Intraoperative miosis associated with higher risk of complications during cataract surgery

Issue: June 25, 2016

NEW ORLEANS — Intraoperative miosis increased the risk of complications during cataract surgery, according to a study presented here.

Perspective from Nick Mamalis, MD

“Understanding the rates of complications associated with intraoperative miosis provides an estimate of economic burden and the potential gain associated with the opportunity to reduce their incidence,” Steven M. Silverstein, MD, FACS, said at the American Society of Cataract and Refractive Surgery meeting.

Steven M. Silverstein

Silverstein and colleagues conducted a meta-analysis evaluating 40 studies that included 195,340 cataract procedures performed between 1992 and 2014.

Complications included posterior capsule rupture, anterior capsule tear, vitreous loss, zonular rupture, iris trauma, cystoid macular edema, corneal edema, retained lens fragments and misaligned lens.

The most common complications associated with intraoperative miosis were posterior capsule rupture, vitreous loss, corneal edema and cystoid macular edema.

The use of femtosecond lasers, the use of alpha blockers for prostatic hypertrophy and diabetes, “all of which are on the rise,” are risk factors that can lead to intraoperative miosis, Silverstein said.

The risk of complications associated with intraoperative miosis may have a negative effect on key outcomes in cataract surgery, including recovery of functional vision, need for reoperation and ocular pain, Silverstein said.

The rates of complications related to intraoperative miosis ranged from 1% to 4%.

“With approximately 4 million cataract procedures performed annually in the U.S., such complication rates result in a substantial toll in patient outcomes and resource utilization,” Silverstein said.

The use of mechanical pupil expansion devices to address intraoperative miosis has risks, including increased surgical time and cost, iris damage and permanently enlarged pupils, he said.

“It’s certainly intuitive that measures to prevent intraoperative miosis may significantly improve patient outcomes and lead to the result of substantial cost savings,” he said. – by Nhu Te

Reference:

Silverstein SM. Rates of complications associated with intraoperative miosis during cataract surgery in the U.S. Presented at: American Society of Cataract and Refractive Surgery meeting; May 6-10, 2016; New Orleans.

Disclosure: Silverstein reports he is a consultant, researcher and lecturer for Omeros. The study was funded by Omeros.

Perspective

Nick Mamalis, MD

This is an important study because surgeons tend to underestimate the risk of complications that are associated with intraoperative miosis when they are performing cataract surgery. Studies like this with a large meta-analysis that looks at data from multiple studies have shown clearly that when you are operating on a small pupil and there is intraoperative miosis, there is, indeed, increased risk for significant complications, especially posterior capsular rupture and vitreous loss, and the subsequent complications that can occur, such as cystoid macular edema and corneal macular edema. It is important to have adequate pupil dilation to avoid some of these complications. At my center, we see people with delayed onset complications following cataract surgery. We are seeing more and more patients with significant proliferation of lens cortical material, or Soemmering’s ring, postoperatively because of inadequate cortical cleanup during the cataract surgery, and that can lead to complications remote from the cataract surgery. Again, if you have pupillary miosis, you cannot ensure that you have good removal of the cortical material all the way out to the fornix of the capsular bag, so if you are leaving a significant amount of material in there that is unbeknownst to you, that can lead to a lot of complications down the road.

As cataract surgeons, we should be aware of the potential problems with intraoperative miosis and use steps necessary to obtain adequate pupil dilation. There are excellent modalities for dilating the pupil, including various ring devices and various hooks. I think we as surgeons should perhaps lower the threshold when we consider using these devices to provide adequate dilation during cataract surgery.

Nick Mamalis, MD

Moran Eye Center

Salt Lake City

Disclosures: Mamalis reports no relevant financial disclosures.