Efficacy and safety of subthreshold micropulse laser in the treatment of acute central serous chorioretinopathy

·AIM:To analyze the efficacy and safety of subthreshold micropulse laser(SML)in the treatment of acute central serous chorioretinopathy(CSC).·METHODS:This is a retrospective case analysis study.Totally 58 eyes of 58 patients were enrolled,and they were divided into different groups.And 39 patients were treated with SML(SML group)and 19 patients were only observed(observation group).The follow-up period was 3mo after diagnosis.The best corrected visual acuity(BCVA),central retinal thickness(CRT),superficial retinal vascular density(SRVD),deep retinal vascular density(DRVD),the superficial and deep foveal avascular zone(FAZ)area,retinal light sensitivity(RLS),perfusion area of choroidal capillary layer(CCL),subfoveal choroidal thickness(SFCT)and fundus autofluorescence(FAF)were investigated.·RESULTS:The BCVA,CRT,SRVD,DRVD,the superficial and deep FAZ area,RLS,SFCT of SML group were significantly improved at 3mo(all P<0.05).In the observation group,only CRT,DRVD and SFCT were improved(all P<0.05).Other research items in the observation group were not significantly different from baseline(all P>0.05).At the last follow-up,the BCVA and RLS in the SML group were better than those in the observation group,and CRT was lower,SRVD and DRVD,perfusion area of CCL were larger(all P<0.05).On FAF,no change of treatment spots was found after treatment.No structural laser damage was observed on optical coherence tomography(OCT)and optical coherence tomography angiography(OCTA),and no choroidal neovascularization was observed.·CONCLUSION:SML treatment of acute CSC can improve BCVA,RLS,and perfusion area of CCL,reduce CRT,increase SRVD and DRVD,and is safe.

Comparison of success rate and intraocular pressure spikes between selective laser trabeculoplasty and micropulse laser trabeculoplasty in African American and Hispanic patients

AIM:To examine the efficacy and safety of micropulse laser trabeculoplasty(MLT)versus selective laser trabeculoplasty(SLT)in a large cohort of primarily African American and Hispanic patients.METHODS:A single center retrospective comparative cohort review conducted at Cook County Health facilities that included patients with a diagnosis of open angle glaucoma or ocular hypertension who received an SLT or MLT procedure between January 2017 and May 2021.RESULTS:Totally 131 eyes of 99 patients were analyzed.The 77 eyes received SLT and 54 received MLT.Seven out of 77 eyes in the SLT group(9.1%)and 1 out of 54 eyes in the MLT group(1.9%)had an IOP spike(defined as>5 mm Hg)at either 1h or 1wk after procedure(P=0.05,Chisquared test with Haldane-Anscombe correction).The procedure failure rate at one year was 50%for SLT and 48%for MLT(P=0.31).CONCLUSION:MLT has a significantly lower incidence of pressure spikes and a similar treatment failure rate at 1-year post-procedure,demonstrating that it is a reasonable alternative compared to SLT.

Subthreshold micropulse laser versus intravitreal anti-VEGF for diabetic macular edema patients with relatively better visual acuity

AIM:To compare the effects of yellow(577 nm)subthreshold micropulse laser(SML)and intravitreal(IV)anti-vascular endothelial growth factor(VEGF)treatment in patients with diabetic macular edema(DME)with relatively better visual acuity[best corrected visual acuity(BCVA)≤0.15 log MAR].METHODS:The medical records of 76 eyes of 47 patients underwent IV(0.5 mg)anti-VEGF injection or SML for the DME with relatively better BCVA were reviewed.The IV group received three consecutive monthly IV anti-VEGF injections,then were retreated as needed.The laser treatment group was treated at baseline and 3 mo,and then retreated at 6 and 9 mo if needed.All participants were followed up for one year.The mean BCVA and mean central macular thickness(CMT)values changes over the follow-up were evaluated.RESULTS:Twenty-four and 23 patients were assigned to the SML and IV subgroups,respectively.The mean number of treatments was 3.64±0.76 in SML group and 5.85±1.38 in IV group(P<0.05).The subgroups were similar with regard to the mean BCVA score at baseline and at the 1st and 3rd months,but the score of SML group was better than that of IV group at the 6th,9th,and 12th months(P<0.05).The decrease in the mean CMT values from baseline values was higher in SML group at the 6th,9th,and 12th months(P<0.05).CONCLUSION:Yellow SML treatment is superior to IV anti-VEGF injection in DME patients with relatively better BCVA for increasing visual acuity and decreasing CMT at 6,9,and 12 mo.SML can be a good alternative first-line therapy for DME with BCVA≤0.15 log MAR.

