Medical Laser Research Articles

Evolution of first-line glaucoma therapy, 2007–2018: a population-based analysis

ObjectiveTo evaluate the long-term evolution of first-line glaucoma therapy (FLGT) initiated by ophthalmologists and optometrists. DesignRetrospective population-based study using validated provincial health care databases. Participants194,759 Ontario residents, 66 years of age or older, who received FLGT between 2007 and 2018. MethodsA total of 194,759 individuals from 12 annual cohorts were enrolled, and rates of first-line medical treatment (prostaglandin analogue [PGA], beta-blocker, alpha-2-agonist, and carbonic anhydrase inhibitor) and laser trabeculoplasty (LT) were calculated. Provider (ophthalmologist or optometrist) rates also were assessed. ResultsAcross the entire study period, of the 194,759 enrolled individuals who received FLGT, 60.2% initially received medical treatment and 39.8% underwent LT. Approximately 94.6% were treated by ophthalmologists. PGA therapy was the most common therapy prior to 2010, whereupon LT became the most common FLGT. By 2015, LT exceeded the total of all medications as FLGT. The annual rate of initial medication prescriptions by optometrists rose to 101.4 per 100,000 population between 2011 and 2018. In 2018, PGA and non-PGA prescription rates by ophthalmologists were 2.6 and 5.0 times higher, respectively, than prescription rates by optometrists. ConclusionLT therapy has become the most common FLGT for Ontario residents 66 years of age or older. PGAs remain the most frequently prescribed glaucoma medication. While ophthalmologists continue to provide the majority of FLGT, optometrists now provide a small but growing fraction of FLGT following the introduction of glaucoma medication prescribing privileges.

Determination of microscopic optical properties of agar and Zerdine phantoms at 635 nm using Kubelka-Munk function approach: A numerical study

<p><span>Since the precise and accurate determination of the optical properties of materials is very important for the development and application of optical technology, the investigation of the optical properties of biological tissues with tissue-like phantoms is an important research field in the applications of lasers in medicine. In this study, after directly determining the macroscopic optical properties of the agar and Zerdine phantoms at 635 nm, including the absorbance, transmittance, reflectance, refractive index, and total attenuation coefficient with the single integrating sphere test apparatus; the microscopic optical characterization of these two different soft tissue phantoms were realized at 635 nm by using the Kubelka-Munk function approach. For this, the microscopic optical parameters, which are the absorption coefficient, scattering coefficient, reduced scattering coefficient, and penetration depth, were calculated over these determined macroscopic optical properties.</span></p>

In Memoriam: Hamit Ziya Gökalp, 1929 to 2022.

In Memoriam: Hamit Ziya Gökalp, 1929 to 2022.

Advanced Diode Laser with Specialized Beam-delivery Instrument in Combined Mini Invasive Laser Hemorrhoid Treatment

As the wavelength range of diode lasers expands, they become increasingly attractive for laser medicine because they are compact, allow the use of convenient fiber delivery systems, and are relatively inexpensive and long-lived. Russian diode lasers are based on world-level achievements in nanotechnologies used in their production. The paper presents the results of clinical application of an improved diode laser apparatus “ACT” model of a domestic company “Uricon Group” equipped with unique multifunctional instruments which enable to minimize mucous lesion in treating vascular pathology of the anorectal zone. A dual-frequency apparatus generating at wavelengths of 980 and 1470 nm permitted the development of a combined technique, which was verified by practical clinical application. The study was aimed at improving the mini-invasive method of surgical treatment of vascular anorectal pathology to ensure maximum efficiency of surgery at any stage of the disease, reducing the duration of surgery, minimizing pain during and after surgery. The technique of laser mini-invasive transdermal and subdermal-submucosal destruction, applied in treatment of 362 patients using the diode laser of “ACT” model and the developed specialized instrument, has shown its effectiveness. All patients returned to daily activities 2-3 days after surgery. Economic effect of the developed treatment technology is provided by low price of the equipment and absence of necessity of the patient’s stay in the clinic in the postoperative period.

