September 2019

IN FOCUS

Challenging Cataract Cases
Guide to refixation and exchange


by Chiles Aedam Samaniego EyeWorld Contributing Writer


Intraoperative photo of iris suture fixation

Method of loading suture for fixating
Source (all): Nicole Fram, MD

Yamane intrascleral fixation technique

Retrieved haptics with heated flange on the ends
Source (all): Nicole Fram, MD

Subluxated IOL
Source: Richard Hoffman, MD

An IOL that isn’t where it should be after surgery is a serious complication, but not the end of the world. In these cases, the surgeon may have the option to either refixate or exchange the lens. EyeWorld corresponded with five experts about this.

Fix or exchange?

“I prefer to refixate an already present IOL whenever possible since this typically requires fewer steps and is less invasive for the eye,” said Samantha Schockman, MD. “I generally plan on an IOL exchange with scleral fixation when there is a one-piece acrylic IOL or when the capsular bag does not allow for safe fixation. A thick capsular bag with a large Soemmering’s ring can potentially push the iris forward and create angle closure while an unusually friable capsule may not be strong enough for a stable fixation. One-piece acrylic IOLs are rather short and quite flexible, so loop fixation of the haptics can be challenged by tilt, torque, or degloving of the capsule off the haptics if tied too tight. If tied too loose, the complex can trampoline against the iris with eye movement or rubbing. There are rare anecdotal reports of in-the-bag UGH [uveitis-glaucoma-hyphema syndrome].”
Sumitra Khandelwal, MD, prefers repositioning and refixation, but said it “only works if the current lens is the correct type of lens and the power is correct.” Repositioning a rotated but correctly powered toric IOL is a good example of this.
A dislocated one-piece lens, however, might best be exchanged for a three-piece for more options for fixation and less iris chafing, she said.
“In general, if a patient was happy with their vision previously and the lens is amenable to repositioning, I will do so,” said Sumit “Sam” Garg, MD. He noted a wide range of factors go into this decision: lens status, degree of dislocation, lens type, patient age, capsule status, iris state, cornea status, and patient expectations.
In terms of feasibility, “if an IOL is accessible from an anterior approach it can usually be repositioned or refixated,” said Richard Hoffman, MD. “Single-piece IOLs that are not in the capsular bag will usually need to be removed and exchanged. Three-piece IOLs that are decentered and in the ciliary sulcus can be either scleral fixated or iris fixated if there is still vitreous present in the posterior segment or if there is some capsule support behind the IOL to help reduce pseudophakodonesis.”
“The key question to ask the patient is if they were happy with the vision prior to subluxation,” said Nicole Fram, MD. If yes, keeping the IOL is appropriate; otherwise or if there is significant Soemmering’s ring that could lead to UGH syndrome, an IOL exchange may be best.
To assess accessibility via the anterior approach, she recommended examining the patient the week before surgery in upright and supine positions to assess full dislocation and see if the retina is involved. The surgeon should be comfortable with retrobulbar or sub-Tenon’s block techniques and preservative-free triamcinolone-assisted vitrectomy, and backup IOLs should be chosen preoperatively.
When evaluating a patient with a subluxated/mispositioned IOL, Dr. Fram asks: (1) Can I use the capsule? (2) Can I use the iris for fixation? (3) Can I use the sclera for fixation?

Locating IOL dislocation

“Location is key,” Dr. Khandelwal said. It might seem like just the lens, but often these lenses dislocate in the bag and are attended by weak zonules and disruption in the bag.
If an IOL is out of position, the surgeon should evaluate whether it is simple IOL dislocation or capsular bag dislocation, generally due to diffuse zonulopathy.
While IOL and bag subluxation typically go hand in hand since the IOL is encased in the bag, Dr. Schockman said, “In cases in which the IOL is not within the capsule, or there is an extensive break in the capsule, the IOL or capsule may move separately. Careful examination at the slit lamp is critical in differentiating this and determining a surgical plan.”
Dr. Schockman has the patient look in all directions in a “dynamic” slit lamp exam to maximize visualization. She suggested having the patient look into extreme side gaze then rapidly fixate on the examiner’s ear. “As the globe comes to a stop, if the IOL and bag are not moving as a unit together, they will decelerate at different moments,” she said.
The relative positions of the bag and capsule are often obvious but may be difficult to evaluate in a small pupil. Dr. Khandelwal suggested dilating the pupil some more or using a pupillary expansion device in the OR.
Dr. Fram suggested ultrasound biomicroscopy in cases of a small or poorly dilated pupil to evaluate IOL and haptic position, capsule bag, and Soemmering’s ring.

