Subthreshold Diode Micropulse Laser Research Articles

Comparison of subthreshold diode laser micropulse therapy versus conventional photocoagulation laser therapy as primary treatment of diabetic macular edema

PurposeThe aim of the present study was to investigate the effect of subthreshold diode laser micropulse (SDM) in comparison with conventional laser photocoagulation in the treatment of the diabetic macular edema (DME). MethodsSixty-eight eyes from 68 patients with clinically significant DME were divided randomly into two equal groups. In the first group, SDM photocoagulation was employed, while conventional laser photocoagulation was performed on the eyes of the second group. Central macular thickness (CMT), central macular volume (CMV), and best corrected visual acuity (BCVA) were measured before, 2, and 4 months after intervention, and the results were compared. ResultsThe mean CMT was 357.3 and 354.8 microns before the treatment in Groups 1 and 2, respectively (P = 0.85), and decreased significantly to 344.3 and 349.8 after 4 months, respectively (P = 0.012 and P = 0.049). The changes in the central macular thickness was statistically higher in the first group (P = 0.001). The mean CMV significantly decreased in Group 1 (P = 0.003), but it was similar to pretreatment in Group 2 after 4 months (P = 0.31). The BCVA improved significantly in Group 1 (P < 0.001), but it remained unchanged in Group 2 (P = 0.38). ConclusionsIn this study, SDM was more effective than conventional laser photocoagulation in reducing CMT and CMV and improving visual acuity in patients with DME.

Sub-threshold micro-pulse diode laser treatment in diabetic macular edema: A Meta-analysis of randomized controlled trials.

To examine possible differences in clinical outcomes between sub-threshold micro-pulse diode laser photocoagulation (SDM) and traditional modified Early Treatment Diabetic Retinopathy Study (mETDRS) treatment protocol in diabetic macular edema (DME). A comprehensive literature search using the Cochrane Collaboration methodology to identify RCTs comparing SDM with mETDRS for DME. The participants were type I or type II diabetes mellitus with clinically significant macular edema treated by SDM from previously reported randomized controlled trials (RCTs). The primary outcome measures were the changes in the best corrected visual acuity (BCVA) and the central macular thickness (CMT) as measured by optical coherence tomography (OCT). The secondary outcomes were the contrast sensitivity and the damages of the retina. Seven studies were identified and analyzed for comparing SDM (215 eyes) with mETDRS (210 eyes) for DME. There were no statistical differences in the BCVA after treatment between the SDM and mETDRS based on the follow-up: 3mo (MD, -0.02; 95% CI, -0.12 to 0.09; P=0.77), 6mo (MD, -0.02; 95% CI, -0.12 to 0.09; P=0.75), 12mo (MD, -0.05; 95% CI, -0.17 to 0.07; P=0.40). Likewise, there were no statistical differences in the CMT after treatment between the SDM and mETDRS in 3mo (MD, -9.92; 95% CI, -28.69 to 8.85; P=0.30), 6mo (MD, -11.37; 95% CI, -29.65 to 6.91; P=0.22), 12mo (MD, 8.44; 95% CI, -29.89 to 46.77; P=0.67). Three RCTs suggested that SDM laser results in good preservation of contrast sensitivity as mETDRS, in two different follow-up evaluations: 3mo (MD, 0.05; 95% CI, 0 to 0.09; P=0.04) and 6mo (MD, 0.02; 95% CI, -0.10 to 0.14; P=0.78). Two RCTs showed that the SDM laser treatment did less retinal damage than that mETDRS did (OR, 0.05; 95% CI, 0.02 to 0.13; P<0.01). SDM laser photocoagulation shows an equally good effect on visual acuity, contrast sensitivity, and reduction of DME as compared to conventional mETDRS protocol with less retinal damage.

