A balloon catheter according to the present disclosure includes: an elongated member; and an inflatable member supported on an outer surface of the elongated member and inflatable outward in a radial direction of the elongated member, in which from an inner side to an outer side in the radial direction, a laser emission unit that can emit a laser beam outward in the radial direction, a transmission portion that can transmit the laser beam emitted from the laser emission unit in the radial direction, and a light absorption portion that can absorb the laser beam having passed through the transmission portion are provided, and the laser emission unit, the transmission portion, and the light absorption portion are provided only in the elongated member, only in the inflatable member, or in both the elongated member and the inflatable member in a divided manner.

An ophthalmological device and system is described that allows the simultaneous imaging of an eye using both scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT). Further the device and system is capable of targeting and delivering a treatment laser for treatment of an eye condition.

A catheter system (100) for treating a treatment site (106) includes a first light source (124), a plurality of light guides (122A), a multiplexer (128), a multiplexer alignment system (142), and a first beamsplitter (268). The first light source (124) generates a source beam (124A). The multiplexer (128) receives the source beam (124A), and alternatively directs the source beam (124A) to each of the plurality of light guides (122A). The multiplexer alignment system (142) is operatively coupled to the multiplexer (128). The multiplexer alignment system (142) includes a second light source (270) that generates a probe source beam (270A) that is directed to scan across a guide proximal end (122P) of each of the plurality of light guides (122A) so that a time is determined to generate the source beam (124A) so that the source beam (124A) is optically coupled to the guide proximal end (122P) of each of the plurality of light guides (122A). The first beamsplitter (268) receives the source beam (124A) and the probe source beam (270A), and alternately directs the probe source beam (270A) and the source beam (124A) toward the guide proximal end (122P) of each of the plurality of light guides (122A).