Subthreshold Diode Micropulse Laser Research Articles

Subthreshold micropulse diode laser treatment in diabetic macular edema: biological impact, therapeutic effects, and safety.

To introduce the treatment of diabetic macular edema (DME) with subthreshold micropulse diode laser (SMPL), to summarize the biological impact, therapeutic effects, and safety of this treatment, and to discuss the response to DME when SMPL is combined with anti-vascular endothelial growth factor (anti-VEGF) or steroid. The literature search was performed on the PubMed database, with a selection of English-language articles published from 2000 to 2023 with the following combinations of search terms: diabetes macular (o) edema, micropulse laser or subthreshold micropulse laser, anti-vascular endothelial growth factor, and steroid. SMPL is a popular, invisible retinal laser phototherapy that is inexpensive, safe, and effective in the treatment of DME. It can selectively target the retinal pigment epithelium, reduce the expression of pro-inflammatory factors, promote the absorption of macular edema, and exert a similar and lasting clinical effect to traditional lasers. No significant difference was found in the therapeutic effects of SMPL between different wavelengths. However, HbA1c level and pretreatment central macular thickness (CMT) may affect the therapeutic outcomes of SMPL. SMPL has a slow onset and produces lasting clinical effects similar to conventional photocoagulation. It has been reported that SMPL combined with the intravitreal anti-VEGF injection can significantly reduce the number of injections without influencing the therapeutic effect, which is essential for clinical applications and research. Although 577nm SMPL is widely used clinically, there are no standardized protocols for SMPL. Additionally, some important problems regarding the treatment of SMPL require further discussion and exploration.

Exposure of the retina to subthreshold micro- and nanosecond laser at early stages of age-related macular degeneration

At the moment, there are no effective methods of treatment for age-related macular degeneration at its early stages. The perspective of treatment for age-related macular degeneration may be a method using subthreshold laser radiation.
 In the present review of literature, analysis is represented of using both subthreshold micro- and nanosecond laser radiation on the retina in intermediate AMD stage. Subthreshold diode micro-pulse laser exposure of the retina in AMD has proven to be a safe procedure that allows for the regression of macular drusen.
 While some authors noted an improvement in visual functions and a decrease in the probability of developing choroidal neovascularization with such treatment, multicenter trials have not yet confirmed the effectiveness of micro-pulse therapy as a method to prevent the neovascular AMD development.
 Subthreshold nanosecond laser impact on the retina is safe for the structures of the eye fundus, theoretically more selective stimulates the natural biological and regenerative potential in the pigment epithelium and neuroepithelium due to remodeling of extracellular matrix, restores the thickness of the Bruchs membrane and metabolism between external retinal layers and choriocapillaris.
 Encouraging results have been achieved from the use of nanopulse therapy as a method of preventing the development of advanced stage AMD in the absence of reticular pseudodrusen, however, it seems premature to recommend this technology for widespread clinical use - further research is needed.
 The prospects of invading in wide clinical practice of subthreshold nanosecond laser impact on the intermediate stage of AMD on the basis of the obtained clinical research results are encouraging (regression of drusen, preventing of AMD progression in absence of reticular pseudodrusen), but there is currently no evidence base. It is required to conduct further researches.

