Why the Rayone EMV is not popular in the US even though it might be better than the Eyhance

Here is a graphic that illustrates the impact of positive asphericity on depth of focus and visual acuity. This is from B+L, and I modified it with a red dot where I think the Eyhance lands. The spherical lens is not shown but I understand they have about +0.37 um of asphericity.

An iol that is considered a premium lens costs the patient more because their insurance won't cover it. But if a patient pays for it , both Medicare and private insurance will pay the cataract surgeon more for the actual surgery and associated costs.

This article shows very different defocus curves for the RayOne EMV and Eyhance. They indicate the EMV is very slightly better for focus extension than the Tecnis 1, and not even close to the Eyhance.

It's a bench test. No human cornea. If they simulated a human cornea, they don't specify what spherical aberrations it had. Maybe it had none, or very little, like a young person's cornea. Maybe there was no cornea in the simulation.

Since the Rayone EMV depends on spherical aberrations for its EDOF, and the spherical aberrations that matter are the spherical aberrations of the total eye system, the characteristics of the cornea that the IOL is interacting with is critical.

Remember, the Eyhance gets its EDOF from changing the power from the periphery to the center and its good contrast sensitivity from offsetting the cornea's natural positive SA in old age to achieve near zero SA for the total system.

The Rayone EMV on the other hand is working with the cornea's presumed SA to get EDOF through positive SA of the total system. On a bench test, if they use a zero-SA simulated cornea, or no cornea, that's not fair to the Rayone. We need defocus curves of human subjects to see how it performs in concert with corneas in human eyes.

Remember also that aberration-free monofocals get some EDOF by not suppressing the cornea's natural increased SA in old age. But I doubt that would show up on this bench test. See article "Aspheric, aberration-free IOL leverages technology for performance"

As we lose true accommodation, we gain some pseudo accommodation through increased SA of the aging cornea. IOL makers at first set out to offset that SA to regain contrast sensitivity and that was the big benefit of aspheric IOLs with negative SA. Now the trend seems to be going in the other direction in the quest for EDOF. Eyhance swims agains that stream with an approach to EDOF that is coupled with still suppressing the SA of the total system. It will naturally do better on a bench testthan a lens that depends on the SA of the total system if they don't give the lenses that depend on SA for EDOF a realistic old-person's cornea to interact with.

Corneal topography is not only used. to measure astigmatism but also to examine the surface of cornea for dryness and other conditions. It is routinely used in my area prior to all cataract surgeries.

I very much agree with this ^, Jim. Regardless of bench tests and graphs, my real life experience of the Rayner EMV shows that it has very similar, maybe even slightly better EDOF properties than my Vivity lenses.

The reason is quite simple. The RayOne EMV is overpriced, and under delivers. I can find no solid information based on defocus curves on single eye basis that shows the EMV provides any significantly better depth of focus than a standard monofocal. In the UK the EMV costs £2,895 per eye or $3,532 US, or $4777 CDN. Most public healthcare systems in Canada and basic insurance companies in the US provide a lens that has as much range of focus as the EMV at a cost of $0. Examples would be the Clareon or enVista lens.

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Buyer beware of the EMV. Most of the claims they make are based on a monovision configuration with an offset of 1.0 to 1.25 D. I would suggest this is deceptive marketing.