Eyeworld

SPRING 2024 | EYEWORLD | 73 R clinical trial were using STAAR's nomogram, and you see the same kind of mean and variability in the 6-month data, he said. Lens vault is variable due to how the lens sits in the ciliary sulcus, Dr. Packer said. If you think about the footplates of the ICL, he said, they're soft pliable collamer material, and some- times they're lying flat, but sometimes they're up on tippy toes, and sometimes on zonular fibers. "Recently, there was a publication 2 show- ing all these positions using high resolution ultrasound, which shows that the lens sits in dif- ferent ways, and there's no way to control that when you're putting it in the eye. Even if you could, the haptic positioning could change with natural movement of the ciliary body and iris." So, where does that leave us? In a good place, Dr. Packer said, because even though we see variability in vault, the problems due to vault have almost disappeared with the central port design, so it's not so much about the vault; it's more about aqueous flow. Even if you have a very low vault, because aqueous is flowing over the top of the crystalline lens and out the port, the crystalline lens is protected. In the published literature, there's close to zero incidence of an- terior subcapsular cataract, 3 Dr. Packer said. The other potential problem is angle closure glau- coma due to excessive vault. That has virtually disappeared as well, he added. "What we do see still is that surgeons may be uncomfortable with an extremely high vault, and they may decide to exchange a lens," Dr. Packer said. When you look at the angle with gonioscopy or OCT, it might look disturbingly narrow. The good news with the central port de- sign is that adverse events or complications due to extremes of vault have virtually disappeared. He said he thinks the mindset of trying to fix the problem of vault, however, persists. A safe vault, Dr. Nikpoor said, is between 250–750 microns. "Even if it's less than 250, I'm usually not so worried about it with an EVO. I've had maybe one high vault, hovering around 1,000 or 1,500, that I'm observing because they tend to drop back over time." High vault by itself isn't a reason to exchange, she explained, but a high vault with a sign of high IOP or inter- mittent angle closure is. "With a low vault, as long as it's not zero, as long as there's some space between the lens and the crystalline lens, then I think you're safe to just observe, and I observe those patients because the risk is that they could develop a cataract," Dr. Nikpoor said. "In my opinion, if you go in and are trying to exchange a low vault lens for another lens, you have a risk of induc- ing a cataract just from exchanging that lens, and it can be hard to get that low vault lens el- evated up and untucked. I would just leave that alone, especially knowing incidence of cataracts with EVO is so much lower. Exchanging these patients is just not necessary, in my opinion." With high vault, Dr. Nikpoor is more con- cerned and more likely to follow the patient frequently and check the IOP and angles for signs of glaucoma. If their pressure is high or the angle is intermittently closed or too narrow or closed, then I'd consider exchanging that high vault lens, she said. "I think there's a lot more tolerance and forgiveness because people are using so many different sizing methods and so many different nomograms and having good success, so there must be some tolerance built into this, other- wise there would be one method better than the other," Dr. Nikpoor said. "I think people worried about sizing are warranted because the last thing you want to do is have a super high vault and some emergent problem, but I think that's why I generally tend to size down. I think peo- ple can rest assured that if you just got a digital caliper and measured your white-to-white and did nothing else, you'd probably be fine the majority of the time." Low vault is not as scary as it used to be with the non-central port design, Dr. Pack- er said, so undersizing is not that big a deal, except with the toric because if you have an undersized lens it might rotate. When you find yourself between two sizes in the nomogram, if it's non-toric, dropping down a size is almost never a problem, Dr. Packer said. But if it's a toric lens, going to the larger size is probably a better move because you don't want a toric lens to rotate, especially a higher power toric. "A lot continued on page 74 Relevant disclosures Nikpoor: STAAR Surgical Packer: STAAR Surgical Zaldivar: STAAR Surgical

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