SUBTHRESHOLD MICROPULSE DIODE LASER VERSUS CONVENTIONAL LASER PHOTOCOAGULATION FOR DIABETIC MACULAR EDEMA: A Meta-Analysis of Randomized Controlled Trials

Subthreshold laser treatment in retinal diseases: a mini review

PURPOSE

To summarize the mechanism and the clinical applications of subthreshold laser (STL) in retinal practice. Subthreshold or "non-destructive" laser includes all types of laser treatments that produce minimal or no damage to the tissues and no visible signs after application.

METHODS

A descriptive review of articles from literature databases (PubMed, Medline, Embase, Cochrane, Web of Science) published before August 2023, which discuss current STL treatments of retinal diseases.

RESULTS

This review provides evidence for STL as a treatment option for central serous chorioretinopathy, diabetic retinopathy, age-related macular degeneration, macular edema due to retinal vein occlusion, and other maculopathies. In most published reports, STL has shown a therapeutic effect without damage to the underlying tissue.

CONCLUSION

Subthreshold laser treatment has shown safety and efficacy in the management of some retinal and macular diseases. Stimulation of the retinal pigment epithelium without destroying adjacent neuroretina has been shown to be sufficient in inducing retinal repair in many clinical cases. Recent research and clinical studies continue to explore the mechanisms and improving therapeutic benefits of this technology as well as extend the range of retinal disorders treatable by this modality.

Subthreshold micropulse laser therapy for early postoperative macular thickening following surgical removal of epiretinal membrane

BACKGROUND

This study aimed to investigate the functional and anatomical outcomes of subthreshold micropulse laser (SMPL) therapy in eyes with early postoperative macular thickening after idiopathic epiretinal membrane (iERM) removal.

METHODS

This was a prospective and interventional study. Forty-eight eyes from 48 patients with macular edema at 1 month after iERM removal were randomly divided into two groups. Patients in the SMPL group (n = 24) received SMPL therapy while no special intervention was used for the observation group (n = 24). Baseline demographic data and clinical findings before and at 1 and 3 months after SMPL treatment or observation, including best-corrected visual acuity (BCVA) and the changes in central subfield thickness (CST) and average macular thickness (AMT), were analyzed.

RESULTS

An improvement in BCVA with a decrease in CST and AMT from baseline to the 3-month follow-ups were observed in both SMPL and observation groups. No significant difference in BCVA was observed between the SMPL group and observation group either in the 1-month (0.26 [0.15, 0.52] vs. 0.26 [0.15, 0.39], P = 0.852) or the 3-month (0.15 [0.10, 0.30] vs. 0.23 [0.15, 0.30], P = 0.329) follow-up. There was a greater reduction in CST in the SMPL group versus observation group between baseline and the 3-month follow-up (-77.8 ± 72.3 μm vs. -45.0 ± 46.9 μm, P = 0.049). The alteration in AMT did not differ between the two groups in either 1-month (-16.5 ± 20.1 μm vs. -19.7 ± 16.3 μm, P = 0.547) or 3-month (-36.9 ± 26.9 μm vs. -34.0 ± 20.1 μm, P = 0.678) follow-up.

CONCLUSIONS

SMPL therapy led to a significant decrease in CST at the 3-month follow-up while did not significantly improve the visual acuity in patients with postoperative macular thickening following iERM surgery.

TRIAL REGISTRATION

The study was registered on Aug 27, 2020 (Trial Registration Number: ChiCTR 2000037227).

Subthreshold Compared with Threshold Macular Photocoagulation for Diabetic Macular Edema: A Systematic Review and Meta-Analysis

TOPIC

To compare the efficacy and safety of subthreshold macular laser to conventional focal laser photocoagulation for the treatment of vision loss secondary to diabetic macular edema (DME).

CLINICAL RELEVANCE

Macular laser remains an important and cost effective treatment option for vision loss secondary to DME. Although anti-VEGF therapy is often first-line, macular laser is of utility in low-resource or remote settings, for patients at risk of loss to follow-up, and for DME not meeting country-specific reimbursement criteria for anti-VEGF therapy. Subthreshold laser is a modality that does not produce clinical or histologic evidence of thermal damage, thereby potentially limiting the common complications of conventional laser.

METHODS

Ovid MEDLINE, EMBASE, and CENTRAL databases were searched for randomized controlled trials (RCTs) from inception to September 28, 2022. Meta-analyses were performed using random-effects modeling. Data were collected at 12 and 24 months for best-corrected visual acuity (BCVA), central retinal thickness, diabetic retinopathy severity scale, rate of adverse events, rate of enrolled patients not completing treatment, rate of patients receiving retreatment, and quality-of-life measures. The risk of bias and certainty of evidence were assessed using Cochrane's Risk-of-Bias version 2 and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) frameworks, respectively. Subgroup analysis was performed between subthreshold laser modalities and evaluated with Instrument to assess the Credibility of Effect Modification Analyses tool.

RESULTS

Fourteen RCTs comprising 514 eyes receiving conventional laser and 574 eyes receiving subthreshold laser were included. Subthreshold laser likely results in no difference to BCVA (moderate GRADE certainty) compared with conventional laser. Conventional laser demonstrated a small, statistically significant improvement in central retinal thickness (low GRADE certainty); however, the magnitude of this improvement is unlikely to be clinically important. There may not be a difference in the rate of adverse events (low GRADE certainty) at 12 months when comparing subthreshold laser to conventional laser for DME.

CONCLUSION

Randomized controlled trial literature to date suggests subthreshold laser to be as effective as conventional laser in the treatment of DME. Increased follow-up duration is needed to observe any long-term safety benefit from reduced retinal damage.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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 577 nm 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.

Subthreshold Photocoagulation, Laser Endpoint Management Based on Optical Coherence Tomography Angiography in Cases of Diabetic Macular Edema Refractory to Anti-VEGF

PURPOSE

This study aimed to determine the changes that occur in the vasculature, as based on optical coherence tomography angiography (OCTA) after non-damaging endpoint management (EpM), using a continuous wave yellow laser. The study was on eyes with diabetic macular edema (DME) that were resistant to anti-vascular endothelial growth factors (anti-VEGFs).

MATERIALS AND METHODS

This was a retrospective analysis of OCTA images of 44 eyes in 44 patients with DME refractory to anti-VEGF. The eyes were treated with a PASCAL Streamline yellow laser (577 nm wavelength, 200 mm spot size). Treatment was administered to the DME area and utilized 10% continuous wave laser energy and 0.50 µm beam diameter spot spacing. Best-corrected visual acuity (BCVA) and enhanced in-depth imaging with optical coherence tomography (EDI-OCT) and fundus autofluorescence (FAF) images were recorded at baseline, and 3 and 6 months posttreatment. Total choroidal area (TCA), luminal area (LA), stromal area (SA), and the choroidal vascularity index (CVI) were calculated using Image J software. The macula was divided into five quadrants in accordance with the mapping system in the Early Treatment Diabetic Retinopathy Study (ETDRS).

RESULTS

All patients (mean age: 58.90 ± 9.55 years) were diagnosed with diabetes mellitus type 2. Mean BCVA at baseline was 0.30 ± 0.11 logarithm of the minimum angle of resolution (logMAR) versus 0.23 ± 0.10 logMAR at 3 months (p = 0.032) and 0.17 ± 0.10 logMAR at 6 months (p = 0.013). The foveal avascular zone area (FAZ) decreased in the deep capillary plexus (DCP) from baseline to 6 months (p = 0.028). Vessel densities (VDs) of the superficial capillary plexus (SCP), DCP, and choriocapillaris decreased significantly in the fovea at 3 and 6 months compared to baseline (p < 0.05 for both follow-up time points). There were significant decreases in SCP and DCP in the superior quadrant at the end of month 6 (p = 0.001 and p = 0.038, respectively). There was a significant decrease in the nasal quadrant of the DCP and choriocapillaris at the end of month 6 (p = 0.024 and p = 0.049, respectively). Although there was a significant decrease in central macular thickness (CMT) (p < 0.001), subfoveal choroidal thickness (SFCT) (p < 0.001), and LA (p = 0.034) at months 3 and 6, there was no significant change in the CVI (p = 0.19). According to the DME recovery rate, 36 eyes (81%) were irradiated once, whereas 8 eyes (19%) were irradiated twice.

