Volk’s Merlin surgical system offers visualization and flexibility for vitreoretinal surgery.

The decision to purchase a noncontact surgical visualization system usually is motivated by the following: the confidence that comes with the ability to survey the entire surgical field and potential concern about contact with the cornea. “Even a small fraction of swelling can degrade one’s view of the inside of the eye. It is like fog on a bathroom mirror,” says Suber Huang, MD. “Water vapor on the mirror can be negligibly thin, yet it takes very little water vapor to degrade one’s view very quickly.”

Volk Optical’s latest generation of the Merlin surgical system is designed to provide solutions for both, giving retinal surgeons a noncontact visualization option for vitreoretinal surgery.

A CLEAR FIELD OF VIEW

The Merlin’s indirect, wide-angle viewing system brings Volk’s double aspheric technology into the operating room. Three lenses are available:

• A standard, widefield lens that provides a maximum 120-degree field of view and enables visualization of the peripheral retina to the ora serrata;
• A midfield lens that allows a high magnification view for detailed imaging of the posterior pole to the equator;
• A small-diameter, wide-angle lens that delivers a widefield of view (112 degrees) in a small and ergonomic footprint.

“You have a very clear, ultrawide field to examine the eye,” says Dr. Huang, president and chief executive officer of the Retina Center of Ohio in Cleveland and former ASRS president. “This helps you avoid complications in small eyes and also helps inexperienced surgeons avoid complications.”

Gareth Lema, MD, PhD, director, Retina, Vitreous and Uveitis Service, Ross Eye Institute and assistant professor of ophthalmology, University at Buffalo Jacobs School of Medicine, Buffalo, NY, says that Volk’s new surgical system makes procedures like retinal detachment surgeries easier to perform. “The Volk lenses do not cause significant distortion at the perimeter of the lens.”

The small wide-angle lens is particularly beneficial for patients who have small pupils or for those with a prominent brow for whom space is a consideration, says Dr. Lema. “Despite its small size, there’s no considerable decrease in depth of field versus the larger lens,” he says. Also, the midfield lens delivers an excellent, high-magnification view of the central retina, providing a noncontact option for macula work like membrane peeling.

WORKFLOW IMPROVEMENTS

The Merlin also offers several features designed to optimize surgical workflow. A lens positioning unit (LPU) enables the surgeon to position and focus the lens by adjusting a fine focus wheel. When not in use, the LPU’s pivoting design allows it to fold away underneath the microscope, occupying a minimal footprint and providing unobstructed access to the surgical field, says Hafeez Dhalla, PhD, associate director of product at Volk Optical.

It’s a welcome improvement: Dr. Dhalla notes that users of Volk’s technology had found the previous iteration of its surgical system less than optimal because it did not easily permit the surgeon to reposition the Merlin lens assembly repeatably.

“That part of the system has been completely redesigned, so that the lens can be repositioned to be in exactly the same place,” says Dr. Dhalla.

A motorized condensing lens assembly lets the surgeon switch between viewing the eye’s anterior and posterior segment without having to refocus the microscope. When the LPU folds away, the condenser lens automatically retracts into a protective housing, returning the microscope focus to the anterior segment. Storing the condenser lens in this housing improves light transmission because it can be anti-reflection coated.

Dr. Huang notes that the improved light transmission means surgeons can inject less light into the patient’s eye, decreasing the likelihood of retinal phototoxicity.

QUICKER SURGERY, LESS STRAIN

The ergonomic design of the Merlin system can reduce the duration of surgical cases, says Dr. Huang. “The faster and more confidently that you can move about the eye, the more efficiently and faster you can do the surgery, and the less likely you will have medial opacity from the cornea or other structures of the eye.”

“The less time you spend in the eye, and the less light you inject, the lower the chances are for complications and toxicity,” says Dr. Huang. “The duration of surgery is in direct correlation to the amount of light.”

CONCLUSION

Dr. Dhalla is confident the latest generation of the Merlin system will make life easier for surgeons.

“The Merlin folds away unobtrusively, minimizes the need for refocusing of the microscope, and provides an additional factor of safety against phototoxicity.” All of this ultimately leads to a device that’s both more comfortable and more efficient, he says. OM