Comparison of laser iridotomy using short duration532-nm Nd: YAG laser (PASCAL) vs conventional laser in dark irides

AIM: To evaluate the outcome of laser iridotomy using532-nm Nd: YAG laser(PASCAL) with short pulse duration and Nd: YAG laser compared to conventional combined laser iridotomy.METHODS: Retrospective, nonrandomized, comparative case series. Forty-five eyes of 34 patients underwent laser iridotomy. Twenty-two eyes underwent iridotomy using short duration PASCAL and Nd: YAG laser, and 23 eyes underwent iridotomy using conventional combined laser method. The average settings of PASCAL were60 μm and 700-900 m W with a short duration of 0.01 s to reduce the total applied energy. The conventional laser was 50 μm and 700-900 m W for 0.1s. After photocoagulation with these laser, the Nd: YAG laser was added in each group. Endothelial cell counts of preiridotomy and 2mo after iridotomy were measured and compared.RESULTS: All eyes completed iridotomy successfully.The total energy used in the PASCAL group was 1.85 ±1.17 J. Compared to conventional laser 13.25 ±1.67 J, the energy used was very small due to the short exposure time of PASCAL. Endothelial cell counts were reduced by0.88% in the PASCAL group and 6.72% in the conventional laser group(P =0.044). The change in corneal endothelial cell counts before and after iridotomy was significant in conventional combined laser iridotomy group(P =0.004).CONCLUSION: Combined PASCAL and Nd:YAG laseriridotomy is an effective and safe technique in the dark brown irides of Asians. Furthermore, the short duration of exposure in PASCAL offers the advantages of reducing the total energy used and minimizing the corneal damage.

调Q 532 nm激光联合超脉冲CO_(2)激光治疗面部脂溢性角化病的疗效及对患者生活质量的影响

目的:探讨调Q 532 nm激光联合超脉冲CO_(2)激光治疗面部脂溢性角化病患者的临床效果。方法:采用单中心临床试验研究方法,选取2019年6月30日-2022年12月31日在笔者医院接受治疗的186例面部脂溢性角化病患者进行随机分组,其中联合组93例患者采用调Q 532 nm激光联合超脉冲CO_(2)激光治疗,对照组93例患者采用超脉冲CO_(2)激光治疗,对比两组患者治疗前后的临床疗效、皮肤病生活质量指数(Dermatology Life Quality Index,DLQI)评分、并发症的发生情况。结果:联合组疗效优于对照组(P<0.05);治疗后,两组衣物选择评分、患者的日常活动评分、症状与躯体感受评分、心理感受程度评分方面及DLQI总分均低于治疗前(均P<0.05),且联合组改善均优于对照组(均P<0.05)。两组并发症率比较,差异无统计学意义(P>0.05)。结论:调Q 532 nm激光联合超脉冲CO_(2)激光治疗面部脂溢性角化病患者较单纯采用超脉冲CO_(2)激光治疗具有更好的效果,能更有效地改善患者的生存质量。

532nm激光联合Nd∶YAG激光行虹膜周边切除术的效果分析

目的探究对闭角型青光眼患者实施532 nm激光联合Nd∶YAG激光行虹膜周边切除术的作用。方法方便选取2020年1月—2023年12月宜兴市中医医院收治的82例闭角型青光眼患者为研究对象,采用盲摸双色球法分为观察组和参照组,各41例。参照组单独用Nd∶YAG激光行虹膜周边切除术治疗,观察组先给予532 nm激光烧灼虹膜周边隐窝,再使用Nd∶YAG激光行虹膜周边切除术。比较两组手术情况、治疗效果及眼压水平。结果观察组激光总点数、激光能量及虹膜一次穿透率明显优于参照组,差异有统计学意义(P均<0.05)。观察组治疗总有效率(97.56%)高于参照组(82.93%),差异有统计学意义(χ^(2)=4.987,P<0.05)。观察组术后1 h、术后7 d眼压水平明显优于参照组,差异有统计学意义(P均<0.05)。结论532 nm激光联合Nd∶YAG激光行虹膜周边切除术能够明显改善青光眼患者的手术情况、提高治疗效果,眼压得到明显降低。