INCIDENCE AND UPDATES MANAGEMENT OF DIABETIC RETINOPATHY

One of the biggest causes of vision loss in the globe is diabetic retinopathy (DR), a consequence of diabetes. Despite significant attempts to lower the prevalence of vision impairment, DR continues to grow. There is damage to the vascular endothelial cells as the first pathophysiology of DRcells and a decrease in pericytes. As a result of the hypoxic reactions that follow, vascular endothelialvascular endothelial growth factor (VEGF) The most effective treatment available right nowControlling blood sugar levels is the key to preventing diabetic retinopathy and diabetic macular edema (DME). Superior in every way Laser therapy, anti-VEGF therapy, steroid therapy, and vitrectomy are all necessary treatments in these situations. Photocoagulation of the retinal pigment epithelium There is strong evidence that non-proliferative diabetic retinopathy (NPDR) is a viable treatment option.results that can be used to keep DR from progressing further. Furthermore, laser therapy has proven to be effective.For example, grid and subthreshold diode laser micropulse photocoagulation (SDM) for DME has been used.reported. In cases of vitreous hemorrhage or tractional retinal detachment in PDR patients, vitrectomy has been undertaken. There has also been significant interest in the ability of anti-VEGF medication to slow the progression of PDR from DME patients. Even with these therapies, many individuals with DR are still at risk of losing their eyesight and developing potentially dangerous side effects.. In the most advanced stages of DR, laser photocoagulation and vitrectomy are effective treatments for preventing severe vision loss. Both approaches, however, have their limitations. Evidence from preclinical and clinical studies shows that targeting renin-angiotensin system inhibition, vascular endothelial growth factor, and renin-angiotensin system blockade can reduce cardiovascular disease risk.the growth hormone, corticosteroids and protein kinase C.DR may be treated with these methodsMethodsThe study between January 2017 and November 2020 total number of patients 2968, Retrospective three year analysis.ResultsIncidence of referable retinopathy was independently associated with known duration of diabetes, age at diagnosis, and use of insulin treatment. For participants needing insulin treatment with a duration of diabetes of 10 years or more, cumulative incidence of referable retinopathy at one and three years was 9.61 and 30.99 per 1000 people, respectively.

Real World Data Comparison of Standard Care vs SDM Laser Vision Protection Therapy for Prevention of Neovascular AMD.

PurposeTo access the impact of regular periodic subthreshold diode micropulse laser (SDM) as Vision Protection Therapy on the rate of neovascular conversion of dry age-related macular degeneration (AMD).MethodsPatient unidentified clinical data aggregated by Vestrum Health, LLC (VH) from 300 retina specialists across the United States was analyzed to examine the effect of a program of regular periodic panmacular low-intensity/high-density subthreshold diode micropulse laser as vision protection therapy (VPT) compared to standard care alone, on the incidence of neovascular conversion in patients with dry age-related macular degeneration (AMD), between January 4, 2016, and September 30, 2020, producing 392,250 eyes for study.ResultsAfter applying inclusion and exclusion criteria, eyes were matched by propensity scoring for key risk factors. This produced 830 eyes managed by standard care plus VPT, performed on average every 108 days per eye; and 8300 eyes managed with standard care alone (SCA) in a 1/10 ratio for comparison. Comparison found that VPT eyes had a markedly lower rate of neovascular conversion than SCA eyes (hazard ratio 13.04) overall, and for each propensity score matched quintile. VA worsened over time in the SCA group but improved in the VPT group.ConclusionOur findings suggest that, compared to standard care alone, VPT may markedly reduce the rate of neovascular conversion in AMD, the main cause of irreversible visual loss worldwide.

Updates on the Current Treatments for Diabetic Retinopathy and Possibility of Future Oral Therapy.

Diabetic retinopathy (DR) is a complication of diabetes and one of the leading causes of vision loss worldwide. Despite extensive efforts to reduce visual impairment, the prevalence of DR is still increasing. The initial pathophysiology of DR includes damage to vascular endothelial cells and loss of pericytes. Ensuing hypoxic responses trigger the expression of vascular endothelial growth factor (VEGF) and other pro-angiogenic factors. At present, the most effective treatment for DR and diabetic macular edema (DME) is the control of blood glucose levels. More advanced cases require laser, anti-VEGF therapy, steroid, and vitrectomy. Pan-retinal photocoagulation for non-proliferative diabetic retinopathy (NPDR) is well established and has demonstrated promising outcomes for preventing the progressive stage of DR. Furthermore, the efficacy of laser therapies such as grid and subthreshold diode laser micropulse photocoagulation (SDM) for DME has been reported. Vitrectomy has been performed for vitreous hemorrhage and tractional retinal detachment for patients with PDR. In addition, anti-VEGF treatment has been widely used for DME, and recently its potential to prevent the progression of PDR has been remarked. Even with these treatments, many patients with DR lose their vision and suffer from potential side effects. Thus, we need alternative treatments to address these limitations. In recent years, the relationship between DR, lipid metabolism, and inflammation has been featured. Research in diabetic animal models points to peroxisome proliferator-activated receptor alpha (PPARα) activation in cellular metabolism and inflammation by oral fenofibrate and/or pemafibrate as a promising target for DR. In this paper, we review the status of existing therapies, summarize PPARα activation therapies for DR, and discuss their potentials as promising DR treatments.