Efficacy and safety of micropulse laser trabeculoplasty for primary open angle glaucoma

AIM: To evaluate the efficiency and safety of micropulse laser trabeculoplasty(MLT) for primary open angle glaucoma(POAG) patients. METHODS: Retrospective study. POAG patients undergoing MLT in Peking University Third Hospital from June 2016 to November 2017. Seventy-two eyes of 72 POAG patients were enrolled. Only one eye of each patient was treated by MLT. The intraocular pressure(IOP) before MLT and at 1 d, 1, 4, 12 and 24 wk and glaucoma medication before and after treatment were compared.RESULTS: The IOP was 20.6±5.9 mm Hg before MLT and 20.8±6.8 mm Hg at 2 h after MTL. The IOP at 1 d, 1, 4, 12 and 24 wk was 17.9±4.4, 18.0±4.3, 17.5±3.4, 17.0±2.7, and 16.5±2.9 mm Hg, respectively. The IOP before and after MLT demonstrated a statistically significant difference by ANOVA analyses(F=5.797, P<0.001). Least significant difference t-tests showed there was no statistically significant difference between pre-MLT IOP within 2 h after MLT(P=0.207). The statistically significant difference was confirmed between the pre-MLT IOP at 1 d, 1, 4, 12 and 24 wk after MLT(P=0.006, 0.009, 0.001, <0.001, <0.001, respectively). The number of glaucoma medications before MLT was 1.7±1.4 and 1.5±1.4 24 wk after MLT with a significantly statistical difference(t=2.219, P=0.031)CONCLUSION: MLT is effective and safe for POAG patients. No patient experienced IOP spikes after MLT. The IOP 6 mo after treatment decreased significantly with less glaucoma medication.

Efficacy of the subthreshold micropulse yellow wavelength laser photostimulation in the treatment of chronic central serous chorioretinopathy

AIM:To evaluate the efficacy and safety of subthreshold micropulse yellow laser(SMYL)in the treatment of chronic central serous chorioretinopathy(CCSC).METHODS:The medical records of 58 eyes of 58 patients with CCSC were reviewed.A 577-nm SMYL system was used for the treatment.Fundus fluorescein angiography was used as the primary method of identifying CCSC,and resolution of subretinal fluid(SRF)evaluated by optical coherence tomography(OCT)and fundus autofluorescence.Central macular thickness(CMT),central macular volume(CMV),total macular volume(TMV),subfoveal choroidal thickness(SFCT),subretinal fluid height(SRFH),and subfoveal fluid basement diameter values were measured by spectral domain-OCT(SD-OCT)for all eyes.RESULTS:The mean age of the patients was 42.4±9.9(range:20-72)y.The mean follow-up was 11.4±8.5(range:6-37)mo.Median BCVA at at the final follow up after treatment was statistically significant from the baseline.Complete SRF resolution was 12.1%of the eyes in the 1^st month,67.2%of the eyes in the 3rd month and 67.2%of the eyes in the last follow up.The initial median CMT,CMV,TMV,and SFCT values before treatment was significantly higher than 3^rd month visit values(P<0.001).In the multivariate analysis performed,age and disease duration were found to be a risk factor for persistent SRF(P=0.017,P=0.016,respectively).CONCLUSION:SMYL treatment provides a significant anatomical and functional improvement and is effective in eliminating SRF in eyes with CCSC.

Long-term outcomes of drusenoid pigment epithelium detachment in intermediate AMD treated with 577 nm subthreshold micropulse laser: a preliminary clinical study

