Understanding How Lens Thickness Varies with Different Frames

When it comes to eyewear, choosing the right lenses and frames is key to both comfort and style. Many people don't realize that the same prescription lenses can look different depending on the frame they are placed in. In today’s blog, I’ll show you how lens thickness varies between different frames and share some tips for selecting the best lens material and frame style.

What We're Comparing

First, let me introduce the lenses I'm using for this comparison. My prescription is as follows:

Right Eye: -3.25 DS / -0.50 DC x 30

Left Eye: -3.00 DS / -1.50 DC x 165

I have about -3.00 diopters of nearsightedness, which is moderate, so my lenses are not too thick. I had the option to choose between two refractive indexes for the lenses: 1.56 and 1.60. I opted for 1.60 because it results in thinner lenses—always a plus for aesthetics and comfort.

Now, let’s look at the frames. I’m comparing two different styles: one is a pure titanium frame, and the other is a combination of acetate and beta-titanium. Both frames have similar overall widths: one is 50mm, and the other is 51mm. The slight difference shows that the 50mm frame is more suited to my face. When shopping for frames online, it's always a good idea to measure your current glasses to find the width that fits you best to avoid buying frames that are too large or too small.

The main difference between the two frames is the lens size. The acetate-beta titanium frame has a lens height of 41.5mm, while the pure titanium frame has a height of 35.5mm. The width of the lenses is approximately the same in both frames.

Lens Thickness Comparison

Now, let's look at the lens thickness for the 1.60 refractive index. You’ll notice that the bottom outer edges of the lenses are thicker in one frame—approximately 3mm in one and 4mm in the other. The difference in thickness is noticeable, but the thicker frame (the acetate-beta titanium) hides the edge of the lens due to its wider frame design.

Frame Weight Comparison

Next, let’s compare the weight of both frames. One weighs 19.56g, and the other is 15.51g. While both frames are comfortable, the pure titanium frame feels noticeably lighter, and even though the difference is only 5g, it makes a big difference in comfort, especially on the nose. The titanium frame feels nearly weightless!

For High Prescription Lenses: Tips for Choosing Lenses and Frames

Since my prescription is not very high, the thickness difference between the two frames isn’t very noticeable. However, for those with higher prescriptions, the difference becomes much more apparent. For instance, I have a friend with a prescription of +7.00 diopters, and they use 1.71 refractive index lenses. If they had chosen 1.60 refractive index, the lenses would be noticeably thicker.

Here are a few tips for those with higher prescriptions to make lenses look thinner and more aesthetic:

• The higher the refractive index, the thinner the lens—but this doesn’t necessarily mean that higher refractive index lenses are more comfortable to wear.
• Avoid large frame sizes—for high prescriptions, large frames tend to make the lenses thicker and heavier. Smaller frames are often a better choice for those with high prescriptions.
• Opt for full-frame glasses—a frame that fully encircles the lens will better hide the thickness at the edges compared to half-frames or rimless frames.

Conclusion

Choosing the right frames and lenses is a balance of style, comfort, and functionality. For those with higher prescriptions, paying attention to frame size and lens refractive index is key to getting the best results. If you have any tips or experiences with selecting eyewear, feel free to share in the comments below!

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