Distributed fiber-optic vibration sensors based on phase-sensitive optical timedomain reflectometry (-OTDR) have found many applications in various fields. In this paper, we analyze the phase noise of -OTDR, which is the main limiting factor of the measurement range. We found that the laser phase noise and phase extraction error caused by the intensity noise in photodetection contribute to the total phase noise. By introducing a series of auxiliary weak reflection points along the fiber, we develop a phase-noise-compensated -OTDR and realize a long-range distributed vibration sensing based on the phase extraction. Furthermore, a statistical analysis was proposed to maintain the vibration measurement sensitivity along the whole fiber. In the experiment, vibrations at 30 km were measured with a linear response, which confirmed the validity of our proposed system.

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Purpose The aim of the present study was to report the clinical outcomes of the use of 810 nm in situ laser‐generated fenestration (ISLF) for the treatment of aortic aneurysms (AAs) and intramural hematomas (IMHs) located in the aortic arch. Study Design and Methods Between April 2014 and September 2017, 23 patients (15 men, mean age 66.0 years) with AAs (n = 12) or IMHs (n = 11) underwent thoracic endovascular aortic repair (TEVAR) with 810 nm ISLF of the arch. The primary outcomes of the safety assessment were the presence of endoleaks, mortality and morbidity, including adverse in situ fenestration‐related, cardiovascular, and cerebral events. Results Technical success was achieved in all cases. Urgent intervention was performed in 15 (65.2%) cases. Left subclavian artery (LSA) ISLF was applied in six patients, LSA and left common carotid artery (LCCA) ISLF in three patients, and total aortic arch vessel ISLF in two patients. One patient suffered minimal stroke after the procedure and recovered without permanent disability to the extremities in 2 weeks. There were no fenestration‐related complications except in one patient with brachial artery access who suffered a hematoma and underwent incision repair at the puncture site. All fenestrations remained patent, and there were no endoleaks during a mean follow‐up of 10.5 ± 5.7 (range: 2–21) months. Conclusions Complete or incomplete endovascular arch reconstruction by ISLF in arch diseases (AAs and IMHs) is feasible and reproducible with safe, effective, and favorable primary results and no need for customized endografts. Lasers Surg. Med. 50:837–843, 2018. © 2018 Wiley Periodicals, Inc.

Super formula (LSF), and Emmetropia Verifying Optical formulas in highly myopic eyes.DESIGN: Retrospective, consecutive case-series study. METHODS: A total of 164 eyes of 164 patients with AL ‡26.0 mm were included and divided into 2 groups: AL <28.0 mm (Group 1) and AL ‡28.0 mm (Group 2). The average arithmetic spherical equivalent prediction error (PE), mean absolute PE, median absolute error (MedAE), and the percentage of eyes within ±0.25 diopter (D), ±0.50 D, and ±1.0 D of PE were determined. RESULTS: The Holladay 1 formulas showed the smallest MedAE when combined with the first linear or nonlinear version of Wang-Koch AL adjustment methods, both in total and in subgroups. The SRK/T formula displayed the highest prediction accuracy in combination with the first linear version of Wang-Koch adjustment method in total and subgroups. The CMAL reduced the absolute PE of LSF in total (P [ .003) and in Group 1 (P [ .017).CONCLUSIONS: The Holladay 1 and SRK/T formulas combined with specific AL adjustment methods had accuracy similar to the fourth-generation formulas for highly myopic eyes. Moreover, the CMAL can improve the accuracy of the LSF for highly myopic eyes.