CONCLUSIONS

Non-damaging EpM therapy using a continuous wave yellow laser in eyes with DME that are resistant to anti-VEGFs induces significant changes in the SCP, choriocapillaris, and, most commonly, the DCP, which caused a significant decrease in VDs during 6 months of follow-up.

Vision protection therapy for prevention of neovascular age-related macular degeneration

To access the effect of vision protection therapy on neovascular conversion in age-related macular degeneration (AMD). Patient unidentified data aggregated by Vestrum Health, LLC (VH) from over 320 US retina specialists was analyzed to compare the conversion rate from dry to neovascular (wet) AMD in a practice employing VPT (VPT group) compared to those employing standard care alone (SCA group) between January 2017 through July 2023. 500,00 eyes were filtered then matched for neovascular conversion risk factors by propensity scoring and compared in a 10/1 ratio of 7370 SCA and 737 VPT treated eyes. SCA eyes had significantly fewer clinical encounters and shorter follow up than the VPT group. Despite this, the risk of neovascular conversion by PS was significantly lower in the VPT group compared to SCA (HR 5.73, p < 0.0001). Analysis matching the encounter frequency of both groups as a post-randomization variable produced a similar HR (HR 5.98, p < 0.0001). Because 9% of eyes in the VPT group were not treated with VPT due to bilateral early (low-risk) AMD, analysis comparing the SCA group to VPT-treated eyes was done that also showed significantly lower conversion rates in the VPT-treated eyes, with or without encounter frequency matching (HR 5.84, 5.65, p < 0.0001). Visual acuity was consistently better in VPT eyes compared to SCA eyes throughout the study time window. The advantage of VPT over SCA increased with increased SCA encounter frequency and higher conversion risk factors, including age and ICD10 coded dry AMD severity. Neovascular (wet) AMD is the main cause of irreversible visual loss worldwide. Consistent with two prior studies, the current study finds Vision Protection Therapy markedly more effective at both recognizing and preventing neovascular AMD than the current standard of care, benefiting the highest risk dry AMD eyes the most.

Short-pulse laser plus subthreshold diffuse laser for serous retinal detachment in dome-shaped macula

BACKGROUND

First described by Gaucher and associates in 2008, dome-shaped macula (DSM) is an anterior convex protrusion of the macula visible on OCT (optical coherence tomography). Visual impairment in DSM results mainly from sub-foveal serous retinal detachment (SRD). Herein, this original study from retrospective data analysis evaluate the anatomical and functional effects of Pascal® short-pulse (SP) laser plus endpoint management (EpM) subthreshold diffuse laser (SDL) in patients with SRD due to DSM.

METHODS

This retrospective study included seven consecutive patients (eight eyes) with SRD secondary to dome-shaped macula who underwent a comprehensive ophthalmological evaluation including logMAR BCVA, slit-lamp biomicroscopy, indirect ophthalmoscopy, and spectral-domain optical coherence tomography (SD-OCT) (Spectralis; Heidelberg Engineering, Germany) before combined Pascal® SP laser plus EpM-SDL with 1 to 6 month intervals, postoperatively, with a mean ± standard error (SE) follow-up time of 12.92 ± 1.34 months.

RESULTS

Eight eyes from seven patients were analyzed in this study. At baseline, mean BCVA (LogMAR) ± standard error (SE) and mean CST (central subfield thickness)(µm) ± SE were 0.6125 ± 0.14 and 412.50 ± 24.65, respectively. After a mean follow-up time of 12.92 ± 1.34 months, mean CST (µm) ± SE and BCVA (LogMAR) ± SE were 294.75 ± 19.68 (p = 0.0078) and 0.4537 ± 0.12 (p = 0.0313), respectively. A statistically significant reduction in mean CST and an improvement in mean BCVA were noted after SRD resolution with laser therapy application. The mean serous retinal detachment resolution time (months) ± SE was 3.75 ± 1.08. No adverse events were registered, including enlargement of atrophic alterations and choroidal neovascularization.

CONCLUSIONS

The novel combined laser modality with Pascal® SP laser plus EpM-SDL treatment may induce subretinal fluid regression and BCVA improvement 1 year after treatment in DSM patients with SRD.

COMPARING FUNCTIONAL AND VASCULAR LAYER OUTCOMES OF LASER PHOTOCOAGULATION VERSUS SUBTHRESHOLD MICROPULSE LASER FOR DIABETIC MACULAR EDEMA: An OCT-Angiography Study

PURPOSE

To compare the efficacy of conventional laser and subthreshold micropulse laser (SML) in treating diabetic macular edema in terms of functional outcomes and changes in quantitative metrics for the retinal capillary and choriocapillary vascular layers.

METHODS

Fifty-two eyes from 52 patients with treatment-naive, clinically significant macular edema were randomly assigned to the conventional laser group or SML group in a 1:1 ratio. Best-corrected visual acuity, central macular thickness (CMT), and optical coherence tomography angiography scans were measured at baseline, 1, 3, and 6 months after treatment.

RESULTS

The SML group showed rapid visual recovery, improving from baseline of 0.320 ± 0.31 logarithm of the minimum angle of resolution (20/42 Snellen) to 0.270 ± 0.22 logarithm of the minimum angle of resolution (20/37 Snellen) at 1 month ( P = 0.038) and had significant improvements in CMT at 6-month post-treatment (353.88-301.00 µ m, P = 0.005). Statistically significant changes were detected across all optical coherence tomography angiography metrics, including vessel density, vessel length density, vessel diameter index, and fractal dimension, at 6 months for both groups in the deep capillary plexus and choriocapillary plexus.

CONCLUSION

Subthreshold micropulse laser resulted in early visual recovery and sustained macular thickness improvement in the treatment of diabetic macular edema. Microvascular perfusion parameters, including vessel density, vessel length density, and fractal dimension, improved in the deep capillary plexus and choriocapillary plexus for both treatment groups at 6 months post-treatment.

Comparative Efficacy of Subthreshold Micropulse Laser Photocoagulation versus Conventional Laser Photocoagulation for Diabetic Macular Edema: A Meta-Analysis

BACKGROUND

Laser photocoagulation is an effective procedure for the treatment of diabetic macular edema (DME). However, the beneficial effects of conventional laser photocoagulation (CLP) are accompanied by the destruction of retinal photoreceptors. Therefore, subthreshold micropulse laser photocoagulation (SMLP) was proposed for DME.

OBJECTIVES

This meta-analysis study was performed to evaluate the efficacy and safety of SMLP compared with CLP for the management of DME.

METHODS

The PubMed, Embase, Web of Science, Cochrane, SinoMed, ClinicalTrials.gov, Wanfang, and China National Knowledge Infrastructure (CNKI) databases, published until Dec 2021, were searched to identify studies evaluating the clinical outcomes of SMLP for DME.

RESULTS

Eight randomized controlled trials were selected for this meta-analysis involving a total of 546 eyes (275 eyes in SMLP group and 271 eyes in CLP group). SMLP of different wavelengths (577 nm and 810 nm) and duty cycles (5% and 15%) was applied. The pooled outcomes showed that SMLP group, especially 577 nm and 810 nm 15% duty cycle parameter settings, had a statistically significant higher efficacy than CLP group in terms of BCVA (MD = -0.02, 95% CI: -0.03 to -0.01, p < 0.01; MD = -0.09, 95% CI: -0.09 to -0.09, p < 0.01) and showed more significant advantages than CLP group in resolving macular edema assessed by reduction of CMT (MD = -32.87, 95% CI: -37.61 to -28.13, p < 0.01; MD = -8.01, 95% CI: -9.06 to -6.96, p < 0.01), whereas the efficacy of 577 nm and 810 nm 5% duty cycle SMLP subgroups remained numerically superior to CLP group, but nonsignificantly (p > 0.05). In the field of CS, SMLP group (no matter parameter settings) resulted in better preservation of CS compared to CLP group (MD = 1.96, 95% CI: 1.47-2.46, p < 0.01).

CONCLUSIONS

Compared with CLP, SMLP may get superior efficacy and safety on improvement of BCVA, reduction of CMT, and preservation of CS. In clinical, SMLP can be considered as a safe and effective therapy in the management of DME.

