Off axis? Fixing a toric IOL that's malpositioned
Toric IOLs
Off axis? Fixing a toric IOL that's
malpositioned
by Vanessa Caceres EyeWorld Contributing Writer
Ophthalmic surgeons
share pearls, perspectives
There's a starter question to
ask if your patient has a toric IOL that is not at the right position
postoperatively: Is the patient happy with his/her vision? "If their
vision is 20/25 or perhaps even 20/40, I advise leaving it alone. There's no
need to reposition their toric lens if they are happy," said Terry Kim,
MD, professor of ophthalmology, Duke University Eye Center, Durham, N.C.
"Many patients are happy with better, though not perfect, refractive outcomes," said Michael Y. Wong, MD, Princeton Eye Group, Princeton, N.J., and instructor, Rutgers Medical School, New Brunswick, N.J. However, if the patient is unhappy, there are a few choices to consider.
First, consider the possible cause of his/her dissatisfaction. "If the patient is not happy, you have to go through a systematic process of evaluation," Dr. Kim said. "Other things could be limiting vision, such as dry eye or a retinal issue."
Factors that help fixate a toric IOL include rotational friction of the haptics at the capsular bag equator, the tackiness of the acrylic material, the adhesiveness of fibronectin between the IOL and the bag and the square edge of the implant, Dr. Wong said. Anything interfering with these factors are possible causes of lens rotation.
Dr. Horn finds that certain lenses tend to return to the same position repeatedly. "The lens seems to have a home. It's not just twirling around. Often, it will return to its previously maligned position," he said. It's also possible that the lens was never placed where you had originally planned to place it, due to common inaccuracies during preop planning for lens alignment.
If the patient would benefit from a minor or moderate change, Brad Black, MD, founder, Eye Associates,Jeffersonville ,
Ind.
In situations where a "fix" is absolutely needed, Dr. Black said he is quick to discuss rotating the lens with surgery. "I see no reason to wait, especially if the patient is unhappy and there is significant rotation of the IOL." After reopening the original incision, he will use a cohesive viscoelastic material like DisCoVisc (Alcon, Fort Worth Texas), which he finds is viscous enough to separate the anterior capsule from the posterior capsule but is still easy enough to remove once the implant is repositioned. He will then remark the new axis as determined by the Astigmatism Fix website. "We'll place marks at the limbus based on where the IOL is currently located," he said. "If the implant axis is at 80 and we need it at 92, we simply mark 12 degrees from where the lens is. When rotating the lens, remember it is important to rotate it at least 180 degrees to make sure the footplates are freed up from any 'tunnels' that surround the haptics within the capsular bag. If the IOL is only rotated a few degrees, there's a chance it'll rotate back to where it was before." Some surgeons, like Jeff Horn, MD, Vision for Life,Nashville , Tenn.
"If you have to reposition the lens more than once, an argument can be made to put in a CTR first and then reposition the lens," Dr. Black said. There are some surgeons who support reverse capture of the optic when the lens repeatedly rotates out of position, Dr. Black said. This situation seems to be more common in highly myopic eyes.
"Many patients are happy with better, though not perfect, refractive outcomes," said Michael Y. Wong, MD, Princeton Eye Group, Princeton, N.J., and instructor, Rutgers Medical School, New Brunswick, N.J. However, if the patient is unhappy, there are a few choices to consider.
First, consider the possible cause of his/her dissatisfaction. "If the patient is not happy, you have to go through a systematic process of evaluation," Dr. Kim said. "Other things could be limiting vision, such as dry eye or a retinal issue."
Factors that help fixate a toric IOL include rotational friction of the haptics at the capsular bag equator, the tackiness of the acrylic material, the adhesiveness of fibronectin between the IOL and the bag and the square edge of the implant, Dr. Wong said. Anything interfering with these factors are possible causes of lens rotation.
Dr. Horn finds that certain lenses tend to return to the same position repeatedly. "The lens seems to have a home. It's not just twirling around. Often, it will return to its previously maligned position," he said. It's also possible that the lens was never placed where you had originally planned to place it, due to common inaccuracies during preop planning for lens alignment.
If the patient would benefit from a minor or moderate change, Brad Black, MD, founder, Eye Associates,
In situations where a "fix" is absolutely needed, Dr. Black said he is quick to discuss rotating the lens with surgery. "I see no reason to wait, especially if the patient is unhappy and there is significant rotation of the IOL." After reopening the original incision, he will use a cohesive viscoelastic material like DisCoVisc (Alcon, Fort Worth Texas), which he finds is viscous enough to separate the anterior capsule from the posterior capsule but is still easy enough to remove once the implant is repositioned. He will then remark the new axis as determined by the Astigmatism Fix website. "We'll place marks at the limbus based on where the IOL is currently located," he said. "If the implant axis is at 80 and we need it at 92, we simply mark 12 degrees from where the lens is. When rotating the lens, remember it is important to rotate it at least 180 degrees to make sure the footplates are freed up from any 'tunnels' that surround the haptics within the capsular bag. If the IOL is only rotated a few degrees, there's a chance it'll rotate back to where it was before." Some surgeons, like Jeff Horn, MD, Vision for Life,
"If you have to reposition the lens more than once, an argument can be made to put in a CTR first and then reposition the lens," Dr. Black said. There are some surgeons who support reverse capture of the optic when the lens repeatedly rotates out of position, Dr. Black said. This situation seems to be more common in highly myopic eyes.
Is timing everything?
If a patient's toric IOL has rotated, how soon should you fix it? Dr. Kim will consider the patient's vision at one month postoperatively and then decide if any action is needed. He does not recommend rotating the toric lens too early in the immediate postop period because other factors such as corneal edema may affect visual and refractive results, he said.
Although there are many surgeons who will fix the problem as soon as possible to make patients happy, other surgeons believe in waiting a little longer.
"If a repositioning is the chosen treatment, it's better to wait a month or two," Dr. Wong said. "You want a confident and stable refraction, and it is helpful that the capsular bag has had a chance to shrink a bit. There is no rush to get in, as it is surprising how easy it is to viscodissect the capsular bag, freeing the IOL."
"If you fix it quickly and the lens rotates again, patients are more unhappy than they were before," Dr. Horn said. "Managing patients' expectations goes a long way."
Although Dr. Wong prefers to go back in within three months, he said surgeons can safely go in up to one year postoperatively. If the patient has a strong fibrotic band adherent to the anterior capsulotomy edge, Dr. Wong recommends starting the dissection with a stream of balanced salt solution bevel down and placed between the optic and anterior capsule. "Once a radial channel is dissected, viscoelastic material can follow."
Editors' note: Drs. Black and Horn have financial interests with Alcon. Dr. Kim has financial interests with Alcon, Bausch + Lomb (
Contact information
Black: drbradblack@aol.com
Horn: Jeff.Horn@bestvisionforlife.com
Kim: terry.kim@duke.edu
Wong: mwong2020@gmail.com
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