Subthreshold Diode Micropulse Laser Combined with Intravitreal Therapy for Macular Edema-A Systematized Review and Critical Approach.

Objective: intravitreal therapy for macular edema (ME) is a common clinical approach to treating most retinal vascular diseases; however, it generates high costs and requires multiple follow-up visits. Combining intravitreal anti–vascular endothelial growth factor (VEGF) or steroid therapy with subthreshold diode micropulse laser (SDM) application could potentially reduce the burden of numerous intravitreal injections. This review sought to explore whether this combination treatment is effective in the course of ME secondary to retinal vascular disease, and in particular, determine whether it is comparable or superior to intravitreal therapy alone. Materials and methods: the following terms and Boolean operators were used to search the PubMed literature database: subthreshold micropulse laser, subthreshold diode micropulse OR micropulse laser treatment AND anti-VEGF, anti-VEGF treatment, intravitreal steroids, OR combined therapy.This analysis included all studies discussing the combination of SDM and intravitreal anti-VEGF or steroid treatment. Results: the search revealed nine studies that met the inclusion criteria, including five comparing combined treatment and anti-VEGF treatment alone, four covering diabetic ME, and one covering ME secondary to branch retinal vein occlusion. All of these five studies suggested that combination therapy results in fewer intravitreal injections than anti-VEGF monotherapy with non-inferior functional and morphological outcomes. The remaining four studies report functional and morphological improvements after combined treatment; however, SDM alone was never superior to intravitreal-alone or combined treatment. There were substantial differences in treatment protocols and inclusion criteria between the studies. Conclusions: the available material was too scarce to provide a reliable assessment of the effects of combined therapy and its relation to intravitreal monotherapy in the treatment of ME secondary to retinal vascular disease. One assumption of note is that it is possible that SDM plus anti-VEGF might require fewer intravitreal injections than anti-VEGF monotherapy with equally good functional and morphological results. However, further randomized research is required to confirm this thesis.

Role of focal laser retinal photocoagulation in treatment of diabetic macular edema

Vascular endothelial growth factor (anti-VEGF) inhibitors in action have demonstrated efficacy and safety in the treatment of diabetic macular edema (DME), and have changed both the goal and prospects for treatment of this disease. Consequently, the role of focal laser retinal photocoagulation in the treatment of DME has been actively debated. However, technical advances in new laser systems, treatment protocols for anti-VEGF drug research, and the functional impact of modern focal photocoagulation are necessary to assess the role of laser coagulation in the treatment of DME. A wide range of clinical studies of laser therapy was necessary as an additional treatment for 20 to 50 % of patients receiving monotherapy with anti-VEGF drugs in patients with diabetic macular edema. In addition, a lower frequency of repeated treatment and a more stable reduction in retinal thickness have been demonstrated in other studies. However, the lack of information about the laser systems used, their technical characteristics, and application protocols often make it difficult to compare directly the results of anti-VEGF tests. Therefore, the aim of our work was to analyze the currently available data related to the potential role of focal laser photocoagulation in the treatment of DME, including a detailed review of the most commonly used laser systems. The results obtained with sub-threshold diode micro-pulse laser photocoagulation may be a valuable option as an adjunct therapy to treatment with angiogenesis inhibitors. Current evidence suggests that focal laser therapy should still exist as an adjunct therapy for many patients.