Diabetic Macular Edema and Diode Subthreshold Micropulse Laser: A Randomized Double-Masked Noninferiority Clinical Trial

PURPOSE

To determine clinical effectiveness, safety, and cost-effectiveness of subthreshold micropulse laser (SML), compared with standard laser (SL), for diabetic macular edema (DME) with central retinal thickness (CRT) < 400 μm.

DESIGN

Pragmatic, multicenter, allocation-concealed, double-masked, randomized, noninferiority trial.

PARTICIPANTS

Adults with center-involved DME < 400 μm and best-corrected visual acuity (BCVA) of > 24 Early Treatment Diabetic Retinopathy Study (ETDRS) letters in one/both eyes.

METHODS

Randomization 1:1 to 577 nm SML or SL treatment. Retreatments were allowed. Rescue with intravitreal anti-vascular endothelial growth factor therapies or steroids was permitted if 10 or more ETDRS letter loss occurred, CRT increased > 400 μm, or both.

MAIN OUTCOME MEASURES

Primary outcome was mean change in BCVA in the study eye at 24 months (noninferiority margin 5 ETDRS letters). Secondary outcomes were mean change from baseline to month 24 in binocular BCVA; CRT and mean deviation of Humphrey 10-2 visual field in the study eye; percentage meeting driving standards; EuroQoL EQ-5D-5L, 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25), and Vision and Quality of Life Index (VisQoL) scores; cost per quality-adjusted life-years (QALYs) gained; adverse effects; and number of laser and rescue treatments.

RESULTS

The study recruited fully (n = 266); 87% of SML-treated and 86% of SL-treated patients had primary outcome data. Mean ± standard deviation BCVA change from baseline to month 24 was -2.43 ± 8.20 letters and -0.45 ± 6.72 letters in the SML and SL groups, respectively. Subthreshold micropulse laser therapy was deemed not only noninferior but also equivalent to SL therapy because the 95% confidence interval (CI; -3.9 to -0.04 letters) lay wholly within both upper and lower margins of the permitted maximum difference (5 ETDRS letters). No statistically significant difference was found in binocular BCVA (0.32 ETDRS letters; 95% CI, -0.99 to 1.64 ETDRS letters; P = 0.63); CRT (-0.64 μm; 95% CI, -14.25 to 12.98 μm; P = 0.93); mean deviation of the visual field (0.39 decibels (dB); 95% CI, -0.23 to 1.02 dB; P = 0.21); meeting driving standards (percentage point difference, 1.6%; 95% CI, -25.3% to 28.5%; P = 0.91); adverse effects (risk ratio, 0.28; 95% CI, 0.06-1.34; P = 0.11); rescue treatments (percentage point difference, -2.8%; 95% CI, -13.1% to 7.5%; P = 0.59); or EQ-5D, NEI-VFQ-25, or VisQoL scores. Number of laser treatments was higher in the SML group (0.48; 95% CI, 0.18-0.79; P = 0.002). Base-case analysis indicated no differences in costs or QALYs.

CONCLUSIONS

Subthreshold micropulse laser therapy was equivalent to SL therapy, requiring slightly higher laser treatments.

Intravitreal anti-vascular endothelial growth factor, laser photocoagulation, or combined therapy for diabetic macular edema: A systematic review and network meta-analysis

PURPOSE

To conduct a network meta-analysis (NMA) comparing the efficacy of anti-vascular endothelial growth factor (VEGF) therapy alone versus laser photocoagulation (LP) therapy alone or anti-VEGF therapy combined with LP therapy for diabetic macular edema (DME).

METHODS

PubMed, Embase, Web of Science, and Cochrane Central Register of Controlled Trials were systematically searched for studies comparing anti-VEGF therapy alone versus LP therapy alone or anti-VEGF therapy combined with LP therapy for DME. Primary outcomes were mean best-corrected visual acuity (BCVA) and central macular thickness (CMT) change. Relevant data were collected and pooled using NMA.

RESULTS

A total of 13 randomized controlled trials were included in our NMA. Anti-VEGF therapy significantly improved BCVA the most compared to the combined (mean difference [MD] = 1.5; 95% confidence interval [CI]: 0.084, 2.7) and LP (MD = 6.3; 95% CI: 5.1, 7.6) therapies at six months, while there was no difference in reducing CMT at six months between the anti-VEGF and combined therapies (MD = -16; 95% CI: -46, 13). At 12 months, no significant difference was found between the anti-VEGF and combined therapy in terms of BCVA (MD = 0.1; 95% CI: -1.7, 1.5) and CMT (MD = 21; 95% CI: -3.0, 44).

CONCLUSION

There was no significant difference between the anti-VEGF therapy and combined therapy. For the long-term treatment of patients with DME, combined therapy is recommended.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD42022376401.

Subthreshold Micropulse Laser for Diabetic Macular Edema: A Review

Diabetic macular edema (DME) is one of the main causes of visual impairment in patients of working age. DME occurs in 4% of patients at all stages of diabetic retinopathy. Using a subthreshold micropulse laser is an alternative or adjuvant treatment of DME. Micropulse technology demonstrates a high safety profile by selectively targeting the retinal pigment epithelium. There are no standardized protocols for micropulse treatment, however, a 577 nm laser application over the entire macula using a 200 μm retinal spot, 200 ms pulse duration, 400 mW power, and 5% duty cycle is a cost-effective, noninvasive, and safe therapy in mild and moderate macular edemas with retinal thickness below 400 μm. Micropulse lasers, as an addition to the current gold-standard treatment for DME, i.e., anti-vascular endothelial growth factor (anti-VEGF), stabilize the anatomic and functional retinal parameters 3 months after the procedure and reduce the number of required injections per year. This paper discusses the published literature on the safety and application of subthreshold micropulse lasers in DME and compares them with intravitreal anti-VEGF or steroid therapies and conventional grid laser photocoagulation. Only English peer-reviewed articles reporting research within the years 2010-2022 were included.

Standard threshold laser versus subthreshold micropulse laser for adults with diabetic macular oedema: the DIAMONDS non-inferiority RCT

BACKGROUND

The National Institute for Health and Care Excellence recommends macular laser to treat diabetic macular oedema with a central retinal subfield thickness of < 400 µm on optical coherence tomography. The DIAMONDS (DIAbetic Macular Oedema aNd Diode Subthreshold micropulse laser) trial compared standard threshold macular laser with subthreshold micropulse laser to treat diabetic macular oedema suitable for macular laser.

OBJECTIVES

Determining the clinical effectiveness, safety and cost-effectiveness of subthreshold micropulse laser compared with standard threshold macular laser to treat diabetic macular oedema with a central retinal subfield thickness of < 400 µm.

DESIGN

A pragmatic, multicentre, allocation-concealed, double-masked, randomised, non-inferiority, clinical trial.

SETTING

Hospital eye services in the UK.

PARTICIPANTS

Adults with diabetes and centre-involving diabetic macular oedema with a central retinal subfield thickness of < 400 µm, and a visual acuity of > 24 Early Treatment Diabetic Retinopathy Study letters (Snellen equivalent > 20/320) in one/both eyes.

INTERVENTIONS

Participants were randomised 1 : 1 to receive 577 nm subthreshold micropulse laser or standard threshold macular laser (e.g. argon laser, frequency-doubled neodymium-doped yttrium aluminium garnet 532 nm laser); laser treatments could be repeated as needed. Rescue therapy with intravitreal anti-vascular endothelial growth factor therapies or steroids was allowed if a loss of ≥ 10 Early Treatment Diabetic Retinopathy Study letters between visits occurred and/or central retinal subfield thickness increased to > 400 µm.

MAIN OUTCOME MEASURES

The primary outcome was the mean change in best-corrected visual acuity in the study eye at 24 months (non-inferiority margin 5 Early Treatment Diabetic Retinopathy Study letters). Secondary outcomes included the mean change from baseline to 24 months in the following: binocular best-corrected visual acuity; central retinal subfield thickness; the mean deviation of the Humphrey 10-2 visual field in the study eye; the percentage of people meeting driving standards; and the EuroQol-5 Dimensions, five-level version, National Eye Institute Visual Function Questionnaire - 25 and Vision and Quality of Life Index scores. Other secondary outcomes were the cost per quality-adjusted life-years gained, adverse effects, number of laser treatments and additional rescue treatments.