Refixation by IOL type

The best approach to refixation “is unique to each patient situation,” Dr. Schockman said. “When there is an intact IOL/capsular bag complex, the lasso technique for sutured scleral fixation works well, particularly when a CTR or three-piece IOL is present.”
Dr. Hoffman agreed that care must be taken with single-piece IOLs as too much tension on the sutures may cause them to slip off and “cheese wire” through the capsule. “A single-piece IOL should probably not be fixated to the iris but a three-piece IOL with adequate posterior vitreous or capsule support can be fixated to the iris safely,” he said. “If the IOL is completely dislocated into the posterior segment, it will require a pars plana vitrectomy and retrieval and is then best dealt with by performing an IOL exchange for a scleral fixated three-piece IOL.”
“However, in rare instances in which it is important to minimize incision number and size, refixating a one-piece acrylic IOL may be in the patient’s best interest,” Dr. Schockman continued. “In such situations, radial incisions for the lasso suture should be used. If there is an intact capsulorhexis with some capsulorhexis margin fibrosis, Siegel and Condon describe an elegant technique to suture the anterior capsule to the iris.1 This can be a very useful tool in eyes with large blebs where conjunctival real estate is limited.”
Dr. Khandelwal noted that dislocations usually occur due to issues with the zonules or bag. Meanwhile, care must be taken when refixating three-piece IOLs whether to the iris or sclera as the haptics may be weak.

Iris vs. sclera

The physicians tend to favor scleral fixation over iris fixation—although the latter can work “if there is an intact anterior or posterior capsule that allows support for the optic,” Dr. Khandelwal said. “There can be a PC tear or an AC tear or both, but the key is to avoid this technique in eyes without any capsule support especially those that are vitrectomized. These eyes tend to get pseudophakodonesis and UGH.”
“Iris fixation has higher risk of corectopia and CME,” Dr. Garg said. “Additionally, iris fixation generally requires Prolene suture. It is known that this suture can degrade with time.”
He added, “In general, I have gravitated toward intrascleral haptic fixation [ISHF] over iris fixated IOLs. With innovations such as the glued IOL and Yamane ISHF techniques, I find that secondary fixation of IOLs has become fairly straightforward.” 
“In almost all cases, I find scleral fixation superior to iris fixation for both IOL stability and long-term safety,” Dr. Schockman said. “Over time, a polypropylene suture encasing both the IOL haptic and iris tissue can result in pressure necrosis or cheese wiring of the iris. This then reduces the friction within the fixated knot and results in haptic movement and IOL instability. Subsequent repeat dislocation or UGH syndrome may then ensue, resulting in increased IOP, hyphema, vitreous hemorrhage, among other complications.”
“If I was going to exchange the IOL, I would perform sclera fixation,” Dr. Hoffman said. “For subluxated capsular bag/IOL complexes I prefer sclera fixation with lasso sutures. If a three-piece IOL is subluxated within the sulcus, with vitreous or posterior capsular support, I currently prefer iris fixation with either 10-0 or 9-0 Prolene.”
Describing her algorithm for IOL exchange, Dr. Fram said that she will use anterior or posterior capsule fixation of a three-piece IOL if she can. “This requires intact zonules and appropriately sized capsulotomy openings relative to optic size (1 mm less than optic size ideally),” she said. “I avoid placing three-piece IOLs in the sulcus without iris suture fixation as the IOL can typically move over time. If there is no sulcus support or capsule, then I will choose an intrascleral or Gore-Tex suture fixation technique.”

Time to exchange?

The physicians noted potential indications for IOL exchange including: decentration without bag support, damage to the IOL, patient dissatisfaction with vision or residual refractive error that cannot be corrected with cornea refractive surgery or lens repositioning, iris optic capture, iris chafing, dislocation into the vitreous cavity, and other conditions such as UGH syndrome.
“The level of IOL subluxation as well as the amount of IOL movement during exam is important in deciding when to intervene,” Dr. Schockman said. Exchange is reasonable if the vision is affected or if the IOL looks like it is about to fall posteriorly. “A fallen IOL risks retinal damage, inflammation, and long-term vision loss,” she said. While it is impossible to predict, a slit lamp exam can provide a good sense of the possibility of it occurring. “I find it helpful to have the patient lay their head back to see how the IOL will behave once they are supine in the operating room. During this maneuver, some IOLs rotate posteriorly enough that I am able to properly plan for intraoperative help from my retinal colleagues.” Vitreous in the anterior chamber should also be noted.
Dr. Garg highlighted the need for the surgeon to be prepared and to discuss the situation with the patient in these cases. “When to exchange an IOL requires a thorough discussion with the patient about the risks, benefits, alternatives, and complications,” he said.

