With modern calculations and state-of-the-art lenses, there is no need to replace the intraocular lens regularly.

According to Uday Devgan, MD, part editor of Healio/OSN, this is very rare, at least in his practice.

"For at least 99% or more of the patients who have undergone IOL implantation, you will never remove the lens," he said. "That's the shot they got for the rest of their lives."

If he were to re-enter the eye to transplant and replace the lens, he would make sure that the patient knew what would happen.

"No artificial lens can give you perfect vision," Devgen said. "You won't let their vision return to what they were when they were 30. You will make it better, but in a way, they should expect it to be less than perfect."

However, for the 1% of patients, intraocular lens replacement may be the best option. Knowing which patients are the best candidates, and knowing what to look for before and during surgery, is essential to produce the best visual results.

According to OSN Technical Committee member Kathryn M. Hatch, MD, the simplest and most common reason patients seek IOL replacement is that they are not satisfied with the initial results.

"Especially in conventional surgery, when certain expectations are not met," she said. "This may mean that the patient has refractive abnormalities, or that they did not achieve the desired goal in the end."

Another reason the patient may need to change dressing is the intolerable hallucinations.

"Even years after cataract surgery, patients rarely encounter problems that require replacement," Hatch said. "The dislocation of the lens may have mechanical problems, which may be related to zonule disease or trauma."

For patients with refractive errors, if they are not suitable for LASIK or PRK for enhancement, J. Morgan Micheletti, MD, will consider replacing them. If he is working with a patient who has recently undergone cataract surgery, he will not rush to exchange to stabilize the refractive power.

"I like to push them at least far enough so that we can make a good assessment," he said. "When both eyes are completed, we can decide whether to have LASIK surgery or need to be exchanged to solve it. It is assumed that we are dealing with refractive errors. If their first eye is glare or due to multifocal or EDOF intraocular lens Halo, sometimes we will change the lens of the second eye and determine if we need to go back and replace the first lens."

The replacement process after the implantation of a multifocal or deep focus intraocular lens is usually performed 3 to 6 months after the initial surgery, so that the patient has time for potential neurological adaptation.

"When a decision is made to switch due to visual impairment, it is actually a balance between neurological adaptation, stabilizing refraction, and controlling the patient's symptoms," Micheletti said.

Before implanting and replacing intraocular lenses, there are some important considerations, many of which are related to the condition of the eye and the number of operations.

"It is best to perform surgery on an eye that has never undergone surgery, but when performing an intraocular lens replacement, you have to have at least a second surgery," Devgan said. "Their eyes may have other surgeons. The risk is that for each subsequent operation, it will become more challenging than the previous one because there is more scar tissue. Then there may be problems with the endothelial cell count. Is it sufficient, Or will this lens replacement push the patient to the brink of corneal failure?"

According to Hatch, the time interval between surgeries is also an issue.

"The farther the exchange is from the original surgery, the greater the likelihood of fibrosis and scarring," she said. "If we want to replace the lenses, ideally, we want to do it in the first few months after the operation. We can definitely transplant the lenses in a few years, but when you do something in the future, there will be additional challenges."

The most important factor may be the condition of the posterior capsule. The integrity of the capsular bag may determine the technique used to transplant the lens and the new type of implant. In addition, if the capsular bag is intact, it is important to protect it from moving forward during transplantation.

"If you are dealing with open capsules and closed systems, it may make the operation more difficult," Hatch said. "An open capsule obviously brings some potential risks, such as loss of vitreous body and other challenges."

Devgan said this is a problem for patients who have previously undergone YAG laser capsulotomy.

"You might end up with vitreous prolapse," he said. "Removing the lens from the eye is not that simple. It may become fibrotic or stuck in place. Sometimes, it is difficult to dissect that lens."

Regardless of the initial state of the eye or capsule, Micheletti said surgeons should take their time.

"Come slowly, don't worry," he said. "Use the OVD or two-hand method to ensure that the touch on all planes is completely out of the capsule. Once you pick up the lens, protect the endothelium and capsular bag."

Some patients may not be suitable for replacement of intraocular lenses. Micheletti said that this includes first of all patients with a higher risk of surgery, such as patients with pseudoexfoliation or zonule disease.

"These are places where you have to be very careful and really make sure that the lens exchange is the right choice, because as part of the exchange, you will only put more pressure on the small belt," he said. "Another problem is patients with shallow anterior chambers. It's not that it can't be done, but it's more challenging because you don't have so much working space."

Ashvin Agarwal, MD, has several steps to protect the eyes with the capsular bag intact.

"In some cases, the bag may stick to each side of the tactile dot," he said. "I first tried to release them by injecting some viscoelastic material into the anterior and posterior chambers, and then used a simple rod to sweep in and out to make sure it swelled and opened well."

Once the haptics are released, Agarwal says the next step is to visualize them. The best way is to use iris hook.

"Don't try to be a hero, and don't use iris hooks, because they can really help us visualize," he said. "If I can see it, I can do it. This is a simple philosophy."

Hatch also advocates the use of iris hooks to aid visualization, especially for patients with a more complicated medical history.