RESULTS

The DIAMONDS trial recruited fully (n = 266); 87% of participants in the subthreshold micropulse laser group and 86% of participants in the standard threshold macular laser group had primary outcome data. Groups were balanced regarding baseline characteristics. Mean best-corrected visual acuity change in the study eye from baseline to month 24 was -2.43 letters (standard deviation 8.20 letters) in the subthreshold micropulse laser group and -0.45 letters (standard deviation 6.72 letters) in the standard threshold macular laser group. Subthreshold micropulse laser was deemed to be not only non-inferior but also equivalent to standard threshold macular laser as the 95% confidence interval (-3.9 to -0.04 letters) lay wholly within both the upper and lower margins of the permitted maximum difference (5 Early Treatment Diabetic Retinopathy Study letters). There was no statistically significant difference between groups in any of the secondary outcomes investigated with the exception of the number of laser treatments performed, which was slightly higher in the subthreshold micropulse laser group (mean difference 0.48, 95% confidence interval 0.18 to 0.79; p = 0.002). Base-case analysis indicated no significant difference in the cost per quality-adjusted life-years between groups.

FUTURE WORK

A trial in people with ≥ 400 µm diabetic macular oedema comparing anti-vascular endothelial growth factor therapy alone with anti-vascular endothelial growth factor therapy and macular laser applied at the time when central retinal subfield thickness has decreased to < 400 µm following anti-vascular endothelial growth factor injections would be of value because it could reduce the number of injections and, subsequently, costs and risks and inconvenience to patients.

LIMITATIONS

The majority of participants enrolled had poorly controlled diabetes.

CONCLUSIONS

Subthreshold micropulse laser was equivalent to standard threshold macular laser but required a slightly higher number of laser treatments.

TRIAL REGISTRATION

This trial is registered as EudraCT 2015-001940-12, ISRCTN17742985 and NCT03690050.

FUNDING

This project was funded by the National Institute for Health and Care Research ( NIHR ) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 50. See the NIHR Journals Library website for further project information.

Therapeutic Effects of Combination Therapy and Photobiomodulation Therapy on Retinal Regeneration

Introduction: Many systemic and ocular diseases cause macular edema (ME). Macular edema is seen in two primary forms; the first is diffuse thickening of the macula, and the other is a macula with a distinct petaloid (cloverleaf) appearance called cystoid macular edema. Macular edema has a known role in the reduction of visual equity, and many options have been proposed for the reversal of this condition. Methods: Articles on the effects of macular laser grid photocoagulation on diabetic macular edema (DME) or cystoid macular edema published between 2000 and 2022 were collected from PubMed, Google Scholar, and Web of Science. The following keywords were used for the search: "macular laser photocoagulation", "macular edema", "cystoid macular edema", "intravitreal pharmacotherapies", and "antivascular endothelial growth factor". Two hundred nineteen articles were found in google scholar and 165 articles in PubMed, and a total of 58 articles were included in the study after applying the exclusion criteria. Results: We investigated the effects of various lasers photocoagulation such as Focal and/or grid macular laser, subthreshold micropulse laser (SMPL), as well as intravitreal pharmacotherapies with triamcinolone acetonide, and fluocinolone, and extended released intraocular implants such as Ozurdex, Retisert, Iluvien, and anti-vascular endothelial growth factors such as bevacizumab (Avastin), Eyela, and Lucentis. Corticosteroids were more effective than lasers, although some researchers have found that lasers and combined lasers and corticosteroids are more effective. In addition, some studies have shown that the frequency and concentrations of intravitreal pharmacotherapies are effective in increasing visual outcomes. Conclusion: The results of the studies showed that the combined intravitreal corticosteroids are much more effective in improving visual acuity (VA) than a single corticosteroid, and the low concentration of the drug is safer. Still, corticosteroids have side effects such as increased intraocular pressure and glaucoma. Therefore, combining the medication with a laser is much more reasonable than each alone. Also, the subthreshold photocoagulation laser (670 nm) is better at reducing the central macular thickness (CMT) and improving VA than the micro pulse yellow laser and pan-retinal photocoagulation (PRP).

Differential gene expression analysis using RNA sequencing: retinal pigment epithelial cells after exposure to continuous-wave and subthreshold micropulse laser

PURPOSE

Subthreshold micropulse laser (SMPL) is more clinically efficient for the treatment of diabetic macular edema (DME) than the conventional continuous-wave (CW) laser. We aimed to characterize transcriptome changes after the application of these lasers and to compare the transcripts.

METHODS

Human pluripotent stem cell-derived retinal pigment epithelial cells were exposed to laser irradiation. Differentially expressed genes (DEGs), distribution of heat shock protein (Hsp) family, gene expression profile, and gene ontology (GO) enrichment analysis based on RNA sequencing data were investigated at 3 h and 24 h after irradiation.

RESULTS

CW laser induced more DEGs than SMPL (1771 vs. 520 genes). The expression of the Hsp family was confirmed in both groups: however, the induction patterns was different for different genes. GO enrichment analysis revealed that CW laser upregulated the expression of DEGs involved in vasculature development (GO: 0001944), related to apoptosis and repair after cell injury whereas SMPL upregulated the expression of DEGs involved in photoreceptor cell maintenance (GO: 0045494), photoreceptor cell development (GO: 0042461), and sensory perception of light stimuli (GO: 0050953).

CONCLUSIONS

The results provide insights into the genetic responses and may contribute to the understanding of the molecular mechanisms of laser-induced thermal effects.

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

Purpose

To 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).

Methods

Patient 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.

Results

After 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.

Conclusion

Our 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.

Changes in entropy on polarized-sensitive optical coherence tomography images after therapeutic subthreshold micropulse laser for diabetic macular edema: A pilot study

Purpose

To investigate the dynamics of the healing process after therapeutic subthreshold micropulse laser (SMPL) for diabetic macular edema (DME) using polarization-sensitive optical coherence tomography (PS-OCT).

Methods

Patients with treatment-native or previously-treated DME were prospectively imaged using PS-OCT at baseline, 1, 2, 3, and 6 months. The following outcomes were evaluated: changes in the entropy value per unit area (pixel²) in the retinal pigment epithelium (RPE) on the B-scan image; changes in the entropy value in each stratified layer (retina, RPE, choroid) based on the ETDRS grid circle overlaid with en face entropy mapping, not only the whole ETDRS grid area but also a sector irradiated by the SMPL; and the relationship between edema reduction and entropy changes.

Results

A total of 11 eyes of 11 consecutive DME patients were enrolled. No visible signs of SMPL treatment were detected on PS-OCT images. The entropy value per unit area (pixel²) in the RPE tended to decrease at 3 and 6 months from baseline (35.8 ± 17.0 vs 26.1 ± 9.8, P = 0.14; vs 28.2 ± 18.3, P = 0.14). Based on the en face entropy mapping, the overall entropy value did not change in each layer in the whole ETDRS grid; however, decrease of entropy in the RPE was observed at 2, 3, and 6 months post-treatment within the SMPL-irradiated sectors (P < 0.01, each). There was a positive correlation between the change rate of retinal thickness and that of entropy in the RPE within the SMPL-irradiated sector at 6 months (r² = 0.19, P = 0.039).

Conclusion

Entropy measured using PS-OCT may be a new parameter that facilitates objective monitoring of SMPL-induced functional changes in the RPE that could not previously be assessed directly. This may contribute to a more promising therapeutic evaluation of DME.

Clinical trial

This clinical study was registered in UMIN-CTR (ID: UMIN000042420).

Subthreshold micropulse laser adjuvant to bevacizumab versus bevacizumab monotherapy in treating diabetic macular edema: one- year- follow-up

Purpose

To compare the therapeutic impact of combining intravitreal injections of bevacizumab (IVB) with micropulse laser (MPL) in central diffuse diabetic macular edema (DME) versus IVB monotherapy during 12 months follow-up.

Methods

We conducted a retrospective comparative study of 98 treatment-naive eyes (63 patients) with central diffuse DME. The first group of patients (IVB + MPL group, n = 49) was treated with 3 monthly IVB followed by MPL within 1 week after the third injection. Patients were then followed and treated on a pro re nata (PRN) basis, with MPL retreatment if necessary. The changes in best-corrected visual acuity (BCVA), central macular thickness (CMT), number of IVB injections and MPL sessions were evaluated at 4, 8, and 12 months. A control group of diabetic patients with treatment-naive DME was treated with standard protocol of 3 monthly IVB as monotherapy then followed on a PRN basis (IVB group, n = 49). Statistic comparaison of BCVA, CMT, and IVB number variation was interpreted at 12 months between both groups.

