Reducing minification: Zeiss Individual SV or ____?

[choleb]

Hi, I was just hoping to get some insight on this:

I've had a friend come to me who is very concerned about minification (Rx -8.25, -1.00, 100 and -8.50, -1.25, 075), and is intent on finding the very thinnest lens but not sacrificing on optics. He’s keen on the 1.74 Zeiss Individual SV, but I'm wondering if, in your opinion, there's much reason to suggest anything else that would have a perceptible cosmetic difference in a 48-21 frame. He's also asked about Nikon’s SeeMax AP, but I'm not as familiar with this product. Any thoughts on the comparison between these two?

Of course Zeiss has the 1.9 glass lens, but we’re counting that out. Also, I’m not sure if Hoya’s Nulux EP still exists, and I know Tokai does a 1.76 lens, but would there be any real perceptible minification difference between these and the Individual SV? Or is it just a matter of splitting hairs - or perhaps dust particles - at this point? He seems to be rather set on the Individual, but I just wanted to do my due diligence on this.

In any case, I'd be very grateful for any input!

[Kwill212]

This sounds suspiciously like a consumer post. To have that many specific names of lenses and details, but not grasp how basic spectacle magnification works? On one hand your talking about magnification, on the other your talking about lens thickness, seems strange to me.

[choleb]

This sounds suspiciously like a consumer post. To have that many specific names of lenses and details, but not grasp how basic spectacle magnification works? On one hand your talking about magnification, on the other your talking about lens thickness, seems strange to me.

Well-spotted in terms of the knowledge deficit - I'm an optical stylist not a dispensing optician, but just wanted to widen my net a bit beyond those who I've had the opportunity to ask personally, if that's permitted.

[lensmanmd]

48/21 is a great size for this RX.
Using an average mono PD of 31, there will be about 0.6mm of thickness differential between 174 and 167. 0.6mm is basically imperceptible to the naked eye. If this is an acetate frame, it will be less perceptible between the two, especially if a 33% 5 degree hide a bevel is used at the edger. However, 167 will provide better optics than 174. If 0.6mm is that big of an issue and your client is willing to sacrifice VA, then by all means, choose 174.

I would recommend adding opiticinary to your tool box as a stylist. It will enhance your abilities.

[AngeHamm]

When you say "minification," am I correct in assuming you're referring to the effect that minus lenses have in "shrinking" the appearance of the eye for people looking at the eyeglass wearer?

Any time you have extreme prescriptions like this, your task is twofold: 1) dispense the best product for the patient, and 2) manage their expectations. Minification is part and parcel of your glasses when you have a high minus RX like this, period. We can reduce it with high-index lenses, smaller eye sizes, and digital aspheric designs, but we can't make it go away.

[lensmanmd]

AngeHamm is correct. With this RX, minification comes with the RX.
This can be slightly controlled with fit and curves. The flatter the back curve will yeild a fit that is closer to the eye, reducing vertex induced minification.
You will also want to request the flattest BC possible. Individual is an atoric/aspheric compensated design.

[AngeHamm]

I can not overemphasize the importance of managing expectations in this business. Physics are physics. There are things we can't do. Eyewear is science, not magic.

[lensmanmd]

I can not overemphasize the importance of managing expectations in this business. Physics are physics. There are things we can't do. Eyewear is science, not magic.

+1
Optics is about carefully controlling prisms. Plain and simple. Geometry, trigonometry and some calculus. Nothing overly complicated.