This issue of ACTA, printed and electronic

The cover illustration shows a variety of orbital implants that have been used following enucleation. This is discussed by Mourits et al in this issue of ACTA. Prins et al. in the Netherlands review the use of MRI imaging of the brain in eye disease. Structural changes in the visual pathways of the brain are seen in glaucoma, AMD and other eye diseases and might suggest a general neurological disorder. Yassin in Saudi Arabia reviews bleb-related infections following glaucoma filtering surgery. The prognosis is usually good if the infection is limited to the bleb but poor when endophthalmitis develops. de Vries et al. in the Netherlands report that the relatively few patients require glaucoma drainage surgery following vitreoretinal surgery. These patients were more likely to have history of glaucoma, many vitreoretinal operations and silicon oil. Tryggvason et al. in Norway, Iceland and USA examined the hearing of patients with glaucoma and/or exfoliation syndrome. Many individuals have hearing loss, and this was associated with age and male gender but not with glaucoma or exfoliation syndrome. Jonas et al. in Germany report thinning of Bruch's membrane in patients in secondary high axial myopia caused by congenital glaucoma. Timlin et al. in London recommend anterior segment OCT for diagnostic examination of lacrimal puncta. Ringvold and Reubsaet in Norway found that acetylcholine affects corneal epithelial cells in vitro and influences iron channels. Mourits et al. in the Netherlands evaluate complications from different types of orbital implants following enucleation for retinoblastoma. They recommend acrylic implants. Klingenstein et al. in Germany and USA examine microcirculation patterns and suggest that these may guide in differentiating uveal nevi from malignant melanomas. Munch et al. in Denmark and Austria validate the Radner reading chart for reading acuity and speed in a Danish cohort. Breukink et al. in the Netherlands recommend half-dose photodynamic therapy and subthreshold diode micropulse laser for chronic central serous chorioretinopathy. Haas et al. in Austria found no difference in pain during intravitreal injections with 27 and 30 gauge needles. However, 30 gauge needles were preferred by the surgeons. Segal et al. in Israel found an association between anxiety levels and perceived pain during intravitreal injections. Norn documents the history of ophthalmology in Denmark up to 1865. The following articles are published electronically only. They are accessible on www.actaophthalmologica.com, where you can find all published articles of ACTA from the beginning. Kim and Choi in Korea found that early postoperative overcorrection was associated with success in surgical treatment of intermittent exotropia. Creuzot-Garcher et al. in France examined elderly people over 75 years old and found visual impairment (visual acuity <0.3) in 2.3% and increasing to 5.6% in patients over 85 years old. Lee et al. in Korea associated the location of retinal nerve fibre layer defects with peripapillary atrophy in glaucoma patients. Kiliç et al. in Turkey found exfoliation syndrome in 5.7% of a Turkish population and this was associated with advancing age and male gender. Hayes et al. in UK recommend a modification of iontophoresis technique for riboflavin penetration into corneal stroma for cross-linking. Prakash et al. in the United Arab Emirates discuss the differences between central and non-central keratoconus in terms of corneal topography. GamalElDin et al. in Egypt recommend big-bubble technique for Descemet's endothelial grafts. Agrawal et al. in UK and Singapore propose a classification for semi-automated laser flare readings in uveitis. Gupta et al. in Singapore suggest that the visibility of choroidal–scleral interface on OCT images influences choroidal thickness measurements. Fernández-Vigo et al. in Spain found the variation in anterior chamber depth to be associated with age, sex, spherical error, corneal diameter and anterior chamber angle. Njikam et al. in Kenya, Cameroon and Germany report on the epidemiology of diabetic retinopathy in Cameroon. Sansom et al. in UK found an association between systolic blood pressure and ocular perfusion pressure with subfoveal choroidal thickness. Vannozzi et al. in Italy report cytomegalovirus retinitis in a patient who received a dexamethasone implant. Barteselli et al. in Italy and USA report transient structural abnormalities of the retina following intravitreal ocriplasmin injection. Suh and Kee in Korea examined long-term outcome of patients with congenital glaucoma and found that many need reoperation. Mulder et al. in the Netherlands and Belgium suggest shallowing of the anterior chamber to protect the crystalline lens during vitrectomy. Kessel et al. in Denmark discuss early results from preoperative scoring of cataract patients. Mazeikaite et al. in Lithuania and USA report elevated levels of antiphospholipid antibodies in patients with pseudoexfoliation syndrome. Alberti and la Cour in Denmark compare treatment of macular holes with vitrectomy and ocriplasmin. More macular holes are closed after vitrectomy but visual acuity outcomes are similar. Cennamo et al. in Italy recommend transpupillary thermotherapy for choroidal haemangioma. I hope you find This Issue of ACTA informative and interesting.

