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Eyesight Tests & Exams: Online vs In-office, When to Get Them, and More

Eyesight tests are a series of standard examinations that eye specialists conduct to check for diseases, disorders and routine problems that need to be corrected.

woman with doctor eye testing

Common issues that tests can detect include:

  • Presbyopia
  • Myopia
  • Glaucoma
  • Diabetic retinopathy
  • Astigmatism
  • Amblyopia

The National Eye Institute Recommends having a dilated eye exam annually starting at the age of 60.

Why Are Eyesight Tests Done?

Eye tests are an important part of an overall health program for people of any age. As with many health conditions, eye problems that doctors identify in an early stage have a better chance of being corrected with available (and often less-invasive) treatment.

Doctors prefer their patients see them at least once a year, although some people make a trip to the eye doctor every two years for insurance reasons. Some vision insurances will cover the cost of annual eye exams but will only provide financial benefits for eyewear every two years.

Regular eye exams enhance the chances of correcting or adapting vision problems when they are most treatable. They also allow doctors to develop a trendline by tracking a patient’s vision needs and prescriptions over time.

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What Different Types of Eyesight Test Are Available?

Vision specialists rely on a myriad of eye tests to help them understand all the possible eye conditions that their patients could have. Among the exams:

  • Applanation Tonometry
  • Corneal Topography
  • Fluorescein Angiogram
  • Dilated Pupillary Exam
  • Refraction
  • Slit-Lamp Exam
  • Non-Contact Tonometry
  • Retinal Tomography
  • Ultrasound
  • Visual Accuity
  • Visual Field Test

Each test measures a different aspect of eye health and vision.

Applanation Tonometry

An applanation tonometry test measures the fluid pressure in the eye and the amount of force required to temporarily flatten a part of the cornea. All adults with an eye appointment, people with glaucoma and children who have had cataract surgery should take this test.

Corneal Topography

Corneal topography refers to a unique photographic technique that maps the cornea. It helps detect distortions in the cornea’s curvature, which is smooth under normal circumstances. Doctors can also monitor eye diseases like astigmatism and scarring and plan for surgery. The test is recommended for people who need contact lenses after a refractive surgery.

You will sit facing a large bowl with lighted circles inside, resting your chin and forehead on a supportive frame for the most precise images. Your doctor will ask you to stare at a focal point while taking pictures of your eyes. The test is painless and only takes a few seconds.

Fluorescein Angiogram

Fluorescein Angiogram (FA) is a diagnostic test that utilizes a special camera to check and record the blood flow in the retina. It is instrumental in the management of macular degeneration and diabetic retinopathy. It does not involve direct contact with the eye.

An ophthalmologist will put drops in your eyes to widen the pupil for the exam. They will also inject a yellowish-colored dye in a vein in your arm. As dye reaches the tiny blood vessels, the eyes brighten, enabling a technician to snap detailed digital pictures.

Dilated Pupillary Exam

This is one of the most fundamental tests. Doctors consider it important for diagnosing, preventing and treating eye problems that could cause short- or long-term vision loss. The doctor dilates the pupils with drops, leading to a better view of the optic nerve and retina.


A refraction test comes during a comprehensive eye exam and measures your contact lenses or eyeglasses prescription.

During the test, you will sit in a chair and look through special equipment known as a refractor or phoroptor. You will then focus your vision on an eye chart 20 feet away. The doctor will move the lenses in the machine and ask you to identify the one that provides the most precise chart view.

Eye doctors consider regular refraction tests necessary for adults and children.

Slit-Lamp Exam

A slit-lamp is a microscope an eye care provider uses to shine light intensely into the eye for an enhanced view. Doing so allows them to examine the iris, cornea, lens and anterior chamber. The doctor may use eye drops with fluorescein dye to enhance the eye’s clarity to check for scrapes, infections, minor cuts, foreign objects and tears. The dye may temporarily increase your eyes’ sensitivity to light.

Non-Contact Tonometry

The tonometry test detects changes in eye pressure, usually well before you are aware there is a problem. It is considered an essential exam for detecting glaucoma.

Non-contact tonometry entails the application of air pressure to the eye using a tool that slightly flattens the cornea. It blows a brief puff of air into the cornea to measure its pressure.

The doctor puts numbing eye drops in your eyes, staining them with an orange dye, which helps the test accuracy. You will sit behind a machine that supports your chin and forehead and look straight ahead. Using a slip-lamp machine, the doctor will move the lamp toward your eye until the tip slightly touches your cornea to detect pressure.

Retinal Tomography

This diagnostic procedure is for precise observation and documentation of the optic nerve. It takes 3D photographs of the nerve and retina to check for “cupping,” a type of damage that affects the nerve. Retinal tomography helps diagnose and manage glaucoma, diabetic retinopathy, hypertension, macular degeneration, and detached retina.

The doctor will use some medication to dilate the eyes and look through a special microscope for a clear view of the blood vessels, retina, and optic nerve.


