Nd:YAG激光对泪道组织损伤程度和恢复过程的观察

目的：观察几种不同能量激光对泪道组织所造成的损伤程度和恢复过程。 方法：应用Nd：YAG激光,通过400μm激光纤维插入到10只新西兰白兔和5只家犬的泪道内分别进行10,15,20和25W输出功率的泪道内激光实验。 结果：输出功率为10～20W的损伤主要限于上皮层,极少累及上皮下层。输出功率为25W的损伤较重且易致瘢痕结缔组织增生。单纯上皮层损伤一般20d可以修复,伴有较深层损伤通常需要60d才能完成修复。 结论：以输出功率10～20W进行泪道管腔内激光切除局部阻塞是安全有效的。     

Nd:YAG激光对泪道粘膜影响的实验研究

目的 观察不同能量激光对兔及犬泪道粘膜的损伤程度和恢复过程。方法 应用Nd：YAG激光，通过400．μm激光纤维插入到10只新西兰白兔和5只家犬的泪道内分别进行10、15、20和25W输出功率的泪道内激光实验。结果 显示输出功率为10～20W的损伤主要限于上皮层，极少累及上皮下层。输出功率为25W的损伤较重且易致瘢痕结缔组织增生。单纯上皮层损伤一般在20天就可以修复，伴有较深层损伤通常需要60天恢复才能完成。结论 试验提示以输出功率10～20W进行泪道管腔内激光切除局部阻塞是安全有效的。     

KTP-Nd:YAG激光泪道成形术

采用ＫＴＰＮｄ:ＹＡＧ激光疏通泪道阻塞是国内正在开展的一项新技术,自1998年11月至1999年4月,我们采用国产ＫＴＰＮｄ:ＹＡＧ泪道激光治疗机,治疗多种原因所致的泪道阻塞41例48只眼,报告如下。1　资料与方法1.1　对象:48只眼中,男10只眼,女38只眼,年龄10～35岁19例,35～60岁19例,60～73岁3例,病程2个月至20年。1.2　设备:(1)ＫＴＰＮｄ:ＹＡＧ泪道激光波长为532ｎｍ,脉冲频率为3000～5000Ｈｚ,输出功率1～15Ｗ可调,用02～06光纤传输;(2)特制9号空芯泪道探针(带针芯);(3)泪道冲洗针头(其前端封,针头两侧有小孔);(4)常规泪道冲洗物品。1.3　…     

贝复舒应用于激光泪道成形术

贝复舒(珠海亿胜生物制药有限公司生产)是目前治疗角膜炎、角膜损伤的临床用药,其主要成分为重组牛碱性成纤维细胞生长因子,对细胞具有促进修复和再生作用,将其用于YAG激光泪道治疗机(HGL MYK8KTP激光泪道治疗机,武汉华工激光工程有限责任公司生产)治疗泪道阻塞的激光泪道成形术中,能够促进泪道细胞的修复和再生,从而减轻泪道壁的损伤,提高泪道阻塞患者的治疗成功率。1资料与方法1.1一般资料2003年1月～2005年1月我院共进行激光泪道成形术323例360眼,男158眼,女202眼;年龄19～75岁,平均47岁;单眼286例,双眼37例,病程2个月～20a。1.2分…     

Nd:YAG激光泪道成形术治疗泪道阻塞的疗效观察

目的总结探讨Nd:YAG激光泪道成形术治疗泪道阻塞的疗效。方法应用国产Nd:YAG激光治疗机对72例(92只[)由各种原因造成的泪道阻塞进行激光治疗,留置泪道插管,术后定期冲洗泪道。结果随访10～18个月,治愈74只[,好转7只[,总有效率88%。无效11只[,占12%。结论用YAG激光治疗泪道阻塞操作简便、对组织损伤小、不留瘢痕。其对无炎症的泪道阻塞治疗效果好于慢性泪囊炎及其他原因引起的泪道阻塞。     

