eye Diseases
  • Eyeglasses
    • Eyeglass Lenses
  • Eye Symptoms
  • Tips and Tricks
  • How the Eyes Work
    • Basic Visual Skills
  • Pediatric Vision
  • Protecting Your Eyes
  • Visual Rehabilitation
  • Vision Problems
  • What is Vision Therapy
  • Vision Therapy Programs
  • We Can Help With
    • Cataracts
    • Corneal Disorders
      • Disorders
    • Glaucoma
    • Refractive Disorders
    • Adult Strabismus
    • Retinal Disorders
  • Newsletters
    • Glasses & Frames
    • Contacts
    • Kid's Vision
    • Conditions That Affect Vision
    • Tips for Healthy Eyes
    • Amazing, Interesting Eyes
    • Medical Perspectives

Newsletter Signup

Office Hours

Lancaster | 150 Main St Lancaster, NH 03584

Monday - Thursday:

8:00 am - 4:30 pm

Friday:

8:00 am - 1:00 pm

Saturday, Sunday:

Closed

St. Johnsbury | 468 Hospital Dr. St. Johnsbury, VT

Monday - Friday:

8:00 am - 4:30 pm

Saturday, Sunday:

Closed

Montpelier | 114 Main St Montpelier, VT 05602

Monday - Friday:

8:00 am - 4:30 pm

Saturday, Sunday:

Closed

Littleton | 580 St Johnsbury Road, Littleton NH

Monday - Friday:

8:00 am - 4:30 pm

Saturday, Sunday:

Closed

Locations

  • Copyright © 2023 MH Sub I, LLC dba iMatrix.
  • Admin Log In
  • Site Map