Sub-Threshold Micro Pulse Laser (810NM): Treatment for Chronic Central Serous Retinopathy

Purpose: To find the effectiveness of sub-threshold (810nm) micropulse diode laser treatment (SMT) in chronic central serous retinopathy (CSR).
 Study Design: Interventional case series.
 Place and Duration of Study: Layton Rahmatulla benevolent trust eye hospital, from April 2019 to July 2020.
 Methods: The patients of chronic CSR (≥ 6 months) participated in the study. We used Spectral Domain Optical coherence tomography (SD-OCT) to record baseline central retinal thickness (CT). Best corrected visual acuity (BCVA) was recorded with Snellen’s chart and converted to Log MAR for statistical analysis. All patients underwent treatment with sub-threshold laser (810nm) in micropulse mode with 5% duty cycle (DC).
 Results: Twenty five eyes with chronic CSR were enrolled in the study. The patients were treated with laser and final assessment was made at 6 months. Mean BCVA at presentation was 0.46 Log MAR ± 0.12 and a mean baseline CT of 362.2 μm ± 32.6µm. At final follow-up there was a mean decrease in CT of 97.2 μm ± 21.8 from the baseline. After treatment mean BCVA was 0.33 Log MAR ± 0.12 and mean CT was 266 μm ± 20.9. Nineteen out of twenty-five eyes (76%) achieved a gain of vision between 1 to 3 lines and gain of 3 lines was achieved in 8% of cases. At the final follow-up there was incomplete resolution of sub retinal fluid in 4 eyes (16%) with no improvement in BCVA.
 Conclusion: SMT (810 nm) is an effective and minimally invasive treatment modality for chronic CSR.
 Key Words: Sub-Threshold micropulse laser, Central serous retinopathy, Central retinal thickness, sub retinal fluid.

Subthreshold micro-impulse laser coagulation of retinal detachment in children

Retinal detachment in children often requires multiple revisions. Despite active surgical treatment, subretinal fluid can persist for a long time in the macular region of the fundus. This leads to a decrease in visual acuity after surgery and an unsatisfactory functional result of treatment. In the absence of central vision, children develop amblyopia and secondary strabismus. Reoperations increase the risk of complications. Threshold laser coagulation leads to thermal burns of all layers of the retina with the formation of chorioretinal adhesion, which ensures adhesion of the retinal layers, but irreversibly damages the retinal neuroepithelium. Аs a result, the use of threshold laser coagulation in the macular zone is limited. The method of subthreshold micropulse diode laser ablation (STDLA) was developed on the basis of a clinical examination of 44 pediatric patients of the pediatric ophthalmology department of the Minsk Regional Children's Clinical Hospital, whose level of subretinal fluid in the posterior pole of the eyes remained for a long time after extrascleral surgery for retinal detachment. The proposed exposure parameters provide a selective effect on the cells of the retinal pigment epithelium with laser radiation in the micropulse mode without irreversible thermal denaturation of photoreceptors and without damage to the neuroepithelium in order to stimulate the resorption of subretinal fluid and correct transudative disorders. As a result, the adhesion of the retinal photoreceptor layer to the pigment epithelium is restored. The effectiveness of the method is confirmed by a decrease or complete disappearance of subretinal fluid, adhesion of neuroepithelium according to optical coherence tomography and leads to an increase in visual acuity. The proposed method made it possible to optimize the treatment of children with retinal detachment, to improve the anatomical and functional outcomes of treatment, which is of medical and socio-economic importance.

Short Term Presence of Subretinal Fluid in Central Serous Chorioretinopathy Affects Retinal Thickness and Function.

