Need advise on monocular patient

[Optom]

Hello,

I refracted 56 yrs old monocular patient this afternoon.

Her prescription is:

R: Plano/-1.00DC X 080 ADD 2.50DS

L: Plano(Artificial Eye).

She requested progressive powered lenses with MAR coating. I took her order. Mono Pd 30mm, she selected metal frame, vertical height(B)32mm.Fitting ht.17mm.

Now the problem:

Other ECP in my office advised me against prescribing PPL because she is one-eyed customer. He advised me to prescribe her round seg or flat-top bifocal instead. I don’t see any problem with her having progressives. I talked with lab tech and he puts “let’s give try”.

What would you fit her with? Please advise.
Best regards,
Optom

[shanbaum]

Progressive - why not? The more important choice would be the material: use a polycarbonate lens, if possible, to better protect her remaining eye.

Is poly available, and if so, is it widely used, in Africa?

[shanbaum]

I am quick to add: "poly or Trivex"...

[Texas Ranger]

optom, I have many pts that are monocular, and the ones with pal lenses are the most pleased, it is a good idea as shanbaum reccomended, poly or trivex, safety is an important issue...

[Homer]

"Why not" is the answer! I agree with the advice above.

[Robert Martellaro]

Check the near PD. If it's the same as the far, you (lab) will need to rotate the lens to eliminate the inset. Once rotated, a new 180 line is created for surfacing.

Robert

[Homer]

I do tend to set the MRP (or whatever you want to call it) wider for nonocular patients, thinking that this is closer to reality for their field vision. I don't think the inset on the PAL will be a problem at all.

[Joann Raytar]

Dr. Kapasi, is the other ECP concerned about peripheral vision?

My father has sight in only one eye and did fine with a progressive. He had an accident as a young boy so he had already learned to deal with his vision a long time ago, the progressive wan't too hard an adjustment.

[Optom]

Shanbaum I do not know of professional surfacing lab in Africa (not sure of South Africa). Our office usually places orders to a lab in Dubai.

Yes, I have put remark on customer rx for poly or trivex.

Jo, the other ECP was concerned of monocular sight, and patient selection of small frame. What brand of progressive lens your father is wearing?

I really appreciate prompt advises and thank you all for the same. I can go ahead with order now.
Best regards,

Optom

[Joann Raytar]

Varilux Comfort.

[drk]

There is legitimate concern with a monocular patient wearing a progressive. I've found monocular patients are more sensitive to the drawbacks of progressive lenses, chiefly the reduction in peripheral vision, and often do better with segmented multifocals.

And we are overlooking the possibility that this patient wears her glasses for near only, in which case a segmented multifocal (8x35 TF) would be the best overall for vision.

Nevertheless, there are many advantages to progressives, not the least of which is fashion, and it's worth a try. A design that respected the distance peripheral vision would be the best, therefore a "harder" design. Despite the 17mm fitting height, I'd avoid a short corridor lens. I'd actually try a Percepta, first, since it emphasizes distance vision.

Robert, I've never considered adjusting the inset due to reduction of convergence. By rotating the lens temporally, would you not increase temporal blur above the 180 line? I'm not aware that monocular patients have a reduction in their convergence when reading. You could argue that absolute presbyopes do not converge as much as emerging presbyopes, since they do not have accommodative convergence. Do we take that into account? (I really don't know the answer to that.)

Similarly, Homer, by increasing the distance pd you seem to be inferring that a monocular patient somehow does not look straight ahead, but turns his head in order to maximize his field of vision. What is the rationale behind that?

[Optom]

Order sent for poly kodak concise, noted percepta for future consideration, does it work well with small frames?

Rgds,
Optom

[chip anderson]

It's simple. Progressives achieve their add with greater or lesser degrees of controlled aberration. With a binocular patient the brain can ignore some of the aberration when things are in an outward gaze in one eye by focusing on the clearer image in the other eye (lens.) With a monocular patient he must deal with one set of aberrations with no fellow image to use. Much as one can ignore the optic nerve blind spot (scotoma) with one eye as long as the other sees the object and compensates.

Not to mention when one is monocular the nose gets in the way for a lot of things and this would be less obvious with a segmented bifocal.

Chip

[Robert Martellaro]

Robert, I've never considered adjusting the inset due to reduction of convergence. By rotating the lens temporally, would you not increase temporal blur above the 180 line? I'm not aware that monocular patients have a reduction in their convergence when reading.

DRK,

It depends on how long they have been monocular. If the vision loss was recent there will probably be a normal amount of convergence. If it has been since birth there will probably be none. I haven't had any complaints with the distance peripheral vision when this is done, probably because I use PALs that are cleaner on the 180 like the Life and the Gradal. I am getting very positive feedback with the near vision though.



Optom,

The Concise has about has much distance peripheral blur as any lens I've tried, essentially no worse or no better than any other short corridor design. Contrary to conventional wisdom I prefer the short design (add 2.25) and use it frequently for higher add powers (>1.50) when the frequency of close tasks is above average.

The Percepta will not work well in a small frame. A 2.50 add will need the full 22mm rec. by Sola. Even then I would only use it (higher adds) if the client was a very light reader.

