Expansion Ring for Small Pupil Cataract Surgery

small pupil expansion ring

For small pupil cases, I prefer to do stretching in order to expand the pupil and then I can proceed with phaco chop. If the pupil is midsize, such as 4 mm, I may simply make the capsulorhexis under the iris and then prolapse the nucleus for a flip and chop procedure. After not using a Malyugin ring for more than 1000 cases, a colleague encouraged me to give it another try, this time with the new version which provides a 7 mm opening to access the cataract.

When Boris Malyugin, MD, PhD invented this device many years ago, I was in awe because it was so simple and elegant and didn’t require the additional incisions and maneuvers compared to iris hooks. I applaud Boris for job well done and an invention which can be quite helpful.

This patient has about a 3 mm pupil after instillation of multiple sets of dilating drops. The Malyugin ring is placed in the eye, but there is a snag: the two lateral scrolls get stuck together, requiring manipulation with the chopper for release. The ring does its job quite well and the surgery proceeds normally. At the end of the case there is iatrogenic corectopia from the trauma of the device, but I suspect this is similar to most other devices and methods for pupil expansion.

There are other devices which also serve the same purpose and plan to try these in the future. In particular the B-Hex device from Dr. Suven Bhattacharjee goes through a sub 1 mm incision and is lower profile, a simpler design, and gives a hexagonal pupil during surgery.

Click below to see how the Malyugin ring helps with a small pupil cataract surgery:

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