Abstract. A microfluidic chip with microchannels ranging from 8 to 96 μm was used to mimic blood vessels down to the capillary level. Blood flow within the microfluidic channels was analyzed with split-spectrum amplitudedecorrelation angiography (SSADA)-based optical coherence tomography (OCT) angiography. It was found that the SSADA decorrelation value was related to both blood flow speed and channel width. SSADA could differentiate nonflowing blood inside the microfluidic channels from static paper. The SSADA decorrelation value was approximately linear with blood flow velocity up to a threshold V sat of 5.83 AE 1.33 mm∕s (mean AE standard deviation over the range of channel widths). Beyond this threshold, it approached a saturation value D sat . D sat was higher for wider channels, and approached a maximum value D sm as the channel width became much larger than the beam focal spot diameter. These results indicate that decorrelation values (flow signal) in capillary networks would be proportional to both flow velocity and vessel caliber but would be capped at a saturation value in larger blood vessels. These findings are useful for interpretation and quantification of clinical OCT angiography results.

A phase gradient angiography (PGA) method is proposed for optical coherence tomography (OCT). This method allows the use of phase information to map the microvasculature in tissue without the correction of bulk motion and laser trigger jitter induced phase artifacts. PGA can also be combined with the amplitude/intensity to improve the performance. Split-spectrum technique can further increase the signal to noise ratio by more than two times. In-vivo imaging of human retinal circulation is shown with a 70 kHz, 840 nm spectral domain OCT system and a 200 kHz, 1050 nm swept source OCT system. Four different OCT angiography methods are compared. The best performance was achieved with split-spectrum amplitude and phase-gradient angiography.

Conjunctivochalasis is a common cause of tear dysfunction due to the conjunctiva becoming loose and wrinkly with age. The current solutions to this disease include either surgical excision in the operating room, or thermoreduction of the loose tissue with hot wire in the clinic. We developed a near-infrared laser thermal conjunctivoplasty system. The system utilizes a 1460-nm programmable laser diode system as the light source. At this wavelength, a water absorption peak exists and the blood absorption is minimal, so the heating of redundant conjunctiva is even and there is no bleeding. A miniaturized handheld probe delivers the laser light and reshapes the laser into a 10 × 1 mm2 line on the working plane. A foot pedal is used to deliver a preset number of calibrated laser pulses. A fold of loose conjunctiva is grasped by a pair of forceps. The NIR laser light is delivered through an optical fiber and a laser line is aimed exactly on the conjunctival fold by a cylindrical lens. Ex vivo experiments using porcine eye was performed to investigate the induced shrinkage of conjunctiva and decide the optimal laser parameters. It was found that up to 45% of conjunctiva shrinkage could be achieved.

A polarization-multiplexed, dual-beam setup is proposed to expand the field of view for a swept source optical coherence tomography angiography (OCTA) system. This method used a Wollaston prism to split sample path light into two orthogonal-polarized beams. This allowed two beams to shine on the cornea at an angle separation of ~ 14 degrees, which led to a separation of ~ 4.2 mm on the retina. A 3-mm glass plate was inserted into one of the beam paths to set a constant path length difference between the two polarized beams so the interferogram from the two beams are coded at different frequency bands. The resulting OCTA images from the two beams were coded with a depth separation of ~ 2 mm. 5×5 mm 2 angiograms from the two beams were obtained simultaneously in 4 seconds. The two angiograms then were montaged to get a wider field of view (FOV) of ~ 5×9.2 mm 2 .

Background Despite the rising incidence of lung cancer in patients who never smoked, environmental risk factors such as ambient air pollution in this group are poorly described. Our objective was to identify the relationship of environmental exposures with lung cancer in patients who never smoked. Methods A prospectively collected database was reviewed for all patients with non-small cell lung carcinoma (NSCLC) who underwent resection from 2006 to 2021. Environmental exposures were estimated using the geocoded home address of patients. Logistic regression was used to determine the association of clinical and environmental variables with smoking status. Kaplan-Meier and Cox proportional hazards analyses were used to assess survival. Results A total of 665 patients underwent resection for NSCLC, of which 67 (10.1%) were patients who never smoked and 598 (89.9%) were current/former smokers. Patients who never smoked were more likely of white race (p = 0.001) and had well-differentiated tumors with carcinoid or adenocarcinoma histology (p \ 0.001). Environmental exposures were similar between groups, but patients who never smoked had less community material deprivation (p = 0.002) measured by household income, education, health insurance, and vacancies. They had improved overall survival (p = 0.012) but equivalent cancer recurrence (p = 0.818) as those who smoked. In univariable Cox analyses, fine particulate matter , p \ 0.001), distance to nearest major roadway ], p = 0.002), and greenspace (HR: 0.253 [0.087-0.737], p = 0.012) were associated with overall survival in patients who never smoked. Conclusions Lung cancer patients who never smoked have unique clinical and pathologic characteristics, including higher socioeconomic status. Interventions to reduce environmental exposures may improve lung cancer survival in this population.