泪道腔内激光治疗先天性鼻泪管阻塞

目的　探讨先天性鼻泪管阻塞 ,特别是顽固性先天性鼻泪管阻塞的治疗。方法　在特制空芯泪道探针引导下或直接将激光导光纤维插入到鼻泪管内段阻塞处 ,以 8～ 1 5W输出功率激光对阻塞处的异常组织或肥厚Hasner瓣进行气化和切除 ,疏通泪道。结果　共 33例 34眼 ,一次治愈 31眼 ,二次治愈 3眼。随访半年～ 5年 ,全部患儿溢泪、溢脓消失 ,泪道冲洗通畅。结论　激光能有效疏通鼻泪管 ,开放Hasner瓣 ,且操作简便 ,痛苦小 ,成功率高     

丝裂霉素C在激光泪道成形术中的应用

激光泪道成形术不仅对鼻泪管阻塞和慢性泪囊炎有较好的疗效,而且对不适合手术的泪小(总)管阻塞有独到之处。但如何防止术后创面粘连保持泪道通畅一直是探讨的问题。我们在激光泪道成形术中应用丝裂霉素C(MMC),收到良好效果。2000年3月至2003年9月施行激光泪道成形术508例(698眼),其中男性180例(242眼),女性328例(456眼),平均年龄为50.5岁。病程2个月至30年。使用武汉亚格激光设备有限公司的YY-P25脉冲激光治疗机,激光波长1060nm,脉冲频率1￣100Hz,输出功率0￣25W,用石英光导纤维传输。术前常规泪道冲洗,确定阻塞部位。表面麻醉,扩张泪小…     

低能量532nm激光对小鼠视网膜损伤的研究

目的 探讨低能量532 nm激光是否对小鼠视网膜产生不可逆的损伤.方法检测20、40、80 mV的激光在0.05、1、3 m距离不同持续照射时间内对视网膜的损伤.激光损伤后5～6 d,做视力、对比敏感度和视网膜电图(ERG)检测,并取出眼球做病理学检测.结果损伤时间为1 s的模型中,小鼠的视力、对比敏感度及ERG未见明显改变;延长至10 s和30 s时,小鼠的视力(P=0.000 3,P=0.000 5)、对比敏感度(P=0.003,P=0.000 4)的改变有统计学意义.所有处理组F-ERG b波振幅无明显降低(P>0.05). 结论低能量532 nm激光眼外照射,可以造成视网膜不可逆的损伤;损伤局限在视网膜神经上皮层,不累及色素上皮层.     

泪道激光联合泪道插管治疗各型泪道阻塞的疗效观察

目的 评价Nd:YAG激光联合泪道插管治疗泪道阻塞的疗效.方法 对415例(450只眼)泪道阻塞患者均采用Nd:YAC激光联合泪道插管手术治疗.结果 术后随访6个月以上,单纯泪点闭锁10只眼,治愈10只眼,治愈率100%;单纯泪小管阻塞147只眼,治愈126只眼,好转12只眼,无效9只眼,有效率93.88%;单纯泪总管阻塞158只眼,治愈137只眼,好转10只眼,无效11只眼,有效率93.04%;鼻泪管阻塞42只眼,治愈32只眼,好转6只眼,无效4只眼,有效率90.48%;泪点和泪小管阻塞7只眼,治愈5只眼,好转2只眼,有效率100.00%;泪小管和泪总管阻塞86只眼,治愈72只眼,好转5只眼,无效9只眼,有效率89.53%.结论 泪道激光联合泪道插管治疗泪道阻塞具有无痛苦、损伤小和疗效好等特点,值得推广.     

激光泪道成形术联合泪道内注入典必舒眼膏治疗小儿泪囊炎

目的　探讨激光泪道成形术联合泪道内注入药物治疗小儿泪囊炎的临床疗效。方法　采用Nd :YAG泪道激光泪道成形术联合泪道内分别注入典必舒眼膏和生理盐水 ,共治疗慢性泪囊炎患者1 0 2例 1 1 2只眼。随访观察 3～ 6月。结果　典必舒组 6月冲洗通畅率为 98 2 1 % ,生理盐水组保持通畅者为 3 1眼 ,占 5 5 3 6% ,两组疗效差异有显著性 (χ2 =2 8 85 ,P <0 0 1 )。结论　采用Nd :YAG泪道激光泪道成形术联合泪道内注入典必舒眼膏 ,是成功率较高的治疗小儿泪囊炎的方法之一。     

Irradiation of rabbit retina with diode and Nd:YAG lasers.

