Neodymium-doped Yttrium Aluminum Garnet Laser Research Articles

Does Laser Iridotomy Cause Secondary Epiretinal Membrane?

This study aimed to determine the frequency of epiretinal membrane (ERM) in the long term after neodymium-doped yttrium aluminum garnet laser iridotomy (LI) using spectral domain optical coherence tomography (SD-OCT). This retrospective study included 94 eyes that underwent LI for primary angle-closure glaucoma, were followed for at least 4 years, and had no ERM before the procedure. The control group consisted of 66 eyes that were followed for suspected glaucoma did not have a previous ERM. We compared the ERM frequencies of the groups at the last visit. Additionally, ERM frequencies were compared between those who had cataract surgery in the post-LI period and those who did not. After a follow-up period of at least 4 years, ERM developed in 36 of 94 eyes (38.2%) in the LI group. Of these, 32 were stage 1 ERM (34.0%) and 4 were stage 2 ERM (4.2%). In the control group, ERM developed in 13 of 66 eyes (19.6%), 12 of which were stage 1 ERM (18.1%) and 1 was stage 2 ERM (1.5%) (p=0.012). ERM developed in 14 of 32 eyes (43.7%) who underwent phacoemulsification surgery after LI and in 22 of 62 eyes (35.4%) that underwent only LI without subsequent cataract surgery (p=0.435). ERM developed significantly more frequently in the 62 phakic eyes that underwent only LI than in the eyes in the control group (p=0.045). LI appears to be a predisposing factor for the development of ERM, regardless of subsequent cataract surgery.

Study on the Mechanism of Nd:YAG Laser-Assisted Therapy on the Changes of Subgingival Flora in Periodontitis.

This study evaluated the therapeutic efficacy of combining Neodymium-doped Yttrium Aluminum Garnet (Nd:YAG) laser with subgingival curettage and root planing (SRP) in generalised stage III/grade C periodontitis patients and its effects on cytokine dynamics and microbial community. Fifteen patients diagnosed with stage III/grade C periodontitis were included in the cohort. The right and left sides of the mouth were randomly assigned either the conventional SRP (control) group or the SRP supplemented with Nd:YAG laser group (experimental group, 160 mJ, 4 W) in a split-mouth design. Clinical periodontal indices were recorded at baseline and at the 6-week follow-up post-treatment. ELISA was utilised to measure IL-1β and TNF-α levels in gingival crevicular fluid. The subgingival microbiota's composition and variations were characterised using 16S rDNA amplicon sequencing, while quantitative real-time polymerase chain reaction (qRT-PCR) was employed to analyse the changes in the red-complex bacteria in subgingival plaque. The SRP+Nd group exhibited a statistically significant reduction in record probing depth (PD) and bleeding on probing (BOP) compared to the SRP group after treatment (p0.05). The SRP+Nd group showed a markedly lower IL-1β level than the SRP group (p0.05). Furthermore, there was no statistically significant difference in the dominant subgingival microbiota composition and level of the red-complex bacteria between the two groups (p>0.05). The adjunctive use of Nd:YAG laser with SRP demonstrates promising short-term therapeutic benefits for patients with extensive stage III/grade C periodontitis. Both SRP as a standalone treatment and its combination with Nd:YAG laser effectively facilitate a transition in the dominant bacterial community from periodontitis-associated to periodontal health-associated microbiota.

Pseudophakic cystoid macular oedema and posterior capsular opacification rates after combined phaco-trabeculectomy vs. phaco alone.

To assess the risk for pseudophakic cystoid macular oedema (PCME) and posterior capsular opacification (PCO) associated with combined cataract surgery and trabeculectomy compared to cataract surgery alone. Data analysis of subjects who underwent routine cataract surgery without and with concomitant trabeculectomy at the Department of Ophthalmology, Bristol Eye Hospital, the UK, between January 2008 and December 2017. Odds ratios (ORs) for PCME between the types of surgeries were calculated using univariate and multivariate regression analysis. Multivariate Cox regression controlling for age and gender was used to estimate the hazard ratio (HR) for neodymium-doped yttrium aluminium garnet (Nd:YAG) laser capsulotomies. This study included 56 973 cataract surgeries without and 288 with concomitant trabeculectomy (phaco-trab) with a mean follow-up time of 6.9 ± 4.2 years. Baseline variables (age and gender, diabetes, pseudoexfoliation, use of pupil expansion device and postoperative follow-up time) were comparable between the groups. Postoperative rates of PCME remained non-significant between the cataract surgery and phaco-trabe groups both in uni- and multi-variate analysis (OR 0.347, 95%CI 0.049-2.477, p = 0.291). Furthermore, in Cox regression analysis adjusted for the patients' age and gender, Nd:YAG laser capsulotomy rates remained non-significant between the cataract surgery and phaco-trabe groups (HR 1.250, 95%CI 0.883-1.769, p = 0.209). In our large cohort study, combining trabeculectomy with cataract surgery did not predispose to an increased PCME or Nd:YAG laser capsulotomy rates.

