Progressive Lens Prescription

by Laurence
(San Ramon, CA)

Q: Help me with understanding my progressive lens prescription.

I have been wearing progressive lenses for a while and they have been good for all purposes, viz reading, monitor and distance. Lately I started to have problems with reading monitors and had a checkup and a new script. But the new script is the same.

The optometrist told me that my distance and reading are the same but my medium distance has worsened and the progressive lens cannot correct for that since there is no way to specify where the progressive lens starts. I took that on face value until I read there is a setting called segment height which she didn't mention.

My current script is:

Sphere Cyl Axis Add
R -3.25 -1 5 +2.5
L -3.00 - - +2.5

I found a pair I got many years ago with this script

Sphere Cyl Axis Add
R -3.00 -0.75 15 +2.0
L -2.25 -0.50 120 +2.00 segment 23

I find I can read monitors (and books) fine with this script but the distance is not so sharp. And interestingly this script has a segment measurement whereas my current and new one doesn't That could be because the optometrist didn't measure segment as I didn't have glasses yet.

I am wondering if I specify a new pair with the stronger spherical power so I can drive/watch movies clearly but use the weaker add measurements and then set the segment height so that I am using the lower part of the lens for reading and monitor, that would work?

I am getting glasses mail order so it's not so easy to get these measurements done in the store.


A: Hello Laurence,

First, I need to say that the distance vision diopters between the two prescriptions are different which shows that your myopia is advancing, so I think that you need a stronger prescription indeed for the far vision.

If your optometrist said that the distance and reading are the same, this could be. This means you should see well far, and close (reading), and here is the catch any diopters you have for far and near, the intermediary diopters are in between.

So, your intermediary vision is there on the lenses, but you have to find the right position for your eyes to see clearly. You should move up and down your eyes until you find the precise intermediary image.

If he said your distance and close diopters did not change, you don't need new glasses. You just need to adjust your position in front of the monitor. This should save you some money.

About the segment, the height of the diopters, this change depending on the frame, how narrow the frame is, so if you have the standard minimum height for the frame, the diopter segment will be normal. This can be changed only on some lenses that are customized, some of the last generation high-end lenses, but the standard works well, so I don't think this is the problem.

Hope this helps,

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