Gonioscopy-assisted transluminal trabeculotomy: Passing the right way decoding suture.

Trabeculectomy is still the most frequently performed glaucoma surgery. But being an invasive procedure, it has numerous vision-threatening complications along with bleb-related complications like cystic bleb, overhanging bleb blebitis, or endophthalmitis. The choice of therapy between medical laser and filtering surgery is now bridged by minimally invasive glaucoma surgeries (MIGS), which are conjunctiva-sparing procedures with adequate intraocular pressure (IOP)-lowering effects and good safety profiles. Among the armamentarium of MIGS procedures, gonioscopy-assisted transluminal trabeculotomy (GATT) is a frontrunner safe procedure. The procedure is a blebless and sutureless procedure in which a readily available Prolene suture is used to cleave the entire trabecular meshwork. An ab interno approach also allows direct visualization of a so-called trabecular shelf that, when present, indicates an open, cleaved collector system commonly associated with a positive postoperative outcome. Thus, it not only saves the eye from various postoperative complications of other previous penetrating procedures, but is also an effective glaucoma surgery that can be performed with very low costs, which would have big economic implications for glaucoma care in developing countries. The purpose of this video is to illustrate transluminal novel trabeculotomy technique and video-based skill transfer to a novice surgeon. This video depicts detailed steps of GATT surgery in a patient with primary open angle glaucoma and in a case of silicon oil induced secondary open angle glaucoma. The authors also share their experience regarding possible intraoperative problems and solutions with some tips and tricks to make the surgery easy. GATT can be performed with cataract surgery with minimal patient morbidity and a short recovery time with preserving healthy conjunctiva. There is no risk of post op hypotony or bleb related complications, with a short surgical learning curve. https://youtu.be/gk1of38EX1g.

Effect of different surface pretreatment methods on repair bond strength of resin composite subjected to pH-cycling

Objectives: The aim of this study was to evaluate the effect of two different repair methods (Er:YAG laser and bur) with or without silane application on the microtensile bond strength of a nanohybrid resin composite aged with two different aging methods (pH cycling and thermocycling). 
 Material and Method: Resin composite blocks (Clearfil Majesty Esthetic, Kuraray, Japan) were randomly assigned into two groups for aging process: (a) pH cycling (b) thermocycling (5,000 cycles). After aging, the blocks were assigned to one of the following repair procedures: (1) Er:YAG laser (LightWalker STE-E, Fotona Medical Lasers, Ljubljana, Slovenia) (2) Er:YAG laser+silane (3) bur (4) bur+silane and (5) no-pretreatment group and (6) Cohesive control (cohesive strength of the resin). Resin composite (Clearfil Majesty Esthetic) was bonded to the conditioned substrates incrementally and light polymerized. Repaired samples were thermocycled (5.000 cycles). The microtensile bonding test was performed. The data were analyzed using Scheirer-Ray-Hare, Kruskal-Wallis Mann-Whitney U tests, Chi-square and Z tests with Bonferroni correction (p=0.05). 
 Results: No statistically significant difference was found between the aging methods applied to filling material (p=0.821) and the interaction of applied surface treatments and aging (p=0.289). All repair procedures achieved bond strength values higher than the no-pretreatment group but they did not reach the resin composite’s cohesive bond strength. Failure modes distribution was found statistically different according to repair procedure and also aging methods (p

Diversity trends in the leadership of the American Society for Laser Medicine And Surgery, 1996-2021.