AIMS--This study was carried out to compare the effects of continuous wave infrared laser radiation on pigmented and albino rabbit retinas at two wavelengths: 810 nm (diode) and 1064 nm (Nd:YAG). METHODS--Transpupillary laser pulses were applied with a spot size of 200 microns and durations of 200 ms (pigmented rabbits) and 0.5-1 s (albino rabbits). Light and electron microscopic analyses were performed immediately after exposure. RESULTS--In pigmented rabbits, threshold lesions were induced using a power of 100 mW with the diode and 200 mW with the Nd:YAG lasers. Damage was incurred by the retinal pigment epithelium with extension into the superficial and mid choroid posteriorly and into the outer retina anteriorly. In albino rabbits, lesions of comparable anteroposterior extension were identified using a power of 10 W with the Nd:YAG laser. Using diode laser irradiation, a maximum power output of 1.2 W failed to produce discernible lesions. CONCLUSIONS--The observed patterns of morphological damage are produced by complex tissue radiation interactions. In pigmented animals, this was primarily related to absorption of radiant energy by melanin within the retinal pigment epithelium and the choroidal melanocytes. In albino rabbits, laser induced effects occurred as a consequence of multiple scattering, together with absorption within haemoglobin and possibly also within tissue water. The data obtained provide further insight into the biological mechanisms arising from retinal photocoagulation with near infrared lasers.     

Miscalibration and severe complications after diode laser cyclophotocoagulation: two case reports

Because two similar transscleral cyclophotocoagulation diode lasers with identical power & duration settings induced significantly different postoperative inflammation, we wanted to compare the real output of both lasers. Using a Power/Energy Meter (Fieldmaster) we compared the output of the two lasers (the Iridis [Quantel Medical] and the Iris Medical [OcuLight SLx]) at different energy levels. At a setting of 600, 1000, 1400, 1700, 2000 and 2500 mW, the measured output for the Iridis and Iris Medical diode laser were respectively 685 and 400 mW, 970 and 650 mW, 1470 and 875 mW, 1700 and 1000 mW, and 1990 compared to 1000 mW. On the average the output of the Iridis laser was correct and the output of the Iris Medical laser was 40% lower than the setting. Overtreatment and severe complications occurred with the Iridis laser because the manufacturer recommended using wrong power settings based on the Iris Medical laser, which was undercalibrated. The calibration of cyclophotocoagulation diode lasers should be performed prior to use when changing to a new device and whenever over- or undertreatment is observed.     

The power output of laser pointers: do they exceed federal standards?

BACKGROUND: Concern about the safety of laser pointers has increased as these devices have become readily available to the public, which includes children who may use them improperly. According to federal (Food and Drug Administration) standards, laser pointers are class 3a devices, and power output cannot exceed 5.0 mW. METHODS: We tested a sample consisting of 29 red diode laser pointers obtained from various sources that were equipped with fresh batteries. Power output was measured with an optical power meter with the sensor 5.0 cm from the laser. The laser was turned on for 60 s and a reading was taken every 10 s. This procedure was repeated five times for every laser. RESULTS: The power output of unaltered lasers ranged from 0.7 mW to a high of 3.9 mW. Alterations to some of the lasers increased the output slightly above 5.0 mW. CONCLUSIONS: When the laser pointers in our sample were used as packaged, they did not exceed the federal standards of 5.0 mW.     