Functionally Guided Retinal Protective Therapy for Dry Age-Related Macular and Inherited Retinal Degenerations: A Pilot Study.

To review the results of retinal function testing in eyes undergoing panmacular subthreshold diode micropulse laser (SDM) prophylaxis for chronic progressive retinal disease. The records of all patients undergoing prophylactic panmacular SDM for high-risk age-related macular degeneration (AMD) and inherited photoreceptor degenerations (IRDs) examined by pattern electroretinography (PERG), automated microperimetry (AMP), and Central Vision Analyzer (CVA) testing before and after treatment were reviewed. A total of 158 consecutive eyes of 108 patients with AMD and 10 consecutive eyes of 8 patients with IRDs, evaluated both before and after SDM by PERG, were eligible for study. The IRD diagnoses included rod-cone degeneration (four eyes), cone-rod degeneration (three eyes), and Stargardt's disease (three eyes). In AMD, AMP was performed in 40 consecutive eyes, and CVA in the subsequent 73 consecutive eyes concurrent with PERG. The SDM treatment consisted of 1800 to 3000 confluent spots throughout the retina circumscribed by the major vascular arcades, including the fovea ("panmacular"). Testing was performed 1 week before and by 1 month after treatment. Results indicated that 149/168 eyes were improved by primary PERG measures: 139/158 eyes with AMD by PERG low-contrast scan Magnitude D (MagD)(μV)/Magnitude (Mag)(μV) ratios (P = 0.0001) and 10/10 eyes with IRDs by 24⁰ concentric ring scan MagD(μV)/Mag(μV) ratios (P = 0.002). Snellen visual acuity (VA) was unchanged, but macular sensitivity by AMP (P = 0.0439) and mesopic contrast VA by CVA (P = 0.006) were improved. There were no adverse treatment effects. Our findings suggest a role for SDM as retinal protective therapy in chronic progressive retinal diseases. Pattern electroretinography enables (early, preventive) functionally guided, rather than (late, therapeutic) image-guided, disease management.

LASER RESENSITIZATION OF MEDICALLY UNRESPONSIVE NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: Efficacy and Implications.

Drug tolerance is the most common cause of treatment failure in neovascular age-related macular degeneration. "Low-intensity/high-density" subthreshold diode micropulse laser (SDM) has been reported effective for a number of retinal disorders without adverse effects. It has been proposed that SDM normalizes retinal pigment epithelial function. On this basis, it has been postulated that SDM treatment might restore responsiveness to anti-vascular endothelial growth factor drugs in drug-tolerant eyes. Subthreshold diode micropulse laser treatment was performed in consecutive eyes unresponsive to all anti-vascular endothelial growth factor drugs, including at least three consecutive ineffective aflibercept injections. Monthly aflibercept was resumed 1 month after SDM treatment. Thirteen eyes of 12 patients, aged 73 to 97 years (average, 84 years), receiving 16 to 67 (average, 34) anti-vascular endothelial growth factor injections before SDM treatment were included and followed for 3 months to 7 months (average, 5 months) after SDM treatment. After SDM treatment and resumption of aflibercept, 92% (12 of 13) of eyes improved, with complete resolution of macular exudation in 69% (9 of 13). Visual acuity remained unchanged. Central and maximum macular thicknesses significantly improved. Subthreshold diode micropulse laser treatment restored drug response in drug-tolerant eyes with neovascular age-related macular degeneration. Based on these findings, a theory of SDM action is proposed, suggesting a wider role for SDM as retinal reparative/protective therapy.

Biological Modulation of Mouse RPE Cells in Response to Subthreshold Diode Micropulse Laser Treatment.