Robert

[drk]

Robert,

Thanks for the correction on the Percepta call. My thinking is that it has a clear distance portion with nothing above the 180. Is there a better idea for a small frame for clear distance, or are we in a catch-22?

[Spexvet]

Check the near PD. If it's the same as the far, you (lab) will need to rotate the lens to eliminate the inset. Once rotated, a new 180 line is created for surfacing.

Robert

...


DRK,

It depends on how long they have been monocular. If the vision loss was recent there will probably be a normal amount of convergence. If it has been since birth there will probably be none. I haven't had any complaints with the distance peripheral vision when this is done, probably because I use PALs that are cleaner on the 180 like the Life and the Gradal. I am getting very positive feedback with the near vision though.

Robert,
I agree that convergence needs to be taken into consideration, but can you measure that with the pupilometer? I ask the patient to read something, and watch where they hold the material. Some will hold the material in front of their nose, while others will hold directly in front of their eye.

Have you used the pupilometer and gotten the same distance and near PDs for a monocular patient?

[Pivot]

Currently I have 3 patients we've fitted with monocular progressives.

I tend to use V.Panamic with the full 22mm depth frame allowing.
Fitting it 0.5 lower by default and pad adjustment to raise if required.

Observing the patients reading habit is good advice. I have decentered 2 of these clients 1 mm long of their near half pd with good results. However their distance Rx's are not very strong.

They are very sensitive to visual discomfort when they knock the frame out of alignment over time, so be sure to advise them to return any time they feel they've bashed them about.

If they are avid "Bed readers" - suggest these will be great for everyday but they might still prefer to have a reading set for bed so they can get comfy.

[Robert Martellaro]

Drk,

There was nothing wrong with your recommendation. The small frame prerequisite came afterwards.

Except under certain circumstances I'am ignoring the performance of PAL performance on the distant periphery. I make note of it and show my clients the difference so that they know that the blur is normal, but I'am more concerned with near vision performance. Most of my clients are age 60 and older and really appreciate improved vision at near. I'am using a lot of short corridor lenses and probably fitting more occupational lenses (computer) than sunglasses.

Robert

[Robert Martellaro]

I agree that convergence needs to be taken into consideration, but can you measure that with the pupilometer? I ask the patient to read something, and watch where they hold the material. Some will hold the material in front of their nose, while others will hold directly in front of their eye.

Have you used the pupilometer and gotten the same distance and near PDs for a monocular patient?

Sexvet,

I have one but I haven't used it in fifteen or so years. I get the distance monocular PD by observing the lens markings I place on a pre-adjusted frame and their alignment with the corneal reflection I get from a really cool hand held that shoots the light out from the side. It looks like what the "Men in Black" used to erase peoples memory. Now when I measure an adolescents PD I tell the boys "this won't hurt a bit... and even if it did you won't remember it". The light came with a device that looks like a frame but is very narrow with slits in front of both eyes. Above and below the openings are millimeter scales. There is vertical line on the bridge and another one on an overhang about a half inch in front of the bridge. This gets the your eye aligned to eliminate parallax error. Its function was to measure near PDs only. There were charts that showed how much to add to each eye to get the far PD (that won't work with todays PALs). It came from a now defunct Minneapolis Co. called Precision Cosmet ( I believe the first CL company to make a GASP with a soft lens flange). It was called the "PD light and Meter". If there are any ex-Bensons folks reading this you know what I'am talking about.

You should be able to measure the near PD by changing the focal distance on the pupilometer, with 40cm being typical for near. And yes, I have had two people this year with essentially the same far and near PD. Both were very young when the vision loss was detected and presently have no vision or light perception in one of their eyes and are wearing PALs.

Robert

[Optom]

Hello all,

This patient lost her left eye to fire work displays decennium ago. I did not find it necessary to measure her near PD since she is monocular for long time now (please correct me if this was wrong) though her occupation demands more use of near vision.

Convergence inapplicable, normal EOM movements. I considered her request for PPL for appeal reason, what would be the best choice for her in a small frame?

Also I have recommended her to have a separate pair of reading glasses for longer period of close work.

Best regards,
Optom

[chip anderson]

Optom: Yes you need to measure the P.D. on all lenses. In this case only the seeing eye is important but prism and alignment is still important. Unfortunately you need to state a P.D. for both eyes or the lab is liable to think it is a binocular measurement and send the back with a 32 combined P.D. (Yes, I have had this happen.

[Clive Noble]

I can think of at least 6 'one eyed' patients we have.

One is a very good friend of mine who lost his left eye in a road accident 25 years ago. We often travel together, him driving, so when it comes to making his glasses, I take into account my own safety!!!!!!

The last 3 pairs have been Gradal Top, I insist on a frame with a sensible 'B' measurement where the height can be adjusted with metal pad arms, I cut the lenses about 1mm lower than normal to give him the maximum distance peripheral undistorted vision. for the occasional close reading, he just 'honks' his glasses up on his nose.

I apply this formula to all mono patients and would not be happy fitting short 'b' measurement frames.

I use regular TOP lenses on all our mono patients, and have never had a problem over the many years I've been fitting these guys, in fact I always say they are the most successful PAL patients

[Optom]

Thank you very much everyone for sharing your experiences, surely now I am going to make better choice of multifocal lenses in exceptional cases.

Best regards,

Optom