Results

In IVB + MPL group, baseline BCVA improvement was not significant at 4 and 8 months (p = 0.90, p = 0.08), and was statistically significant (p = 0.01) at 12 months. Mean CMT significantly decreased at 4, 8, and 12 months (p < 0.01) in IVB + MPL group. The difference in BCVA (p = 0.091) and CMT (p = 0.082) variation at 12 months between both groups was not significant but the number of injections was significantly lower in IVB + MPL group (4.1 ± 1.5 injections) compared to IVB group (7.2 ± 1.3 injections) (p < 0.005).

Conclusion

Combining intravitreal injections of bevacizumab and MPL in the treatment of DME is effective and safe. This protocol may decrease the number of IVB and its frequency. It offers the advantage of lasting therapeutic response with fewer recurrences.

Retinal temperature determination based on photopic porcine electroretinogram

OBJECTIVE

Subthreshold retinal laser therapy (SLT) is a treatment modality where the temperature of the retinal pigment epithelium (RPE) is briefly elevated to trigger the therapeutic benefits of sublethal heat shock. However, the temperature elevation induced by a laser exposure varies between patients due to individual differences in RPE pigmentation and choroidal perfusion. This study describes an electroretinography (ERG)-based method for controlling the temperature elevation during SLT.

METHODS

The temperature dependence of the photopic ERG response kinetics were investigated both ex vivo with isolated pig retinas and in vivo with anesthetized pigs by altering the temperature of the subject and recording ERG in different temperatures. A model was created for ERG-based temperature estimation and the feasibility of the model for controlling SLT was assessed through computational simulations.

RESULTS

The kinetics of the photopic in vivo flash ERG signaling accelerated between 3.6 and 4.7%/C, depending on the strength of the stimulus. The temperature dependence was 5.0%/C in the entire investigated range of 33 to 44C in ex vivo ERG. The simulations showed that the method is suitable for determining the steady-state temperature elevation in SLT treatments with a sufficiently long laser exposure and large spot size, e.g., during > 30 s laser exposures with > 3 mm stimulus spot diameter.

CONCLUSIONS

The described ERG-based temperature estimation model could be used to control SLT treatments such as transpupillary thermotherapy.

SIGNIFICANCE

The introduced ERG-based method for controlling SLT could improve the repeatability, safety, and efficacy of the treatment of various retinal disorders.

Comparison of two-year treatment outcomes between subthreshold micropulse (577 nm) laser and aflibercept for diabetic macular edema

PURPOSE

To compare two-year treatment outcomes of subthreshold micropulse (577 nm) laser and aflibercept for diabetic macular edema (DME).

STUDY DESIGN

Retrospective case-control study.

METHODS

A total 164 eyes in 164 DME patients treated with either micropulse laser (86 eyes) or intravitreal aflibercept monotherapy (78 eyes) were recruited. Main outcome measures included at least five Early Treatment Diabetic Retinopathy Study (ETDRS) letters' improvement from baseline at 6, 12 and 24 months.

RESULTS

Rescue aflibercept was initiated in 24% of eyes in micropulse laser group. At 6-month visit the aflibercept group achieved a higher percentage of eyes with at least 5-letter visual acuity improvement than micropulse laser group (56% vs 38%, P = 0.044), however, this was not the case at 12-month (45% vs 49%, P = 0.584) and 24-month visits (49% vs 57%, P = 0.227). At 6-month visit the aflibercept group achieved a higher percentage of eyes with at least 10% improvement of central macular thickness (73% vs 49%, P = 0.005), but this was not the case at 12-month (73% vs 70%, P = 0.995) and 24-month visits (85% vs 84%, P = 0.872).

CONCLUSION

Aflibercept achieved faster and higher rates of anatomical and functional improvement than micropulse laser in DME patients. Long term efficacy of treatment did not result in significant differences between aflibercept monotherapy and micropulse laser in DME patients. Primary treatment of micropulse laser with deferred rescue aflibercept might be the treatment option without reducing the chance of visual improvement in DME eyes.

Does conventional laser photocoagulation still have a place in the treatment of diabetic macular edema?

Objective: The study aimed to investigate the long-term efficacy of conventional laser photocoagulation in the treatment of diabetic macular edema. Methods: In this retrospective study, the records of patients presented with diabetic macular edema (DME) and non-proliferative diabetic retinopathy were reviewed. DME defined as clinically significant macular edema was treated by using argon green or yellow dye laser with focal, grid, and modified grid techniques according to Early Treatment Diabetic Retinopathy Study parameters. Best-corrected visual acuity (BCVA) was measured. BCVA change after the treatment and its relationship with other factors were evaluated. Results: The study included 133 eyes of 81 patients. The mean follow-up was 28.26 months. BCVA demonstrated the increase of 2 lines or more in 20.7% of the eyes, stabilization within 2 lines in 60.7% of the eyes, and loss of 2 lines or more in 18.3% of the eyes. The eyes with baseline BCVA lower than or equal to 0.50 showed a statistically significant increase (p=0.001) whereas the eyes with baseline BCVA of more than 0.50 did not show a statistically significant change (p=0.070) after laser photocoagulation treatment. Conclusions: Conventional laser photocoagulation is an effective treatment in diabetic macular edema including center-involved type and stabilizes visual acuity in the majority of the patients. Improvement in BCVA is significant in the group with lower baseline BCVA. Abbreviations: DM = diabetes mellitus, DME = diabetic macular edema, ETDRS = early treatment diabetic retinopathy study, CSME = clinically significant macular edema, CLP = conventional laser photocoagulation, VEGF = vascular endothelial growth factor, BCVA = best-corrected visual acuity, ANOVA = analysis of variance, VA = visual acuity.

Comparison of Subthreshold 532 nm Diode Micropulse Laser with Conventional Laser Photocoagulation in the Treatment of Non-Centre Involved Clinically Significant Diabetic Macular Edema

BACKGROUND

The aim of the study was to investigate the effect of the 532 nm (green) diode subthreshold micropulse laser (SML) in the treatment of non-centre involved clinically significant macular edema (CSME) in comparison to the conventional laser photocoagulation (CLP).

METHODS

A total of 60 eyes of patients diagnosed with non-centre involved CSME were randomly divided into two groups. SML photocoagulation was performed in the first group (G1), while CLP in the second one (G2). Central macular thickness (CMT) and best corrected visual acuity (BCVA) were measured prior to treatment and at 3 and 6 months after intervention.

RESULTS

G1 participants had significantly better CMT at 6 months after laser application (p = 0.04) compared to G2. Additionally, CMT in both groups was significantly lower 6 months after laser application in comparison to baseline values (G1: p < 0.001, G2: p = 0.002). Moreover, significant improvement was detected 6 months after SML in G1 regarding BCVA compared to values before laser treatment (p = 0.001).

CONCLUSION

SML was more effective than CLP in reducing CMT and improving BCVA in patients with non-centre involved CSME. Therefore, it seems that SML can be a good substitute for CLP in DME treatment if confirmed in future studies.

CHANGES OF AQUEOUS HUMOR MÜLLER CELLS' BIOMARKERS IN HUMAN PATIENTS AFFECTED BY DIABETIC MACULAR EDEMA AFTER SUBTHRESHOLD MICROPULSE LASER TREATMENT

PURPOSE

To evaluate the changes in activity of biomarkers of Mu[Combining Diaeresis]ller cells (MC) in aqueous humor of patients with diabetic macular edema after subthreshold micropulse laser, over 1 year.

METHODS

Patients with untreated diabetic macular edema and central retinal thickness ≤ 400 μm were enrolled. Best-corrected visual acuity, full ophthalmic examination, and optical coherence tomography were performed. Subthreshold micropulse laser was applied every 3 months. Glial fibrillary acidic protein and inwardly rectifying potassium channel (Kir 4.1), MC activity markers, and vascular endothelial growth factor were quantified in the aqueous humor collected at baseline and at 1, 3, and 12 months after laser. Changes in the macular thickness and inner nuclear layer thickness, where MC bodies are located, were measured.