532nm激光全视网膜光凝治疗糖尿病性视网膜病变的疗效

目的探讨532nm激光全视网膜光凝治疗糖尿病性视网膜病变的疗效。方法选取2020年1月至2021年9月北京市房山区第一医院收治的106例(149眼)糖尿病性视网膜病变患者作为研究对象。患者均给予532nm激光全视网膜光凝治疗,随访6个月,患者视力、黄斑中心视网膜厚度(CMT)值及眼底情况。结果治疗后,治疗总有效率为85.91%。治疗后,患者CMT值明显低于治疗前,差异有统计学意义(P<0.05)。治疗后,患眼中新生血管消退占94.63%,玻璃体积血占5.37%。结论532nm激光全视网膜光凝治疗糖尿病性视网膜病变疗效确切,可改善患者视力变化水平,改善眼底情况,降低CMT值,安全性较高。

Effects of 946-nm thermal shift and broadening on Nd^(3+):YAG laser performance

Spectroscopic properties of flashlamp pumped Nd^3＋：YAG laser are studied as a function of temperature in a range from-30℃ to 60℃. The spectral width and shift of quasi three-level 946.0-nm inter-Stark emission within the respective intermanifold transitions of ^4F3/2→^4I9/2are investigated. The 946.0-nm line shifts toward the shorter wavelength and broadens. In addition, the threshold power and slope efficiency of the 946.0-nm laser line are quantified with temperature.The lower the temperature, the lower the threshold power is and the higher the slope efficiency of the 946.0-nm laser line is,thus the higher the laser output is. This phenomenon is attributed to the ion-phonon interaction and the thermal population in the ground state.

Transportable 1555-nm Ultra-Stable Laser with Sub-0.185-Hz Linewidth

We present two cavity-stabilized lasers at 1555 nm, which are built to be the frequency source for a transportable photonic microwave generation system. The frequency instability reaches the thermal noise limit （7 ×10-16） of the 10-cm ultra-low expansion glass cavity at 1-10s averaging time and the beat signal of the two lasers reveals a remarkable linewidth of 185mHz.

Contemporary review of the 532 nm laser for treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia(BPH)is a condition that occurs increasingly with age.The established gold standard treatment for BPH has been the electrocautery-based transurethral resection of the prostate(TURP).TURP,however,is associated with several complications and side effects.Therefore,there is an increasing interest in a number of emerging minimally invasive therapies as alterative treatment options.Laser therapy using the Greenlight laser is a promising alternative to the traditional TURP.Selective absorption by hemoglobin allows rapid,hemostatic vaporization of prostate tissue.Additional advantages include avoidance or minimization of complications such as intraoperative fluid absorption,and bleeding,retrograde ejaculation,impotence,and incontinence,as well as its use in treating high volume BPH.We review the use of the Greenlight laser in the treatment of BPH,when comparing complications and advantages in relation to TURP.

The thermal effect in diode-end-pumped continuous-wave 914-nm Nd:YVO_4 laser

The thermal effect and the heat generation in diode-end-pumped continuous-wave 914-nm Nd：YVO4 lasers are investigated in detail. A theoretical model of a diode end-pumped solid-state laser is constructed to analyse the influence of fractional thermal loading on the thermal effect in the Nd：YVO4 laser based on finite element analysis. The thermal focal lengths and the end-surface deformations of laser rods in Nd：YVO4 quasi-three-level and four-level lasers are measured and compared with the results obtained by ordinary interferometry for the demonstration of higher thermal loading in 914-nm laser. Finally the fractional thermal loading in the Nd：YVO4 quasi-three-level laser is calculated by matching the experimental and the simulated end deformations.