Background: Acute central serous chorioretinopathy (CSCR), with subretinal fluid (SRF) resolving spontaneously within a few months from disease onset, has been considered as a benign and self-limiting disease for many years. This study sought to discover if a short presence of SRF can result in morphological and functional damage to the retina. Materials and methods: The study included patients treated by subthreshold diode micropulse laser (SDM) application for acute CSCR at the Dobry Wzrok Ophthalmological Clinic between January 2018 and November 2019. Inclusion criteria were: first episode of CSCR; duration of symptoms of two months or less; complete resolution of subretinal fluid (SRF) after a single session of SDM; and a lack of any retinal pathology, previous CSCR episode, significant anisometropia or amblyopia in the collateral eye. Fifteen patients fulfilled the inclusion criteria, including 13 males and two females aged 42.3 ± 9.5 years. The mean duration of symptoms before treatment was 4.7 ± 1.3 weeks on average. Baseline and follow-up examinations were performed in both the affected and collateral eyes and included best-corrected visual acuity (BCVA); spectral-domain optical coherent tomography measurements such as central retinal thickness (CRT) and minimal foveal thickness (MFT) (at the follow-up visit only); fluorescein angiography (at presentation only) and fundus autofluorescence. The first follow-up visit, when the total resolution of SRF was noted, was conducted between 8 and 12 weeks after SDM. Results: Resolved CSCR eyes had significantly poorer BCVA, CRT, and MFT findings in comparison with healthy collateral eyes (respectively, 0.11 +/− 0.1 vs. 0.01 +/− 0.04 logMAR; 238.80 +/− 23.39 vs. 264.87 +/− 21.22 µm and 178.93 +/− 16.88 vs. 199.47 +/− 17.87 µm) despite the short period of CSCR duration (maximum of 14 ± 2.15 weeks on average). Conclusion: Short presence of SRF typical for acute CSCR can affect retinal function and morphology resulting in poorer visual outcome.

Slowed Progression of Age-Related Geographic Atrophy Following Subthreshold Laser.

PurposeTo determine the effect of panmacular low-intensity/high-density subthreshold diode micropulse laser (SDM) on age-related geographic atrophy (ARGA) progression.MethodsThe retinal images of all eyes with ARGA in a previously reported database, consisting of all eyes with dry age-related macular degeneration (AMD) active in a vitreoretinal practice electronic medical record (EMR), were identified and analyzed to determine the velocity of radial linear ARGA progression during observation and after panmacular SDM.ResultsSixty-seven eyes of 49 patients with ARGA, mean age of 86 years were identified as having follow-up both before and after initiation of SDM treatment. All were included in the study. These eyes were followed a mean 910 days (2.5 years) prior to SDM treatment and a mean 805 days (2.2 years) after. Measurement masked to treatment vs observation found the radius of ARGA lesions progressed 1 to 540 µm per year (mean 137µm, SD 107) prior to treatment (controls); and −44 to 303 µm per year (mean 73µm, SD 59) after initiation of periodic panmacular SDM laser. Thus, the velocity of radial linear progression decreased 47% per year following panmacular SDM (p<0.0001). There were no adverse treatment effects.ConclusionIn cohort of eyes with high-risk dry AMD, panmacular SDM slowed linear radial ARGA progression velocity 47% per year (p<0.0001) without adverse treatment effects. Validated, these findings would constitute an important advance in the prevention of age-related visual loss and a benchmark for future therapies.

Subthreshold Diode Micropulse Laser (SDM) for Persistent Macular Thickening and Limited Visual Acuity After Epiretinal Membrane Peeling.

PurposeTo examine the effect of low-intensity/high-density subthreshold diode micropulse laser (SDM) on visual acuity (VA) and macular thickness in eyes with limited visual recovery and persistent macular thickening after epiretinal membrane peeling.MethodsA retrospective review of medical records identified all patients undergoing SDM after membrane peeling in a clinical vitreoretinal subspecialty practice. Exclusion criteria included other obfuscating ocular disease or loss to follow-up after SDM treatment.ResultsAll 19 eyes of 18 patients identified were included for study. After membrane peeling, VA improved from an avg. Snellen 20/240 [logMAR 1.08] to 20/72 [0.56] (p=0.0004). Attributed to persistent macular thickening following membrane peeling, overall VAs then gradually declined to an avg. of 20/91 [0.66] by 4−109 months (avg. 41) post vitrectomy, at which point panmacular SDM was performed. An avg. 15 months post SDM, both VA (to avg. 20/68 [0.53]) and maximum macular thickness improved (p=0.007 and p=0.008, respectively). There were no adverse treatment effects.ConclusionLow-intensity/high-density subthreshold (sublethal) diode micropulse laser (SDM) may reduce macular thickening and improve visual in eyes with persistent macular thickening after membrane peeling even years after vitrectomy.

