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Feature Series On Innovative Surgical Instruments | Jul 2012

Device for Enlarging the Pupil

Expanding and stabilizing the iris during surgical procedures.

The Oasis Iris Expander (Oasis Medical, Inc.) is a molded, single-piece polypropylene device that expands to a 7-mm rectangular shape after insertion and maintains access and visibility throughout the cataract surgical procedure (Figure 1). The disposable device is indicated in cases in which miosis and/ or intraoperative floppy iris syndrome are factors.


In my experience, the ring is gentle on iris tissue, and it is easily inserted and removed through the primary incision, which eliminates the need for additional incisions and saves surgical time. By opening the iris to 7 mm, the device creates excellent visual access, which increases my comfort level and the safety margin for my patients. Because of its unique rectangular configuration, the expander does not interfere with the phaco or I/A tip. Additionally, I have found this device to be more stable and planar in the eye than other expanding devices, and the iris looks nice postoperatively.


A sterile holder contains the device and inserter/holder assembly. After I load the device, I introduce the tip of the inserter slightly through my 2.4-mm incision and just inside the anterior chamber. Next, I slowly advance the expander out of the inserter. It is important simply to “float” the unfolding iris expander over the anterior surface of the iris, while making no attempt to engage the iris.

After I disengage the device from the inserter, I use a modified Sinskey hook to engage one of the positioning holes found at each corner pocket of the expander. These pockets support and stabilize the iris when it is expanded (Figure 2). Using the Sinskey hook, I maneuver the first corner of the expander into the pupillary space, engage the margin of the iris into the device's pocket, and then release the Sinskey hook from that hole. Repeating this step for each corner, I place either of the proximal pockets first and then the respective diagonal opposite corner. Next, I place the other proximal pocket and then its respective diagonal opposite corner.

To remove the expander, a Kuglen or button hook works well. First, I gently push at the center of the span between the two proximal corners of the device. As that cross-span bends inward, the two proximal corners are drawn slightly toward each other. I slightly lift the device, and the proximal corners disengage from the margin of the iris. I use the Kuglen hook to go underneath that middle span and pull the device out of the eye. The distal pockets automatically disengage as the device is removed. In conjunction with Rhein Medical, Inc., Oasis Medical designed an elegant double-ended instrument that makes inserting and removing the expander quick and easy.


There is a small learning curve for surgeons who have never before used a similar device, because its design requires a different positioning and removal technique compared with other devices. I recommend that these colleagues perform about five straightforward cases to become fully comfortable with this expander. Oasis Medical's instructional video on how to insert and remove the expander is a helpful learning tool. Also helpful is watching an experienced colleague demonstrate how to use the device.


The Oasis Iris Expander enhances visualization and is reasonably priced, a perk for the practitioner who wants to manage costs. Placement and removal of the device is simple and safe, and visual access is excellent.

Adelaide Priester, DO, is a surgeon at Better Vision Ahead in Tulsa, Oklahoma. She acknowledged no financial interest in the products or companies mentioned herein. Dr. Priester may be reached at alpmiowa@earthlink.net.

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