Compact,efficient diode-end-pumped Nd:GdVO_4 slab continuous-wave 912-nm laser

A fiber-coupled laser-diode （LD） end-pumped Nd：GdVO4 slab continuous-wave （CW） 912-nm laser and an LD bar end-pumped Nd：GdVO4 slab CW 912-nm laser are both demonstrated in this paper. Using the fiber-coupled LD of end-pumped type, a highest CW 912-nm laser output power of 10.17 W is obtained with a high optical to-optical conversion efficiency of 24.6% and a slope efficiency of 34.5%. The measured M2 factors of beam quality in x and y directions are 5.3 and 5.1, respectively. Besides, an LD bar of end-pumped type is used to realize CW 912-nm laser output, which has the advantages of compactness and low cost. When the pump power is 38.8 W, the output power is 8.87 W and the measured M^2 factors of beam quality in x and y directions are 16 and 1.31, respectively. In order to improve the beam quality of the 912-nm laser at x direction, a new quasi-concentric laser resonator will be designed, and an LD bar end-pumped Nd：GdVO4 slab high-power CW 912-nm TEM00 laser will be realized in the future.

A 515-nm laser-pumped idler-resonant femtosecond BiB_(3)O_(6) optical parametric oscillator

We report on an idler-resonant femtosecond optical parametrical oscillator(OPO)based on BiB_(3)O_(6)(BiBO)crystal,synchronously pumped by a frequency-doubled,mode-locked Yb:KGW laser at 515 nm.The idler wavelengths of OPO can be tuned from 1100 nm to 1540 nm.At a repetition rate of 75.5 MHz,the OPO generates as much as 400 mW of idler power with 3.1 W of pump power,the corresponding pulse duration is 80 fs,which is 1.04 times of Fourier transform-limited(FTL)pulse duration at 1305 nm.In addition,the OPO exhibits excellent beam quality with M^(2)<1.8 at 1150 nm.To the best of our knowledge,this is the first idler-resonant femtosecond OPO pumped by 515 nm.

532 nm激光光凝联合复方樟柳碱治疗重度非增生型糖尿病视网膜病变的疗效分析

目的分析532 nm激光光凝联合复方樟柳碱治疗重度非增生型糖尿病视网膜病变的疗效。方法选取2018年7月—2021年7月惠安惠光爱尔眼科医院收治的60例重度非增生型糖尿病视网膜病变患者作为研究对象,遵循入院顺序进行1~60号编号,其中1~30号归入参照组(n=30),并实施532 nm激光光凝治疗,31~60号归入联合组(n=30),并实施532 nm激光光凝联合复方樟柳碱治疗。评估两组治疗前后的最佳矫正视力、视野平均缺损情况、黄斑中心凹视网膜厚度和治疗有效率。结果治疗前,两组最佳矫正视力、视野平均缺损情况、黄斑中心凹视网膜厚度比较,差异无统计学意义(P>0.05);治疗后,联合组最佳矫正视力、黄斑中心凹视网膜厚度高于参照组,视野平均缺损情况低于参照组,差异有统计学意义(P<0.05)。联合组治疗有效率高于参照组,差异有统计学意义(P<0.05)。结论较532 nm激光光凝治疗相比,为患者实施532 nm激光光凝联合复方樟柳碱治疗的效果更好,能够增强最佳矫正视力,减少视野平均缺损情况,提高治疗有效性,建议借鉴。

Q开关532nm激光、铒激光、强脉冲光治疗脂溢性角化病的疗效与安全性比较

将108例面部脂溢性角化病患者随机分为3组,分别用Q开关Nd:YAG 532 nm激光、铒激光和强脉冲光(IPL)治疗,根据患者每次治疗前的照片评估治疗效果及不良反应。结果显示3种治疗方法停工期比较差异有统计学意义(P<0.05),IPL组优于Q开关532 nm激光组及铒激光组;患者疼痛度的比较差异无统计学意义;3种治疗方法均安全有效,有效率和术后局部色素改变比较差异均无统计学意义。