Comparative study of using the Neodymium-doped yttrium Aluminium Garnet laser alone or in combination with the High Intensity Focussed Ultrasound technique for removing the professional tattoo.

To evaluate the effects of combining neodymium-doped yttrium aluminium garnet laser and highintensity focussed ultrasound techniques to remove a professionally-done tattoo. The interventional study was conducted from November 2021 to April 2022 at the at the Postgraduate Medical Physics Laboratory of Mustansiriyah University, Baghdad, Iraq, and comprised healthy adults aged 18-60 years who wished to have their tattoo areas from their hands, arms and forearms removed. Each tattoo was divided into 3 areas. The first area was treated with multiple passes of neodymium-doped yttrium aluminium garnet laser with 450mJ. The second area was treated with multiple passes of neodymium-doped yttrium aluminium garnet laser with 450mJ and 850mJ. The third area was treated with multiple passes of neodymium-doped yttrium aluminium garnet laser with 450mJ, followed by 5-10 consecutive strokes of HIFU waves with energy 0.25-0.6mJ, 1.4mm depth, 10MHz and 7MHz frequency, and a second blow of the neodymium-doped yttrium aluminium garnet laser with 450mJ. The intervention lasted 8 sessions, and the time required between the sessions ranged 15-20 days. The percentage of pigmentation was evaluated using the image segmentation method based on fuzzy c-means. Data was analysed using SPSS 24. Of the 20 subjects, 12(60%) were males and 8(40%) were females. There were 10(50%) subjects aged 17-24 years, 6(30%) aged 25-35 years and 4(20%) aged 36-45 years. The tattoo pigments showed a significant reduction in all the 3 groups (p<0.05), but intergroup comparison showed that the reduction was most significant in the group treated with neodymium-doped yttrium aluminium garnet laser plus high-intensity focussed ultrasound (p<0.05). The combination of high-intensity focussed ultrasound and neodymium-doped yttrium aluminium garnet laser led to more positive outcome compared to the use of low- or high-intensity laser alone.

Melasma removal using Q-Switched Neodymium-doped Yttrium Aluminium Garnet laser toning and high-intensity focussed ultrasound.

To evaluate the effectiveness of combining high-intensity focussed ultrasound and a Q-switched neodymium-doped yttrium aluminium garnet 1064nm low-fluence toning laser in the treatment of melasma. The experimental study was conducted from November 2020 to August 2021 at the medical physics laboratory, College of Medicine, Mustansiriyah University, Baghdad, Iraq, and comprised individuals of either gender aged >25 years having mixed form melasma in malar and forehead areas. Each participant received high-intensity focussed ultrasound treatment on the right side. After 2 weeks, Q-switched neodymium-doped yttrium aluminium garnet 1064nm low-fluence toning laser was applied to the melasma patches 4 times at one-week intervals. Melasma area and severity index scores were noted at baseline and at each visit for each patient. Visual analogue scale was used for objective evaluation. After the 4 laser sessions, all the patients completed a 3-month follow-up. Data was analysed using SPSS 24. Of the 25 subjects, 15(60%) were females and 10(40%) were males. The overall mean age was 41.6±8.46 years (range: 22-60 years). There was a significant improvement with high-intensity focussed ultrasound (p<0.05). In the 3rd laser session, there was a significant difference in melasma area and severity index score of 2.48 for the right side and 3.12 for the left side (p<0.05). In the 4th session, there was a significant difference in melasma area and severity index score of 1.68 for the right side and 2 for the left side (p<0.05). No post-inflammatory hyperpigmentation or rebound was noted. High-intensity focussed ultrasound combined with toning laser was more effective than Q-switched neodymium-doped yttrium aluminium garnet 1064nm low-fluence laser alone in removing difficult melasma from the malar area in the 2nd, 3rd and 4th sessions, and from the forehead in the 3d and 4th sessions.