RESULTS

Ten eyes of 10 patients were included. Best-corrected visual acuity improved at 3 months (P = 0.047) and remained stable. Inner nuclear layer thickness significantly reduced at 12 months (P = 0.012). Glial fibrillary acidic protein, Kir 4.1, and vascular endothelial growth factor decreased at 1 and/or 3 and/or 12 months compared with baseline (P < 0.05).

CONCLUSION

Subthreshold micropulse laser improves visual function in diabetic macular edema. Kir 4.1 and glial fibrillary acidic protein decrease and inner nuclear layer thickness reduction demonstrate that subthreshold micropulse laser may restore MC function. Subthreshold micropulse laser also reduces vascular endothelial growth factor concentration. The effect of subthreshold micropulse laser in diabetic macular edema may in part be due to changes of MC metabolic activity.

Real-life outcomes of subthreshold laser therapy for diabetic macular edema

BACKGROUND

Diabetic macular edema (DME) is a major cause of visual impairment and its treatment is a public health challenge. Even though anti-angiogenic drugs are the gold-standard treatment, they are not ideal and subthreshold laser (SL) remains a viable and promising therapy in selected cases. The aim of this study was to evaluate its efficacy in a real-life setting.

METHODS

Retrospective case series of 56 eyes of 36 patients with center-involving DME treated with SL monotherapy. Treatment was performed in a single session with the EasyRet® photocoagulator with the following parameters: 5% duty cycle, 200-ms pulse duration, 160-µm spot size and 50% power of the barely visible threshold. A high-density pattern was then applied to the whole edematous area, using multispot mode. Best corrected visual acuity (BCVA) and optical coherence tomography (OCT) data were obtained at baseline and around 3 months after treatment.

RESULTS

Fifty-six eyes of 36 patients were included (39% women, mean age 64.8 years old); mean time between treatment day and follow-up visit was 14 ± 6 weeks. BCVA (Snellen converted to logMAR) was 0.59 ± 0.32 and 0.43 ± 0.25 at baseline and follow-up, respectively (p = 0.002). Thirty-two percent had prior panretinal photocoagulation (p = 0.011). Mean laser power was 555 ± 150 mW and number of spots was 1,109 ± 580. Intraretinal and subretinal fluid (SRF) was seen in 96 and 41% of eyes at baseline and improved in 35 and 74% of those after treatment, respectively. Quantitative analysis of central macular thickness (CMT) change was performed in a subset of 23 eyes, 43% of which exhibited > 10% CMT reduction post-treatment.

CONCLUSIONS

Subthreshold laser therapy is known to have RPE function as its main target, modulating the activation of heat-shock proteins and normalizing cytokine expression. In the present study, the DME cases associated with SRF had the best anatomical response, while intraretinal edema responded poorly to laser monotherapy. BCVA and macular thickness exhibited a mild response, suggesting the need for combined treatment in most patients. Given the effect on SRF reabsorption, subthreshold laser therapy could be a viable treatment option in selected cases.

Comparison of short-pulse subthreshold (532 nm) and infrared micropulse (810 nm) macular laser for diabetic macular edema

The purpose of the study was to assess both anatomic and functional outcomes between short-pulse continuous wavelength and infrared micropulse lasers in the treatment of DME. This was a prospective interventional study from tertiary care eye hospital—King Khaled Eye Specialist Hospital (Riyadh, Saudi Arabia). Patients with center-involving diabetic macular edema were treated with subthreshold laser therapy. Patients in the micropulse group were treated with the 810-nm diode micropulse scanning laser TxCell (IRIDEX Corporation, Mountain View, CA, USA) (subthreshold micropulse—STMP group). Laser was applied according to recommendations for MicroPulse (125 microns spot size, 300 ms pulse duration and power adjustment following barely visible testing burn) in a confluent mode (low intensity/high density) to the entire area of the macular edema. Patients in the short-pulse group were treated with grid pattern laser with 20 ms pulse PASCAL laser 532 nm (TopCon Medical Laser Systems, Tokyo, Japan) with EndPoint algorithm, which was either 30% or 50% of testing burn (EndPoint 30% and EndPoint 50% groups, respectively). Main outcome measures included best-corrected visual acuity (BCVA in logMAR) and foveal thickness at baseline and the last follow-up visit at 6 months. There were 44 eyes in the micropulse group, 54 eyes in the EndPoint 50% group and 18 eyes in the EndPoint 30% group. BCVA for the whole cohort (logMAR) was 0.451 (Snellen equivalent 20/56) at baseline, 0.495 (Snellen equivalent 20/62) (p = 0.053) at 3 months, and 0.494 (Snellen equivalent 20/62) at the last follow-up (p = 0.052). Foveal thickness for the whole cohort was 378.2 ± 51.7 microns at baseline, 347.2 ± 61.3 microns (p = 0.002) at 3 months, and 346.0 ± 24.6 microns at the final follow-up (p = 0.027). As such the short-pulse system yields more temporary reduction in edema. Comparison of BCVA between baseline and 6 months for EndPoint 30%, EndPoint 50% and STMP groups was p = 0.88, p = 0.76 and p = 0.003, respectively. Comparison of foveal thickness between baseline and 6 months for EndPoint 30%, EndPoint 50% and STMP groups was p = 0.38, p = 0.22 and p = 0.14, respectively. We conclude that the infrared micropulse system seems to improve functional outcomes. When applied according to previously published reports, short-pulse system may yield more temporary reduction in edema while infrared micropulse system may yield slightly better functional outcomes.

Subthreshold Micropulse Laser in Diabetic Macular Edema: 1-Year Improvement in OCT/OCT-Angiography Biomarkers

Purpose

The aim of this study was to evaluate 1-year quantitative changes in specific inflammatory parameters on optical coherence tomography (OCT) / optical coherence tomography angiography (OCTA) in diabetic macular edema (DME) treated with subthreshold micropulse laser (SMPL).

Methods

Thirty-seven patients / eyes with previously treatment-naïve DME treated with SMPL were prospectively evaluated at 3, 6, and 12 months. Fifteen fellow eyes with only microaneurysms (MAS) not eligible for treatment were controls. Evaluated OCT / OCTA parameters included: central macular thickness (CMT); hyper-reflective retinal spots (HRS); disorganization of inner retinal layers (DRILs); MA in the superficial / deep capillary plexuses (SCP/DCP); cysts in the area at the SCP / DCP; and macular perfusion parameters (MATLAB, version 2017b).

Results

In the treated group, mean best corrected visual acuity (BCVA) progressively increased from 69.4 ± 12.0 to 76.0 ± 9.1 Early Treatment Diabetic Retinopathy Study (ETDRS) letters (P < 0.001) at 12 months; HRS decreased from baseline (80.75 ± 20.41) at 3 (73.81 ± 17.1, P = 0.002), 6 (69.16 ± 16.48, P < 0.0001), and 12 months (66.29 ± 18.53, P < 0.0001). MA decreased at 3 months in the DCP (P = 0.015), at 6 and 12 months in both plexuses (P ≤ 0.0007). BCVA, HRS, and MA remained stable in the controls during all follow-ups. DRIL was present in 18 of 37 patients at baseline and progressively decreased from 557.0 ± 238.7 to 387.1 ± 282.1 μm (P = 0.01). The area of cyst decreased both in the SCP (P = 0.03) and the DCP (P = 0.02). CMT and perfusion parameters did not change.

Conclusions

SMPL reduced the number of HRS (sign of activated microglia cells in the retina), MA, DRIL extension, and the area of cysts. Further studies are needed to confirm these preliminary data on the anti-inflammatory effect of SMPL, and to explore the mechanism of action.

Translational Relevance

The follow-up of OCT/OCTA noninvasive biomarkers offers a unique insight in the mechanism of laser action, suggesting an anti-inflammatory effect of SMPL.

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

Purpose

To 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.

Methods

A 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.

Results

All 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.

Conclusion

Low-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.

Comparison of Subthreshold 577 and 810 nm Micropulse Laser Effects on Heat-Shock Protein Activation Kinetics: Implications for Treatment Efficacy and Safety

Purpose

To compare the safety and efficacy of 810 versus 577 nm laser wavelengths for micropulse subthreshold (sublethal) laser treatment by mathematical analysis.

Methods

Two different representative laser parameter sets for micropulsed subthreshold diode laser treatment, one employing 810 nm and the other 577 nm, are compared with regard to efficacy by analysis of the kinetics of laser-induced heat-shock protein (HSP) activation; and for safety, by scaling law analysis.