532nm连续激光对砷化镓材料损伤的研究

利用532 nm连续激光对掺Si的n型砷化镓材料进行作用,材料的晶轴方向为<100>偏<111A>方向15°。实验观察到,连续激光与材料相互作用过程中,材料作用表面的反射光在观察屏上形成环状结构,认为是由夫琅和费衍射产生的,并首次提出将衍射作为探测材料损伤的方法。实验测得砷化镓的阈值损伤功率密度为2.56×10~5 W/cm^2。利用温度场的热传导方程计算获得材料的损伤阈值时间与入射光功率密度的关系曲线,并与实验曲线进行了比较。

Ar^+激光和532nm激光及其线偏振激光辐照光学模型下人正常小肠组织光学特性

采用双积分球系统和光辐射测量技术的基本原理以及运用生物组织的光学模型 ,研究了 4 76 5 ,4 88,4 96 5 ,5 14 5 ,5 32nm激光及其线偏振激光辐照人正常小肠组织的光学特性。结果表明 :组织对激光及线偏振激光的衰减系数和散射系数随着波长的减小而增大 ,而 5 14 5～ 5 32nm波长之间 ,线偏振光与非线偏振光入射则开始有明显差异。吸收系数是随着波长的减小而缓慢地增大 ,而 5 14 5～ 5 32nm波长之间吸收系数的改变则明显变小 ,与是否线偏振光入射无明显差异。平均散射余弦也是随着波长的减小而增大 ,光学穿透深度则是随着波长的增大而增大 ,折射率在这五个波长范围内的值在 (1 38～ 1 4 8)之间。Kubel ka Munk二流模型下组织对同一波长的激光及其线偏振激光的吸收系数、散射系数、总衰减系数、有效衰减系数没有显著性差异 (P >0 0 5 )。组织对不同波长的激光或其线偏振激光的吸收系数、散射系数、总衰减系数、有效衰减系数是有差异的。而在 5 14 5～ 5 32nm波长之间其光学特性参数有较为明显的差异。

532nm和808nm激光及其线偏振激光辐照人正常膀胱与膀胱癌组织光学特性

采用双积分球系统和光辐射测量技术的基本原理 ,以及运用生物组织的光学模型 ,研究了 5 32nm和80 8nm激光及其线偏振激光辐照人正常膀胱和膀胱癌组织的光学特性 .结果表明 :膀胱癌组织对同一波长的激光或其线偏振激光的衰减明显较正常膀胱组织的要大 ,膀胱癌组织对 5 32nm和 80 8nm激光的衰减均较其线偏振激光的要略大一些 .膀胱癌组织对 5 32nm和 80 8nm激光及其线偏振激光的衰减明显较正常膀胱组织的要大 .正常膀胱或膀胱癌组织对同一波长的激光及其线偏振激光的折射率均没有明显的差异 ,膀胱癌组织对 5 32nm和80 8nm激光的折射率比正常膀胱的明显要大 .Kubelka Munk二流模型下 ,两种组织对同一波长的激光或其线偏振激光的光学特性均有显著性差异 (P <0 0 1) .同一组织对不同波长的激光及其线偏振激光的光学特性也有显著性差异 (P <0 0 1) ,正常膀胱组织对同一波长的激光及其线偏振激光的光学性有明显差异 ,而膀胱癌组织对同一波长的激光及其线偏振激光的光学特性则没有明显差异 .膀胱癌组织对 5 32nm和 80 8nm激光及其线偏振激光的前向散射通量i (x)、后向散射通量 j (x)、总散射通量I (x)的衰减均较正常膀胱组织的明显要大得多 ,且其i (x)均明显较j (x)