Subthreshold diode micropulse laser versus observation in acute central serous chorioretinopathy

BackgroundThe purpose of this study was to evaluate subthreshold diode micropulse (SDM) laser as a treatment modality in acute central serous chorioretinopathy (CSC) and compare it with the current standard of care (observation).MethodsA randomised controlled trial was conducted on 68 eyes (34 eyes in SDM laser group and 34 eyes in observation group) with acute CSC, with a single angiographic leak and duration of complaints less than two months. Detailed history, examination and investigations were performed at the baseline and at regular intervals until six months.ResultsEyes in the laser group had significantly higher best‐corrected visual acuity at two weeks (p = 0.002), four weeks (p < 0.001), eight weeks (p < 0.001), 16 weeks (p = 0.042) and six months (p = 0.008), and higher contrast sensitivity at eight weeks (p = 0.008), 16 weeks (p < 0.001) and six months (p < 0.001). A recurrent/persistent neurosensory detachment was observed at the end of six months in 11.76 per cent of SDM laser treated eyes versus 29.41 per cent of eyes in the observation group (p = 0.036).ConclusionSDM laser produces faster and superior visual rehabilitation without any adverse effects. It also reduces the chances of CSC going into chronicity and recurrence compared to the current standard of care (observation).

How do we evaluate the role of focal/grid photocoagulation in the treatment of diabetic macular edema?

Vascular endothelial growth factor inhibitors (anti-VEGF) have consistently demonstrated efficacy and safety and changed both the aim and perspectives of diabetic macular edema (DME) treatment. Hence, the present and future role of focal/grid laser photocoagulation in DME treatment has been subjected to some debate. However, extensive insight into technical advances in novel laser systems, treatment protocols of anti-VEGF trials and the functional impact of modern focal/grid photocoagulation is needed to evaluate the present and future role of photocoagulation in DME treatment. Across a wide range of clinical trials laser therapy was required as adjunctive/rescue treatment in approximately 20-50% of patients receiving anti-VEGF monotherapy for centre involving DME. Further, a lower retreatment rate and a more stable reduction in retinal thickness have been demonstrated in more studies. However, lacking information on the laser systems used, their technical specifications and protocols of application often complicates direct comparison of results in anti-VEGF trials. Hence, this paper aimed to provide an overview of the currently available data relevant to the potential role of focal/grid laser photocoagulation in DME treatment including a thorough overview of the current most commonly used laser systems. Results with subthreshold diode micropulse laser photocoagulation are intriguing and may offer a valuable option as adjunctive therapy to anti-VEGF treatment. However, more well-designed studies on combination therapy are warranted to determine the full potential of modern retinal photocoagulation systems. In conclusion, current data suggest that focal/grid laser therapy should still be an option for consideration as adjunctive therapy in many patients.

Effects of subthreshold diode micropulse laser photocoagulation on treating patients with refractory diabetic macular edema

PurposeTo evaluate the effects of subthreshold diode micropulse laser photocoagulation on treating patients with refractory diabetic macular edema (DME). MethodsThis randomized clinical trial recruited patients with DME in both eyes that were resistant to treatment with intravitreal bevacizumab (IVB). The eyes were randomly divided into two groups who received laser therapy and IVB, or IVB alone. Subthreshold diode micropulse laser photocoagulation and IVB injection were administered in one eye, and an IVB injection was administered in the second eye. IVB injections were repeated in both eyes within one month and two months after the first injection. Best corrected visual acuity (BCVA) logarithm of the minimum angle of resolution (logMAR) and central macular thickness (CMT) were measured before, within a month, and three months after start of intervention. ResultsIn this study, 42 eyes of 21 patients were evaluated. The mean age of patients was 60.86 ± 8.57 years. Ten patients (47.6%) were male. Within-group analysis showed a significant decreased in BCVA logMAR in the laser + IVB group reflecting improvement in visual acuity (VA) (P < 0.001); it increased in the control group during study reflecting more vision loss (P = 0.01). In the laser + IVB group, a significant decrease in mean ± standard deviation (SD) CMT at 3 months compared to baseline was observed (baseline: 513 ± 126.29 vs. three months: 408.1 ± 95.28; P < 0.001). The mean ± SD CMT was significantly lower in the laser + IVB group of eyes than in the control group three months after intervention (P = 0.02). ConclusionUsing subthreshold diode micropulse laser photocoagulation in combination with IVB can significantly reduce CMT and improve BCVA in patients with refractory DME.

