A comprehensive eye exam goes above and beyond a routine eye check-up—it runs the full gamut from assessing visual acuity and refraction to performing eye dilation and screening for eye conditions and diseases.
It’s natural (instinctive, even) to be a bit squeamish about letting someone near your eyes. But there’s one person for whom you should always make an exception: your eye doctor.
As a medical professional, your optometrist is qualified to inspect your eyes and prescribe important treatments for your eye health and vision. You should see them at the first sign of eye trouble, as well as for regular maintenance visits.
Nervous? That’s perfectly understandable—all those scopes and tools can look a bit scary. (But they’re not—don’t worry!) We wrote this article to demystify the whole process for you, so you know exactly what to expect at a comprehensive eye exam.
How to Prepare for a Comprehensive Eye Exam
To get ready for your exam, you should prepare a few pieces of information:
An overview of your and your family’s medical history
A list of any eye- or vision-related symptoms you’re experiencing
Any medications you’re taking (non-prescription medications included)
You should also bring any corrective lenses you’re currently using—glasses and contacts—to your eye appointment.
Finally, it’s a good idea to bring a pair of sunglasses to wear afterwards in case your eyes will be dilated during your exam. A dilation checks your retinal health, and the drops used to dilate your pupils can cause sensitivity to light and blurred vision for a few hours.
If your optometrist’s office isn’t walkable from your location, you might also consider asking a trusted person to drive you home from the appointment.
What Not to Do Before (And After) A Comprehensive Eye Exam
We’ve covered the do’s, but what about the don’ts? Here’s what to avoid prior to a comprehensive eye exam—and afterwards:
Eye strain: Don’t spend a ton of time looking at screens or vigorously reading close-up text before your exam. This can cause eye strain, and you want your peepers in tip-top shape before they undergo their vision tests.
A bad night’s sleep: Try to get a full night of restful sleep the night before your eye exam. It’s another way to avoid fatigued eyes.
A busy schedule: If your eyes will be dilated during your eye exam, you’ll want a pretty clear schedule for the remainder of the day as the effects wear off.
Comprehensive Eye Exam vs. Routine Eye Exam
When booking an eye exam, be sure to clarify that you’ll be getting a comprehensive eye exam. This is a more complete eye exam, which will include screening for eye conditions and diseases that could put your eye health and vision at risk.
What Does an Eye Exam Consist Of?
During a comprehensive eye exam, your optometrist will thoroughly check your vision and gauge the health of the different parts of your eye. They’ll run various eye tests with pieces of specialized equipment, and although these tools can look intimidating, none of these procedures should hurt.
Exactly what’s covered in a comprehensive eye exam can vary from person to person, depending on their needs, but generally, an exam will include some or all of the following.
Visual Acuity & Refraction Exam
The two main components of any comprehensive eye exam are arguably the visual acuity test and refraction exam.
Vision tests tell the optometrist how clearly you can see, and whether or not you need prescription glasses or contacts. They also look at other aspects of your eyesight, such as your peripheral vision.
Visual Acuity Test: This is the test everyone thinks of when they imagine going to the eye doctor: the one with the big eye exam chart!
This chart, which depicts progressively smaller rows of letters, is called a Snellen chart, and it helps the doctor measure your visual acuity. They’ll ask you to read lines from the chart until you’re unable to distinguish the letters.
Refraction: The refraction portion of the comprehensive eye exam is what determines your prescription for corrective lenses (if you need them). You’ll look through various lenses mounted on a machine called a phoropter. The optometrist will switch out different lenses and ask which gives you clearer vision: “Number one, or number two?”
They may also use other tools to help pinpoint your eye prescription. These tools are especially helpful when the patient is a young child or otherwise unable to provide feedback to the optometrist.
Retinoscope: a handheld device that shines light into the eye. The optometrist watches the reflection of this light as it bounces off the back of the eye, and has the patient look through different lenses until they can confidently gauge what prescription strength is needed.
Autorefractor: True to its name, an autorefractor automates the refraction process. It shines a light into the patient’s eye and electronically estimates prescription information. Like the retinoscope, it will give the doctor an approximation of what your prescription may be. From there, they’ll perform a refraction to fine-tune and adjust the prescription so it feels comfortable and is customized to your specific visual needs.
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This portion of the comprehensive eye exam involves tests to observe how your eyes move and look for any abnormalities, such as eye muscle weakness or one eye drifting to the side.
Ocular Motility Test: The doctor will ask you to follow an object or light with your eyes without moving your head. This allows them to see how the muscles that control your eye movement work.
Cover Test: The doctor will cover one of your eyes and have you focus your exposed eye on a target, which could be far away or close up. They’ll then take the cover off of your eye and watch how well it syncs up with its partner.
This test helps to diagnose or rule out strabismus, a condition commonly known as “crossed eyes” that causes the eyes to point in different directions. It also gives the eye doctor a general sense of your eye posture when you’re looking at distant and near objects. (That’s right—your back isn’t the only part of you with a posture!)
Depth Perception Test (aka Stereopsis): If your doctor wants to test your depth perception, they’ll likely show you a series of images to look at through a pair of 3D glasses. You’ll then pick out which of the images appear in 3D.
Ocular Health Exam
During this part of the comprehensive eye exam, your optometrist will make sure everything looks good both inside and outside of your eyes.
Pupil Function: Briefly shining a handheld light into each eye and then moving the light away allows the doctor to watch how your pupils dilate and constrict to assess their function.
Slit-Lamp Exam: A slit lamp is a type of microscope that enables the optometrist to see your eye in close-up detail. You’ll rest your chin and forehead on part of the machine while the doctor takes a good gander at the front of your eye through the scope.