Solid-state laser (266 nm) as an alternative to ArF excimer laser (193 nm) for corneal reshaping: Comparative numerical study of the thermal effect.

Laser corneal reshaping is a safe and effective technique utilized to treat common vision disorders. An advanced laser delivery system equipped with a pulsed UV laser with specific parameters is used to ablate parts of the cornea surface to correct the existing refractive error. The argon fluoride (ArF) excimer pulsed gas laser at 193 nm is the most employed type in the commercial devices for such treatments. This laser is generated using a mixture of Argon, Fluorine, and a significant amount of Neon gases. However, due to the ongoing Russian-Ukraine war, the availability of Neon gas is currently very limited, as this region is considered the primary supplier of pure Neon gas. Consequently we suggest replacing the common ArF laser source in the commercial devices with a solid-state (forth harmonic neodymium-doped yttrium aluminum garnet laser at 266 nm). This replacement uses the same operation parameters, optics, and scanning algorithm. Parameters from five commercial devices (Zeiss MEL 90, Technolas TENEO 317, Alcon Wave Light EX 500, Schwind Amaris 750 s, OptoSystems MICROSCAN VISUM) were compared with those of the i-ablation device, a research device that uses a 266 nm laser source. Our goal is to reduce production costs through a simple modification that has a significant impact. Consequently, the present study aims to find an alternative laser source for the current ArF laser without exchanging the complete system's design. This recommendation is based on a numerical simulation study. The thermal effect on a human cornea model was numerically evaluated using finite-element solutions of Pennes' bioheat equation on the COMSOL platform by applying two laser wavelengths. The results demonstrated that changing the laser source significantly impacts the thermal effect, even with the same laser settings. All studied devices showed a reduction in the thermal effect to below 40°C, compared with nearly 100°C under ordinary conditions.

Unilateral lifebuoy cataract: A case report.

Lifebuoy cataract is a rare congenital condition characterized by lens thinning. Due to its rarity, detailed treatment reports and standardized surgical approaches are limited. This study aims to enhance the current body of knowledge by presenting comprehensive case reports and describing surgical techniques for the treatment of lifebuoy cataracts. A 14-year-old boy was diagnosed with a congenital cataract in his right eye at the age of 9, which was left untreated. The patient visited our hospital due to progressive visual impairment. The visual acuity of the right eye was counting fingers at 30 cm. The uncorrected visual acuity of the left eye was 20/100, whereas the best corrected visual acuity was 20/20. The intraocular pressures were 18 mm Hg (left eye) and 20 mm Hg (right eye). Slit-lamp microscopy revealed central calcification of the lens capsule in the right eye and slightly opaque cortical tissue in the periphery, with no observable lens nucleus. Anterior segment optical coherence tomography (CASIA2, TOMEY, Nagoya, Japan) of the right eye showed fused anterior and posterior capsules and an absence of the lens nucleus, leading to a diagnosis of lifebuoy cataract. Cataract surgery was performed on the right eye. Following a 2.4-mm sclerocorneal incision and trypan blue staining, continuous curvilinear capsulorrhexis was performed around the central opacity. The surrounding cortex was removed using irrigation and aspiration, while a viscoelastic agent was injected between the central calcified membrane and the posterior capsule. The membranous tissue was carefully peeled away and removed using forceps. Despite residual posterior capsular opacification, posterior capsulotomy was not performed due to concerns about vitreous prolapse. The intraocular lens was fixed within the capsule. Ten days post-surgery, the remaining posterior capsular opacification was treated with neodymium-doped yttrium aluminum garnet laser capsulotomy. The uncorrected visual acuity and best corrected visual acuity of the right eye improved to 20/100 and 20/50, respectively. This case report demonstrates a successful surgical approach for a lifebuoy cataract, highlighting its unique morphology and the need for careful, specialized techniques. These findings aim to guide ophthalmologists in managing this rare condition, potentially improving patient care.

Eccrine angiomatous hamartoma treated with multimodal vascular laser and incobotulinum.

Eccrine angiomatous hamartoma (EAH) is a rare benign vascular lesion that is distinguished histologically by vascular and eccrine overgrowth. We report the case of a 46-year-old woman with EAH who was successfully treated with multimodal incobotulinum toxin A, pulsed dye laser and long-pulsed neodymium-doped yttrium aluminium garnet laser.

