ADVANCED MATERIALS & PROCESSES | MARCH 2026 38 ophthalmologists often turn to implantable shunts to drain fluid from the eye and relieve this pressure (e.g., Ahmed Glaucoma Valve, Baerveldt Glaucoma Implant). Myra Vision’s novel shape memory implant, the CalibrEye System, offers an adjustable fluid outflow that can be tailored to a patient’s dynamic needs as their glaucoma advances. Unlike existing shunts with a fixed drainage flow, the CalibrEye device can double or triple its fluid flow by opening two optional drainage channels that are capped by shape memory Nitinol actuators. Selectively heating the innermost arm of each actuator triggers the cap to open the optional drainage channel, and activating the outermost arm closes the cap (Fig. 2). Atraumatic heating of the Nitinol actuators is achieved using a common green laser system mounted on an ophthalmic slit lamp. Although temperatures of approximately 90°C are required to actuate the device, tissue damage is prevented due to the highly localized spot size (200 µm) that engages only the Nitinol implant, and the incredibly short pulse duration (100 ms). Recent innovations suggest that a reduction of heart failure symptoms may be achieved by artificially creating a hole in the atrial septum to shunt blood from the left FEATURE atrium to the right atrium thereby reducing arterial pressure and fluid load (e.g., Corvia Medical, V-Wave Medical, NoYA Medical, and Adona Medical). Interestingly, two interatrial shunt device companies independently arrived at novel shape memory solutions. Citing the clinical need that “A flexible shunt size may help meet the specific or changing requirements of individual patients,” Dr. Neal Eigler posed the question “What if a shunt’s orifice could be serially adjusted (larger or smaller) in vivo?”[3] Dr. Eigler then introduced the V-Wave Magical shunt as a solution where the proximal and distal conical anchoring ends of the device remained superelastic while the waist of the shunt underwent a selective thermomechanical treatment to locally tune the Af to ≥ 60°C (Fig. 3). This waist region is manufactured such that the shunt diameter would be smallest when heated above the tran- sition temperature, and deformable at body temperature. In such a configuration, the waist can be enlarged to 9.2 mm via a balloon. To shrink the waist, a warm saline flush actuates the device and reduces the diameter to 4.8 mm. This mechanism of ballooning and saline flushing provides physicians with familiar and established techniques that offer bidirectional movement of a Nitinol device in vivo rather than the unidirectional self-expanding mechanism used in the prior decades. Developed in parallel, Adona Medical’s Delphi shunt operates on a shape memory principle similar to the V-Wave Magical device. However, unlike the Magical device that uses warm saline, which may risk temperature elevation to adjacent tissue, Adona’s implant uses in vivo induction heating of an electrically and thermally insulated shape memory Nitinol orifice to adjust the shunt diameter without risking a local temperature rise to surrounding tissue[4,5]. Fig. 2 — The CalibrEye glaucoma shunt provides one primary and two secondary (optional) drainage channels for the management of eye pressure. Two independent thin-film shape memory Nitinol actuators provide caps to the optional channels. When green laser energy activates either of these actuators, the cap moves to an open or closed position to optionally increase or decrease fluid flow from the eye through the secondary drainage channels. Adapted from Chang[2]. Fig. 3 — V-Wave Ventura device (similar to the Magical device) showing the conical inlet and outlet features of the implant. These superelastic features anchor the device to the patient’s atrial septum. The waist region is locally tuned to render its shape memory property (i.e., As > 37°C). With this pretrained shape, the waist is malleable and expandable via a balloon at body temperature, and can be contracted to its original small diameter when warm saline is flushed through the device. (continued from page 36)
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