I recently had eye checkup (after 3 yrs). I'm 51 and have been wearing Progressive lenses (my first pair) for last 3 years. My distance prescription hasn't changed, however, the axis increased in both eyes. The doctor changed my reading power from 1.75 to 2.25. I'm having eye strain and headaches all the time now.

With my old lenses, they told me I saw 20/20. Things just seemed to not be as clear as they should be. I could see well though from top to bottom of lenses and the normal distortion at the sides of lenses was minimal and not bothersome.

With the new lenses, the "distance" is clearer, but sometimes I feel like it might be a little too strong. Also, there is "more" noticeable distortion(or blurriness) at bottom and sides of lenses which is very bothersome (I guess from the increase in bifocal power). Looking through my lenses now seems like it has the binocular effect. That's the best way I can describe it.

I have eye strain and headaches all the time now. I didn't change frames, just lenses. They tell me that both old and new lenses are made the same way with same material, etc. Both lenses have anti-reflective coating and they are transition lenses.

I wonder if the "axis" isn't correct which might make them seem a little strong and could a doctor make a mistake? Or could it be the increased power of the bifocal causing the increased noticeable distortion at the bottom and sides of the lenses that I see that is causing all my eye strain and headaches? I think the increased power in the bifocal has caused the way I see the "mid" distance to change also. I see well enough to read and sit at computer without glasses. If my problem is from the increase in the bifocal, I'd much rather go back to the 1.75 power. They keep telling me that 2.25 is where I should be, but it isn't worth it if I have eye strain and headaches all the time.

With my "old" lenses, my eyes felt more relaxed. Even though things looked like they could be a little clearer overall, I wasn't bothered with the 'minimal' distortion and I wasn't having eye strain and headaches. The doctor seems to think this new prescription is right, but clearly something "isn't" right.

I hope all this makes sense. I'm feeling very frustrated right now. Any help would be much appreciated.

Thanks!

Is the 1.75 and the 2.25 negative numbers?

If they are, take off your glasses and take a normal typewritten page and measure the distance from your eye to the paper and report back.

The numbers are (+) positive numbers.

Are you nearsighted or farsighted?

How is the prescription written?

Something like:
-4.25 +75x140 / 1.75

I am nearsighted. My prescription reads like this:

Spherical Cylindrical Axis

(distance) O.D. -275 +.50 165
O.S. -275 +.25 055

(near) O.D. +225
O.S. +225


My "old" prescription read like this:

Spherical Cylindrical Axis

(distance) O.D. -3.00 +.50 147
O.S. -2.75 +.25 038

(near) O.D. +1.75
O.S. +1.75


The doctor said there wasn't much of a difference between the 2.75 and 3.00 for the distance. Does that seem like a big change in the "axis"? Does the axis change because your eye changes shape? Therefore, that is where you see the 'best' according to the tests they do? So there is no way that could be wrong?

Would the increase in the "reading" power be enough to cause "more noticeable distortion at the bottom and sides of the lenses? Does it change the "mid" power? If so, do some people just not get adjusted to that and have to go back to the weaker power so they can see more clear overall? If I have to be bothered by seeing that and the "mid" is not as good either, then I'd just as soon go back. I thought the 1.75 power was OK and besides I don't read with my glasses. I usually take them off to sit and read or look at the computer. I even watch TV a lot without them. They just tell me that the 2.25 power is where I should be and I should try to get used to it. I wonder about at least going back to the 2.0 power. I guess, to me, seeing good overall, is more important. I like seeing as close to 'natural' as I can, not having that 'handicapped' feeling. Having to put up with seeing all the distortion and not having the mid be as good as it should be. Maybe this is just part of getting older and everybody has to learn to deal with it.

I don't know what size my frames are, but the guy mentioned about thinking about getting a little bit larger(deeper) frames. (Mine aren't really narrow though) He said it wouldn't change things. It would just mean having to look lower in the lense ( I guess for reading)

Well, if you have any other thoughts let me know. Thanks!

Ahh! Your nearsighted. The decimal place was dropped on the first script.

So distance is basically the same with a little change in astigmatism. The -2.75 translates into a normal focal length of 1/2.75 meters or about 14" so you should see reasonably well without glasses from to 14" away from your eye.


Bifocals are specified as an ADD power, so -275+225 is a reading prescription of -0.50 diopters for the old or about a focal length of 2 meters (1/0.5).

The -2.75+1.75 is a prescription of -1.00 for "reading glasses" or about a focal length of 1 meter (1/1.00).

You can work out the numbers for the left and right eyes.

My opinion is that the nearsighted prescriptions are WAY overcorrected and are almost not needed.

If I remember right, the "normal" focal length for close is about 12". Essentially the distance when your holding something to read.

YOU have to pick a happy medium if you want these to be a pair of "All purpose" glasses. Tell the doc where you want your focal length to be and it can be set there or get glasses that are "task oriented".

The astigmatism corrections will be most apparent when reading signs at night. Some are difficult to correct. Verticle astigmatism will be more of a problem when driving because most uppercase characters are made from verticle strokes.

"Computer" glasses can be made in a number of ways. One way is to just make a pair at your normal distance from the screen. The other way is to make the bifocal HIGH. These glasses will be annoying if you had to drive with them, for you would have to "look up" to see at a distance. They would be great for someone sitting behind a counter in front of a computer.