Many clinical trials have demonstrated the effectiveness of subthreshold phototherapy with no visible damage in retinal vascular diseases, such as diabetic retinopathy. We aimed primarily to investigate the effect of subthreshold diode micropulse laser (SDM) treatment on mouse retinal pigmented epithelium (RPE) cells. The expression of angiogenesis-modulating cytokines in response to SDM was also explored. The least toxic laser dose was selected by measuring cell viability with MTT assay and 5% duty cycle (DC) was chosen for use in further experiments. RPE cells were treated with laser-induced radiation ranging from 0 to 400mW for 24h. The apoptotic rate of RPE cells was assessed by flow cytometry. Expressions of vascular endothelial growth factor A (VEGF-A), transforming growth factor beta (TGF-β), basic fibroblast growth factor (bFGF), and pigment epithelium-derived factor (PEDF) were determined by Western Blotting and real-time PCR, respectively. After 24h of laser irradiation, cell viability was reduced dose dependently and the effect was significant compared to the controls (P<0.05). In addition, laser treatment with intensities of 100 and 200mW with DC of 5% produced no significant effect on cell viability and apoptosis as compared with the control group (P>0.05). The protein and mRNA expressions of angiogenic stimulators (VEGF-A, TGF-β, and bFGF) were significantly down-regulated (P<0.05), whereas those of the angiogenic inhibitor (PEDF) were up-regulated (P<0.05). No significant difference was found between the cells treated with different intensities of laser radiation (P>0.05). Our results showed that SDM treatment of the RPE cells suppressed the expression of choroid neovasculization-promoting cytokines and up-regulated the angiogenic inhibitor, PEDF without damaging the cells. Further investigation is needed to understand the mechanism and to optimize the use of SDM as a novel method of treatment for retinal vascular diseases.

Low-intensity/high-density subthreshold microPulse diode laser for chronic central serous chorioretinopathy.

To evaluate the visual outcomes and macular thickness change in patients with symptomatic chronic central serous chorioretinopathy after treatment with a subthreshold MicroPulse diode laser. In this retrospective, interventional case series, 10 patients were treated with the subthreshold 810-nm diode MicroPulse laser. Selected patients had symptomatic disease that may or may not have involved the foveal center. The MicroPulse laser was applied to the areas of leakage seen on fluorescein angiogram, over the areas of clinical neurosensory detachment, and/or pigment epithelial detachments. Pretreatment and posttreatment vision, change in maximum macular thickness, number of treatment sessions, and number of laser spot applications were recorded. Patients were excluded if they did not attend follow-up, had other confounding macular diseases, were using steroid medications, or application of another treatment modality had been used (i.e., photodynamic therapy or anti-vascular endothelial growth factor medication). Ten patients met the inclusion criteria, with 1 patient treated in both eyes. Three patients were excluded for lack of follow-up, one for the use of systemic steroids, and one for treatment with anti-vascular endothelial growth factor injection. Maximum macular thickness decreased after subthreshold MicroPulse laser treatment between 20 μm and 338 μm (mean = 97 μm decrease, P = 0.0046) in 11 treated eyes. Subthreshold diode MicroPulse laser is a potential treatment option for patients with symptomatic chronic central serous chorioretinopathy.

Increase in Central Retinal Edema after Subthreshold Diode Micropulse Laser Treatment of Chronic Central Serous Chorioretinopathy.

Purpose. Subthreshold diode micropulse laser (SDM) treatment is believed to be safe method of treating clinical entities involving retinal edema. We present a case of serous edematous reaction of the retina to SDM treatment. Methods. Case report. Results. A patient with chronic central serous chorioretinopathy (CSCR) was treated with SDM Yellow multispot laser. Procedure had been preceded by careful titration of the laser power, which after achieving of the threshold parameter was decreased by 50%. The follow-up visit two days after treatment revealed significant central retinal edema and subretinal fluid. Fundus autofluorescence image showed thermal reaction from the RPE in the form of small spots of hyperfluorescence corresponding to the laser multispot pattern used for treatment. Retinal edema resolved after topical bromfenac and single intravitreal bevacizumab injection. Slight pigmentary reaction from the RPE persisted. Conclusion. In the treatment of CSCR, there is a need to significantly reduce threshold SDM power parameters or simply use very low power without titration.

Risk Factors for Refractory Diabetic Macular Oedema after Sub-Tenon's Capsule Triamcinolone Acetonide Injection.

