If you've never had an eye exam before — or if it's been a while since your last appointment — you might feel a little hesitant. It's understandable if the idea of a doctor poking around your eyes doesn't sound like the most pleasant experience.

But you'll be happy to know that eye exams are completely safe, simple and painless. Plus, they're essential for maintaining good vision and eye health. Here's an overview of what occurs during a routine eye examination to help you feel calm and confident at your next check-up.

What tests should you expect during an eye exam?

During an eye exam, your doctor conducts several tests to check the following things:

• Your vision to determine if you need glasses

• Your eye health to check for eye diseases

• Your overall health to evaluate you for other health issues (problems in your eyes can indicate certain medical conditions, including autoimmune disorders, diabetes and cardiovascular disease)

To perform these tests, your eye doctor will use special tools and lights to look inside your eyes. While these unfamiliar gadgets may look strange or intimidating, most of these instruments are non-invasive and won't cause any discomfort. Here are some standard tests to expect:

Visual acuity: This test evaluates how clearly you can see and helps your doctor determine whether you require glasses. Your doctor will simply ask you to read letters on a chart from a distance, one eye at a time.

Refractive assessment: This test assesses refraction (how light rays focus on the back of your eye) and helps your doctor determine the proper lens prescription you need to perfect your vision. You'll look through an instrument called a phoropter, a mask-like device that contains multiple lenses of varying strengths, to help your doctor find the right combination of lenses to give you the sharpest vision. Your doctor may also opt to use a computerized device called an autorefractor, which automatically determines your correct lens prescription.

Visual field: This test assesses your full range of vision, including your peripheral (side) vision. Your doctor will slowly move a finger or an object in front of your face — side to side and up and down — and ask you to follow it with your eyes without moving your head.

Color vision test: This test does exactly what it says: assess whether you can see color. Your doctor will show you images with colored dots. If you can see the numbers and shapes hidden within the dot patterns, your color vision is good. If you can't, you likely have a color deficiency.

Corneal topography: This test allows your doctor to view the shape of your cornea to check for an astigmatism, an irregular curve that causes blurred vision. It can also help determine what type of contact lenses you need. Using a special photography technique, your doctor takes a scan of your eye to make a three-dimensional map of your cornea.

Ophthalmoscopy (also called a fundoscopy): This test helps your doctor examine the structures in the back of your eye such as the retina, the optic disk and the surrounding blood vessels. To do this, your doctor will use pain-free eye drops to widen your pupils. Once your pupils are fully dilated (after 15 to 20 minutes), they will shine a light through your pupil to view the back of your eye.

Slit-lamp exam: A slit lamp is a special type of microscope that magnifies and illuminates the front of your eye. This test enables your doctor to examine your eyelids and lashes, as well as all the cornea, lens and iris. Sometimes, your doctor may use eye drops containing a harmless dye during this test. These drops can help them check for damaged cells and other injuries.

Tonometry: This test measures the pressure inside your eye and helps detect conditions like glaucoma, a disease that causes optic nerve damage. Your doctor will apply numbing eye drops, then use an instrument called a tonometer, which releases a tiny puff of air on your eye, to calculate how much force is necessary to flatten a portion of your cornea.

Alternatively, your doctor may use a flat-tipped cone device, which touches your cornea to evaluate your eye pressure. This may sound uncomfortable, but don't fret: the procedure is painless since your eyes are numbed.

Fundus photography and optical coherence tomography (OCT): These imaging tests help identify various retinal, optic nerve and corneal conditions. Your doctor will first dilate your pupils, then use a camera or an imaging scanning system to take digital photos of your eye structures.

What to expect after an eye exam

After your eyes have been dilated, they'll be more sensitive to light, and your vision will be a little blurry for a few hours. For this reason, you should avoid activities such as driving or looking at bright screens for several hours after an eye dilation. Be sure to plan ahead and make sure you have a ride home after your exam. Wearing sunglasses is also a smart idea to help protect your eyes until your pupils return to their normal size.

Now that you know what to expect during routine eye exams — and that they're simple, easy and painless — you can feel confident visiting your eye doctor for regular annual check-ups. Doing so lets your doctor detect and treat any eye problems to help keep your eyes healthy for years to come.