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Myopia is becoming more and more common all over the world, and the incidence of myopia is gradually increasing. Many treatments have been used to prevent and control myopia, including optics, drugs, environment or behavior, but the results are different and lack standardization. At present, many experiments have proved that peripheral defocus technology has a certain effect on myopia control. Based on this technology, three kinds of framed eyeglass lenses with peripheral defocus design, namely defocus incorporated multiple segments(DIMS), highly aspherical lenslets(HAL)and cylindrical annular reactive elements(CARE), are commonly used in medical and optometry institutions in China. These lenses provide not only clear vision in the central area, but also a certain amount of myopic defocus in the periphery to control the progression of myopia. This paper aims to focus on the design principle and myopia prevention and control effect of the above three peripheral defocus lenses, and evaluate their effectiveness in clinical practice.

AIM: To evaluate the clinical outcomes of using the cross-positioning method for correcting low and moderate astigmatism during small incision lenticule extraction(SMILE)surgery with Alpins vector analysis.METHODS: A total of 50 patients(81 eyes)with low and moderate astigmatism with the rule ≤1.50 D who underwent SMILE surgery at the laser myopia treatment center of Xi'an No.1 Hospital from May 2022 to November 2022 were included in the prospective randomized controlled study, and they were divided into two groups according to the random table, with 25 case(41 eyes)in cross-positioning group and 25 cases(40 eyes)in control group. In the cross-positioning group, the patients' head position was adjusted based on the cross intersection lines before the standard SMILE procedure, aligning the lateral canthi with the horizontal line and the midpoint of the eyebrows and the nose bridge with the vertical line. Postoperative visual acuity and refractive results at 3 mo were observed in both groups, and astigmatic changes were analyzed and evaluated using the Alpins vector analysis method.RESULTS: During the follow-up period, 6 cases(11 eyes)in the cross-positioning group were lost to follow-up, while in the control group, 8 cases(14 eyes)were lost to follow-up, with 19 cases(30 eyes)and 17 cases(26 eyes)finally included in the cross-positioning group and the control group, respectively. At 3 mo postoperatively, the uncorrected visual acuity(UCVA)of both groups' operated eyes was ≥1.0, and no serious complications occurred, with no significant differences in UCVA, best corrected visual acuity(BCVA), spherical power, and spherical equivalent between the cross-positioning group and the control group(all P>0.05). The cylindrical power in the cross-positioning group was 0.00(0.00, 0.00)D, which was lower than -0.13(-0.50, 0.00)D in the control group(P=0.01). The vector analysis results showed that the difference vector(DV)in the cross-positioning group was lower than that in the control group [0.00(0.00, 0.00)vs 0.13(0.00, 0.50), P=0.01], and the index of success(IOS)was better than that of the control group [0.00(0.00, 0.00)vs 0.18(0.00, 0.77), P

AIM:To evaluate corrective effect and stability of corneal morphology in patients with moderate to high myopia after 2a treatment of femtosecond laser assisted laser in situ keratomileusis(FS-LASIK)Xtra.METHODS:Retrospective case-control study. A total of 30 cases(58 eyes)Patients with moderate to high myopia combined with astigmatism who planned to undergo refractive surgery in our hospital from August 2019 to August 2020 were included, and different types of surgery were performed respectively based on the relevant index of keratoconus screening in the preoperative corneal topography. They were divided into FS-LASIK group and Xtra group, with 15 cases(29 eyes)in each group. Uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), spherical equivalent(SE)and the corneal curvature of the anterior and posterior surfaces of different diameters(3, 5 and 7 mm)measured by Sirius three-dimensional corneal topography were observed preoperatively and 3 mo, 1 and 2 a postoperatively.RESULTS: The UCVA of the two groups of patients at different time points after surgery was significantly increased compared with preoperatively(both P0.05). After 2 a postoperatively, residual astigmatism was -0.25-0 D in 25 eyes(86%)of the FS-LASIK Xtra group and 24 eyes(83%)of the FS-LASIK group. The actual corrected SE and expected corrected SE of both groups were positively correlated(both P

With the improvement of radar and ground-to-air weapon system performance, the gradual establishment of multi-level air defense system makes the situation of penetration more severe. At the same time, the superiority of unmanned combat aircraft in the battlefield becomes more and more prominent, and the penetration of combat aircraft presents a new development trend. As an important part of mission planning for penetration, route planning for penetration is of great significance. This paper first summarizes the main contents of route planning for penetration, then analyzes and summarizes the previous work in planning space, cost function, route optimization and planning algorithm, and finally draws the new challenge and future research direction of route planning for penetration.

In order to improve the identification ability of air targets, a comprehensive identification method of air target based on intuitionistic fuzzy set and evidence theory is proposed. This method adopts the idea of multi-attribute decision-making to solve the problem of air target comprehensive recognition. Firstly, the problem of air target comprehensive identification is described by referring to the advanced practice of the U.S. military. Then, the multi-attribute decision-making modeling is carried out for air target comprehensive identification, the attribute weight and expert weight are calculated by combining AIFS cross entropy, conflict coefficient and evidence distance, and the evidence discount method is used to modify and fuse the evidence in aggregation process of attribute information and expert information.Finally, an example is given to verify the feasibility of the proposed method.