Results

Kinetics analysis of laser-induced HSP activation shows that the primary therapeutic effect of laser is thermal incitement of a long-term wavelength-independent increase in the rate of HSP-mediated protein repair specific to sick and dysfunctional cells, rather than from short-term increases in free intracellular HSP concentrations. Scaling law analysis of the same 810 and 577 nm laser parameters, however, finds treatment safety highly wavelength-sensitive, favoring 810 over 577 nm.

Conclusions

Mathematical analyses of the effects retinal laser-induced HSP activation provide important insights into the mechanism of action and the importance of wavelength selection in modern retinal laser therapy. Our analyses find 810 and 577 nm to be equally effective, but 810 nm having a significantly wider therapeutic range/safety margin, and thus less likely to cause inadvertent, and thus unpredictable, laser-induced retinal damage, than 577 nm.

Translational Relevance

Mathematical analysis of enzyme reaction kinetics provides important insights into the mechanism of action and clinical implications of wavelength selection in modern retinal laser therapy.

Subthreshold yellow micropulse laser for treatment of diabetic macular edema: Comparison between fixed and variable treatment regimen

PURPOSE

To compare the efficacy between fixed and variable treatment regimens of subthreshold yellow micropulse laser for the treatment of diabetic macular edema.

METHODS

This is a retrospective, comparative, 12-month study of 39 eyes: 24 eyes received fixed treatment regimen of subthreshold micropulse laser treatment and 15 eyes underwent variable treatment regimen of subthreshold micropulse laser, all eyes were followed up for 12 months. Subthreshold micropulse laser was performed with the following parameters: 100 μm spot size on slit lamp, 5% duty cycle of 0.2 s, and 250 mW power. To choose the power of the variable treatment regimen of subthreshold micropulse laser group, continuous laser power was titrated to a barely visible burn and then switched to MicroPulse mode, multiplying the test burn power by 4 and using a 5% duty cycle of 0.2 s. Main outcomes included changes in central macular thickness and best-corrected visual acuity.

RESULTS

At baseline, the mean LogMAR best-corrected visual acuity was 0.297 ± 0.431 in the variable treatment regimen of subthreshold micropulse laser group and 0.228 ± 0.341 in the fixed treatment regimen of subthreshold micropulse laser group. At the end of follow-up, the mean LogMAR best-corrected visual acuity was 0.289 ± 0.473 (p = 0.785) and 0.245 ± 0.376 (p = 0.480) in the variable and fixed treatment regimens of subthreshold micropulse laser groups, respectively. Similarly, central macular thickness decreased in both groups after treatment; at baseline, the mean central macular thickness was 371.06 ± 37.8 in the variable treatment regimen of subthreshold micropulse laser group and improved to 325.60 ± 110.0 μm (p = 0.025) at the end of the follow-ups, while it was 342.30 ± 35.4 in the fixed treatment regimen of subthreshold micropulse laser group and improved to 308.51 ± 67.5 (p = 0.037).

CONCLUSION

Both treatment regimens are effective for the treatment of mild center-involving diabetic macular edema: fixed treatment appears more suitable minimizing treatment time and reducing the possible errors due to wrong titration in the switch from continuous to micropulse mode.

Macular laser photocoagulation in the management of diabetic macular edema: Still relevant in 2020?

Macular laser photocoagulation (MLP) is inferior to intravitreal vascular endothelial growth factor (VEGF) inhibitors in the treatment of center-involved diabetic macular edema (DME). Ultra-widefield fluorescein angiography-guided laser photocoagulation to presumed ischemic areas of the peripheral retina or MLP do not reduce the treatment burden nor improve the visual outcomes of eyes treated with anti-VEGF drugs. Destruction of retinal tissue is not necessary to induce a therapeutic response in DME. Modern lasers are capable of producing invisible laser "burns" that do not destroy the targeted tissue using micropulse subthreshold (ST) mode where the laser's duty cycle is modified or alternatively selective retinal therapy (SRT) where ultrashort pulses of continuous wave laser selectively target the RPE. The best results with micropulse ST laser are obtained in eyes with a central macular thickness ≤400 μm. Eyes need to be treated in a continuous manner with no spaces between burns in the edematous area. Micropulse ST-MLP downregulates inflammatory biomarkers produced by activated microglial cells and Müller cells. Micropulse ST-MLP may reduce the anti-VEGF injection burden in DME. In SRT, the diseased RPE is targeted and heated with the laser with the hope that the adjacent RPE migrates and proliferates into these areas to heal the diseased RPE. There is much less experience with SRT, but the results are promising and deserve further study.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY CHANGES AFTER SUBTHRESHOLD MICROPULSE YELLOW LASER IN DIABETIC MACULAR EDEMA

PURPOSE

To assess changes on optical coherence tomography (OCT) angiography in diabetic macular edema (DME) treated with subthreshold micropulse yellow laser (SMPL) over a period of 6 months.

METHODS

Thirty-five eyes (35 consecutive patients) with treatment-naive DME prospectively underwent (at baseline, 3 and 6 months) best-corrected visual acuity, swept-source OCT angiography/OCT, and fundus autofluorescence. Following parameters were evaluated on OCT angiography in the superficial capillary plexus (SCP) and deep capillary plexus (DCP): the area of foveal avascular zone, number of microaneurysms (MA), area of cysts, and presence of capillary network alterations. Microaneurysm change was also evaluated in 15 fellow eyes, not needing treatment over 6 months. Vessel and perfusion densities were evaluated in the SCP, DCP, and choriocapillaris, with image J. Retina thickness, number of hyperreflective retinal spots, and external limiting membrane integrity were evaluated on OCT. All measurements were performed by two masked graders, independently.

RESULTS

All patients had diabetes mellitus Type 2 (mean age, 69.4 ± 10.9 years; duration of diabetes mellitus, 15.7 ± 8.7 years; and HbA1c 7.7 ± 1.2%). Mean best-corrected visual acuity at baseline was 69.7 ± 12.0 letters ETDRS, 72.7 ± 10.7 at 3 months (gain 3.1 ± 4.3, P = 0.0049) and 74.3 ± 9.5 at 6 months (gain 4.6 ± 7.2, P < 0.0001). Foveal avascular zone area decreased in the DCP at 6 months (P = 0.01). Area of cysts decreased in the SCP at 3 months and 6 months (P = 0.038; P = 0.049), and in the DCP at 6 months (P = 0.0071). Number of MA decreased at 6 months in the SCP (P = 0.0007) and at 3 months and 6 months in the DCP (P = 0.048; P < 0.0001) in treated eyes. No significant change in number of MA was found in nontreated eyes. There was no statistically significant change in any other OCT angiography/OCT parameter.

CONCLUSION

Subthreshold micropulse yellow laser induces more pronounced changes in the DCP than in the SCP in DME. These changes occurred as early as 3 months after treatment. The evaluation of specific parameters in the DCP may help in determining treatment response.

Aflibercept plus micropulse laser versus aflibercept monotherapy for diabetic macular edema: 1-year results of a randomized clinical trial

PURPOSE

To evaluate the role of adjuvant micropulse laser with aflibercept injections in the management of treatment naive center involving DME, looking at decreased treatment burden and increased efficacy as outcomes after 1 year.

METHODS

This was a prospective, single center, randomized trial that included 40 eyes (40 patients) with previously untreated center involved DME. Patients were randomly assigned to receive either aflibercept plus micropulse laser (group A) or aflibercept monotherapy (group B).

RESULTS

Overall, 40 patients were included in the study; they were randomized into either group A (aflibercept + micropulse; 20 patients) or group B (aflibercept monotherapy; 20 patients). The mean number of injections after the loading dose was 4.5 ± 1.4 in group A and was 5.4 ± 1.7 in group B, and the difference between both groups was statistically significant (P = 0.029).

CONCLUSION

Adding 577-nm micropulse laser to aflibercept is effective for treatment naïve DME and is associated with decreased number of injections.

Emerging Concepts in the Treatment of Diabetic Retinopathy

PURPOSE OF REVIEW

Diabetic retinopathy (DR) is the leading cause of vision loss in working-age adults in the developed world. This review discusses the current approach to managing the disease, such as glycemic and blood pressure control, as well as laser photocoagulation, as well as emerging concepts and controversies on novel therapies.

