EyeWorld Asia-Pacific September 2013 Issue

30 EWAP CATARACT/IOL September 2013 APX: Novel device for pupil expansion by Ehud I. Assia, MD A new instrument for managing small pupil S mall pupil is a major challenge in intraocular surgery, mainly cataract surgery, that may lead to severe complications. In recent years, IFIS (intraoperative floppy iris syndrome) has become a common cause of intraoperative constricted pupil with the increasing use of alpha- 1A adrenergic blockers for benign prostatic hypertrophy in men at the cataract age. There are several strategies to dilate the constricted pupil, including mechanical stretching, sphincterotomies, iris hooks, and intraocular pupillary rings, with the Malyugin ring (MicroSurgical Technology, Redmond, Wash., USA) being the most popular option currently. However, all of these procedures are cumbersome and time consuming and usually require excessive intraocular iris manipulation during insertion and removal. The APX (Assia Pupil Expander, APX Ophthalmology Ltd., Haifa, Israel) is a novel device for pupil dilation, based on a concept different from any other device on the market. Pupil expansion is achieved by using two devices inserted through two 19G (1.1 mm) side-port incisions opposite to each other. Each device looks like a miniature blunt scissors with a spring. A designated forceps is used to close the device during insertion and positioning. The distal curved tips are inserted behind the iris through the pupil, and releasing of the forceps results in a smooth opening of the device. Using two devices creates a quadrangular opening of about 6X6 mm. A second hook near the tip provides a firm grasp of the pupil and prevents sliding of the iris over the APX shaft. In case the tips are not positioned well on first attempt, they can be repositioned by maneuvering the external element of the device. No intraocular manipulations are needed for the insertion, positioning, or removal of the APX devices. Removal of the pupil expanders is done by using the same designated forceps. The device is simply closed and pulled out in a manner of a few seconds. The stainless steel APX-100 is cleared for clinical use by the FDA (510K exempt) and was used in 35 patients—15 cases in Israel and 20 cases operated on by several leading surgeons in the U.S. Surgeries were done in a variety of cases including pseudoexfoliation, uveitic cataract, post filtration surgery, mature and hypermature dense nuclear cataract, patients with clinical IFIS, and for secondary implantation of PC-IOLs in aphakic eyes previously operated on for congenital cataract. In one case surgery included pars plana vitrectomy for removal of the dislocated crystalline lens followed by “glue fixation” of a posterior chamber IOL to the scleral wall. In all cases the operations were successfully performed with effective pupil dilation throughout surgery, and no intraoperative or postoperative device-related complications were noted. Surgeries were done in superior, lateral, or oblique approaches according to surgeons’ preference, and the devices were placed perpendicular to the main incision of the phaco tip. In three cases the APX was positioned in an asymmetrical (non-opposite) fashion. This created a trapezoidal- shaped opening with the wide diameter located closer to the surgical incision to allow more Capsulorhexis under direct visualization in a patient with a 4-mm pupil. The APX devices are positioned horizontally. Vertical positioning of APX prior to pars plana vitrectomy. The devices did not interfere with the surgical instruments and maneuvers. Non-symmetrical placement of the APX dilators creates a trapezoidal papillary opening. This provides a wide “device- free” area that does not impede the surgical instruments. PC-IOL implantation in-the-bag. ACCC margin is readily visible. Pupil diameter is 3 mm “device-free” area that would not impede the access of surgical instruments. The plastic version, APX-200, is now at its final preproduction and regulatory stages. Experimental studies on porcine eyes demonstrated the feasibility, efficacy, and comfortable use of the disposable devices. EWAP Editors’ note: Dr. Assia is professor of ophthalmology, Sackler School of Medicine, Tel Aviv University; director, Department of Ophthalmology, Meir Medical Center, Kfar Saba, Israel; and medical director, Ein Tal Eye Center, Tel Aviv, Israel. Dr. Assia is the inventor of the APX and partner in APX Ophthalmology. He has financial interests with Bio-Technology General (Kiryat Malachi, Israel), IOPtima (Tel Aviv, Israel), and Hanita Lenses (Hanita, Israel). Contact information Assia: assia@netvision.net.il The APX is removed at the end of the procedure. The pupil resumes its circular shape. Source (all): Ehud I. Assia, MD