The purpose of this study is to identify the risk factors for a recurrence or persistence of diabetic macular oedema (DME) after a sub-Tenon's capsule triamcinolone acetonide (STTA) injection. The medical records of 124 patients (124 eyes) treated by STTA were reviewed. The age, sex, HbA1c level, best-corrected visual acuity, central macular thickness, insulin use, pioglitazone use, systemic hypertension, serous retinal detachment, proteinuria, panretinal photocoagulation, microaneurysm photocoagulation (MAPC), subthreshold micropulse diode laser photocoagulation (SMDLP), cataract surgery, and history of vitrectomy were examined by logistic regression analysis. Procedures of MAPC and SMDLP were significantly associated with DME treated with STTA (P = 0.0315, P = 0.04, resp.). However, a history of vitrectomy was found to have significantly fewer recurrences or persistent DME after STTA (P = 0.0464). In conclusion, patients who required combined MAPC or SMDLP with a STTA injection had significantly higher refractoriness to STTA, but postvitrectomy may prevent the recurrence or persistence of DME after STTA injection.

Safety of transfoveal subthreshold diode micropulse laser for fovea-involving diabetic macular edema in eyes with good visual acuity.

To determine the safety of transfoveal subthreshold diode micropulse laser for fovea-involving diabetic macular edema. The records of all patients treated with transfoveal subthreshold diode micropulse laser for fovea-involving diabetic macular edema in two retina clinics were reviewed. The eligibility included fovea-involving diabetic macular edema by spectral domain optical coherence tomography and pretreatment visual acuity of 20/40 or better. Thirty-nine eyes of 27 patients aged 50 years to 87 years (mean, 69 years) were included. Postoperative follow-up ranged from 3 months to 36 months (mean, 11 months). Fourteen patients were insulin dependent, and 19 had nonproliferative retinopathy. The preoperative visual acuity was 20/20 (10 eyes), 20/25 (10 eyes), 20/30 (8 eyes), and 20/40 (11 eyes). No eye had evidence of laser-induced macular damage by any imaging means postoperatively. There were no adverse treatment effects. Logarithm of the minimum angle of resolution visual acuity was improved on average of 0.03 units at 4 months to 7 months of follow-up (P = 0.0449, paired t-test) and otherwise stable. The central foveal thickness was improved at 4 months to 7 months (P = 0.05, paired t-test) and 8 months to 12 months, postoperatively (P = 0.04, mixed model accounting). Maximum macular thickness was improved at 4 months to 7 months postoperatively (P = 0.01, paired t-test and mixed model accounting). In a small retrospective series, transfoveal subthreshold diode micropulse laser was safe and effective for the treatment of fovea-involving diabetic macular edema in eyes with good preoperative visual acuity that were not the candidates for conventional photocoagulation or intravitreal injection. Further study is warranted.

Subthreshold diode-laser micropulse photocoagulation as a primary and secondary line of treatment in management of diabetic macular edema.

BackgroundThe purpose of this study was to evaluate subthreshold diode-laser micropulse (SDM) photocoagulation as a primary and secondary line of treatment for clinically significant diabetic macular edema (CSDME).MethodsIn this prospective nonrandomized case series, 220 cases of nonischemic CSDME were managed primarily and secondarily by SDM photocoagulation on a 15% duty cycle with a mean power of 828 mW and a spot size of 75–125 μm. SDM treatment was repeated at 3–4-month intervals if residual leakage was observed. Additional intravitreal pharmacologic therapy was used according to the response. Follow-up varied from 12 to 19 (mean 14±2.8) months. Novel software designed by the authors was used to record the subvisible threshold laser applications and their parameters on the fundus image of the eye. Evaluation of the results of treatment was done using fluorescein angiography and optical coherence tomography (OCT). Primary outcome measures included changes in visual acuity and foveal thickness at OCT. Secondary outcome measures included visual loss of one or more Snellen lines and laser scars detectable on fundus biomicroscopy or fluorescein angiography.ResultsIn the primary treatment group, there was significant improvement or stabilization of visual acuity after the first 3–4 months, which was stable thereafter. Visual acuity was stable in the secondary treatment group. A corresponding reduction of macular thickness on OCT was noted during the follow-up period in both groups. Additional therapy included repeat SDM photocoagulation, intravitreal injection of triamcinolone, and pars plana vitrectomy. Laser marks seen as changes in retinal pigment epithelium on fundus biomicroscopy and fluorescein angiography were noted in 3.3% and 5.7% of cases. Our novel software could accurately record the location of all SDM-invisible applications.ConclusionMicropulse laser is an effective minimal intensity therapy that offers the clear advantage of minimizing or avoiding laser-induced visible retinal burn/scarring while reducing the foveal thickness in the management of selected cases of CSDME. Future prospective studies should include the use of SDM photocoagulation as a combined minimally invasive therapy to consolidate the prompt but temporary effects of anti-vascular endothelial growth factor or anti-inflammatory agents. Virtual localization of SDM-invisible applications using our proprietary software could be used to guide further retreatments.