CO2 laser-assisted sclerectomy surgery for secondary open-angle glaucoma after vitrectomy.

To explore the efficiency and safety of carbon dioxide (CO2) laser-assisted sclerectomy surgery (CLASS) in Chinese patients with glaucoma secondary to vitrectomy. This retrospective study consisted of 16 eyes from 16 patients with glaucoma secondary to vitrectomy who underwent CLASS and were followed up for 12 months. Main outcome measures included preoperative and postoperative intraocular pressure, best corrected visual acuity (BCVA), number of anti-glaucoma medications, and postoperative surgical success rate and complications. The postoperative IOP and number of anti-glaucoma medications used at all follow-up time point were significantly lower than those preoperatively. The difference in BCVA was not significant before and after surgery. The main complicatios were peripheral anterior synechiae (PAS) and scleral reservoir reduction, which were controlled after neodymium-doped yttrium aluminum garnet (Nd:YAG) laser, 2 (12.50%) patients underwent re-operation. The complete and total success rates at 12 months were 68.75% and 87.50%, respectively. CLASS is a safe and effective procedure for Chinese patients with glaucoma secondary to vitrectomy. PAS and scleral reservoir reduction is a major contributor to postoperative IOP elevation, and trabecular minimally invasive perforation with the Nd:YAG laser is effective in lowering IOP and increasing scleral cistern volume.

Time- and angular-distribution of ion current in pulse-laser ablation plume of aluminum

Thrust generation through pulse-laser ablation has been proposed for use in propulsion systems in space. However, to achieve a high thrust performance, the energy efficiency must be improved and it is important to determine the behavior of the ablation plume to identify where energy losses occur. In this study, the ion-current distribution of a plume with aluminum ablation was measured. A neodymium-doped yttrium aluminum garnet (Nd:YAG) laser with a wavelength and pulse width of 1064 nm and 9 ± 2 ns, respectively, was used for the ablation. Experiments were conducted at three different fluences: 10, 15, and 20 J/cm2. The fluence was varied in two ways: changing the beam-spot diameter while maintaining the single-pulse energy and changing the single-pulse energy while maintaining the beam-spot diameter. The ion current was measured at various angles using Faraday probes. The generated impulse and reduction mass were also measured. By combining and analyzing the results, the divergence angle of momentum, mean valence of ablated aluminum, and energy efficiencies of several processes were estimated.

Microchanneling and ultrasonic delivery of gold and platinum nanoparticles for selective photothermolysis of sebaceous follicles in the treatment of acne: a pilot study using porcine skin.

Several treatment options for acne vulgaris are limited by their associated adverse effects. An innovative approach involves introducing light-absorbing nanoparticles into sebaceous follicles before destroying the follicles using selective photothermolysis. We aimed to investigate efficient methods for introducing gold and platinum nanoparticles into sebaceous follicles and to identify suitable laser equipment and parameters for the effective destruction of these follicles. We used porcine skin as the experimental model. We compared the efficacies of a thulium laser, ultrasound, and manual massage and evaluated the optimal method for delivering nanoparticles in close proximity to sebaceous follicles. Subsequently, a 1064-nm-wavelength neodymium-doped yttrium aluminum garnet (Nd: YAG) laser was employed to induce selective photothermolysis. We compared different parameters to identify the optimal pulse duration and fluence of the Nd: YAG laser. The extent of penetration and destruction of sebaceous follicles was assessed using hematoxylin and eosin (H&E) staining, and a numerical evaluation was conducted. H&E staining showed that irradiation with a long-pulsed Nd: YAG laser following a combination of thulium laser and sonophoresis effectively destroyed sebaceous follicles, with destruction rates exceeding 50%. These results were valid with a long pulse duration and a high fluence of the Nd: YAG laser. This study demonstrated that sebaceous follicles can be effectively destroyed through a mixture of gold and platinum nanoparticle delivery by a combination of microchanneling and sonophoresis, followed by selective thermal damage induced by a 1064-nm long-pulsed high-fluence Nd: YAG laser.

Neodymium-doped yttrium aluminum garnet (Nd: YAG) laser treatment in ophthalmology: a review of the most common procedures Capsulotomy and Iridotomy.

