Ever wonder how your optometrist can tell what's really going on inside your eye? It's possible because of specific machines that were designed to examine different parts of your eye and check its functions.

When you get a comprehensive eye exam at Eyeglass World, these are the machines that a optometric technician and optometrist will use when checking out your eye health.

These machines may be used to run assessments before your eye exam (during pre-screening).

Tonometer

Many know this as the "air puff machine" because that's what it does. After sitting on a stool behind the machine, patients place their chin on the rest, look at the light and then you feel a puff of air in your eyes. This machine tests read the pressure on your eyeball and can help diagnose glaucoma. Because of the importance of this test, especially for those more disposed to glaucoma, this test is performed at every eye exam. (PS: the puff doesn't hurt! It may just startle you a little)

Auto-refractor

This machine will read your eyes and automatically figure out your prescription. How does it work? It takes a measurement of the way light changes as it enters your eye and how the light hits the retina. You don't have to do anything but sit there and have the machine read your eyeballs. Simple and painless thanks to the technology this machine uses.

These machines may be used during your actual eye exam.

Slit Lamp

This lighted microscope tool is what your doctor uses to look deep into the back of your eyes. With the help of this tool, he or she can examine the structure of your eye and assess the back of the eye. The magnification it offers allows your doctor to see things a little bit more clearly than he would with just a regular flashlight.

Opthalmoscope

This is a small handheld machine used to check your retina, as well as the arteries and veins in your eye. If you are visiting your doctor for a special eye condition, like conjunctivitis, this tool is used to see the redness and irritation more clearly.

Phoroptor

You may know the phoroptor machine because it looks a like owl eyes. It has many lenses that can be flipped back and forth (Is it better with 1 or 2?), and every optometrist uses a phoroptor to test your level of vision correction. While sitting in the exam chair, patients look through the phoroptor while the doctor switches the lens strength in front of your eyes to see how well you read through each strength of lens.

Keratometer

This machine measures your cornea's shape. If your cornea is more round or more flat, this will determine whether or not you have astigmatism or corneal problems. For contact lens wearers, this machine assesses the shape of the eye to find the proper contact lens fit.

Retinoscope

The optometrist's retinoscope is a handheld flashlight-like gadget used to test the reflection of light off of the patient's retina.