It seems to me if a PT has uneven OC's, the left is mostly always the higher one.
Am I crazy?
It seems to me if a PT has uneven OC's, the left is mostly always the higher one.
Am I crazy?
Not crazy, I think. Anecdotally 70/30, maybe 80/20 higher pupil height OS compared to higher OD, for those without prescribed vertical prism. I don't have time to prove it though...my software doesn't track it. A portrait artist might have more information on facial asymmetries (or an oculoplastic surgeon).
I've been fooled by a lid ptosis, so make sure you use the corneal reflex on a pre-adjusted frame. I've also noticed that as we get older the asymmetry sometimes increases, or becomes asymmetric from a previous symmetrical appearance.
Last edited by Robert Martellaro; 12-21-2016 at 05:11 PM.
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
My OS is set higher than my OD.
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Run into that several times before. If it's only 1mm I usually don't do 2 different segs due to tolerance, but every now and then someone needs it. No biggie, we just do 2 different segs.
Spoke too soon, this guy's OD is 2mm higher than his OS. lol
Wasn't posting for any issues or anything, just sharing an observation.
The question is, is the the right eye higher than the left eye more often than the left eye is higher than the right eye, when there is a difference, and not the prevalence of dissimilar heights in general.
N=1 doesn't tell us much, but I share your interest in your initial observation.
So, how about the x-axis? I have observed that when there are dissimilar mono IPDs, it's the right eye that has a larger value, especially when the difference is more than 1mm. On our right side, we seem to be down and out, so to speak. Anyone have a searchable database that can shed some light on these observations?
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
Most of my patients that have been asymmetrical have been surgical patients. One was a Pearl Harbor bombing survivor. Another, cancer. The only one I can recall (I know I had a few, but can't remember them) that was natural from God was an older lady that wore a 7x28 and had very minimal difference (1mm) but I can't remember which was higher.
If you measure closely enough you will find facial dissymmetry in just about everyone. We also hold our heads in different positions. Unless the dissymmetry is quite pronounced it is irrelevant to properly fitting a pair of glasses.
It's like measure Jello with a micrometer.
A 2mm error on the vertical meridian with a spherical single vision 1.00 D lens is inconsequential, but misposition that small amount with fitting heights on a trifocal, and it’s likely the client would reject it. I would reject it.
Changing the power to 10 D, even with single vision, will induce 2∆ of vertical imbalance, enough that most eyes can just barely fuse the image, not to mention the pain and fatigue after long term wear. The client will suffer. I would reject it.
Relevancy depends not just on the degree of mispositioning, but on the power of the lens in the meridian in question, as well as the lens design (aspheric/atoric, position of wear optimization, trifocals, etc.).
Best regards,
Robert Martellaro
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
I literally think the exact opposite. It seems OD is always higher than OS to me. I think the OS ear is usually the lower of the two though.
What is reality but a concept unique to each of us? Can anything be classed as real when our perceptions differ greatly on so many things? Just because we see something a particular way does not make it so.
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