New tool marks incision sites for PPV, intravitreal injections

Take-home message: The Melki 3.5 mm ophthalmic marker is designed to help ophthalmologists safely and accurately mark incision sites for pars plana vitrectomy and intravitreal injections.

By Nancy Groves; Reviewed by T.S. Melki, MD

Rockville, MD-The introduction of a new ophthalmic marker (Melki 3.5-mm marker, Rhein Medical) lets surgeons accurately, safely, and quickly mark the incision site on the scleral surface for pars plan vitrectomy (PPV) or various office-based intravitreal injections.

With the new marker’s fixed-pointer setting, the incision spots can be placed the correct distance apart without double-checking. Since the device has no moving parts, inaccuracies due to wear and tear of the setting mechanism will not occur over time and affect measurements.

This is critical in procedures-such as vitrectomies or inravitreal injections-in which the incision points in the pars plana must be exactly 3.5 mm from the limbus. If the location is outside of the pars plana, the lens could be damaged-increasing the risk of cataract, retinal tear, or detachment, said T.S. Melki, MD, who developed the device.

Motivation for invention

Dr. Melki designed a prototype of the marker about 20 years ago when he was a fellow. At that time, it was used for surgical vitrectomies, since intravitreal injections were rarely given in an office setting.

Before this marker was developed, the only available caliper for vitrectomies was adjustable. The surgeon would ask an assistant for caliper set at a specific distance, then double check with the assistant to verify the measurement.

“I didn’t like this waste of time to go back and forth to look at the numbers,” said Dr. Melki, who is in private practice, Rockville, MD, and serves as associate professor, Georgetown University, Washington, DC. He is also director of The Retina Centers of Washington.

As intravitreal injections became more commonly performed in outpatient settings, Dr. Melki modified the marker for use in these procedures as well as surgical vitrectomies. The larger market for the instrument encouraged him to patent the marker and form a relationship with Rhein Medical to distribute it.

“We are now using it a lot in the office, because we can do all the injections more safely,” Dr. Melki said. “With 1.5 million intravitreal injections given in the United States alone every year, there is tremendous need for the marker. It’s quick, reusable, and you know you can go in safely without injuring the retina or injuring the lens.”

In the past 7 years, Dr. Melki said he used the marker for several thousand injections with no complications.

According to Dr. Melki, all retina surgeons can use the 3.5-mm marker regardless of whether they prefer 20-, 23-, or 25-gauge instruments, since they all need to mark their incision sites. The marker has setting points dependent on the age of the patient: 3.5 mm apart for adults, and 1 mm apart for premature infants and infants less than 3 months old.

The eye can be marked in a few seconds. When a patient has been prepped for surgery or intravitreal injection, all the surgeon has to do is take the marker-which has been soaking in betadine-and lightly touch the sclera. The marker will leave a dot of brown from the betadine, and that will be the entry point.

“Another safety bonus is that the sclera has been just painted with betadine, providing a more sterile entry point,” Dr. Melki said.

T.S. Melki, MD

P: 301/279-9123

E: Retina_1_@yahoo.com

Dr. Melki has a financial interest with Rhein Medical regarding this instrument.