AIM: To evaluate the long-term anatomical and visual outcomes of drusenoid pigment epithelial detachment(D-PED) in intermediate age-related macular degeneration(AMD) eyes treated with 577 nm yellow subthreshold micropulse laser(SML).METHODS: In this retrospective study, 21 eyes of 16 patients with D-PED in intermediate AMD were consecutively included and assessed.All the eyes were treated with 577 nm SML in several sessions according to D-PED growth status.The logarithm of the minimum angle of resolution(logMAR) best-corrected visual acuity(BCVA) were assessed at the initial visit and after treatment.Spectral-domain optical coherence tomography(SD-OCT) was performed to evaluate the D-PED lifecycle by volumetric calculations.Regression analysis was used to determine the breakpoint, growth, and collapse rate of the D-PED lesions.The progression to advanced AMD was also documented.RESULTS: All the eyes were treated with SML for 2.9±1.0 sessions.The mean follow-up period was 25.3±12.6 mo.The BCVA was stable from the baseline to final visit.All the eyes were categorized into two groups according to the anatomical changes of the D-PED lesion: the collapse group(n=6, 28.6%) and non-collapse group(n=15, 71.4%).The change in logMAR BCVA did not differ significantly between the collapse group 0.00(-0.31, 0.85) and non-collapse group 0.00(0.00, 0.00;P=1).Regression analysis showed that the growth rate was significantly higher in the collapse group(0.090±0.095 mm;/mo) than in the non-collapse group(0.025±0.035 mm;/mo;P<0.001).One eye(4.8%) developed macular neovascularization at 11 mo after SML treatment in the non-collapse group.Three eyes(14.3%) developed geographic atrophy(GA) in the collapse group.CONCLUSION: Compared to the natural course of D-PED reported by previous studies, our results preliminarily show that SML can alleviate visual loss and possibility of progression to advanced AMD in eyes with D-PED in intermediate AMD.A controlled clinical trial needs to further verify the benefit of the intervention.

Micropulse laser trabeculoplasty under maximal tolerable glaucoma eyedrops:treatment effectiveness and impact of surgical expertise

AIM:To evaluate the effectiveness of micropulse laser trabeculoplasty(MLT)for eyes with open angle glaucoma(OAG)under maximal tolerable glaucoma eyedrops and to assess the effect of expertise performing MLT on its clinical effectiveness.METHODS:Medical records of 42 consecutive eyes of 34 patients diagnosed with OAG who underwent MLT were retrospectively reviewed.The effectiveness was determined using the Kaplan-Meier survival analysis.Failure was defined as an intraocular pressure(IOP)reduction of<20%from baseline,an IOP>21 mm Hg during two consecutive follow-up visits,or surgical intervention for OAG.To determine the impact of MLT surgical expertise on clinical effectiveness,the eyes were divided into two groups according to whether the procedure was conducted by an experienced specialist(defined as a glaucoma specialist who had conducted at least ten MLT procedures)or a less experienced glaucoma specialist.The difference in expertise was determined using a log-rank test.RESULTS:MLT was conducted by three glaucoma specialists.The overall survival rates were 0.76,0.48,and 0.44 at 1,3,and 6 mo,respectively.The survival rates for MLT performed by a less experienced glaucoma specialist were 0.62,0.31,and 0.25(n=21 eyes)at 1,3,and 6 mo,respectively,whereas the survival rates for MLT performed by an experienced glaucoma specialist were 0.90,0.64,and 0.64(n=21 eyes)at 1,3,and 6 mo,respectively.The log-rank test showed a significant difference in the survival curves of the two groups(P=0.0061).CONCLUSION:The 6-month effectiveness of MLT for controlling IOP is relatively limited in eyes with OAG using maximal tolerable glaucoma eyedrops.However,its effectiveness may be improved if performed by a glaucoma specialist with sufficient MLT experience.

Micropulse diode laser therapy in refractory glaucoma

Purpose:Description of safety and efficacy of micropulse lYanssderal cydophotocoagulation as a treatment option for refractory glaucoma.Mahods:This is a prospective study including 39 eyes of 31 patients foil owed for refractory glaucoma,who benefited from transsderal cyclophotocoagulation using a mic topi used laser.The main indication for tire pro­cedure was increased ocular pressure refractory to quadri therapy in various types of glaucoma.Ihe patients were tieated using iridex Cyclo G6 laser with a Micropulse P3 infrared probe with a wavelength of 810 nm.The pa­rameter for tire procedure were a duration of 90 s per hemisphere with a power of 2000 mW and an eneigy of 180 J.Both tire upper and lower hemispheres were treated in tire same procedure,sparing tire 3 o'clock and 9 o'clock meridians,and aD tire patients benefited from a single treatment session.The following parameters were evaluated;ocular pain and overall tolerance;visual acuity;and tire evolution of IOP postoperatively up to 9 months.Results:The glaucoma subtypes treated are as follows:primaty open-angle glaucoma(n=05),chronic angle-closure glaucoma(n=13),neovascular glaucoma(n=07),aphakic glaucoma(n=06),malignant glaucoma(n=04),post-traumatic angle recession(n=02),and inflammatoiy glaucoma(n=02).The mean pre-operative intraocular pressure was 42.3±5.2 mmHg and tire mean post operative intraocular pressure at 9 months was 16.9±1.9 mmHg The reduction in IOP was 49.9%.The average number of intraocular pressure-lowering medications used prior to surgery was four,and tire average number of medications used at tire 9-month post­operative visit was 2.0±1.2(703%of patients were on dual therapy).The overall success rate was 60.9%.Conclusions:Micropulse transsderal cydophotocoagulation appears to be a safe and effident treatment for re­fractory glaucoma.Its indications should therefore be broadened and proposed early in various situations.