You sound knowledgeable. So, let me see if I understand what you are saying. The "new" prescription (with the +225 add power) is too strong? I tried to check and see how far away things are when I read and it looks like about 14"or so. Looking through the bifocals in the "or so. Looking through the bifocals in the " lenses really bothers me. The distortion at the bottom and sides of the lenses is much more "pronounced" lenses really bothers me. The distortion at the bottom and sides of the lenses is much more "old" or noticeable. Things look better and my eyes are more relaxed looking through my "back" lenses with the +1.75 add power. I wonder if I should tell them I want to go "little" to the +1.75 power. Or should I try the +2.0 power? Would that help a lot with the distortion with a "the 2.25 power is where I should be and I should learn to adjust" increase in power? They tell me "small", but it is really bothersome and feels unnatural to me. What do you think?

Also, what do you think about the increase in the axis? Is that considered a "The axis is 'your' eye" change? I went from 147 to 165 in my right eye and from 038 to 055 in my left eye. They tell me, "totally" to my old prescription for now?

I hope I'm not sounding crazy! I'm glad you've taken time to try to help me. I just need to make a decision about what to do.

Thank you so much.

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OK, for fun. Take your glasses off and find a comfortable distance and look at the vertical lines. Cover an eye. Bet they might appear at different lengths, some lighter or at different apparent distances. Look at it corrected.

Now turn your monitor or your head 90 degrees and look at them. Bet they are more behaved.

The first is a result of verticle astigmatism which makes:

HELLO WORLD more difficult to see than

Hello world

This might be better:

HELLO WORLD

hello world

I'm still curious as to what distance you can see close without glasses. This should be about 14". The characters might appear distorted, but in focus.

Second, the prescription doesn't tell all.

The optician measures PD or pupil distance. He/she also comes up with a number relative to the pair of frames where to put the optical center and he bifocal.

There is a Near PD and a FAR PD and most opticans will put them the same unless they are way off.

An interesting lens to check out is the iZon lens at IZON. To me, it's like Lasik surgery on glasses. They, only within the last month or so became available in my area.

Lenses themselves offer some distortions. They have an index of refraction which determines the thinness of the lens.

I'm nearsighted as well and had 3 prescriptions made with the same frame:

Crown glass, AR one side, UV the other, Bifocal
Trivex plastic, inherent UV because of plastic, AR coated, bifocal - same as above

Crown glass, AR one side, UV the other, Hi Bifocal, Focal length probably close to 12". Desisgned for either prolonged close work and using laptop while in bed watching TV.

I was considering a single vision lens at the bifocal strength which I had in the past.

I don't need the bifocals to read, but they provide some relaxation to the eye. As a result, my vision does not change much over time.

When I did my little learning exercise, I did not pay attention to astigmatism because it was of little concern.

Now, I'll get in trouble for this one. With my camera, a ruler and some software, I virtually got the same FAR PD as my optician. We compared notes. I could do better measurements if I had someone else take the pictures.


I'll come back to your questions.

I need the max distance you can see close without glasses. Ignore distortions.

My guess, is that you would be better off with a new script that reads:

Spherical Cylindrical Axis

(distance) O.D. -2.75 +.50 165
O.S. -2.75 +.25 055

(near) O.D. +2.75
O.S. +2.75.

Essentially removing all the corrrections for reading near and put the focal length at about 14". This will keep the astigmatism corrections.

Ask the optician for the values of Near PD and Far PD (measured in mm) If they are significantly different make sure the near PD is used for the bifocal. That misalignment can also cause distortions.

Does this make sense?

I learned plenty! Thanks K.I.S.S..

I Switched from progressive lenses to ordinary bi-focals three years ago. My headaches are gone and the distortion is too. My female head is small, so my glasses must be small or they look really funny. It's hard for them to get the progressive optimal with small lenses, I've been told. Bi-focals are much cheaper too.

Your headaches seem directly related to the new lenses. Does the optometrist know that you are continuing to suffer this far into the adjustment period?

I tried the experiment with the lines like you said and in fact the lines did appear lighter and darker and different lengths! Actually, they looked that way with or without covering an eye.

Without glasses I can see to read at about 14" or so. I even sit across the room and watch tv without glasses and can see well enough. When I'm at home I go all day without putting them on. They did have me in a (+2.50) power bifocal and I complained that seemed too strong so they reduced it to the (+2.25) which I have now. So the +2.75 would "really" be strong.

I put my "old" lenses back in tonight. I'm so much more comfortable in them.

I think I've made up my mind to stay with these for awhile longer and take the new ones back. I'm going to ask them if they'll remake the "old" lenses for me though because I really do need a fresh set. I hope they won't give me any hassle about that.

Well, thank you for all your insight. Looks like you were of help to someone else too.

Take care.

***This is for simoneaugie:
You said you switched from progressive to regular bifocals. Don't you have to have correction for all 3 distances? It seems like that would be worse, but I know that small frames don't work well for progressives though. I know when I first started needing bifocals, I had the lined ones. I just had correction for far and close. Then later I needed correction for the "mid" range too so I went to progressives. It's terrible getting old! :)