Glasses vs Contact Lens Prescription | Eye Associates

When you're getting your vision corrected, it might seem like a prescription is just a prescription. But if you've ever tried to use your glasses prescription to order contact lenses, you've probably learned the hard way: contact lens prescriptions and glasses prescriptions are not the same.

In this article, we’ll compare glasses and contact lenses across key areas like cost, convenience, and eye health. Then we’ll dive into the real technical differences between a contact lens prescription vs glasses. 
 

Glasses vs Contacts: Comparing the Essentials

1. Cost

 

• Glasses: One-time purchase. May last for years if well-maintained.
• Contacts: Ongoing cost for lenses, cleaning solutions, and replacements. Annual expenses can add up.

 

2. Convenience

• Glasses: Easy to put on and take off. No direct eye contact required. Less maintenance.
• Contacts: Great for sports, outdoor activities, and wearing with sunglasses. But they require more care, cleaning, and time to insert.

 

3. Eye Health

• Glasses: Least risk to eye health. They don’t touch your eyes, so no risk of infection.
• Contacts: Higher risk if not handled properly. Poor hygiene or overwear can lead to serious infections and dry eyes.

 

Are Contact Lens Prescriptions the Same as Glasses?

No. While both prescriptions correct your vision, they do so in different ways:

• Glasses sit about 12mm away from your eyes, so the power calculation for each lens is slightly different.
• Contact lenses sit directly on your eye, which changes the way light enters and focuses on your retina.
• A contact lens prescription includes additional details such as base curve, diameter, and brand — things not needed for glasses.

So if you’re wondering, "Can I just use my glasses prescription to order contacts?" the answer is: absolutely not. You'll need a separate contact lens fitting and prescription from your eye doctor.
 

Prescription Differences: Glasses vs Contact Lenses

This is where it gets technical. Your glasses prescription includes:

• Sphere (SPH)
• Cylinder (CYL) and Axis (for astigmatism)
• Pupillary distance (PD)

Your contact lens prescription includes:
All the above plus:

• Base Curve (BC) – determines the lens fit on your eye
• Diameter (DIA) – size of the lens
• Brand/Material – each lens fits differently

This extra data ensures that the contact lens fits your eye comfortably and functions properly.
 

Which Is Right for You?

There’s no one-size-fits-all answer. Here’s how to decide:

Choose glasses if you prioritize comfort, eye health, or cost-effectiveness.
Choose contacts if you value aesthetics, freedom of movement, and have the discipline to care for them properly.

Many people use both, depending on the situation.

Your eye care provider can help tailor a solution to your lifestyle and eye health needs. 

FAQ: Glasses vs Contact Lens Prescription

Can you convert a glasses prescription to a contact lens prescription?

Not directly. You need a separate contact lens fitting. The conversion requires measurements of your eye’s curvature and a proper lens trial.
 

Why is my contact prescription stronger than glasses?

Because contacts sit closer to your eye, the lens power often needs adjusting. It's not uncommon for your contact lens prescription to look stronger or slightly different.
 

How often should I get my prescription for glasses and contact lenses?

Every 1-2 years, or sooner if your vision changes or you're experiencing discomfort. Regular checkups ensure your prescription stays accurate and your eyes stay healthy.

Want to understand your prescription better? Dive into our full guide: How to Read Your Prescription.
 

In Summary

• Glasses and contact lenses require different prescriptions.
• Each has unique pros and cons in cost, convenience, and eye health.
• Always consult with your eye care provider to ensure you’re using the right prescription for the right product.