Optical coherence tomography angiography assessment of 577 nm laser effect on severe non-proliferative diabetic retinopathy with diabetic macular edema

AIM:To quantitatively evaluate the effect of the combined use of 577-nm subthreshold micropulse macular laser(SML)and multi-point mode pan retinal laser photocoagulation(PRP)on severe non-proliferative diabetic retinopathy(NPDR)with central-involved diabetic macular edema(CIDME)using optical coherence tomography angiography(OCTA).METHODS:In this observational clinical study,86 eyes of 86 NPDR patients with CIDME who underwent SML and PRP treatment were included.Images were obtained 1 d before laser and post-laser(1 d,1 wk,1,3,and 6 mo)using AngioV ue software 2.0.Best corrected visual acuity(BCVA,LogM AR),foveal avascular zone area(FAZ),choriocapillary flow area(Ch F),parafoveal vessel density(PVD),capillary density inside disc(CDD),peripapillary capillary density(PCD),macular ganglion cell complex thickness(m GCCT),central macular thickness(CMT),and subfoveal choroidal thickness(ChT)were compared between pre-and post-laser treatment.RESULTS:BCVA remained stable during 6 mo postlaser therapy(pre-laser vs 6 mo post-laser:0.53±0.21 vs 0.5±0.15,P>0.05).PVD,ChF,ChT,CMT,and mGCCT significantly increased 1 d post-laser therapy[pre-laser vs 1 d post-laser:superficial PVD(%),40.51±3.42 vs 42.43±4.68;deep PVD(%),42.66±3.67 vs 44.78±4.52;ChF,1.72±0.21 vs 1.9±0.12 mm^2;ChT,302.45±69.74 vs 319.38±70.93μm;CMT,301.65±110.78 vs 320.86±105.62μm;m GCCT,105.71±10.72 vs 115.46±9.64μm;P<0.05].However,PVD,ChF and ChT decreased to less than baseline level at 6 mo postlaser therapy(pre-laser vs 6 mo post-laser:superficial PVD(%),40.51±3.42 vs 36.32±4.19;deep PVD(%),42.66±3.67 vs 38.76±3.74;Ch F,1.72±0.21 vs 1.62±0.09 mm^2;Ch T,302.45±69.74 vs 289.61±67.55μm;P<0.05),whereas CMT and mG CCT decreased to baseline level at 6 mo postlaser therapy(CMT,301.65±110.78 vs 297.77±90.23μm;m GCCT,105.71±10.72 vs 107.05±11.81μm;P>0.05).Moreover,FAZ continuously increased while CDD and PCD continuously decreased in 6 mo after laser therapy.CMT and ChT had a significant positive correlation with ChF and PVD in most post-laser stages.CONCLUSION:During a 6-month follow-up period after combined use of SML and PRP therapy,BCVA remained stable and there was a decreased trend in macular edema.Blood flow increased at 1 d post-laser therapy and reduced at 6 mo post-laser therapy.

Innovations in Retinal Laser Technology

Retinal laser photocoagulation is a proven, effective treatment for various retinal disorders, including diabetic retinopathy, retinal vein occlusions, and sickle cell retinopathy. To minimize iatrogenic retinal damage while maintaining therapeutic effects, retinal laser technology has evolved significantly since its introduction in ophthalmology more than half a century ago. These innovations have included both optimizations of laser parameters in addition to the development of novel laser delivery systems. This review summarizes recent innovations in retinal laser technology, including subthreshold micropulse laser, selective retinal therapy and nanosecond laser, innovative modes of laser delivery including pattern scanning laser, endpoint management, navigated laser, and newly described photo-mediated ultrasound therapy.

