How do corrective lenses affect what is perceived?

[JulieN]

I assume we have two issues that affect how a diamond is perceived; 1, the lens itself has a refractive index. And 2, the corrective power of the lens, either for hyperopia or myopia. We will assume that people who wear corrective lenses have the same average viewing distance as people who don't wear correction.

Is there something a person with corrected myopia / hyperopia can do in diamond selection to increase the positive attributes of diamond appearance that are different from the commonly recommended TIC parameters?

 

[Garry H (Cut Nut)]

You will see more fire if you are long sighted and take your specs off. Otherwise I do not think us spec / contact wearers have much choice.

 

[Karl_K]

They do not have the same in focus viewing distances as someone who does not have correction and its a much narrower range.
At best with correction close in vision is at its best with in a couple inch range.
If set for screens, computers and phones in general the distance is set around 20 inches, which is 17 degrees obstruction not 24(12 inches) and certainly not 30(8 inches)
What about progressive lens? They have a much smaller range also but wider than a bi or tri lens but they only have a limited difference in viewing distance that can vary depending on how they are prescribed.
Again if you say you look at screens a lot you will get a longer distance, some doctors just assume your going to be using screens and set a longer distance.
It is one of many reasons the obstruction models used for current calculations are way off, even worse than being cyclopes they assume the incorrect distance for a large portion of the population.

 

[Garry H (Cut Nut)]

They do not have the same in focus viewing distances as someone who does not have correction and its a much narrower range.
At best with correction close in vision is at its best with in a couple inch range.
If set for screens, computers and phones in general the distance is set around 20 inches, which is 17 degrees obstruction not 24(12 inches) and certainly not 30(8 inches)
What about progressive lens? They have a much smaller range also but wider than a bi or tri lens but they only have a limited difference in viewing distance that can vary depending on how they are prescribed.
Again if you say you look at screens a lot you will get a longer distance, some doctors just assume your going to be using screens and set a longer distance.
It is one of many reasons the obstruction models used for current calculations are way off, even worse than being cyclopes they assume the incorrect distance for a large portion of the population.

So do you think AGS and GIA will redo their grading standards and come up with even shallower set of optimum cuts than me?

 

[Karl_K]

So do you think AGS and GIA will redo their grading standards and come up with even shallower set of optimum cuts than me?

I think for a fairly large subset of people that shallow pavilion diamonds are over demonized.
But then again you have a small subset of corrective lens wearers that even the ags0 ideal stones are over contrast because of viewing distance and magnification issues. They love princess and crushed ice radiant cuts with little to no obstruction.

 

[Karl_K]

The thing is once you think you have everything corralled something else comes along and complicates it.
When is it good enough is the question I struggle with.
Is the agsl system with all its warts good enough?
Is the gia system with all its huge warts good enough?
The answer varies by day but its maybe and no today for a mrb.

 

[JulieN]

You will see more fire if you are long sighted and take your specs off. Otherwise I do not think us spec / contact wearers have much choice.

I am near- sighted (myope) and I also see more fire if I take the glasses off, but obviously not in focus.

Will a bigger diamond help me see more fire when wearing glasses?
And can I tell my fiance that it is medically necessary?

 

[Ibrakeforpossums]

I am near- sighted (myope) and I also see more fire if I take the glasses off, but obviously not in focus.

Will a bigger diamond help me see more fire when wearing glasses?
And can I tell my fiance that it is medically necessary?

LOVE this!

 

[Garry H (Cut Nut)]

I am near- sighted (myope) and I also see more fire if I take the glasses off, but obviously not in focus.

Will a bigger diamond help me see more fire when wearing glasses?
And can I tell my fiance that it is medically necessary?

Absolutely - the bigger the diamond and the larger the virtual facets the larger the fire you see.

 

[LilAlex]

Is there something a person with corrected myopia / hyperopia can do in diamond selection to increase the positive attributes of diamond appearance that are different from the commonly recommended TIC parameters

Don't really understand this. Contact lens wearers see the world pretty much like those with normal vision. Are there data that they have shallower depth of field or magnified vision, etc? i would not expect that to be the case.

More meaningful, imo, is that the eye's lens yellows with age. Older folks with cataracts see a yellowish world. An older gemologist once tried to sell me an obviously purplish Burma ruby and was perplexed that I did not perceive it as a pure, pure red. Even eyeglass lenses yellow with age -- hold them over a snow-white piece of paper and you may notice that they are not perfectly clear. I do not know what impact that has on "color sensitivity" in diamonds but seeing the world through a yellow filter must do something.

 

[Garry H (Cut Nut)]

An older gemologist once tried to sell me an obviously purplish Burma ruby and was perplexed that I did not perceive it as a pure, pure red.

I have not checked this, but since most spcs are made with Lexan these days - I wonder if the Lexan might filter out some of the burmese fluorescent red?
I doubt it - but you have sown a seed to be tested.

 

[Karl_K]

I have not checked this, but since most spcs are made with Lexan these days - I wonder if the Lexan might filter out some of the burmese fluorescent red?
I doubt it - but you have sown a seed to be tested.

not unless the lens were between the stone and the light source.

 

[Garry H (Cut Nut)]

not unless the lens were between the stone and the light source.

Of course - silly me Karl!

 

[Karl_K]

Don't really understand this. Contact lens wearers see the world pretty much like those with normal vision. Are there data that they have shallower depth of field

Contacts have the types of correction limits as glasses but some are better and some worse.
This is why they have bifocal and trifocal contacts or people still need reading glasses with contacts.