Help with patient/member troubleshooting

[rolandclaur]

OD -4.50 -.75 30
OS -4.75 -1.25 175

Add: +2.25

PD
OD 32.5
OS 31.0

Seg ht 25.0

Frame 54/17 42 B

First time progressive wearer. Fit into Hi-Index Ovation. Distance is fine. Chief complaint is that left eye is not able to read as well as right eye. She notices power change into reading much sooner with OD than OS as she occludes each eye. States that reading area is also much smaller and confined with OS than OD. DR trial framed and says refraction is correct. I went through normal trouble shooting protocol.. Neutralize DRP, NRP, PRP, visual inspection of lenses for warpage, etc. BC's same ou.. Vertex distance Ok.. Normal 10-12 degree amount of panto. Only thing I noticed was slight prism imbalance.. (1D U OD) at the PRP. Would this impact her that much? Any help would be greatly appreciated. Thank you

[Robert Martellaro]

The wearer is not equipped to evaluate the monocular performance of each lens, so tell her to cut it out (SVDO to +2.25 PALs isn't fun, even for a myope, so go nice 'n easy). Otherwise, lose the prism, and let her visual cortex do its thing, about ten to twenty days.

[EyeCare Rich]

+1 Robert. Of course there is going to be a difference between the two, they are different cyl and - powers. should stabilize with time.

[wearegood]

+2 Robert. He needs time to feel good with the very first progressive glasses.

[rolandclaur]

Shes had them for over a month already still w same complaint...distance is fine but as she reads she feels her left eye is not gettig the proper magnification down the corridor at the same time her right eye is.. Also states that reading area smaller OS.. Maybe use unequal seg hts (OS 1-2 mm higher) and/or Unequal ADDs?

[Jubilee]

Is the prism imbalance still there?

Typically there is some prism thinning ground in. Sounds like the OS received more than the OD. Perhaps she is sensitive to it?

[Diane]

OD -4.50 -.75 30
OS -4.75 -1.25 175

Add: +2.25

PD
OD 32.5
OS 31.0

Seg ht 25.0

Frame 54/17 42 B

First time progressive wearer. Fit into Hi-Index Ovation. Distance is fine. Chief complaint is that left eye is not able to read as well as right eye. She notices power change into reading much sooner with OD than OS as she occludes each eye. States that reading area is also much smaller and confined with OS than OD. DR trial framed and says refraction is correct. I went through normal trouble shooting protocol.. Neutralize DRP, NRP, PRP, visual inspection of lenses for warpage, etc. BC's same ou.. Vertex distance Ok.. Normal 10-12 degree amount of panto. Only thing I noticed was slight prism imbalance.. (1D U OD) at the PRP. Would this impact her that much? Any help would be greatly appreciated. Thank you

Using Prentice's Rule, there is approximately .55 D difference in the right and left eye at the reading level. You indicate the SAME seg height/MRP. I would double check the centers, precisely. If EVERYTHING checks out....then my next observation is that the OD is closer to oblique, while the left is WRA. Sometimes this type of patient does much better with a digital PAL.

Let us know how this patient does. I'm interested.

Diane

[Diane]

Looking at the Rx, I am curious why the OS rather than the OD, since the OD is the near oblique. What is the patient's BVA in each eye? Which eye is dominant?

BTW, you mentioned that you observed 1D BU in OD. Without that 1D BU, this is approximately the prism you would have.

OD -3.0625 @ 10 mm below OC would result in .30625 Prism BD OS -2.5125 @ 10 mm below OC would result in .25125 Prism BD
Resulting in 0.055 prism vertical imbalance.

With it, this is what you would have.

OD -3.0625 @ 10 mm below OC would result in .69375 Prism BU OS -2.5125 @ 10 mm below OC would result in .25125 Prism BD
Resulting in 0.945 prism vertical imbalance.

I would have the OS remade with the same prism since she likes it in the OD to see if that works.

I'm still very interested in this.

Diane

[Robert Martellaro]

Only thing I noticed was slight prism imbalance.. (1D U OD) at the PRP. Would this impact her that much?

When looking at a reduced Snellen chart, the BU prism in the right eye will displace the 20/20 line downwards into the higher add power of the PAL, and the BD prism in the left eye will displace the line upwards into less add power.

It's likely that your client is turning her head and/or lifting or lowering her chin when self-testing the near monocular vision, producing uneven and incorrect results.

[rolandclaur]

BVA~20/20 OU.. The prism imbalance at PRP (1D U OD) is not prescribed but from prism thinning (though i thought prism thinning was predominantly in higher plus Rx's). Dominance is unknown to me... Robert your post is interesting.. Im starting to believe that the prism imbalance, due to prism thinning, is whats causing her visual difficulties..

Diane why do u feel a digital lens would work better? (just trying to pick your brain) :D. Like u said earlier im surprised shes having more difficulty w the non oblique eye..

[Happylady]

Have you remarked the lenses with the fitting cross and looked at where they sit on her eyes? Maybe one is off a little.

[junebug72]

i except vertical imbalance as a very possible cause, i would like to point out that prism thin is always ground base down i would have never passed that lens that is why there is a 1/2^ limit in tolerance for prism isn't it? just turned one down last week for the same reason 1 1/4 base down in od 1/2 base down in os, remaking the os. as an inspector its good to know i saved that patient the struggles that your patient is dealing with. i would get another os lens you have to eliminate that prism as part or all of the problem.