FIELD

The present disclosure relates to laser probes useful in medical procedures, including ophthalmology.

BACKGROUND

Laser photocoagulation therapy addresses ocular conditions such as retinal detachments and tears as well as proliferative retinopathy resulting from diseases such as diabetes. The abnormally high blood sugar in a diabetic stimulates the retinal vessels to release growth factors that in turn encourage an undesirable proliferation of blood vessels and capillaries over the retinal surface. These proliferated blood vessels are very delicate and will readily bleed into the vitreous. The body responds to the damaged vessels by producing scar tissue, which may then cause the retina to detach so as to eventually cause blindness.

In laser pan retinal photocoagulation, a laser probe is used to burn spots across the retina. The number of required laser photocoagulations for any one treatment of the retina may be large—1,000 to 1,500 spots are commonly burned. Accordingly, multi-spot laser probes capable of delivering a plurality of photocoagulation beams simultaneously enable the burning of multiple spots at a time and may be used to expedite a photocoagulation procedure. Multi-spot laser probes can be generally classified into two categories: “multi-spot/multi-fiber” laser probes which produce multiple laser beams through a corresponding array of optical fibers, and “multi-spot/single-fiber” laser probes which use a single fiber.

To create a single burn spot on the retina, the laser power requirement is approximately 250-500 mW. To produce multiple burn spots in parallel, multi-spot laser probes must deliver corresponding multiples of this requisite power. For instance, multi-spot probes capable of producing four burn spots simultaneously may generate anywhere from 1 W to 3 W through a confined space at the probe tip. In some surgical use cases, such as in the case of bleeding and occlusion at the probe tip, significant light absorption at the tip may occur, causing thermal-induced failure of the probe. Accordingly, there is a need for an improved multi-spot laser probe which is thermally robust and resistant to meltdown.

SUMMARY

Certain embodiments include a laser probe having a cannula, at least one optical fiber positioned within the cannula, and a lens positioned within the cannula at a distal end of the fiber. The lens is adapted to receive a laser beam from the optical fiber at a proximal end of the lens and to transmit the laser beam towards a distal end of the lens. The laser probe also includes an optical element configured to receive the laser beam from the distal end of the lens and emit the laser beam from the probe. The optical element is coupled to the cannula by a brazed joint. The brazed joint may form a hermetic or liquid-tight seal between the optical element and the cannula.

In certain embodiments the brazed joint comprises a first inter-molecular bond between a braze filler and an outer surface of the optical element, and a second inter-molecular bond between the braze filler and an inner surface of the cannula. Some variants include a first inter-molecular bond between a braze filler and a metallic material (such as titanium or gold) deposited on an outer surface of the optical element, and a second inter-molecular bond between the braze filler and an inner surface of the cannula.

In certain examples, the least one optical fiber included in the probe comprises a multi-core fiber or plurality of optical fibers.

In particular embodiments, a proximal end of the optical element is positioned within the cannula, and a distal end of the optical element protrudes beyond a distal end of the cannula. The optical element may protrude beyond the distal end of the cannula by a length in the range of 50-200 μm.

In certain variants of the disclosed laser probe, the lens may comprise a GRIN lens or a spherical lens, and the optical element may comprise an optically clear material. In certain examples, the optical element comprises sapphire or fused silica, and the cannula comprises stainless steel, nickel, titanium, nitinol, or platinum-iridium.

In certain embodiments of the disclosed laser probe, a diameter of the cannula is in the range of 200-700 μm, the optical element is cylindrically shaped, a diameter of the optical element is in the range of 200-700 μm, a length of the optical element is in the range of 200-700 μm, the lens is cylindrically shaped, a diameter of the lens is in the range of 200-700 μm, a length of the lens is in the range of 200 μm to 1.5 mm, and a thickness of the brazed joint is no greater than 50 μm.

In certain embodiments, the laser probe includes a body sized and shaped for grasping by a user, and the cannula is coupled to the body and is configured to be positioned within the eye of a patient.

Variants of the disclosed laser probe may include a proximal end of the optical element abutting the distal end of the lens. Additionally, a distal surface of the optical fiber may be pressed against a proximal surface of the lens, as a distal surface of the lens is pressed against a proximal surface of the optical element, such that the optical element functions as a mechanical stop with respect to the lens.

These and other aspects and uses will be described in the detailed description.

