Xenon light, fiberoptics help vitreoretinal surgery

Dr. Awh, with Retina-Vitreous Associates, Nashville, TN, tested the fiberoptic devices with the Photon light source and concluded that this virtually eliminates the illumination problems often associated with 25-gauge vitrectomy.

"In 25-gauge surgery, one of the major limitations has been inadequate illumination for some cases," Dr. Awh said. "With the Photon, we are now able to deliver as much light through 25-gauge fiberoptic devices as we are able to deliver through 20-gauge fiberoptics with conventional light sources. In fact, the Photon is capable of delivering significantly more light than we have demonstrated, but we have limited the light output through the 25- and 20-gauge fibers to avoid potential phototoxicity. The value of this potential power is in our ability to create useful illuminated devices using even smaller fiberoptics."

Safe illumination "We were able to demonstrate obvious improvements in illumination over the conventional light sources, even using 25-gauge instruments," he said. "That is what is truly revolutionary about this light source. It allows the surgeon to operate at maximum levels of safe illumination using minimal-diameter optical fibers.

"The Photon can deliver as much light through a 25-gauge endoilluminator, or even through a 25-gauge illuminated laser probe, as is transmitted by a 20-gauge endoilluminator when attached to any commercially available vitrectomy unit light source," Dr. Awh added.

Among the devices he tested, he was particularly impressed with the performance of the 25-gauge chandelier, a transconjunctival fiber that is inserted through a self-sealing hole into the wall of the eye.

"It allows diffuse, total illumination of the inside of the globe," Dr. Awh said. "The surgeon can operate bimanually without any other lighted instruments. One can have forceps in one hand and scissors in the other, and all the light comes from this separate chandelier. And although the light is very bright and useful, because it is dispersed over such a large surface area of the retina, the potential for phototoxicity is dramatically less than with a conventional light pipe hooked up to a conventional light source.

"Although both single-port and multi-port chandelier illuminators have been commercially available for many years, it is the ability of the Photon to focus a tremendous amount of light through a tiny fiber that makes this chandelier unique," Dr. Awh noted.

He also demonstrated a prototype 25-gauge illuminated infusion line constructed with an extremely tiny optical fiber that still allows infusion flow equivalent to a conventional 25-gauge infusion line.

"I have used this a number of times with very nice preliminary results," Dr. Awh said.

The Photon is a stand-alone device intended to replace the standard light source supplied with a vitrectomy unit. It has been filtered to eliminate a significant proportion of the hazardous part of the light spectrum and reduce the potential for phototoxicity.

The Photon also features what Synergetics calls "bull's-eye" technology, in which a laser beam can be co-axially delivered down the center of the light beam.

"When hooked to an external laser source, the Photon can take the laser beam and deliver it through a series of prisms down the center of the beam of light through a single fiber," Dr. Awh said.