532nm激光联合Nd:YAG激光周边虹膜切除术治疗早期瞳孔闭锁性青光眼

目的:探讨532nm激光+Nd:YAG激光周边虹膜切除术治疗早期瞳孔闭锁性青光眼的安全性和有效性。方法:将符合标准的56例瞳孔闭锁性青光眼患者按完全随机对照顺序编号,分成A,B两组。A组28例接受ND:YAG激光治疗,B组28例接受532nm激光+ND:YAG激光治疗,通过对视力、眼压、激光孔洞、视野和房角等观察,重点观察眼压控制情况。结果:经过2a的临床随访观察,眼压:A组术前(28.32±3.43)mmHg,术后(24.82±3.27)mmHg,采用配对t检查(tA=3.256)差异无统计学意义,A组眼压控制不理想;B组术前(28.79±3.63)mmHg,术后(15.31±3.18)mmHg,采用配对t检查(tB=26.315,P<0.05)差异有统计学意义;A,B两组激光治疗后眼压控制情况比较,差异有统计学意义(χ2=42.23,P<0.05)。视力:A,B两组治疗前后经t检验,A组:tA=2.375,B组:tB=2.362,视力变化无统计学意义,A,B两组间比较差异也无统计学意义(χ2=3.845)。并发症:A,B两组均无较严重并发症发生。结论:532nm激光+ND:YAG激光周边虹膜切除术是治疗早期瞳孔闭锁性青光眼的安全、有效方法,能明显降低眼压,保存视功能。

以532nm激光为光源的HMME-PDT对人类乳腺癌细胞的杀伤作用

目的:探讨532nm激光不同光剂量参数及血卟啉单甲醚(HMME)不同浓度参数对体外培养的乳腺癌细胞(MCF-7)的光动力学杀伤作用。方法:MCF-7细胞用浓度分别为5μg/m l、10μg/m l、20μg/m l的HMME孵育2h后,以532nm半导体激光照射,能量密度分别为0.3J/cm 2、0.6J/cm 2、1.2J/cm 2、2.4J/cm 2、4.8J/cm 2,24h后用CCK-8检测细胞存活率,并在光镜及电镜下观察细胞的形态变化。结果:随着激光剂量的增大,在一定的范围内,细胞的抑制率呈现上升趋势;能量密度为2.4J/cm 2,HM M E浓度为20μg/m l时,达到最大的抑制率为55.5%;并且细胞的抑制率也和H M M E浓度呈剂量依赖型;光镜下可观察到细胞坏死和凋亡样改变。结论:以532nm激光为光源的H M M E-PDT对M CF-7细胞有明显的杀伤作用,并在一定范围内呈光剂量和H M M E浓度剂量依赖型。

532 nm激光辐照对白菜幼苗维生素C含量的影响(摘要)(英文)

[目的]探讨532 nm激光选育高维生素C白菜的可行性。[方法]以白菜为实验材料,采用不同功率密度(2、6、10、14和20 mW/mm^2)和不同辐照时间(1、2、3、4和5 min)的Nd:YAG倍频激光对白菜种子胚进行辐照,研究激光作用方式对白菜幼苗功能叶片面积、叶绿素和维生素C含量的影响。功能叶片面积的测定:培养10 d时,取每颗白菜上最大的叶片,利用复印称重法对其面积进行测定,即将白菜叶片用激光复印机复印,沿叶片边缘剪下,准确称量其质量;用直径1.46cm的打孔器打50个纸圆片,算出单位面积纸张的质量(g/cm^2),计算后得出叶面积。叶绿素含量的测定:每组取白菜叶片10 g,以2 ml磷酸缓冲溶液(50 mmol/L,pH≈6.8)将其研磨成均质。吸取上清液40μl,注入1.5 ml的Eppendorf管中,再加入960μl的无水乙醇,置于4℃黑暗条件下30 min,然后于4℃下以1 000 r/min离心15 min。以质量分数为95%的乙醇做空白对照,利用U-2800分光光度计(日立)分别测定待测液的A_(665)和A_(649),由叶绿素总量=6.10×A_(665)+20.04×A_(649)来计算其含量。Vc含量的测定:利用库仑滴定法测定Vc含量,即在预电解后的电解池中准确加入2.0 ml样品溶液,开动搅拌器,按下库仑仪工作键进行10 mA恒电流电解,滴定终点时指示灯亮,记录电解所消耗电量,通过法拉第定律计算Vc含量。[结果]激光辐照功率为2～20 mW/mm^2时,功能叶片面积和叶绿素含量与激光辐照功率、作用时间有关。适当辐照功率、短时间激光处理白菜种子对功能叶片面积表现为刺激效应,当较高功率密度激光辐照时间超过一定阈值(为4 min)时,激光处理表现出抑制效应。短时间激光处理白菜种子对叶绿素含量表现为刺激效应,当激光辐照时间超过一定阈值(5 min)时,激光处理表现出抑制效应,其中以14 mW/mm^2激光预处理白菜种子1 min的效果最佳。激光辐照功率密度为2～10 mW/mm^2时,白菜Vc含量随辐照时间增加而增加;辐照功率密度为14和20 mW/mm^2时,白菜Vc含量与辐照时间呈正态分布,白菜Vc含量与激光辐照能量呈正态分布。其中以2.8 J(20 mW/mm^2,3 min)激光预处理白菜种子效果最佳。当辐照剂量超过一定阈值即3.8 J(20 mW/mm^2,4 min)时,激光处理表现出抑制效应。[结论]适当辐照剂量的532 nm激光辐照白菜种子胚,可显著提高其幼苗维生素C含量。

