Cataract
July 2021

by Ellen Stodola
Editorial Co-Director

According to Ronald Yeoh, MD, dropped nuclei are one of the more unpleasant complications that can happen during cataract surgery. While uncommon, the consequences of a dropped nucleus are significant, he said, and may require vitreoretinal intervention to retrieve the nucleus from the retina and for associated retinal complications, like retinal detachment and macular edema.

“I have certainly encountered cases where the nucleus was ‘dropping,’ but early recognition of this state of affairs can lead to retrieval of the nucleus before it has dropped to the retina,” he said. “Hence the importance of recognizing the scenarios in which it is most likely to happen so that surgeons can avoid the drop entirely or be prepared such that in the event of an impending drop, the nucleus can be retrieved by using a technique like posterior-assisted levitation.”

Dr. Yeoh noted that nuclei drop when the anterior chamber is pressurized by a phaco tip in the presence of an unsuspected and undetected posterior capsule rupture. “Most times, if the posterior capsule ruptures during the phaco chopping or removal of the nucleus stage, the surgeon is aware of it and takes great care to stop the nucleus falling back by using some form of scaffolding or OVD to trap the nucleus before proceeding,” Dr. Yeoh said. “It’s when the PCR is undetected that nuclei tend to drop.”

When you do encounter a dropped lens, Thomas Oetting, MD, said that it’s important to try to fight the natural instinct to dive after the piece that’s fallen. You have to take a few deep breaths, and rather than focus on the personal disappointment of this complication, make sure everything is safe for the patient moving forward.

This problem where lens material falls posteriorly can occur at the very beginning of the case or it can occur at the very end, Dr. Oetting said, noting a recent trend of a dropped lens at the beginning of surgery during hydrodissection, particularly in patients who have had a lot of intravitreal injections. “This is an interesting problem, and it’s a relatively new problem because so many patients are getting intravitreal injections for a variety of conditions,” he said.

Uday Devgan, MD, agreed that the hydrodissection step may be when a dropped nucleus would occur. This is a high risk, he said, because you’re pressurizing the capsular bag.

Conditions that put patients at risk for a dropped nucleus

Dr. Oetting elaborated on how intravitreal injections may put patients at increased risk of a dropped nucleus. The intravitreal injections may be placed a bit too anterior and the posterior capsule could get injured. These injuries can be quite subtle, he said, and you might not even see them when you do an exam. At the time of hydrodissection, where you’re putting a lot of fluid pressure between the lens and capsule, the fluid wave goes around to free the lens from the capsule and it can extend the tear from the injection. A small tear could extend to the point where the nucleus drops immediately, Dr. Oetting said.

The best way to handle this, he said, is to be aware of the possibility of this complication from repeated intravitreal injections. “When consenting patients who’ve had a lot of injections, I always bring this up and say one of the risks of having injections in the vitreous is the potential risk of making cataract surgery a little trickier,” he said.

Dr. Oetting added that it’s important to look prior to surgery to identify any sign that the posterior capsule is injured. When the lens falls posteriorly, it’s a shock, he said, but the thing to do at that point is to let it fall.

“Patients with posterior polar cataracts have a high incidence of posterior capsule rent formation,” Dr. Yeoh said. “If the patient waits too long to have the surgery, the nucleus becomes bigger and harder and the risk of nuclear drop is increased because of greater manipulation of the hard nucleus.” For this reason, Dr. Yeoh always advocates early surgery for posterior polar cataracts.

Additionally, he said that rupturing the posterior capsule during chopping and cracking can lead to the dropping of heminuclei or quadrants if the rent is not detected promptly.

The most common situation leading to dropping of an intact whole nucleus, Dr. Yeoh said, is hydrorupture of the posterior capsule during hydrodissection. He noted that he described the pupil snap sign of posterior capsule rupture with hydrodissection in phacoemulsification in 1996¹ (see page 82 for more on the pupil snap sign).