Subthreshold Micropulse Photocoagulation for Persistent Macular Edema Secondary to Branch Retinal Vein Occlusion including Best-Corrected Visual Acuity Greater Than 20/40.

To assess the efficacy of subthreshold micropulse diode laser photocoagulation (SMDLP) for persistent macular edema secondary to branch retinal vein occlusion (BRVO), including best-corrected visual acuity (BCVA) > 20/40, thirty-two patients (32 eyes) with macular edema secondary to BRVO were treated by SMDLP. After disease onset, all patients had been followed for at least 6 months prior to treatment. Baseline Snellen visual acuity was used to categorize the eyes as BCVA ≤ 20/40 (Group I) or BCVA > 20/40 (Group II). Main outcome measures were reduction in central macular thickness (CMT) in optical coherence tomography (OCT) and BCVA at 6 months. In the total subject-pool at 6 months, BCVA had not changed significantly but CMT was significantly reduced. Group I exhibited no significant change in CMT at 3 months but exhibited significant reductions at 6 and 12 months. Group II exhibited a marginally significant reduction in CMT at 3 months and a significant reduction at 6 months. In patients with persistent macular edema secondary to BRVO, SMDLP appears to control macular edema with minimal retinal damage. Our findings suggest that SMDLP is an effective treatment method for macular edema in BRVO patients with BCVA > 20/40.

Micropulse Diode Laser Treatment for Chronic Central Serous Chorioretinopathy: A Randomized Pilot Trial

To evaluate 810-nm subthreshold diode micropulse (SDM) laser in patients with chronic central serous chorioretinopathy (CSC). Prospective, randomized, double-blind, sham-controlled pilot trial. Patients were randomized to SDM laser treatment (group 1) or sham procedure (group 2). Primary outcome measure was change in best corrected visual acuity (BCVA); secondary outcome was central macular thickness after 3 months. Laser treatment was performed along the detached area. At the 3-month visit, all patients were evaluated for re-treatment if they met re-treatment criteria. Fifteen patients were included in this study: five patients in the sham group and 10 in the treatment group. At 3 months, BCVA was significantly enhanced in the treatment group (P = .006) compared with the sham group (P = .498). All patients from the sham group needed treatment after 3 months. An improvement in central macular thickness and leakage on fluorescein angiography was noted in all treated patients (in both groups). In this limited-size, short-term exploratory study, SDM laser was effective in treating chronic CSC. There was no evidence of retinal damage induced by treatment.

Subthreshold Laser Therapy for Diabetic Macular Edema: Metabolic and Safety Issues

To review the most important metabolic effects and clinical safety data of subthreshold micropulse diode laser (D-MPL) in diabetic macular edema (DME). Review of the literature about the mechanisms of action and role of D-MPL in DME. The MPL treatment does not damage the retina and is selectively absorbed by the retinal pigment epithelium (RPE). MPL stimulates secretion of different protective cytokines by the RPE. No visible laser spots on the retina were noted on any fundus image modality in different studies, and there were no changes of the outer retina integrity. Mean central retinal sensitivity (RS) increased in subthreshold micropulse diode laser group compared to standard ETDRS photocoagulation group. MPL is a new, promising treatment option in DME, with both infrared and yellow wavelengths using the less aggressive duty cycle (5%) and fixed power parameters. It appears to be safe from morphologic and functional point of view in mild center involving DME.

SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY IMAGING OF RETINAL CHANGES AFTER CONVENTIONAL MULTICOLOR LASER, SUBTHRESHOLD MICROPULSE DIODE LASER, OR PATTERN SCANNING LASER THERAPY IN JAPANESE WITH MACULAR EDEMA

To perform optical coherence tomography imaging of retinal healing after conventional multicolor laser, pattern scanning laser, or micropulse laser treatment and compare the characteristics of each method. This was a single-center interventional case series study. Twenty-nine patients with macular edema underwent laser photocoagulation. Changes of retinal morphology because of laser-tissue interaction were assessed within 3 months by using a spectral-domain optical coherence tomography. Immediately after conventional multicolor laser or pattern scanning laser treatment, a hyperreflective band appeared at the laser sites. The photoreceptor inner segment-outer segment line disappeared in all the patients treated with a conventional multicolor laser, but was intact in 22.2% (2/9 eyes) after pattern scanning laser. From 1 week to 1 month, the bands resolved. At 3 months, recovery of the inner segment-outer segment line surrounding the laser site was seen in all patients after conventional grid photocoagulation and pattern scanning laser. Retinal morphology did not change at any time during the observation period after subthreshold micropulse diode laser photocoagulation. The characteristic in vivo effects of retinal photocoagulation were monitored over time by spectral-domain optical coherence tomography. Changes of retinal morphology appeared less intense after pattern scanning laser than conventional grid laser treatment.

Subthreshold Diode Micropulse Laser Photocoagulation (SDM) as Invisible Retinal Phototherapy for Diabetic Macular Edema: A Review

Purpose:To present the state-of-the-art of subthreshold diode laser micropulse photocoagulation (SDM) as invisible retinal phototherapy for diabetic macular edema (DME).Method:To review the role and evolution of retinal laser treatment for DME.Results:Thermal laser retinal photocoagulation has been the cornerstone of treatment for diabetic macular edema for over four decades. Throughout, laser induced retinal damage produced by conventional photocoagulation has been universally accepted as necessary to produce a therapeutic benefit, despite the inherent risks, adverse effects and limitations of thermally destructive treatment. Recently, SDM, performed as invisible retinal phototherapy for DME, has been found to be effective in the absence of any retinal damage or adverse effect, fundamentally altering our understanding of laser treatment for retinal disease.Summary:The discovery of clinically effective and harmless SDM treatment for DME offers exciting new information that will improve our understanding of laser treatment for retinal disease, expand treatment indications, and improve patient outcomes.

Subthreshold diode laser micropulse photocoagulation for the treatment of diabetic macular edema

Diabetic macular edema (DME) is a sight-threatening complication of diabetic retinopathy, the leading cause of visual loss in the working-age population in the industrialized and emerging world. The standard of care for DME is focal/grid laser photocoagulation, which is proven effective in reducing the risk of vision loss, but inherently destructive and associated with tissue damage and collateral effects. Subthreshold diode laser micropulse photocoagulation is a nondestructive tissue-sparing laser procedure, which, in randomized controlled trials for the treatment of DME, has been found equally effective as conventional photocoagulation. Functional and anatomical outcomes from four independent randomized controlled trials provide level one evidence that vision stabilization/improvement and edema resolution/reduction can be elicited with less or no retinal damage, and with fewer or no complications. This review describes the principles of subthreshold diode laser micropulse photocoagulation, its treatment modalities and clinical outcomes in the context of standard laser treatments and of emerging nonlaser therapies for DME.