To evaluate the temporal trends in diversity within the ASLMS board of directions from 1996 to 2021. A list of Board of Directors from 1996 to 2021 was obtained from ASLMS headquarters. Using a composite of publicly available resources through internet searches, board director characteristics, such as age, gender, race/ethnicity, terminal degrees, specialties/field of expertise, and current full-time affiliations, were recorded. One hundred forty-six unique individuals held 628 ALSMS board member positions from the years 1996-2021. The median age of the board members started with a median age of 43.0 years old in 1996 to 54.5 years old in 2021. The age spread between first and third quartiles (interquartile range) in each year in more recent years (2014-2019) was 17.0, 20.0, 18.8, 18.8, 18.0, and 15.3 years, respectively. Female representation started with 10.5% in 1996 to 30.8% in 2021. Diversity, by racial/ethnicity measures, has more representation of Asian (average across 1996-2010: 2.3% to 2010-2022: 19.0%) and Hispanic (average 1996-2010: 0.7% to 2010-2022: 4.4%) board members. No African American has held a position across these decades. MD holders (average 66.5%) and other degree holders (average 33.5%) have been relatively consistent across all years observed. From 2016 to 2021, dermatologists held board member seats at an average rate of 56.5% across these years, while prior, from 1996 to 2015, 67.3% of board member seats on average were held by members of other expertises. Most board members have full-time affiliations in private practice across most years observed (average 43.7% across all years observed). After analyzing the diversity trends across board members in ASLMS across 1996-2020, we have noticed overall trends of increased diversity over time that reflect a greater chance of bringing in new ideas and experiences to grow ASLMS. Although the leadership of ASLMS has become significantly more diverse over time, there remain opportunities to increase diversity further, including women, underrepresented ethnic minorities, and other experts of specialties other than dermatology.

A Case of Bleb Related Endophthalmitis Complicated with Retinal Detachment

Glaucoma-filtering procedures (e.g., trabeculectomy) is a standard surgical procedure commonly done when maximally tolerated medical therapy or laser trabeculoplasty fails to adequately control intraocular pressure (IOP). The filtering procedure creates a fistula between the anterior chamber and the subconjunctival space, covered with thin sclera and conjunctiva that allows excess aqueous humour to be absorbed into the systemic circulation. Thus, the presence of a filtering bleb poses an enduring risk of a bleb related infection (BRI) over the patient’s lifetime (1). To improve the success of these procedures, it has now become routine to use intraoperative antifibrotic agents (e.g., mitomycin and fluorouracil) as an adjunct to standard trabeculectomy (2). Although these agents have improved the chances of long-term IOP control they have further predisposed to an increased incidence of postoperative complications including late-onset filtering bleb-related infections (1).

The The Effectiveness of a 980-nm Diode Laser to Treat Face Haemangioma: A Randomised within-Patient Trial

Haemangiomas are benign noncancerous vascular malformations of capillaries and are commonly present on the face. All types of lasers are suitable for the management of such vascular lesions. Here, we aimed to determine the effectiveness of a 980-nm diode laser for the treatment of Iraqi patients with facial haemangioma. This randomised trial was conducted at Laser Medicine Research Clinics, Iraq, from 15 October 2018 to 15 August 2019. The improvement of the condition at 6 months was the first endpoint. The patient's quality of life, diminished lesions, and safe administration of diode laser were the second endpoints. At follow-up, the lesions were less elevated, smoother in texture, and the colour had changed from red to pink. Based on these results, this laser is an effective and safe tool for the treatment of haemangiomas of the face.

Radiofrequency impedance monitoring of the biological tissues under local heating by optical radiation.

Development of methods for simultaneous control of state of biological tissues during optical treatment is the important tasks in laser surgery. We introduce a novel approach for the monitoring of the state of biological tissues in the process of its local heating by optical radiation. It is based on measurements of the electrical radiofrequency impedance kinetics of the sample during irradiation. The obtained data are processed using interconnected mathematical modeling of corresponding thermodynamic, optical and electrical problems. Experimental applications of this approach, represented in the paper, reveal its high sensitivity, repeatability and consistency with the model. The introduced method can be used for the selection and optimization of radiation parameters of medical laser sources as an alternative or an addition to histological techniques. Radiofrequency impedance measurement can be used directly in the course of surgical operations for monitoring the treated tissues state, including its temperature and degree of damage.