Low incidence of choroidal neovascularization following subthreshold diode micropulse laser (SDM) in high-risk AMD

PurposeTo determine the incidence of new choroidal neovascularization (CNV) in eyes with dry age-related macular degeneration (AMD) following subthreshold diode micropulse laser (SDM).MethodIn an observational retrospective cohort study, the records of all patients active in the electronic medical records database were reviewed to identify eyes with dry AMD treated with SDM. Identified eyes were classified by simplified AREDS categories, and analyzed for the primary endpoint of new CNV after treatment.ResultsThe EMR revealed SDM was offered to 373/392 (95%) patients with dry AMD and elected by 363/373 (97%) between 2008–2017. Follow up was available for 354/363 patients (547 eyes, 98%) (range 6–108 mos., avg. 22). CNV risk factors included age (median 84 years, 67% > 80); reticular pseudodrusen (214 eyes, 39%); AREDS category (78% category 3 and 4); and fellow eye CNV (128 eyes, 23%). New CNV developed in 9/547 eyes (1.6%, annualized rate 0.87%). Visual acuity was unchanged. There were no adverse treatment effects.SummaryIn a review of a large group of eyes with exceptionally high-risk AMD, SDM was followed by a very low incidence of new CNV. If confirmed by further study, SDM would offer a new and highly effective treatment to reduce the risk of vision loss from AMD.

Review of Subthreshold Diode Micropulse Laser Treatment for Retinal Diseases

Subthreshold Diode Micropulse (SDM) laser is a relatively new treatment modality that confers very little to no anatomical risk to the retina. However, its efficacy is still being studied, and the scenario where SDM is most useful is still being elucidated. This paper reviews articles from 1997 to 2017 and reviews the settings, results, and outcomes of SDM in various clinical settings including diabetic macular edema, branch retinal vein occlusion, central serous Chorioretinopathy, proliferative diabetic retinopathy, and age-related macular degeneration.

Improved retinal and visual function following panmacular subthreshold diode micropulse laser for retinitis pigmentosa

ObjectivesTo examine the effect of subthreshold diode micropulse laser (SDM) on pattern electroretinography (PERG) and visual function in retinitis pigmentosa (RP).MethodsThe records of all patients (pts) undergoing SDM in a vitreoretinal subspecialty practice were reviewed. Inclusion criteria included the presence of RP evaluated before and after SDM by PERG. As a secondary outcome measure, the results of automated omnifield resolution perimetry (ORP) were also reviewed.ResultsAll eyes undergoing SDM for RP were eligible study, including 26 eyes of 15 pts; seven male and eight female, aged 16–69 (avg. 47) years. Retinal function by PERG improved by all indices, with significant improvements in the 24° field signal latency measures; the MagD(µV)/ Mag(µV) ratio (P < 0.0001) and the MagD(µV) amplitude (P = 0.0003). ORP significantly improved by all indices (p = 0.02–0.002). Average best-corrected chart visual acuities improved from 0.6 to 0.4 logMAR units (p = 0.02). There were no adverse treatment effects.ConclusionsSDM significantly improved chart visual acuity, mesopic logMAR visual acuity perimetry, and retinal function by PERG in RP without adverse treatment effects. Treatment responses indicate a significant capacity for rescue of dysfunctional retina. These results suggest that early and periodic treatment with SDM might slow disease progression and reduce long-term vision loss.