They’ll be able to see your eyelashes, eyelid, cornea, iris, and lens—all without touching your eye—and they’ll be on the lookout for problems such as cataracts and corneal abrasions.
Eye Pressure Measurement (aka Tonometry): You might know your average blood-pressure reading, but what about your intraocular pressure (IOP)? It’s an important metric when screening for early signs of glaucoma.
There are several ways for your optometrist to measure your intraocular pressure.
Non-contact tonometry (colloquially known as NCT or “that little puff of air that makes you blink like crazy”) involves aiming a tiny squirt of air at the surface of your eye and measuring that surface’s resistance.
For applanation tonometry, the doctor will first administer a yellow dye that mildly numbs your eyes. Then, they’ll use a pressure-sensitive instrument to ever-so-gently tap on the surface of your eye and get a pressure reading.
Finally, for rebound tonometry, the doctor will use a handheld device called a tonometer. This device will determine IOP via a small disposable probe which makes brief contact to the eye, and does not require the use of local anesthesia.
Retinal Exam (aka Ophthalmoscopy or Fundoscopy): During the retinal exam, the doctor will use the slit-lamp device and a handheld lens that allows them to get a look at the back of your eye.
Sometimes, to get a better view, the optometrist may administer eye drops that dilate your pupils. Once your eyes are fully dilated, the doctor can use either the slit lamp or a special headpiece to check the retina and other structures, such as blood vessels and the optic nerve.
Note: Some eyecare offices now possess advanced machinery that can photograph the back of the eye without first dilating the pupils. Using this technology may slightly increase the cost of an eye exam.
Visual Field Test (AKA Perimetry): To test your peripheral vision, the doctor may or may not use a machine. The machine-free version is called a confrontation exam, but don’t worry, it’s not nearly as aggressive as it sounds! The doctor will simply ask you to cover one of your eyes and then tell them how many fingers they’re holding up in their periphery. Or, they might slowly slide their hand into your view, instructing you to announce when you can see it.
There are other variations of this test that might ask you to spot a target or a hand motion, or even look at a screen that displays lights or images on either side of your field of vision.
Color Vision Test:A color vision test may be one of the components of your comprehensive eye exam, used to determine whether you have some degree of color blindness. One specific type of color vision is the Ishihara Test, which utilizes a series of images (aka “Ishihara color plates”) made up of colorful dots. You’ll look through these images and try to discern a number or shape that stands out in each one.
Contact Lens Exam
If you want to wear contact lenses, your optometrist will take additional measurements to find out which lenses will fit you best. They’ll probably use keratometry—the practice of measuring the curve of the cornea—and may also measure your pupil and iris as part of your contact lens exam.
Finally, a tear film evaluation can show them whether you’re at risk for severe dry eyes, which could change their contact lens recommendations.
The doctor will consider frequency of use, lifestyle, and overall visual demands to determine which lens may be the best fit for you. They may provide trial contact lenses for you to test out, and have you come back for a follow-up appointment to confirm the fit and prescription.
Advanced Eye Tests
Depending on your eyes’ needs and symptoms, your doctor may refer you to a specialist for some of the following additional tests after your comprehensive eye exam.
Fundus Photography: Using a camera that can photograph your retina (known as a fundus camera), your doctor can track the progression of various conditions, such as retinal detachment or age-related macular degeneration.
Optical Coherence Tomography (OCT): OCT, much like fundus photography, is used to monitor retinal conditions. It produces images that clearly depict a cross-section of the retina’s layers, allowing doctors to see the retina’s thickness alongside any signs of disease or damage.
Corneal Topography: If your doctor suspects you have a corneal abnormality, they may want to map its surface with corneal topography. This procedure scans your cornea and produces a detailed map of its surface, much like a topographical map of a landscape.
Pachymetry: Pachymetry measures the thickness of your cornea, and may be performed if your doctor wants to check more thoroughly for signs of glaucoma or corneal conditions such as keratoconus. A small device called a pachymeter briefly touches the surface of the eye and measures corneal thickness via ultrasound.
Getting Your Eye Exam Results
Once your comprehensive eye exam is over, your doctor should be ready to discuss the preliminary results with you. Feel free to ask any questions that come to mind at this stage, whether they’re about your eyes specifically or general eye health.
Definitely ask when your optometrist recommends that you come back for your next appointment, especially if they found signs of an eye condition that should be monitored.
This is also the point at which you’ll get your eye prescription! It will spell out all the specifications for your corrective lenses, should you need them. You’re legally entitled to a copy of your prescription, and it’s good to have on hand for later eyewear purchases.
Due for a Check-Up?
We know some pretty great doctors who’d love to meet you and your eyes.
Choosing your new prescription glasses or contacts is the cherry on top of a comprehensive eye exam. Your doctor may have specific lens recommendations based on your prescription, but when it comes to style, the (eye)ball’s in your court.
Most optometrists stock a variety of glasses and contacts at their office so that you can try them on right after your exam. But you don’t need to feel pressured to make a purchase immediately—shopping for eyewear online is becoming a more and more popular option. And with our Home Try-On and Virtual Try-On programs, you can even see how certain frames will look on you without leaving your house.
Comprehensive Eye Exams Keep Your Eyes Healthy
Hopefully, this rundown of what happens at a comprehensive eye exam sets your mind and your eyes at ease. If you’re experiencing any eye health-related concerns, vision changes, or just haven’t had one in a while, we encourage you to book an eye exam. Don’t be afraid to ask questions throughout. See you soon!
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