Application of femtosecond ultrashort pulse laser to photodynamic therapy mediated by indocyanine green

BACKGROUND/AIMS: To evaluate treatment with high peak power pulse energy by femtosecond ultrashort pulse laser (titanium sapphire laser) delivered at an 800 nm wavelength for corneal neovascularisation using photodynamic therapy (PDT) mediated by indocyanine green (ICG). METHODS: Using a gelatin solid as an in vitro corneal model, the safety of laser power was studied to determine if it degenerated gelatin with or without ICG. The authors then induced corneal neovascularisation in rabbit eyes by an intracorneal suturing technique. Fluorescein angiography was used to evaluate occlusion before PDT and 0, 1, 3, and 10 days after PDT. The authors performed light microscopy with haematoxylin eosin staining and transmission electron microscopy to determine thrombosis formation in the neovascular regions. RESULTS: The threshold of peak laser power density ranged from 39 to 53 W/cm(2). Laser irradiation was started 30 seconds after a 10 mg/kg ICG injection, and all irradiated segments were occluded at 0, 1, 3, and 10 days at 3.8 J/cm(2). Light and electron microscopy documented thrombosis formation in the neovascular region. CONCLUSION: Femtosecond pulse laser enhanced by ICG can be used for PDT. Because of effective closure of corneal neovascularisation at a low energy level, the high peak power pulse energy of the femtosecond pulse laser might be more efficacious than continuous wave laser for use with PDT.     

Photodamage to calf lenses in vitro by excimer laser radiation at 308, 337, and 350 nm

Calf lenses in vitro were irradiated using an excimer laser at wavelengths of 308, 337, and 350 nm for times ranging from 10 minutes to 5 hours. The laser power was 2.0 watts (W) at 308 nm, 0.2 W at 337 nm, and 2.0 W at 350 nm. During irradiations, the visible light transmission (632.8 nm) of the lenses was measured and found to be decreased markedly with 308- or 337-nm irradiation. No change in visible light transmission was observed with irradiation at 350 nm. Irradiated lenses were also compared with dark control lenses by photographic record. Lenses exposed to 308-nm ultraviolet (UV) radiation for 10-30 minutes showed significant yellow-brown pigmentation and colorless opacification compared with dark controls. Lenses exposed to 337-nm UV light showed primarily colorless opacity with little pigment production. Lenses exposed to 350-nm radiation for up to 1 hour were visibly indistinguishable from dark controls. After photolysis, the lenses were separated into water-soluble and insoluble fractions and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Compared with dark controls, UV-exposed lenses (308 or 337 nm) showed loss of 20-30-kilodalton (kD) material and production of higher molecular weight material at 40-60 kD and greater than 100 kD. There was no evidence of such changes after 350-nm exposure. The data gave the following order for the degree of photodamage: 308 nm approximately 5 x 337 nm greater than 20 x 350 nm. An action spectrum for lens damage is presented.     

Repeated use of transscleral cyclophotocoagulation laser G-probes

PURPOSE: To evaluate the energy transmission of transscleral cyclophotocoagulation laser G-probes after repeated use. METHODS: In this prospective study, eight new laser probes were each used for 30 transscleral cyclophotocoagulation (TSCPC) sessions in cadaver human eyes with the laser settings of 2000 mW power, 2000 milliseconds duration, and 18 shots. The laser power output was measured using a laser energy output meter before and after each TSCPC session, after swabbing the laser probe tip with alcohol, and finally after thorough cleaning by flushing 70% alcohol inside the plastic footplate tip and swabbing with alcohol the fiberoptic tip. Laser probes were inspected for deterioration. Statistical analysis was done using Analysis of Covariance (ANCOVA). RESULTS: The laser power output increased on average by 1.99 +/- 0.18 mW after each cycle (P < 0.01, 95% confidence interval: 1.63-2.35 mW, ANCOVA). No deterioration of the probes was found after 30 TSCPC and sterilization cycles. Laser energy output increased on average 6% (P < 0.01) from the baseline to the first TSCPC cycle. Probe number one broke during the tenth cycle and accordingly data was recorded for this probe until that cycle. CONCLUSION: G-probes not only remain fully functional after repeated use and sterilization with 70% alcohol but also slightly increase in energy output.     