Evaluation of Chronic Central Serous Chorioretinopathy after Subthreshold Yellow Micropulse Diode Laser Photostimulation at a Wavelength of 577 nm

Objective: This study evaluated the efficacy and safety of subthreshold yellow diode-laser micropulse 577 nm (SDM) in the treatment of chronic central serous chorioretinopathy (CSCR). Methods: 40 eyes of 40 patients with non-resolving CSCR of >12 months duration were treated with SDM yellow laser (577 nm). Best corrected visual acuity (BCVA) and intraocular pressure (IOP) were measured. Amsler grid screening, ophthalmoscopy, fundus autofluorescence (FAF) and SD-OCT were performed. Follow up measurements were recorded from 3 to 12 months. Results: Restoration of normal macular anatomy was obtained in 85.7% of cases with a significant reduction in mean central foveal thickness (CFT). Mean visual acuity gain was 14.95 ETDRS letters, subjective or objective deterioration after treatment was not recorded in any case. Conclusion: The possibility of favouring reabsorption of subretinal liquid by stimulating the retinal pigment epithelium, even at the fovea, without damaging retinal tissue, opens up new frontiers for the therapy of chronic CSCR.

Comparison of retinal histomorphology following laser photocoagulation using 577 nm subliminal micropulse laser versus 577 nm laser in pigmented rabbits

Background Studies showed that 577 nm subliminal micropulse photocoagulation for retinal diseases is more effective and much safer than 577 nm laser, but its mechanism and sensitive target cells are still unelucidated. Objective This study was to compare the histomorphology changes of rabbit retinas following 577 nm subliminal micropulse excitation and 577 nm laser for retinal photocoagulation and offer a conference for the clinical application of 577 nm subliminal micropulse excitation. Methods Twenty-six Chinese pigment rabbits were randomly divided into normal control group (2 rabbits), 577 nm laser photocoagulation group (6 rabbits) and subliminal micropulse photocoagulation group (18 rabbits), in which the rabbits from subliminal micropulse photocoagulation group were subgrouped into 9%, 12% and 15% subthreshold photocoagulation groups according to the different workload rates, and retinal photocoagulation was performed based on grouping.No treatment was carried out in the normal control group.Fundus camera and OCT were obtained after photocoagulation, and the rabbits were sacrificed to prepare the specimen of eyeball wall.Hematoxylin and eosin staining was employed to examine the histopathological change of choroid and retina under the light microscope. Results The retinal morphology was normal on the fundus color photography and OCT in the normal control group.Obscure of retinal structure and slight edema of retinal neuroepithelial layer with obscure of retinal pigment epithelium (RPE) was found respectively in the 9% and 12% subthreshold photocoagulation group, and serious edema of retinal neuroepithelial layer with local RPE elevation was visible in the 15% subthreshold photocoagulation group.The laser spot was invisible in various subliminal micro pulse groups.However, retinal photocoagulation spots, multifocal elevation of retinal layer and serious detachment of retinal neuroepithelium were found in the 577 nm laser group.Retinal histopathological examination revealed that the photoreceptors, bipolar cells and retinal ganglion cell (RGC) layers were normal, while choroidal vessel deformation and bleeding were visible in the 9% and 12% subthreshold photocoagulation groups, and only photoreceptor membrane swelling was seen in the 15% subthreshold photocoagulation group.However, retinal structure abnormality was displayed in 577 nm laser group, including the structural disorders of inner and outer nuclear layers and RGC layer as well as thinning of RPE layer. Conclusions 577 nm micropulse laser under threshold is sensitive for RPE and choroid rather than retina neurepithelium, which can play a treating role and also does not damage retina seriously.However, 577 nm laser photocoagulation results in retinal structure damage. Key words: Laser coagulation; Pigment epithelium of eye/surgery; Retina/pathology; Subthreshold diode laser micropulse; Rabbits