Ultrasound helps identify issues with the eyes like foreign substances, tumors, or retinal detachment. It also diagnoses eye diseases. An ultrasound test uses high-frequency sound waves to create details of the eye and eye orbit, the socket holding the eye into the skull. It provides more incredible details than a routine eye exam.

Doctors use anesthetic eye drops to numb the eyes and minimize discomfort. They will then use an A-scan ultrasound to measure the eyes and a B-scan to examine the back of the eyes.

Visual Acuity Testing

This eye-chart test is another exam that vision assistants conduct during routine visits to the eye doctor. It is the start to measuring whether any significant vision changes took place between doctor visits. It tests your ability to discern shapes and details of what you see as one factor of overall vision.

You will sit 20 feet away from a chart and identify a series of letters on the chart. The size of the letters gets smaller as you move down the chart.

Visual Field Test

Visual field test determines your field of vision for the area right in front of you without moving your eyes. It also checks peripheral vision, with the most common test performed with an auto-perimeter device. This uses a computer program to flash small lights. You will press a button when you see the lights.

Online Eyesight Tests

Online eye exams can help establish whether you need a new prescription. Three exams you can try are for color perception, field of vision and corneal curvature.

However, online exams cannot evaluate the actual health of your eyes or if you have cataracts, glaucoma or macular degeneration. You should not consider them as a suitable substitute for comprehensive eye exams.

When to Get an Eye Exam

Several factors determine when to have eye exams, including the risk of developing eye problems, overall health status and age. General guidelines:

  • Children 3 years old and younger: Eye care providers will check for common childhood eye problems to ensure healthy development. Comprehensive eye exams between 3 and 5 years will check vision and eye alignment.
  • School-age children and teens: Have their vision checked frequently, depending on the doctor’s recommendation.
  • Adults: If you wear eyeglasses, contact lenses, have a history of eye disease or take medications with serious side effects, have your eyes checked at least annually. If you are healthy with no symptoms of vision problems, have a complete eye exam at age 40, when eye problems are likely to start. Based on the results, the doctor will recommend the frequency of future eye tests.
  • Seniors: People 60 and older should have eye exams annually or bi-annually.

What to Expect Before, During and After the Exams

When you go for an eye exam, bring any prescription eyewear with you. The doctor will ask you questions about your general health history and vision. Your answers will help them understand more about your risk of developing vision problems and eye diseases.

As part of the visit, a clinical assistant will give you an initial eye test that involves:

  • A visual acuity test to determine if you need eyeglasses to improve your vision
  • Eye pressure measurements
  • Eye health evaluation using several lights and imaging to assess the front and inside of each eye. 

You can wear some sunglasses after an eye exam to prevent discomfort from sunlight and bright colors.

Who Performs These Exams?

An ophthalmologist or optometrist performs eyesight exams, although a clinician is likely to be responsible for handling most or all of the diagnostic testing.

In some situations, a family doctor or an emergency medicine professional may conduct tests.

What is Next After You Get Results?

After an eye test, your eye care provider will discuss the results with you. They will point out the assessment of your vision, your risk of eye disease and prevention measures to protect your eyesight.

The older you are, the more apt you are to need an updated prescription for glasses or contacts—especially if you have not had LASIK or any other corrective eye procedure.


What are the different vision tests?

Various eyesight tests exist, including Visual Acuity, Visual Field, Ultrasound, Applanation Tonometry, Corneal Topography, Fluorescein Angiogram, Dilated Pupillary Exam, Refraction, Slit-Lamp, Non-Contact Tonometry, and Retinal Tomography exams.

How can I test my eyesight?

You can use online eye exams or various home tests to evaluate your eyesight. However, they should not be a substitute for comprehensive eye exams by an eye specialist.

What is the most accurate eye test?

In-office eye tests conducted by a qualified professional using the recommended eye test machines provide more accurate results than online tests. They allow your eye care provider to capture intricate details of your eyes using a microscope.


  1. Eye Exam. (April 2021). Mayo Clinic.

  2. Vision Health Initiative (VHI). (Reviewed June 2020). Centers for Disease Control and Prevention.

  3. Applanation tonometry. (2022). Mayo Clinic.

  4. How to measure intraocular pressure: applanation tonometry. (December 2007). National Center for Biotechnology Information.

  5. Corneal Topography. (May 2021). American Academy of Ophthalmology.

  6. Fluorescein Angiography. The University of British Columbia.

  7. The Dilated Eye Exam: Why It’s So Important. (July 2021). BrightFocus Foundation.

  8. What is refraction, and Why is it Often Not Covered by a Patient’s Insurance? (February 2020). Geneva Eye Clinic.

  9. Heidelberg Retinal Tomography. The University of British Columbia.

  10. What is a Retinal Eye Exam? (2022). Associated Retina Consultants.

  11. 7 types of eye tests that are part of a healthy eye exam. (August 2021). CareCredit.

  12. Testing Your Child’s Eyes at Home. (April 2020). Boys Town National Research Hospital.

  13. Our Online Eye Test. (2021). RODENSTOCK.

Last Updated April 8, 2022

Note: This page should not serve as a substitute for professional medical advice from a doctor or specialist. Please review our about page for more information.

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