"That's when visualization can be challenging," she said. "Especially for surgeons who are learning new techniques, it is always important to make sure that you can imagine what you are doing. Use the iris hook for visualization, and then move slowly and spend time while performing these complex intraocular manipulations. "

Surgeons can use a variety of techniques to transplant the lens. Hatch said that most modern lenses are made of soft materials, such as acrylic, which can be easily manipulated and can even be cut inside the eye.

"If it is an AcrySof (Alcon) lens, I usually externalize one of the touches to see if I can catch it," she said. "Sometimes, it may require a small'Pac-Man' to pass through the central optical element. From there, you can usually "fry" it out of the cut, which seems to work well."

For harder lenses, such as PMMA lenses, Agarwal said it may be necessary to open the scleral wound to transplant it. However, in cases where the capsular bag is intact, Agarwal almost always chooses to cut the intraocular lens with micro scissors.

"Today, all the lenses we use are acrylic, silicone or some kind of hydrophobic or hydrophilic material," he said. "All of these can be easily cut with micro scissors."

However, this technique introduces two sharp objects into the eyes. Part of the operation is to protect the posterior capsule (lower) and the cornea (upper) from the scissors when the intraocular lens is cut into pieces.

Agarwal said he first inserted a new intraocular lens into the eye to protect the capsular bag.

"If the scissors touch the posterior capsule, a simple contact is enough to rupture it," he said. "However, after putting the new intraocular lens inside, I am protecting my scissors from touching the bag."

In order to protect the cornea, he uses a lot of viscoelastic materials to expand the anterior chamber, giving him more space to cut without touching the endothelium.

The technique of placing a new IOL (called an IOL stent) is becoming more and more popular among surgeons. Hatch said she has used it and called it a good choice, especially for patients with darker eyes.

"The new lens is like a good diaphragm to protect the bag," she said. "It depends on the patient. If their eyes are smaller, it can make your working space smaller, and the anterior chamber may be too shallow."

Devgan and Micheletti are both advocates of "twist and out" technology. The surgeon makes a small incision in the cornea-2.2 mm or 2.4 mm, and approximately 2.75 mm or larger-and separates the IOL from the capsular bag, brings the lens into the anterior chamber and removes one of the tactile elements through the incision. Devgan said that it is important to insert a straight spatula through the puncture incision and place it above the lens to protect the cornea during twisting. This allows the technique to be used even in shallower eyes.

From there, the surgeon uses straight forceps to clamp the IOL.

"In the beginning, your hands should be turned back as much as possible, and then keep rotating," Micheletti said. "You want such a big rotation. By wrapping the lens around the tweezers, you can pull it straight out of the wound."

There are several benefits to the twist and outward technique. It explants the entire lens. Although it is almost impossible to know from the cut lens, it can study the defects of the complete lens.

"Removing the lens as a whole is a very good non-invasive method," Micheletti said. "Especially if there is a problem with the lens, you want to be able to send it back to the manufacturer so they can understand the difference or uniqueness of this lens."

Another benefit is patient tolerance. Devgan said that patients want to change because they can no longer tolerate their current lenses and because they want better vision after the operation is complete.

"Once there are new shots, they want to see 20/20," he said. "If you make a big incision, cut the lens and pull it down without distortion, now you will start to see a lot of astigmatism."

According to Agarwal, it is easier to keep the posterior capsule still intact. When the pouch is no longer intact, things start to become difficult. He said that in these cases, the vitreous body will begin to mix into the anterior chamber, and there is a risk of the intraocular lens hanging or falling into the posterior chamber.

One method he used for these situations was the three-port flat-angle technique.

"The difference here is that you don't pull the lens into the anterior chamber. First, perform a total vitrectomy to release all the vitreous from the intraocular lens," he said. "Once you remove any vitreous or cortex, you will have a freely moving intraocular lens in the middle of the vitreous. You can grab it. Use two-handed techniques to grab it, and then you can take it into the anterior chamber, like It’s the same before."

Once the intraocular lens enters the anterior chamber, it can be removed using the same method as other lenses. In the case of Agarwal, this means the scleral tunnel technique or the use of microscissors.

However, he will first place a new intraocular lens to prevent fragments of the original lens from falling back into the posterior chamber.

"I will fix the intrascleral tactile sensation of the future lens in the eye," he said. "This will serve as a scaffold for me to prevent half of the old intraocular lens from falling."

No matter how the original lens is removed, Agarwal said that the most important part of the replacement process is to get the next IOL calculation correct.

"You want to double or triple check this calculation," he said. "You have to be very sure that you won't repeat it again. If necessary, please consult others, because you don't want to go back to that route."

Devgan said that it is important to let patients know that IOL replacement is a salvage operation and that their vision will not be perfect afterwards.

"Set expectations," he said. "I said,'If you can tolerate your existing lens, then accept it. If you can't, then okay, I will change it and I will do my best to provide you with a good view. There is no artificial body. The part can be as good as the natural part."

Hatch said that setting these expectations and educating patients are all part of this process.

"No intraocular lens can completely avoid these potential small risks," she said. "We must do our best from the beginning to determine what is the most suitable lens for someone. It takes time and careful discussion with the patient."

Click here to read the gist/rebuttal of this cover story.

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