Nowadays, lasers are used in various medical fields. Ophthalmology was the first medical specialty to utilize lasers in patient treatment and still remains the leading medical field that uses laser energy for both therapeutic and diagnostic purposes. The neodymium: yttrium-aluminum-garnet (Nd: YAG) laser is one of the most common lasers used in ophthalmology. It is a solid-state laser with a wavelength of 1064nm that works on the principle of photodisruption. Since its introduction in ophthalmology over 40 years ago, it has found various applications, mainly for procedures where cutting or disruption of ocular tissue is required. Compared to surgical alternatives, the use of Nd: YAG lasers on ocular tissue is minimally invasive. In this review, we focus on the two most common ophthalmic applications of Nd: YAG laser - laser peripheral iridotomy and posterior capsulotomy. The history of the techniques, current trends, potential complications, and the prognosis for future use is discussed.

A Systematic Review on Management of Infantile Hemangiomas: How Far We Have Reached in this Past Decade

Infantile hemangioma (IH) is a common condition in children. It may lead to cosmetic disfigurement, functional impairment, and various complications. There are various treatment options available for this condition. This article aims to discuss the various therapeutic options available for the treatment of IH. We searched PubMed, Google Scholar, and Embase (from December 2013 to December 2023) for human studies/case reports/case series assessing the management of IH. We reviewed 198 papers including different therapeutic regimens. β-blockers other than propranolol, such as nadolol, timolol, atenolol, acebutolol, and captopril, have shown comparable results to propranolol. Pulsed dye laser (PDL) and neodymium-doped yttrium aluminum garnet laser have shown promising results. Other therapies observed were sclerotherapy, cryotherapy, and surgical resection. A conventional combination of β-blockers with a laser might be the first-line treatment to arrest the growth of IH. PDL has shown promising results.

Efficacy of Nd:YAG Laser 1064-nm in the Treatment of Onychomycosis.

To assess the effectiveness of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser 1064 nm in the management of onychomycosis. Descriptive observational study. Place and Duration of the Study: Department of Dermatology, PNS Shifa Hospital, Karachi, Pakistan, from December 2022 to May 2023. Thirty patients, of either gender, aged between 20 and 60 years, with a clinical diagnosis and a positive KOH test for onychomycosis. Long-pulsed 1064-nm Nd:YAG laser therapy was administered to patients. On the basis of nail plate thickness, laser therapy was given once a week for a month at a speed of 25 mm/sec and a spot diameter of 4 mm, with fluencies ranging from 40 - 60 J/cm2. Before and six months' post-treatment, the patients' photos were taken and were evaluated based on dermoscopic results and clinical improvement. The patients' average age was 40.20 ± 15.85 years, and their average duration of disease was 3.0 ± 1.41 years. Six (20%) were males and 24 (80%) cases were females. The most prevalent clinical type was distolateral subungual onychomycosis 22 (73%). Fourteen (46.6%) cases showed excellent improvement, 6 (20%) cases showed good improvement, and 10 (33.3%) cases showed mild improvement. Long-pulsed Nd:YAG laser is a safe and efficient option for onychomycosis because of its high clinical cure rates, lack of side effects, and clinical therapeutic efficacy. Onychomycosis, Nd:YAG laser 1064-nm, Dermatology, Nail, Lasers in dermatology.

Ocular characteristics and outcomes of phacoemulsification in patients with cataract after renal transplantation.

To explore ocular characteristics of patients with cataracts after renal transplantation and analyze the results of phacoemulsification combined with intraocular lens (IOL) implantation. Patients with cataracts after renal transplantation and control patients who underwent phacoemulsification combined with IOL implantation were enrolled. All patients underwent phacoemulsification combined with IOL implantation. Visual acuity, intraocular pressure, type of lens opacity, corneal endothelial cell density, and ocular biological parameters were evaluated before surgery. Visual prognosis, dry eye, and postoperative complications were monitored for 6months after phacoemulsification. We analyzed 25 eyes of 16 patients after renal transplantation and 30 eyes of 21 control patients. The most common type of cataract of renal transplantation group was posterior subcapsular, while the most common type of cataract of control group was cortical. Significant differences in corneal astigmatism, white-to-white ratio, and keratometry values were observed between the groups. The postoperative visual acuity of both groups significantly improved following surgery. Postoperative complications, such as the degree of anterior and posterior capsule opacification and the incidence of a requirement of neodymium-doped yttrium aluminum garnet laser capsulotomy, were significantly lower in the renal transplantation group. Moreover, secondary glaucoma occurred in two eyes in the renal transplantation group. This study showed that cataracts after renal transplantation were mostly posterior subcapsular. Postoperative visual acuity recovered well in most patients, with reduced incidence of postoperative complications. This study suggested that phacoemulsification combined with IOL implantation was safe and effective, providing a reference for multi-focal IOL implantation in kidney transplant recipients.