Integration of blue–green electroluminescence structure in mid-infrared hollow optical fiber for targeting invisible CO2 laser beam

Mid-infrared (IR) CO2 lasers have important applications in laser medicine and material processing. However, the CO2 laser beam is invisible to human eyes, it is not easy to accurately indicate the beam position in practical applications. In this work, we designed a PEDOT (Poly (3, 4-ethylenedioxythiophene))/ZnS: Cu/BaTiO3/Ag electroluminescence (EL) structure and integrated it at the output end of the mid-IR hollow optical fiber. The blue–green light can be output along with the CO2 laser beam in this EL structure integrated fiber, thus achieving the optical path indication and illumination of invisible laser beam. This work provides a possible guide for aiming the CO2 laser beam in the min-IR optical fiber.

10th Anniversary of the International Society for Medical Laser Applications.

This short report is about the International Society for Medical Laser Applications (ISLA). A short list of the most frequently used methods within the research areas of the ISLA is included along with a description of how the great potential of these new laser methods led to numerous improvements in patient treatment. The ISLA attaches great importance to being an opinion leader in the context of evidence-based laser medicine. Many further developments are planned that will enrich the range of methods.

The 43th Annual Meeting of Japan Society for Laser Surgery and Medicine

The 43th Annual Meeting of Japan Society for Laser Surgery and Medicine

Development of Wide-Angle Short-Wave Pass Thin Film Based on the Ultra-Thin Silicate Glass.

With the rapid development of laser medicine, there are higher requirements placed on the performance of optical components in various medical systems. This paper is aimed at exploring the critical optical devices of medical equipment for treating periodontitis and gingivitis. The cathode sputtering method was used to produce the wide-angle short-wave pass filter, and a hundreds grid fastness test was conducted to detect the occurrence of film peeling. Considering the results of SEM, transmission spectrum, and stress test of the sample, an analysis was conducted as to the cause of poor bonding force for the film. By increasing the amount of argon gas and adjusting the baking temperature, the problem of film peeling was resolved. Besides, a short-wave pass filter film with good bonding and low roughness was obtained to meet the requirements of laser medical equipment.

Relationship between Progressive Cup Disc Ratio and Intraocular Pressure in Primary Open Angle Glaucoma After 2 Antiglaucoma Agents for 3 Months

Introduction: Primary open-angle glaucoma (POAG) is a subset of glaucoma defined by an open, normal-appearing anterior chamber angle and raised intraocular pressure (IOP) with no other underlying disease. Globally 57.5 million people were affected by primary open-angle glaucoma (POAG) in 2015, rising to 65.5 million by 2020. POAG can further lead to optic nerve damage, which can cause total blindness. POAG cannot be cured but can be controlled with medical therapy, laser, and surgical procedures. Antiglaucoma drugs are a method of treatment that can overcome this disease. This study aims to determine the characteristics of patients with POAG and progressivity of cup to disc ratio and intraocular pressure after 3 months of management of 2 antiglaucoma agents in POAG patients in Dr. Mohammad Hoesin General Hospital Palembang.
 Methods: This study retrospectively reviewed the medical records specific to primary open-angle glaucoma. Data was obtained from the patient register book recorded from February 2022 to May 2022 in Dr. Mohammad Hoesin General Hospital Palembang. The parameters analyzed were patients' profiles, namely gender, intraocular pressure, and cup to disc ratio before and after 3 months of combination 2 antiglaucoma agents. Timolol and latanoprost are the 2 antiglaucoma agents given to patients diagnosed of previous POAG (by an ophthalmologist).
 Results: From 30 patients diagnosed with POAG by an ophthalmologist, the number of primary open-angle glaucoma patients was more female, namely 19 patients (63.3%) than 11 male patients (36.7%), with a ratio of 1.28:1 between women and men. The cup to disc ratio between before and after 3 months of therapy using timolol and latanoprost was 0.628 ± 0.04 before therapy to 0.645 ± 0.06 after therapy (p<0.05). Intraocular pressure before and after 3 months of therapy was 24.76 ± 2.63 before therapy to 17.75 ± 2.08 (p<0,05). Both cup to disc ratio and intraocular pressure differs statistically from before and after therapy.
 Conclusion: Fixed combination therapy of timolol and latanoprost is effective in lowering intraocular pressure and reducing cup to disc ratio progressivity in patients with primary open-angle glaucoma.

