The Difference Between a Regular Eye Exam and a Contact Lens Exam

You had your eyes checked last year. The doctor gave you a prescription for glasses. Now you are thinking about contact lenses. You might assume you can use that same prescription. That is a common thought, but it is not correct.

What a Regular Eye Exam Covers

A routine eye exam focuses on the health of your eyes and the quality of your vision. Your doctor checks how clearly you see at different distances. This part of the exam finds refractive errors like nearsightedness, farsightedness, and astigmatism. The doctor also examines the front and back of your eye for signs of disease. Glaucoma, cataracts, and macular degeneration are all on the list.

By the end of a regular eye exam, you receive a prescription for eyeglasses. That prescription is designed to correct your vision with lenses that sit about twelve millimeters away from your eyes. It is a snapshot of how your eyes perform on their own, without anything resting on them. That is where its job ends. Contact lenses need more information.

What a Contact Lens Exam Adds

A contact lens exam includes everything in a regular exam, but it goes several steps further. It is designed to find out how a lens will sit on your eye and how your eye will tolerate it. These added steps are not optional. They keep your eyes safe and your vision sharp.

Measuring the Shape of Your Eye

The first big difference is the measurement of your cornea. This is the clear dome at the front of your eye. A regular exam does not measure its shape. A contact lens exam does. You will look into a device that shines a ring of light onto your eye. The test is quick and painless.

The result is a detailed map of your cornea’s curves. This map tells the doctor exactly what size and shape of lens will fit. A lens that does not match the curve of your eye can slide around, cause redness, or even scratch the surface. A good fit keeps the lens centered and comfortable with every blink.

Looking at Your Tear Film

The lens rests on a delicate film of tears that covers the eye. If that layer is not stable, the lens can feel gritty and dry. In a regular exam, your tear film gets a quick look. In a contact lens exam, it gets a much closer look.

Your doctor may place a drop of dye in your eye and look through a microscope to see how your tears spread and how quickly they break apart. If your eyes are dry, the doctor can suggest a lens that holds more moisture. Skipping this step can leave you with scratchy, blurry vision.

Why the Prescription Changes

Your glasses prescription will not work for contact lenses. The strength changes because the lens sits directly on your eye rather than a little farther away. Your doctor will adjust the prescription by putting a trial lens on your eye and asking you to read a chart. This small change makes a big difference in how clearly you see.

Trying the Lens and Follow-Up Care

A regular exam ends when you get your glasses prescription. With a contact lens exam, you try on a lens, and the doctor checks how it moves when you blink and asks about comfort. If it does not fit well, you try another lens until it feels right. You also learn how to put in, remove, and care for your lenses. Usually, you come back in a week or two to make sure everything still fits well and your eyes stay healthy.

For more on the difference between regular eye exams and contact lens exams, visit Eyewear Society. Our office is in Covington, Louisiana. Call (985) 893-2722 to book an appointment today.

https://www.allaboutvision.com/eye-care/eye-exam/types/eyeglasses-vs-contacts-exam/

https://www.optometrists.org/general-practice-optometry/optical/guide-to-contact-lenses/what-are-contact-lenses/the-contact-lens-exam/