Current systems and recent developments of subthreshold laser systems in glaucoma:a narrative review

Background and Objective:Subthreshold laser technologies and their applications in ophthalmology have greatly expanded in the past few decades.Initially used for retinal diseases such as central serous chorioretinopathy and diabetic macular edema,subthreshold lasers have recently shown efficacy in the treatment of various types of glaucoma.Our primary objectives are to review the clinical applications of subthreshold laser in the context of glaucoma treatment and discuss the mechanisms of different subthreshold laser techniques,including subthreshold selective laser trabeculoplasty(SSLT),micropulse laser trabeculoplasty(MLT),pattern-scanning laser trabeculoplasty(PSLT),titanium laser trabeculoplasty(TLT),and micropulse transscleral cyclophotocoagulation(MP-TSCPC).Methods:This was a narrative review compiled from literature of PubMed and Google Scholar.The review was performed from March 2021 to October 2021 and included publications in English.We also included information from web pages to cover details of relevant laser systems.We discuss the history of subthreshold laser,recent advancements in subthreshold techniques,and commercially available systems that provide subthreshold capabilities for glaucoma.We highlight basic science and clinical studies that deepen the understanding of treatment mechanisms and treatment effectiveness in the clinical setting respectively.We review commonly used parameters for each technique and provide comparisons to conventional treatments.Key Content and Findings:We found five distinct types of subthreshold laser used in the management of glaucoma.Numerous subthreshold laser systems are commercially available and can provide this treatment.Therefore,understanding the differences between subthreshold techniques and laser systems will be critical in utilizing subthreshold laser in the clinical setting.Conclusions:Traditional laser trabeculoplasty(LT)and cyclophotocoagulation(CPC)have shown effectiveness in the treatment of various types of glaucoma but are associated with visible damage to the underlying tissue and adverse effects.Subthreshold laser systems aim to provide the therapeutic effect found in traditional lasers,while minimizing unwanted treatment related effects.Further clinical studies are needed to evaluate the role of subthreshold lasers in the management of glaucoma.

Subthreshold laser systems:a narrative review of the current status and advancements for retinal diseases

Background and Objective:Subthreshold laser therapy has emerged as a therapeutic alternative to traditional laser photocoagulation for certain ophthalmic diseases including central serous chorioretinopathy(CSCR),diabetic macular edema(DME),macular edema secondary to branch retinal vein occlusion(BRVO),and age-related macular degeneration(AMD).The objective of this paper is to review and discuss the clinical applications of subthreshold laser and the mechanisms of different subthreshold laser techniques including subthreshold micropulse laser(SMPL),selective retina therapy(SRT),subthreshold nanosecond laser(SNL),endpoint management(EpM),and transpupillary thermotherapy(TTT).Methods:A narrative review of English literature and publicly available information published before November 2021 from literature databases and computerized texts.We discuss the currently available subthreshold laser systems and the advancements made to perform different subthreshold laser techniques for various ophthalmic diseases.We highlight various clinical studies and therapeutic techniques that have been conducted to further understand the effectiveness of subthreshold laser in the clinical setting.We conclude the article by covering emerging subthreshold laser systems that are currently being developed for future clinical use.The PubMed database was utilized for peer-reviewed articles and pertinent information on subthreshold systems was cited from publicly available online websites covering specific systems.Key Content and Findings:Various subthreshold laser systems have been developed to treat certain retinal diseases.Several systems are currently in development for future clinical applications.Conclusions:While conventional laser photocoagulation has been effective in treating various retinal diseases,subthreshold laser systems aim to provide a therapeutic effect without visible signs of damage to the underlying tissue.This technology may be particularly effective in treating macular disorders.Further clinical studies are needed to evaluate their role in the management of retinal diseases.

A Study of the Magnetospheric Micropulsations Pc5 and Pc6 Using Magnetic Stations at Low Latitude Northern Region of Brazil and Ascension Island during Magnetic Stormed Magnetospheric Plasma

In general, micropulsation is generated by the free energy within the magnetosphere, which is mainly caused by the magnetosphere-solar wind interactions and/or magnetic field reconnections in the magnetospheric tail. In this article, we studied the types of low-frequency magnetospheric micropulsations Pc5 and Pc6 (1 - 6 mHz), during three magnetic storms, using ground magnetic observations. One of the main motivations of this study was to produce scientific knowledge on the subject in order to fill knowledge gaps in this region, collaborating with existing bibliographies. The data were recorded in a series of six Brazilian stations close to the Dip Equator (dip = 0), with using data from the Ascension Island observatory. Pulse trains were found to occur simultaneously with almost identical waveforms, with significant amplitude increase near magnetic local noon. Amplitude spectra showed a clear similarity in all equatorial seasons. The results obtained were compared with studies performed in regions with similar low latitudes. The possible mechanisms that induced these micropulsations and the peculiarities presented by these data were also discussed in this article.