Optical Properties of Gallium Nitride Heterostructures Grown on Quartz Using Pulse Laser Deposition Method

An optical analysis was conducted on a Gallium nitride (GaN) thin film grown on a quartz substrate using the physical vapor deposition technique (PVD), specifically, pulsed laser deposition (PLD). The film was grown using different laser wavelengths (1064, 532, and 355) nm from a Q-switch neodymium-doped yttrium aluminum garnet (Nd: YAG) laser, all performed under a vacuum pressure of 10-2 m bar. The absorption coefficient of the GaN thin film was determined by performing UV-Vis diffused spectroscopy at room temperature and measuring wavelengths ranging from 200 to 1000 nm. The absorption peak occurs at 227 nm when the wavelength is 1064 nm, at 217 nm when the wavelength is 532 nm, and at 222 nm when the wavelength is 355 nm. The optical energy gap is a crucial statistic for analyzing the properties of thin films and assessing their potential as gas sensors. The value of the direct energy gap (Eg) for the prepared films was established by analyzing the graph that shows the relationship between (α h) and the energy gap (ev) values at different wavelengths. The energy values were determined to be 3.36 eV, 3.62 eV, and 3.7 eV for 1064, 532, and 355 nm wavelengths, respectively.

Comparing a Low-Fluence Picosecond 1064 nm Nd:YAG Laser with a 532 nm Nd:YAG Laser for the Treatment of Pigmented Lesions in Chinese Patients: A Retrospective Analysis

The use of low-fluence picosecond (LFPS) 1064 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers, referred to as laser toning, is increasingly acknowledged as an effective treatment for pigmentation disorders in the Asian skin phenotype. This study aimed to conduct a comparative analysis on the effectiveness and safety of utilizing LFPS 1064 nm Nd:YAG lasers against picosecond 532 nm Nd:YAG lasers in treating pigmented lesions among Chinese patients. A retrospective photographic analysis and chart reviews were performed on 31 subjects exhibiting Fitzpatrick skin types III–VI who underwent LFPS 1064 nm Nd:YAG or picosecond 532 nm Nd:YAG treatments at a single tertiary center. Utilizing VISIA Complexion Analysis, comparative photographs were taken. Two independent physicians evaluated treatment efficacy using a visual analog scale (VAS) to assess the percentage of pigmentary clearance in standard photographs. Solar lentigines were the most prevalent pigmentary disorder, followed by post-inflammatory hyperpigmentation (PIH), nevus zygomaticus, melasma, freckles, and nevus of Ota. The clinical effectiveness of picosecond 532 nm and LFPS 1064 nm laser treatments proved comparable for lesions on the face, with mean VAS scores of 2.2 ± 1.1 and 1.8 ± 0.8, respectively. There were two cases of PIH in the picosecond 532 nm group, which resolved within one month. Overall, the LFPS 1064 nm laser demonstrates promise as a safe and efficient therapeutic modality for managing pigmented lesions in Chinese patients.

A Novel 3D High Resolution Imaging Method Using Correlative X-Ray and Electron Microscopy to Study Neodymium-Doped Yttrium Aluminum Garnet Laser-Induced Defects in Intraocular Lenses.

