What to Expect During a Comprehensive Eye Exam

Published October 1, 2026 · By Dr. Lu Eye Care · 5 min read · Eye exams

A comprehensive eye exam is much more than reading letters on a chart. It checks how well you see, whether you need glasses or a prescription change, and, just as important, whether your eyes are healthy. Knowing what happens at each step makes the visit less mysterious and helps you get more out of it.

Eye exam or vision screening?

A vision screening, like the quick check at school, at the DMV or at a health fair, only tells you whether you can see well enough to pass a test. It can miss eye diseases that cause no symptoms early on, such as glaucoma or diabetic retinopathy. A comprehensive eye exam, performed by an optometrist or ophthalmologist, evaluates both your vision and the health of every part of the eye. If you are unsure who does what, see our guide to optometrists, ophthalmologists and opticians.

What to bring

• All the glasses you currently use, including reading, computer and prescription sunglasses
• Your contact lens boxes or a photo of the label, if you wear contacts
• A list of medications and supplements, including eye drops
• Your vision and medical insurance cards
• Records from your previous eye doctor, if you are a new patient
• Sunglasses, in case your pupils are dilated

Step 1: Your health and vision history

The visit starts with questions. Expect to be asked about any vision problems, eye strain, headaches, dryness, floaters or flashes; your general health conditions, such as diabetes or high blood pressure; medications; past eye injuries or surgeries; and family history of eye disease, especially glaucoma and macular degeneration. Mention how you use your eyes day to day, such as long hours at a computer or night driving, because that shapes the doctor's recommendations.

Step 2: Visual acuity

You will read letters on a distance chart and a near card, one eye at a time. Results are written as a fraction such as 20/20 or 20/40. The top number is the testing distance in feet; the bottom number is the distance at which a person with typical vision could read the same line. So 20/40 means you need to be at 20 feet to read what a person with typical vision can read at 40 feet.

Step 3: Preliminary tests

Several quick tests check how your eyes function as a team. Depending on the practice, these may include:

• Pupil responses to light and to near focus
• Eye movements and alignment, often with a cover test in which the doctor covers one eye at a time
• Depth perception and color vision
• Peripheral (side) vision, either by a simple finger-counting test or with an automated machine

Step 4: Refraction

Refraction measures the exact lens power you need. A machine called an autorefractor, or a handheld light test called retinoscopy, provides a starting estimate. The doctor then refines it with a phoropter, the instrument with many lenses, asking which option looks clearer: "one or two?" There is no wrong answer; if two choices look the same, say so. The result determines your eyeglass prescription. Our guide on reading your eyeglass prescription explains the numbers you will see.

Step 5: Eye pressure

Tonometry measures the pressure inside your eye, one of the risk factors for glaucoma. The familiar "air puff" test is non-contact. Other methods, such as applanation tonometry, gently touch the eye after numbing drops are applied, and some offices use a small handheld rebound device. None of these tests should hurt. Pressure is only one part of glaucoma screening; learn about the others in glaucoma testing explained.

Step 6: The front of the eye

Using a slit lamp, a microscope with a bright light, the doctor examines your eyelids, lashes, conjunctiva, cornea, iris and lens. This is how problems such as dry eye, eyelid inflammation, corneal scratches and early cataracts are found. A yellow dye may be used to highlight the surface of the cornea, particularly for contact lens wearers.

Step 7: The back of the eye

To see the retina, the macula and the optic nerve clearly, the doctor often dilates your pupils with drops. Dilation takes about 20 to 30 minutes to work and lets the doctor look for signs of glaucoma, macular degeneration, retinal tears and changes caused by diabetes or high blood pressure. Many practices also offer retinal photographs or OCT scans, which create detailed images and give a baseline to compare against at future visits. Imaging can be useful, but it does not always replace dilation; your doctor will advise you.

Step 8: Results and your prescription

At the end, the doctor explains the findings, answers your questions and recommends next steps, such as new glasses, a contact lens fitting, a follow-up visit or a referral. Under the Federal Trade Commission's Eyeglass Rule, you must receive a copy of your eyeglass prescription after the refraction, and you can buy glasses wherever you like. Contact lens wearers need a separate fitting before a contact lens prescription can be written; see contact lens exam vs. regular eye exam.

How long does an eye exam take?

Plan for roughly 30 to 60 minutes, and longer if you are dilated or need extra testing. Contact lens fittings and first visits with a new doctor usually take more time than a routine follow-up.

Tips for after dilation

• Your eyes may be sensitive to light for several hours, so wear sunglasses.
• Close-up vision may be blurry, which can make reading or screen work difficult.
• Many people can drive afterward, but if you feel unsafe, arrange a ride.

How to get the most out of your visit

• Write down symptoms and questions beforehand so you do not forget them.
• Be specific: "my vision blurs when I drive at night" is more useful than "my eyes are bad."
• Ask what was found and when you should return.
• Keep a copy of your prescription and any test results for your records.

Bottom line

A comprehensive eye exam checks your vision, your prescription and the health of your eyes from front to back. It is one of the simplest ways to catch silent eye diseases early. To find out how often you should go, read how often you should get an eye exam.

This article is general health information and is not a substitute for an examination or personal advice from a licensed eye care professional. If you have sudden vision changes, eye pain, or new floaters or flashes, seek care promptly.