日光对532nm激光成像性能影响实验分析

532 nm激光成像雷达在成像过程中容易受到日光干扰而降低图像信噪比。利用532 nm条纹管激光雷达对复杂场景(建筑物群)进行昼夜成像实验,并采用直方图统计法分析同一场景分别在白昼和夜晚的激光强度像和距离像的像素值分布,进而分析日光对激光成像性能影响。实验结果表明:日照光会提高激光强度像的亮度以及背景/目标的对比度,同时也增加了距离像的空天背景噪声;夜晚激光距离像信噪比高,但目标强度像对比度不佳。

532nm激光诱导棕色挪威大鼠脉络膜新生血管模型的研究与评价

目的应用532nm激光采用2种方法诱导棕色挪威(BN)大鼠脉络膜新生血管(CNV)模型,以确定诱导CNV形成的最佳方法。方法将40只BN大鼠随机分为2个光斑组(20只,于每2个血管之间光凝2个光斑)和1个光斑组(20只,于每2个血管之间光凝1个光斑),另取20只大鼠作为空白对照组。所有大鼠分别于造模后第1、2、3、4周行眼底荧光血管造影(FFA)及光学相干断层扫描(OCT)检查,观察空白对照组大鼠视网膜情况及1个光斑组和2个光斑组大鼠造模后CNV的形成情况,记录渗漏光斑数(即CNV形成数目),比较1个光斑组与2个光斑组大鼠的渗漏率。再分别自3组大鼠中随机抽取1只取其左眼行苏木精-伊红(H-E)染色,观察空白对照组大鼠的视网膜脉络膜情况及1个光斑组和2个光斑组大鼠造模后CNV的形成情况。结果 FFA见,2个光斑组大鼠造模后第1、2、3、4周的光斑渗透率分别为45.54%(158/348)、63.03%(208/330)、66.67%(208/312)、29.93%(88/294),均较1个光斑组大鼠的56.49%(135/239)、79.29%(180/227)、81.40%(175/215)、53.20%(108/203)显著降低(P值均<0.05)。两个造模组CNV的渗漏高峰均出现于造模后2～3周;造模后第4周,2个光斑组FFA见大多数光斑已形成瘢痕;而1个光斑组光斑渗漏仍明显。OCT见,1个光斑组大鼠造模后第2周视网膜神经上皮增厚,视网膜色素上皮(RPE)复合层不连续,局部增厚,反射增强,界限不清;造模后第4周仍可见上述改变;2个光斑组大鼠造模后第4周视网膜神经上皮层变薄,RPE复合层不连续,局部见强反射,界限清晰。H-E染色示,1个光斑组造模后第2周,见色素上皮不完整,并可见色素上皮细胞移行,其间夹杂较多新生血管;2个光斑组造模后第4周,见视网膜各层明显变薄,色素上皮紊乱,有大量色素增殖,未见新生血管。结论 532nm激光可成功诱导BN大鼠CNV形成,2支血管之间光凝1个光斑后CNV模型的成模率较高。