视网膜挫伤兔模型的病理学观察

目的:建立视网膜挫伤的动物模型,观察视网膜损伤后的形态特点。方法:选取40只健康成年无眼疾青紫蓝兔,随机分为挫伤后1,3h;1,3,7,14,30d及正常对照共8组,每组5只,选取右眼为致伤眼,以改良Allen重击法制备兔单眼挫伤性视网膜病变模型,挫伤后获取兔眼标本,以光镜及电镜观察视网膜神经感觉层的病理变化,目镜测微尺(0.01mm)对视网膜神经纤维层(nerve fiber layer,NFL)厚度、内核层(inner nucler layer,INL)厚度进行测量,并对视网膜神经节细胞(ganglion cell,GC)计数。结果:挫伤后1,3h组和1d组NFL明显增厚(P<0.05),而7d组和14d组NFL明显变薄(P<0.05),3d组和30d组NFL厚度与正常对照组比较无显著性差异(P>0.05);各挫伤组GC计数明显少于正常对照组(P<0.05)。电镜显示挫伤后3h组;1,3d组视网膜神经感觉层均出现较多的,具有凋亡形态学与生化改变特征的凋亡细胞,其中在3d组视网膜神经感觉层凋亡细胞数量达到高峰,7d组显著下降。结论:视网膜水肿和神经感觉层细胞凋亡是挫伤性视网膜病变的一个重要机制。     

复方樟柳碱对大鼠视网膜缺血再灌注损伤的保护作用

目的:探讨复方樟柳碱对大鼠视网膜缺血再灌注损伤的治疗作用。方法:将成年雌性Wistar大鼠随机分成正常对照组,造模组和复方樟柳碱组,每组10只。采用前房灌注升高眼压制作急性视网膜缺血模型。观察1,3,7d视网膜电图a波b波的恢复情况。每组随机取2只大鼠造模眼球光镜、电镜下观察视网膜形态结构的变化,以及神经节细胞线粒体的变化。结果:复方樟柳碱组较造模组神经节细胞线粒体肿胀程度轻,b波明显恢复,同造模组与正常组间b波的恢复比较差异有显著统计学意义(P<0.01)。结论:复方樟柳碱可减轻大鼠视网膜缺血再灌注损伤,有神经细胞保护作用。     

Ocular refractive changes in patients receiving hyperbaric oxygen administered by oronasal mask or hood

PURPOSE: The aim of this study was to quantify ocular refractive changes after a standard hyperbaric oxygen (HBO) treatment protocol and to characterize the time period of recovery. PATIENTS AND METHODS: Hyperbaric oxygen therapy was given for 90 min daily at a pressure of 240 kPa for 21 days. Oxygen was administered to 20 patients using an oronasal mask and to 12 patients using a hood. Follow-up examinations were carried out 2-4 days after treatment, and thereafter regularly for up to 10 weeks in both groups. Refraction was assessed automatically and by the monocular subjective refraction method. A subgroup of nine of the 20 patients to whom oxygen was administered by an oronasal mask underwent a separate eye examination, which included crystalline lens opacity measurements and LOCS III gradings. RESULTS: In the patients given oxygen by mask, there was a significant myopic shift in the mean spherical equivalent, which was largest 2-4 days after treatment. The shift was - 0.55 +/- 0.40 D in the right eye and - 0.53 +/- 0.42 D in the left eye. In the patients given oxygen by hood, the largest shift was observed after 12-16 days, and was - 1.06 +/- 0.52 D in the right eye and - 1.10 +/- 0.57 D in the left eye. The refractive changes returned to baseline 6 weeks and 10 weeks after HBO treatment, respectively. No significant changes in crystalline lens transparency were revealed. CONCLUSIONS: The myopic shift after HBO therapy recovers within 10 weeks and may be more pronounced when patients are given oxygen using a hood compared with using an oronasal mask.     

Axonal loss after traumatic optic neuropathy documented by optical coherence tomography

PURPOSE: To report longitudinal retinal nerve fiber layer (RNFL) thickness measurements using optical coherence tomography (OCT) in a patient with traumatic optic neuropathy. DESIGN: Observational case report. METHODS: A 14-year-old boy with severe optic nerve trauma had repeated OCT scans of the peripapillary retinal nerve fiber layer at 3 days, 20 days, 40 days, and 70 days after injury. RESULTS: There was gradual loss of nerve fibers as shown by the OCT color-coded map, RNFL thickness profile, and RNFL thickness measurements around the optic disk. At 70 days of follow-up, severe thinning of the RNFL was observable. CONCLUSIONS: These findings suggest that OCT is able to assess and monitor axonal loss after traumatic optic neuropathy.