Prism Effect on Edge of Lens

by Shane
(Warner Robins,Ga. USA)

Q: I just got new eyeglasses. They have much thinner lenses than before and have an antiglare coating.

The edges of the lens is very clear, like it was polished. This is creating a prism like effect that catches light and makes the edge light up. I've never seen this before, I checked all my old eyeglasses and all the lens have a matte finish to them.

What do I do to help stop this, it's very annoying?

Thanks, Shane

A: I understand from your description that you have rimless frames or semi-rimless because you can see the edge of the lenses. These are very nice frames, elegant and discreet.

When mounting the lenses in this kind of frames, the optician has two choices of finishing the polish:

- the dull(mat) edge or
- the transparent edge

Usually, they go with the clear type because is nicer and give the eyeglass an elegant touch.

These two choices are pure aesthetic; they should not interfere with your vision.

You said you have thinner lenses now, so if they are high index lenses, the transparent edge can create a prism effect and bend the light in an annoying way.

Well, there is a solution to this and is simple too… you can go back to your optician and tell him you choose the mat kind of edge because of the problem you have with the vision.

They will put the lenses back to the polishing machine and make the edges dull. This should work; the shaping machine should do this without making the lenses smaller, so they will be the same, only the edge will be dull.

Related Information

Rimless Glasses
High Index Lenses
Frameless Glasses Parts

Hope this helps,

Comments for Prism Effect on Edge of Lens

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Oct 27, 2014
by: Shane

These are full metal frames from Cargo, C5034 and are hi index lens. I'll call my eye Dr and see if they can help. I was thinking of just using paint on the edges.

Oct 29, 2014
by: Arpi

Well I don't advise you to paint the lenses edges, they will look strange and you can ruin your new glasses.

I looked for your frame, they are really nice frames, but I don't know the mounting method used and if they can make corrections to the edge. But if you go to the shop, I'm sure they will help you some way.

Nov 10, 2014
Thanks for the help
by: Shane

Still have the same problem, optician won't do anything to these lens. I have to buy new lens to fix problem.
I'll buy new eyeglasses online when I save up some money.
Thank You for your help you gave me and for helping others.

Nov 10, 2014
prism effect
by: Arpi

You are welcome!

I am sorry that the shop cannot help you. I will make a last comment though; they can try to put your lenses in a smaller frame, this way they can shape them for a smaller frame and make new edges, this time mat.

I tell you this, so you don't have to throw away these lenses. The question is if you will like a smaller frame?

Sep 03, 2015
F mount lenses
by: Balaji Microtechnologies

Good blog shared by you.Thanks for sharing this nice post.

Dec 29, 2016
Double vision 11 prism
by: Emil

My new glasses are giving me a lot of trouble from
the sun or bright rays that hit my edges of the

We painted the edge with marking pen but
it wears off in a week and I have the same trouble.

My last pair was real good no trouble can I use.

Regular black paint my out lens are about more than a halve of inch. What can I do to be able to drive with out going blind?
Thank you

Apr 15, 2017
Answer - Double vision 11 prism
by: Arpi

Hello Emil
As you know, the bigger the diopters are, the thickest the edge. The marker is a temporary fix to this, but as you said, is just temporary.

I think the better solution is to find a better lens, I mean there are high index lenses with the advantage of being thinner at the edge. This is the best possibility, this should solve your problem.

With an antireflex coating to keep away the unwanted light rays and with the edge polished white to block the rays, it is the best option.

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