Cataract extraction is the most frequently performed ophthalmological procedure worldwide. Posterior capsule opacification remains the most common consequence after cataract surgery and can lead to deterioration of the visual performance with cloudy, blurred vision and halo, glare effects. Neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy is the gold standard treatment and a very effective, safe and fast procedure in removing the cloudy posterior capsule. Damaging the intraocular lens (IOL) during the treatment may occur due to wrong focus of the laser beam. These YAG-pits may lead to a permanent impairment of the visual quality. In an experimental study, we intentionally induced YAG pits in hydrophilic and hydrophobic acrylic IOLs using a photodisruption laser with 2.6 mJ. This experimental study established a novel 3D imaging method using correlative X-ray and scanning electron microscopy (SEM) to characterize these damages. By integrating the information obtained from both X-ray microscopy and SEM, a comprehensive picture of the materials structure and performance could be established. It could be revealed that although the exact same energies were used to all samples, the observed defects in the tested lenses showed severe differences in shape and depth. While YAG pits in hydrophilic samples range from 100 to 180 µm depth with a round shape tip, very sharp tipped defects up to 250 µm in depth were found in hydrophobic samples. In all samples, particles/fragments of the IOL material were found on the surface that were blasted out as a result of the laser shelling. Defects in hydrophilic and hydrophobic acrylic materials differ. Material particles can detach from the IOL and were found on the surface of the samples. The results of the laboratory study illustrate the importance of a precise and careful approach to Nd:YAG capsulotomy in order to avoid permanent damage to the IOL. The use of an appropriate contact glass and posterior offset setting to increase safety should be carried out routinely.

Combustion of High-Pressure Hydrogen Diluted Mixtures in ESTHER Shock Tube

European Shock Tube for High-Enthalpy Research (ESTHER) is a new state-of-the-art combustion-driven shock tube developed for supporting future ESA planetary exploration missions. Its high-pressure combustion driver sports a unique innovative design where a mixture of He:H2:O2 or N2:H2:O2 gases, filled to pressures up to 100 bar, is ignited by a high-power Neodymium-doped yttrium aluminum garnet (Nd:YAG) laser. The qualification of this facility driver has allowed for the detailed study of laser-ignited combustion processes at high initial pressures (in the 5–100 bar range), over a series of 100 shots carried out for different configurations and gas mixtures. The influence of the oxygen-to-hydrogen ratio, filling pressure, inert gas dilution, and ignition mode have been studied and are presented in this work. The effects of nitrogen vs helium dilution are also discussed. Filling pressure and helium/nitrogen dilutions have the strongest influence in peak pressure, acoustic oscillation, and combustion velocity. The first two increase, whereas the latter strongly decreases with the filling pressure. Nitrogen diluted shots have drastically lower compression ratios and flame velocity when compared to the helium ones. Acoustic perturbations/instabilities are also found to be stronger. This test campaign allowed the definition of a large range of stable and reproducible firing conditions in deflagration mode, yielding post-combustion pressures up to 660 bar.

The Influence of Neodymium-Doped Yttrium Aluminum Garnet Laser Pulse Repetition Rate on Cytokine Secretion from Peripheral Blood Mononuclear Cells in Vitro

Objective: Biological effects of infrared laser energy at various exposure parameters have been characterized in previous in vitro and animal studies. However, the impact of pulse repetition rate (PRR) has not been evaluated in this context. The purpose of this investigation was to assess the influence of PRR on cytokine secretion from peripheral blood mononuclear cells (PBMCs) subjected to pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) laser energy. Materials and Methods: Rat PBMCs were cultured in vitro then stimulated using a lipopolysaccharide concentration of 0 or 100 ng/ml. Cultures received Nd:YAG laser radiation (1064 nm, 5 W, 30 s) at PRR of 0 (untreated controls), 20, 30, 40, or 60 Hz. Concentrations of tumor necrosis factor-α (TNF-α), macrophage inflammatory protein (MIP)-1α, macrophage inflammatory protein (MIP)-2, monocyte chemoattractant protein-1 (MCP-1), interferon-gamma-induced protein (IP)-10, interleukin (IL)-6, and IL-10 were recorded using a magnetic microsphere immunoassay. The main effects of PRR and LPS stimulation on cytokine concentrations, and the interaction between PRR and LPS stimulation, were assessed using two-way analysis of variance. Bonferroni post hoc tests were used to identify pairwise differences between groups. Results: The main effect of PRR was statistically significant for MIP-1α (P = 0.018), TNF-α (P = 0.025), MCP-1 (P &lt; 0.001), MIP-2 (P = 0.013), and IL-6 (P = 0.031). Five of six pro-inflammatory cytokines exhibited significantly lower mean concentrations in laser-exposed compared with control cultures at one or more PRR. However, no statistically significant differences were found between PRR groups. Conclusions: Under the described conditions, statistically significant differences in cytokine secretion were observed between laser-exposed and control cultures, consistent with prior reports. However, PRR appears to be an irrelevant factor in immunomodulation of PBMCs.