Vertex Distance

Progressive lenses are a modern alternative to bifocal lenses that assist two fields of vision and transition seamlessly between the two. The lens transition is invisible for both the wearer and those the wearer interacts with, as (unlike bifocals) progressive lenses have no visible lines between fields of vision. Various measurements are taken to ensure that the fields of vision sit in the appropriate part of the lens vertically, but vertex distance is a factor that can only be measured once frames have been chosen.

What is vertex distance?

After you’ve chosen your fancy new frames, there’s still an important final measurement that has to take place. That’s vertex distance, and it refers to the distance between your eyes and your progressive lenses.

Magnification effects vary with the distance between your lenses and your eyes. This can affect the quality of your vision, even if the near and far fields of vision sit in the right place vertically within a pair of glasses. You should ensure that the glasses you wear aren’t prone to falling down your nose. If this affects you, we want you to know that you shouldn’t have to adjust your glasses constantly. So whether you’re ready for a new pair or are just tired of pushing your glasses back up your nose, our friendly Calgary optometrists will help you choose your next pair of glasses. We’re also happy to adjust your current ones, so they fit properly.

How is vertex distance affected when switching from contact lenses to glasses?

Vertex distance is also very important to measure for patients who wear contact lenses and glasses. This is especially true if their prescription is -/+4.00D or more. Higher prescriptions will see a stronger magnification effect, and the contact lens power will be completely different from the glasses prescription. If you wear contact lenses, stop by Doig Optometry to ensure a proper match between your contacts and your glasses prescription.

Can you duplicate the vertex distance using your current glasses?

No, and we have many patients who wonder why they can’t just duplicate the vertex distance measured using the glasses they’re wearing right now. Simply put, it’s because every frame fits differently. Even the very same pair of glasses will fit two people very differently. To get an accurate measurement, we’ll have to see how your new frames fit on you. While ordering glasses online in your pyjamas is certainly convenient, it’s impossible to ensure the proper fit and vertex distance measurement unless we see your new frames “as worn” on your face.

The best way to set yourself up for a good and comfortable fit with your glasses is to have them professionally measured by one of our experienced optometrists.

Book an appointment online or call 403-333-3350
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