What Exactly Does Contact Lens Diameter Measure?

Two Contact Lenses with Water Droplets isolated on Grey Wet backgroundQuestion

I am wondering about contact lens diameter.

The contact lens I am currently using is 14.5 in diameter, but I am currently out of the country and I am having a hard time finding lenses with that diameter. Does the contact lens diameter measure the diameter of the iris/area of the contact lens covering the pupil or does it measure the diameter of the entire lens itself?

Also, what differences will I experience if I switched to a 14.2 or 14.0 lens?


There are a few specifications for a contact lens:

  • OS/OD/OU (left eye/right eye/same for both eyes)
  • Add Power (strength, if any)
  • Base Curve (the curvature of the lens)
  • Diameter
  • Cylinder (for astigmatism)
  • Axis (for astigmatism)

The contact lens diameter is measured in millimeters from one edge of the lens to the other edge. The diameter determines where on your eye, the lens will rest. If this is wrong, you can run into problems. The lens will irritate your eye or even cause abrasions.

This specification is important, so get the exact lens diameter that your prescription calls for.

What People Are Saying

PG23 said:

I would not recommend that you wear a different lens other than what you are prescribed, though. Don’t just order something else because you are out of the country. Lots of websites will deliver all over the world, so just go to CoastalContacts.com and order your correct lenses. If you have the boxes with you, you can just get the brand name and all the numbers you need off the side of the box.

w. Hunter said:

It measures the width of the lens in millimeters. · I just hope people aren’t looking only for the cheapest price for contact lenses which isn’t always a good idea according to http://www.coloredcontacts.com where they state: “When it comes to the health of your eyes, the best buy for affordable or cheap contact lenses is purchasing the best quality brand name product at the most affordable price. For example, the Freshlook contact lens brand is a quality product manufactured here in the United States, a manufacturer that follows strict quality control guidelines, and therefore produces a high quality color contact lens.

On the other hand, if you purchase the cheapest priced contacts because they were low priced, you may be getting lesser quality, cheap contacts. When looking for inexpensive or cheap contact lenses online, look for known reputable manufacturers. Finding the lowest, rock bottom price usually does not equal the best quality. You could be putting your eyes at risk. When it comes to colored contacts, if you want the best we recommend Ciba’s Freshlook colors and colorblends contact lenses.”

Dee said:

Hi there, I am a newbie contact lens wearer and my optometrist has prescribed a 14.5 diameter contact lens for me. This seems HUGE around my eye and is +/- 3mm larger than my cornea area. I asked him if I can have a smaller one rather (as a friend told me it looks like I have a fake eye) and apparently the smallest I can go is to a 14 diameter, which wouldn’t be worth it. Just want to check before I take his word on it.
Many thanks!

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  1. Reply

    My prescription diameter is 13.25, but the companies are only listing 13.0 or 13.5, what should I do!? I have looked at every site on the internet and NO ONE has 13.25!

      • Contact Lens Girl
      • April 19, 2020

      We suggest calling a contact lens manufacturer or online store and see if they can get those for you.

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