If you wear glasses, you may have been tempted before to take your prescription and order contact lenses with it online. We understand this impulse, but at River City Eye, we want you to understand how different the prescriptions are, and why it’s not a good idea to use them interchangeably.
The short answer is no, your prescriptions for contact lenses and glasses are not the same. While they both correct your vision, they work in very different ways because of where they sit in relation to your eye, requiring separate exams and unique measurements. If you’re curious about the freedom contacts can offer for sports, special events, or just a new look, our team would love to help walk you through the process.
Why Prescriptions for Glasses and Contacts Are Different
The main reason for 2 separate prescriptions comes down to a simple matter of distance. Your glasses rest on your nose, about 12 millimeters away from your eyes. This small gap changes how light focuses on your retina (the back of your eye). Think of it like using a magnifying glass: The distance you hold it from the page changes its focus.
Contact lenses, on the other hand, sit directly on the surface of your eye, the cornea. With no distance between the lens and your eye, the power required for clear vision changes. A prescription for glasses doesn’t account for this, so the numbers need to be adjusted by an eye care professional.
What a Contact Lens Prescription Includes
Special Measurements for the Right Fit
A contact lens prescription contains much more than just the power needed to correct your vision. It also includes specific measurements to confirm the lens fits the unique shape of your eye for both comfort and health.
Here are some of the measurements a contact lens prescription can include:
- Base curve: This measures the curvature of the contact lens. A proper base curve matches your cornea’s shape, helping the lens sit comfortably.
- Diameter: This is the width of the contact lens from edge to edge. It helps make sure the lens is large enough to cover your cornea correctly.
- Lens brand or type: The prescription can specify the exact lens brand and model, which is important because different brands and materials can affect comfort and moisture retention.
- Lens material: Different materials offer different levels of oxygen flow and moisture. Your eye doctor can help you choose a material that suits your eyes and lifestyle.
Why the Right Fit Matters
Getting the fit of your contact lenses just right is about more than feeling good: It’s also important for your eye health. An accurate fit helps with clear, stable vision without the lens shifting around too much when you blink.
A well-fitted lens also means that the right amount of oxygen can reach your cornea, which is essential for keeping your eyes healthy. This attention to detail, along with proper contact lens care, is key to comfortable, all-day wear.
How to Get a Prescription for Contacts
If you want to try contacts, you need a specific contact lens exam and fitting. This is different from a standard eye exam. During the fitting, the eye doctor checks how the lens moves and settles on your eye to confirm a good fit.
Your eye doctor in Happy Valley can provide you with trial lenses to wear for a short period. This lets you see how they feel in your daily life before you order a full supply, like at work or during your favorite hobbies. A follow-up visit is usually scheduled to check that the trial lenses are working well for you.
Can You Convert a Glasses Prescription Yourself?
The Simple Answer Is No
You may find online calculators that claim to convert a glasses prescription, but it’s not a good idea to do it yourself, as they can’t guarantee accuracy. A qualified eye care professional should perform any conversion, because it involves more than just a simple calculation.
The conversion requires complex formulas that account for the lens power and distance from the eye. It’s especially important for correcting conditions like astigmatism, as the values for this condition vary widely between glasses and contacts.
Your Next Step for Clear Vision
Ready to explore a new way of seeing the world? The first step is to schedule a dedicated contact lens exam. This is a chance to discuss your vision, goals, and lifestyle with a professional who can help you find a great solution.
We know that everyone wants contacts for different reasons. Whether you’re picturing yourself wearing them every day or just throwing them on for the occasional activity, we have options for you.
The goal is to find what works for your life, whether it’s daily disposables or monthly options. Finding the right solution is a collaborative process focused on your unique eyes and what makes you feel comfortable and confident.
Book Your Visit
At River City Eye, our team is here to go above and beyond to help you navigate your vision options. If you’re looking to try out contact lenses and enjoy concierge-level care, we’d love to see you. Schedule your contact lens fitting today.