Gonioscopy-Assisted Transluminal Trabeculotomy Following Failed iStent Surgery.

We describe 4 cases of eyes initially treated with phacoemulsification and iStent trabecular microbypass (Glaukos Corporation). These patients subsequently required further surgery and were successfully treated with the removal of the iStent device followed by gonioscopy-assisted transluminal trabeculotomy (GATT), using the iTrack catheter (Ellex Medical Lasers Ltd). Three of the cases had prior first-generation iStent (G1), and 1 had prior second-generation iStent (G2). This case series demonstrates that in selected cases, a further angle procedure in the form of a GATT can show efficacy and durability in the medium term. Our patients had controlled intraocular pressures (IOPs) at 1-year post-GATT: 2 on IOP-lowering therapy and 2 without any IOP-lowering medications. Three patients had transient hyphema and 2 with high IOP in the immediate postoperative period. No patients experienced a decrease in best-corrected visual acuity postoperatively. To the best of our knowledge, there is no prior literature describing this surgical strategy. This series demonstrates that GATT could potentially be an effective procedure in the case of a failed initial iStent microtrabecular bypass.

Plume control in medical and cosmetic laser clinics: a practical guide

In this article, Godfrey Town and Mike Murphy review risk assessments that aim to control the dangers of plume and make recommendations that laser specialists can use to make their practice safe and secure

Generation of 8–20 μm Mid-Infrared Ultrashort Femtosecond Laser Pulses via Difference Frequency Generation

Mid-infrared (MIR) ultrashort laser pulses have a wide range of applications in the fields of environmental monitoring, laser medicine, food quality control, strong-field physics, attosecond science, and some other aspects. Recent years have seen great developments in MIR laser technologies. Traditional solid-state and fiber lasers focus on the research of the short-wavelength MIR region. However, due to the limitation of the gain medium, they still cannot cover the long-wavelength region from 8 to 20 µm. This paper summarizes the developments of 8–20 μm MIR ultrafast laser generation via difference frequency generation (DFG) and reviews related theoretical models. Finally, the feasibility of MIR power scaling by nonlinear-amplification DFG and methods for measuring the power of DFG-based MIR are analyzed from the author’s perspective.

Wavelength stabilization and spectra narrowing of a 405 nm external-cavity semiconductor laser based on a volume Bragg grating.

We introduce a 405 nm external-cavity semiconductor laser using a volume Bragg grating (VBG) as the feedback element. By decreasing the length of the external cavity and reducing the wavelength difference between the output wavelength of the laser diode during free running and Bragg wavelength of the VBG, the emission wavelength of the semiconductor laser is stably locked at 405.1 nm with a spectral linewidth of 0.08 nm. The output power reaches 292 mW, and the wavelength drift with temperature reduces to 0.0006 nm/°C. These results are helping for the spectroscopy applications of a blue-violet laser diode. In contrast to traditional external-cavity semiconductor lasers, this laser is less expensive and more compact, in addition to having a narrow linewidth and good wavelength stability. These advantages would facilitate the development of associated areas of research, including optical data storage, laser display, and laser medicine.

The Emergence of Medical Laser based Diagnostics to Battle against Complex Diseases

Lately, we have witnessed an explosive growth of innovative lasers and optical devices for clinical diagnostics and therapeutics including assessing human health and treating complex diseases. It is believed that light and optical techniques can have profound impacts on modern medicine. To this end, advances in medical lasers enabled biomedical optics have resulted in sophisticated technologies that integrate several other technologies including photonics with nanotechnology, biomaterials and genetic engineering, to name a few. Especially, novel biomedical laser applications based on new laser types or novel energy delivery systems could increase the usable range of laser-tissue interactions, and thus improve target-oriented, high precision application of laser radiation in clinical practice. Here, we have presented a perspective analysis of recent demonstrations of medical lasers for complex diagnostics including clinical diagnostics applications.