Recalculating powers

Calculating IOL powers is particularly challenging during IOL exchange. Patients should be counseled that the ability to hit the refractive targets is limited with secondary IOL placement.
“IOL exchange power determination can be challenging and all patients are consented to understand that we cannot reliably predict the exact refractive target,” Dr. Fram said. In her experience, the Holladay 1 formula helps obtain the best results. “Additionally, one should attempt to understand where the optic will sit in the eye. If it is sulcus placement with some capsule support, then the surgeon should adjust the IOL calculation and back off the power depending on the power of the IOL. If the fixation technique is optic capture, the IOL calculation should be adjusted for in-the-bag placement. The scleral fixation techniques are typically 2.5–3 mm posterior to the limbus depending on the white-to-white and an in-the-bag calculation is appropriate. That being said, having a record of the previous IOL implanted and a current refraction is an excellent starting point. One can then deduce the new power by adjusting the A-constants. In cases of aphakia or bag-to-bag exchange I find that intraoperative aberrometry is helpful to verify lens power. Lastly, the Barrett Rx formula calculator assists with calculating outcomes for IOL exchange and piggyback IOLs based on refraction after cataract surgery. Preoperative and postoperative biometry is necessary for proper entry and completed results.”
“Sometimes we have to make an educated guess based on the status of the patient’s fellow eye,” Dr. Garg said. “If, however, the currently implanted IOL power is known and a proper refraction can be done, one can estimate the new IOL power. There are also online calculators that can help physicians estimate the power needed.”
“I usually have the patient back monthly for several months to ensure a stable refraction,” Dr. Schockman said. “Once the refraction with the current IOL is known, the 3:2 rule can be used to determine what new IOL power is needed.
“Refractive predictability when scleral fixating an IOL after removing a dislocated IOL is less reliable since the effective lens position is so variable,” Dr. Schockman continued. “I typically choose an IOL power using the traditional methods or base it off a patient’s prior IOL power. In such cases, it is important to discuss with the patient that residual refractive error is likely.”

At a glance

• In general, refixation is preferable when the correct IOL power and refixable IOL type was in place with a satisfied patient prior to subluxation, the IOL is accessible anteriorly, and safe fixation is possible with the existing capsule, iris or sclera; otherwise, replace.
• For repositioning and refixation, the IOL, haptic, and bag positions should be evaluated with direct examination using techniques to maximize visualization, with pharmaceutical or mechanical dilation and/or biomicroscopy if necessary.
• In terms of fixation, whether for refixation or IOL exchange with a compromised bag, scleral fixation is generally preferred.
• Indications for IOL exchange include: decentration without bag support, damage to the IOL, patient dissatisfaction with vision or residual refractive error uncorrectable by cornea surgery or repositioning, iris optic capture, iris chafing, dislocation into the vitreous cavity, and other conditions such as UGH syndrome.

About the doctors

Nicole Fram, MD

Clinical instructor
Stein Eye Institute
University of California,
Los Angeles

Sumit “Sam” Garg, MD
Medical director
Gavin Herbert Eye Institute
University of California, Irvine

Richard Hoffman, MD
Clinical associate professor of ophthalmology
Casey Eye Institute
Oregon Health and
Science University
Eugene, Oregon

Sumitra Khandelwal, MD
Assistant professor of ophthalmology
Baylor College of Medicine
Cullen Eye Institute
Houston

Samantha Schockman, MD
Cincinnati Eye Institute
Volunteer instructor
University of Cincinnati

Reference

1. Siegel MJ, Condon GP. Single suture iris-to-capsulorhexis fixation for in-the-bag intraocular lens subluxation. J Cataract Refractive Surg. 2015;41:2347–52.

Relevant financial interests

Fram
: None
Garg: None
Hoffman: None
Khandelwal: Carl Zeiss Meditec
Schockman: None

Contact information

Fram: DrFram@avceye.com
Garg: gargs@uci.edu
Hoffman: rshoffman@finemd.com
Khandelwal: SKhandel@bcm.edu
Schockman: sschockman@cvphealth.com

Guide to refixation and exchange Guide to refixation and exchange
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