Management strategy

Dr. Yeoh noted that there are two stages of a dropped lens: the “dropping” nucleus and the dropped nucleus. He said it’s essential that the surgeon recognizes if the nucleus is tilting away from the anatomical position and about to slide backward into the vitreous. “If this is recognized, a 25 G needle can be inserted via the pars plana, aiming to go behind the dropping nucleus and the lens elevated forward into the anterior chamber where it can be delivered with the help of a vectis through an enlarged incision. Care has to be taken that vitreous traction is minimized,” he said, adding that if the nucleus has already dropped to the retina, a vitreoretinal surgeon’s assistance to retrieve the nucleus is needed.

“If there is one good thing about hydrorupture of the posterior capsule, it is the fact that the capsular bag with an intact capsulorhexis is usually still well supported by the zonules, and it is straightforward to implant a three-piece lens implant into the sulcus, leaving the haptics in the sulcus and capturing the optic behind the capsulorhexis opening,” Dr. Yeoh said.

If a toric lens implant was planned, it is possible to put the lens into the remaining capsular bag in the right alignment, capturing the optic anterior to the capsulorhexis opening, he added.

Dr. Devgan noted the need for cortical cleanup after a dropped lens. With the nucleus in the vitreous cavity, you’re not getting it up, but you should put in viscoelastic and clean up the cortical material. He recommended avoiding the main phaco incision because “it’s too big, and it leaks.” It is important to preserve as much of the capsule as possible so you can still get the lens into the eye. Dr. Devgan said it’s good if the surgeon is still able to get the lens into the sulcus or anterior chamber. Then the patient can be referred to a retinal colleague. When this situation occurs, Dr. Devgan stressed not chasing the nucleus, not trying to retrieve it, and not denying that a complication occurred.

After a dropped lens, Dr. Oetting focuses on cleaning up residual cortical material and doing the best anterior vitrectomy possible. He said you can usually still place a lens (typically a three-piece lens in this situation) where you put the haptics in the sulcus and prolapse the optic posteriorly so it’s captured. “I think that’s the best service I can do for the patient to get the IOL in as good a position as possible,” he said.

One of the most important things to do is communicate with patients, Dr. Oetting said, describing his three phases of communication.

First, in the operating room, he said it’s important to let the patient know that a complication has occurred. Also let the patient know you are prepared to handle the problem but that you’re shifting gears to address it. “The reason this is important is because the patient is going to know something is different, so they’re going to assume that something bad happened,” Dr. Oetting said. He added that if the surgeon does not feel comfortable handling the cortical material or placing the lens, just stop.

His second phase of communication is to sit down with the patient after the surgery is over. Apologize for the complication and explain what happened, he said.

His third phase of communication is to continue to communicate with the patient and be the patient’s guide. They may have to see a retina surgeon or go to a completely different hospital, so it’s important to be there for the patient, he said.

“My experience has been that if you communicate like this and tell them you’re sorry and it’s clear that this complication occurred but you’re still involved and still care, you’ll find these to be your most loyal patients,” Dr. Oetting said, adding that cataract surgeons shouldn’t be embarrassed to ask their retina colleagues for help in these cases.

Overall, Dr. Oetting stressed the importance of communication, sticking with the patient, and getting a network of people who can help handle any complication you might have.

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About the physicians

Uday Devgan, MD
Clinical Professor of Ophthalmology
Jules Stein Eye Institute
UCLA School of Medicine
Los Angeles, California

Thomas Oetting, MD
Clinical Professor of Ophthalmology and Visual Sciences
Carver College of Medicine
University of Iowa
Iowa City, Iowa

Ronald Yeoh, MD
Medical Director
Eye & Retina Surgeons
Singapore

Reference

1. Yeoh R. The ‘pupil snap’ sign of posterior capsule rupture with hydrodissection in phacoemulsification. Br J Ophthalmol. 1996;80:486.

Relevant disclosures

Devgan: None
Oetting: None
Yeoh: None

Contact

Devgan: devgan@gmail.com
Oetting: oetting143@gmail.com
Yeoh: ersryeoh@gmail.com