Subthreshold diode laser micropulse photocoagulation versus intravitreal injections of bevacizumab in the treatment of central serous chorioretinopathy

To evaluate the treatment of central serous chorioretinopathy (CSC) with either subthreshold diode laser MicroPulse (SDM) or intravitreal bevacizumab (BCZ). This comparative, controlled, prospective study conducted over a period of 10 months examined 52 eyes of 52 patients with (a) treatment with SDM at the active leakage site guided by fluorescein angiography (FA) (n=16 eyes), (b) intravitreal injection of 1.25 mg BCZ (n=10 eyes), or (c) observation (n=26 eyes). Outcome measures included changes in retinal pigment epithelium (RPE) leakage at FA, central macular thickness (CMT), best-corrected visual acuity (BCVA), and 10° macular perimetry. At the end of the study, there was 12.5% persistent leakage in the SDM, compared with 60% in the BCZ and 92% in the control group. Mean CMT decreased by 94 μm in the SDM, 38 μm in the BCZ, and did not change in the control group. Mean BCVA improved more than 6 early treatment of diabetic retinopathy study letters in the SDM, decreased by one letter in the BCZ, and by two letters in the control group. In the SDM group, mean perimetric deficit improved by 1.5 decibels and corrected lost variance by 2.6. In the BCZ, it improved by 0.6, and in the control group by 0.5. Retreatment was required in 7/16 eyes of the SDM group (43.75%), and in 5/10 eyes of the BCZ group (50%). SDM photocoagulation was superior to intravitreal injections of 1.25 mg BCZ in the treatment of CSC, which resulted in enhanced visual acuity and macular perimetry.

Long-term therapeutic efficacy of the subthreshold micropulse diode laser photocoagulation for diabetic macular edema

To investigate the long-term efficacy of subthreshold micropulse diode laser photocoagulation (SMDLP) on diabetic macular edema (DME). The effects of SMDLP (810 nm) were studied on 56 eyes of 44 patients with DME. Optical coherence tomography-determined foveal thickness and best-corrected visual acuity (BCVA) were evaluated at 1, 3, 6, and 12 months after the SMDLP. The mean foveal thickness was 504 μm before the SMDLP, and it was significantly reduced to 439 μm at 1 month (P = 0.001), 409 μm at 3 months (P < 0.0001), 358 μm at 6 months (P < 0.0001), and 320 μm at 12 months (P < 0.0001). The mean BCVA at baseline was 0.47 logarithm of the minimal angle of resolution (logMAR) units, and it was not changed significantly at all of the postoperative examinations. Among the 56 eyes, 10 (17.8%) had an improvement of BCVA of >0.2 logMAR units, 36 (64.2%) remained the same, and 10 eyes (17.8%) had a reduction of >0.2 logMAR units at 12 months postoperatively. Our results indicate that SMDLP has a beneficial effect on DME. However, prospective studies are needed to evaluate this technique in more detail.

Randomized Clinical Trial Evaluating mETDRS versus Normal or High-Density Micropulse Photocoagulation for Diabetic Macular Edema

To compare modified Early Treatment Diabetic Retinopathy Study (mETDRS) focal/grid laser photocoagulation with normal-density (ND-SDM) or high-density (HD-SDM) subthreshold diode-laser micropulse photocoagulation for the treatment diabetic macular edema (DME). A prospective, randomized, controlled, double-masked clinical trial with patients with previously untreated DME and best corrected visual acuity (BCVA) worse than 20/40 and better than 20/400. Patients were randomized to receive either mETDRS focal/grid photocoagulation (42 patients), ND-SDM (39 patients), or HD-SDM (42 patients). Before treatment and 1, 3, 6, and 12 months after treatment, all patients underwent ophthalmic examinations, BCVA, color fundus photography, fluorescein angiography, and optical coherence tomography (OCT). At 12 months, the HD-SDM group had the best improvement in BCVA (0.25 logMAR), followed by the mETDRS group (0.08 logMAR), whereas no improvements were seen in the ND-SDM group (0.03 logMAR). All groups showed statistically significant progressive reduction of central macular thickness (CMT) throughout the study (P < 0.001). The HD-SDM group exhibited the greatest CMT reduction (154 μm), which was not significantly different from that of the mETDRS group (126 μm; P = 0.75). At 1 year, the clinical performance of HD-SDM was superior to that of the mETDRS photocoagulation technique, according to the anatomic and functional measures of improvement used in this investigation. A rationale for this treatment modality as a preferable approach is suggested, and the precise role of subthreshold micropulse laser treatment may become more defined as experience grows, guided by optimized treatment guidelines and more comprehensive trials. (Clinicaltrials.gov number, NCT00552435.).