November 2018

CATARACT

Research highlight
Expanding phaco pupil horizons with sphincterotomies


by Maxine Lipner EyeWorld Senior Contributing Writer


Use of sphincterotomy can be a viable option for pupil expansion during cataract surgery in a case such as this.
Source: Boris Malyugin, MD

 

What to expect with the technique

Patients who undergo sphincterotomies to expand small pupils during phacoemulsification are not at a higher risk for postoperative complications, according to Joanne WY Goh, MD, Melbourne Comprehensive Eye Surgeons, Bellfield, Australia.
While intraoperative pupil dilation is frequently done with devices such as the Malyugin ring or pupil hooks, when these are unavailable, sphincterotomy could be a useful option, Dr. Goh noted. “It has been described as an alternative to pupil hooks or Malyugin rings, and we wanted to see how the outcomes compared to these devices and if this was associated with any adverse outcomes,” she said.
The idea for the retrospective single-surgeon study,1 published in the journal Eye, arose when a practitioner was describing the sphincterotomy technique to Dr. Goh when she was a fellow at Bristol Eye Hospital and was unfamiliar with the approach. This technique involves placing 10–12 small sphincterotomies along the pupil margin, Dr. Goh noted. “What that does is allows the pupil to enlarge and relaxes it because the sphincter muscles have been cut,” she said. “If you then inject viscoelastic, the pupil will enlarge even further to the point where it’s adequate enough for cataract surgery.” In such a case, a higher density viscoelastic such as Healon GV (Johnson & Johnson Vision, Santa Ana, California) is used.
After discussing this with the surgeon who explained the technique during her fellowship, Dr. Goh inquired about the incidence of postoperative complications with the approach. She wanted to know what the outcomes were and whether this was associated with complications such as postoperative uveitis, raised pressure, or CME. The surgeon was unable to answer, and this served as the impetus for the study, Dr. Goh said.

Considering complications

In this retrospective trial, investigators reviewed all of the cases in which the surgeon had performed sphincterotomy in conjunction with phacoemulsification and IOL implantation between March 2012 and February 2017. Included in the study were 114 eyes that had undergone uncomplicated surgery.
Investigators determined that the sphincterotomy technique did not elevate the risk for complications. “Patients were not at significantly higher risk of any postoperative problems,” Dr. Goh said. “Conversely, they do regain good iris function postoperatively, and aesthetically they constrict to a point where it’s cosmetically acceptable.” Patients are not left with a permanently dilated pupil after sphincterotomies, she stressed, adding that while the pupil may be slightly larger, it’s not something that might cause glare.
There were, however, some transient issues, which lasted less than a month, including ocular hypertension in 4% of eyes; a sustained case of this in one eye with pre-existing glaucoma was documented. “Usually it’s because they may have had a little more inflammation after the iris has been manipulated, causing the pressure to go up,” Dr. Goh said. “But once it has been treated, it resolves itself.”
Also, 4% of eyes developed transient uveitis. This resolved with topical therapy in all but one case with a history of uveitis, Dr. Goh noted. In addition, CME occurred in 5% of eyes, but all had a history of uveitis, diabetic macular edema, or epiretinal membrane and all ultimately resolved back to baseline.

Practical pearls

Dr. Goh viewed the approach as potentially useful for uveitic patients with miotic pupils. “Often they have fibrotic membranes around the pupil, and sometimes stretching the pupil with a Malyugin ring may not achieve adequate dilation,” she said. “A Malyugin ring can only get you to a certain point.”
In using the technique, Dr. Goh advised making small radial incisions rather than large ones. Often, when practitioners first get started, they erroneously think that they need to make large incisions in order to get any significant dilation, she noted. “But after making 10 to 12 little nicks along the pupillary margin, you would be surprised at how that relaxes the entire pupil and it dilates,” she said. “The smaller the incisions are, the better the cosmetic results at the end of the day. Patients end up with a pupil that can sometimes look almost completely normal.”
Overall, while Malyugin rings and other devices may dominate most phacoemulsification cases involving small pupils, in Dr. Goh’s view, sphincterotomies are something to keep in mind when these are not available. The sphincterotomy technique is preferable to manually stretching the pupil, she stressed. “It maintains a more sustained pupillary dilation intraoperatively,” Dr. Goh said, adding that with the manual approach, the pupil dilation only lasts as long as you have the viscoelastic in the eye and tends to come down as soon as the phacoemulsification begins.
Complications with the technique tend to resolve. “There was only a trend toward problems like ocular hypertension, uveitis, or macular edema, but it was not statistically significant,” Dr. Goh said.
It may have been that the underlying pathology was a risk factor for the complications rather than because of the sphincterotomies, she concluded.

Reference

1. Goh JWY, et al. Outcomes of sphincterotomy for small pupil phacoemulsification. Eye (Lond). 2018;32:1334–1337.

Editors’ note: Dr. Goh has no financial interests related to her comments.

Contact information

Goh: joanneyau.goh@gmail.com

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