RECENT FINDINGS

In recent years, the rise of intraocular anti-angiogenesis treatments is changing the paradigm of classic laser photocoagulation in the management of DR, but its long-term benefits remain an area of controversy. We also discuss new targets including anti-inflammation, neuroprotection, and novel laser technologies. Finally, we discuss new advances in retinal imaging that has vastly improved the diagnosis and management of DR. Diagnosis and management of diabetic retinopathy is a rapidly progressing field. Emerging concepts in ophthalmic imaging, medical treatments, and surgical approaches provide insights into how DR management will evolve in the near future.

Real-world management and long-term outcomes of diabetic macular oedema with good visual acuity

PURPOSE

To evaluate the management and long-term outcomes of patients with diabetic macular oedema (DMO) and good initial visual acuity in real-world settings.

METHODS

We reviewed 122 eyes of 100 patients with treatment-naive DMO and initial best-corrected visual acuity (BCVA) of 20/25 or better. We assessed clinical characteristics, logMAR BCVA, central subfield thickness (CST), cumulative intravitreal injections and laser treatments at yearly intervals, and characteristics at time of initial treatment. Linear mixed effects models were used to identify predictors of visual outcomes.

RESULTS

At presentation, mean BCVA was 0.057 ± 0.048 logMAR (Snellen 20/23) and mean CST was 288 ± 57 μm. After a median follow-up of 3 years, 51% of eyes underwent treatment. More eyes underwent intravitreal injection as initial treatment (54%), but lasers were initiated at an earlier time and at better BCVA. Final BCVA was associated with better BCVA (P < 0.001) and earlier timing (P = 0.017) at initial treatment, but not CST at first treatment (P = 0.634) or cumulative number of injections or lasers (P = 0.441-0.606).

CONCLUSION

DMO with good initial visual acuity should be monitored closely, as delay in treatment initiation is associated with worse visual outcomes. BCVA at time of initial treatment is the strongest determinant of final visual acuity.

Single Retinal Layer Changes After Subthreshold Micropulse Yellow Laser in Diabetic Macular Edema

A pilot prospective, interventional study has been conducted on 10 patients with diabetic macular edema (DME) treated with subthreshold micropulse laser (SMPL) to evaluate changes of individual retinal layers and to correlate with functional changes. All patients underwent complete ophthalmologic evaluation including spectral-domain optical coherence tomography (OCT) and microperimetry at baseline, 3 months, 6 months, 9 months, and 12 months. Compared with baseline, a significant decrease was found in inner nuclear layer (INL) and outer retinal layer (ORL) thickness in the central 1 mm (P < .05). Increase in best-corrected visual acuity was significantly and inversely correlated to central retinal thickness (CRT) (P = .0027), INL (P = .0167), and outer nuclear layer (ONL) thickness (P = .0107). Increase in retinal sensitivity was significantly and inversely correlated to CRT and ONL thickness (P < .01). Therefore, SMPL showed to improve firstly functional parameters and then morphologic parameters. Functional parameters were inversely correlated to CRT, INL, and ONL thickness. The exact mechanism of reduction of INL thickness induced by SMPL remains to be further evaluated. [Ophthalmic Surg Lasers Imaging Retina. 2018;49:e218-e225.].

Sub-threshold nanosecond laser (SNL) treatment in intermediate AMD (IAMD)

The Laser intervention in early stages of age-related macular degeneration (LEAD) study (1) is a 36-month, multicenter, randomized, sham-controlled trial conducted from 2012-2015 of 292 participants with bilateral soft drusen, aka intermediate AMD (iAMD), who underwent q 6-month treatment with sub-threshold nanosecond laser (SNL) or sham treatment to the study eye. The primary efficacy outcome was the time to develop late AMD [geographic atrophy (GA) or choroidal neovascularization (CNV)] defined by multimodal imaging (MMI), which comprised spectral domain optical coherence tomography (SD-OCT), autofluorescence imaging (AF) and near-infrared reflectance imaging (NIR-R). Although progression to late AMD was not significantly slowed with SNL compared to sham for the entire group, posthoc analysis showed a significant benefit to those subjects without reticular pseudodrusen (RPD), and a worse outcome for those subjects with RPD, aka subretinal drusenoid deposits (SDD). SNL treatment may thus have a role in slowing progression for subjects without coexistent RPD/SDD and may be inappropriate in those with RPD/SDD. Further study is clearly warranted.

Application of subthreshold laser therapy in retinal diseases: a review

Introduction

Laser photocoagulation has been a valuable tool in the ophthalmologist's armamentarium for decades. Conventional laser photocoagulation relies on visible retinal burns as a treatment endpoint, which is thought to result in photocoagulative necrosis of retinal tissue. Recent studies have suggested that using subthreshold (ST) laser, which does not cause detectable damage to the retina may also have therapeutic effects in a variety of retinal diseases. Areas covered: We review the proposed biological mechanisms mediating the therapeutic effects of subthreshold laser on the retina, followed by the evidence for ST laser efficacy in retinal diseases such as diabetic macular edema, central serous chorioretinopathy, age-related macular degeneration, and retinal vein occlusion.

Expert Commentary

Multiple clinical studies demonstrate that subthreshold laser does not cause structural damage to the retina based on multimodal imaging. Evidence suggests that there is a therapeutic effect on decreasing diabetic macular edema and subretinal fluid in chronic central serous retinopathy; however, the effect may be relatively modest and is not as efficacious as first line treatments for these diseases. Given the repeatability and lack of damage to the retina by this treatment, subthreshold laser deserves further study to determine its place in the retina specialist's armamentarium.

Monotherapy laser photocoagulation for diabetic macular oedema

BACKGROUND

Diabetic macular oedema (DMO) is a complication of diabetic retinopathy and one of the most common causes of visual impairment in people with diabetes. Clinically significant macular oedema (CSMO) is the most severe form of DMO. Intravitreal antiangiogenic therapy is now the standard treatment for DMO involving the centre of the macula, but laser photocoagulation is still used in milder or non-central DMO.

OBJECTIVES

To access the efficacy and safety of laser photocoagulation as monotherapy in the treatment of diabetic macular oedema.

SEARCH METHODS

We searched CENTRAL, which contains the Cochrane Eyes and Vision Trials Register; MEDLINE; Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and the WHO ICTRP. The date of the search was 24 July 2018.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing any type of focal/grid macular laser photocoagulation versus another type or technique of laser treatment and no intervention. We did not compare laser versus other interventions as these are covered by other Cochrane Reviews.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. Our primary outcomes were gain or loss of 3 lines (0.3 logMAR or 15 ETDRS letters) of best-corrected visual acuity (BCVA) at one year of follow-up (plus or minus six months) after treatment initiation. Secondary outcomes included final or mean change in BCVA, resolution of macular oedema, central retinal thickness, quality of life and adverse events, all at one year. We graded the certainty of the evidence for each outcome using the GRADE approach.

MAIN RESULTS

We identified 24 studies (4422 eyes). The trials were conducted in Europe (nine studies), USA (seven), Asia (four) and, Africa (one), Latin America (one), Europe-Asian (one) and Oceania (one). The methodological quality of the studies was difficult to assess as they were poorly reported, so the predominant classification of bias was unclear.At one year, people with DMO receiving laser were less likely to lose BCVA compared with no intervention (risk ratio (RR) 0.42, 95% confidence interval (CI) 0.20 to 0.90; 3703 eyes; 4 studies; I² = 71%; moderate-certainty evidence). There were also favourable effects observed at two and three years. One study (350 eyes) reported on partial or complete resolution of clinically significant DMO and found moderate-certainty evidence of a benefit at three years with photocoagulation (RR 1.55, 95% CI 1.30 to 1.86). Data on visual improvement, final BCVA, central macular thickness and quality of life were not available. One study related minor adverse effects on the central visual field and another reported one case of iatrogenic premacular fibrosis.Nine studies compared subthreshold versus standard macular photocoagulation (517 eyes). Subthreshold treatment was achieved with different methods of photocoagulation: non-visible conventional (two studies), micropulse (four) or nanopulse (one).Only one small study (29 eyes) reported on improvement or worsening of BCVA and estimates were very imprecise (improvement: RR 0.31, 95% CI 0.01 to 7.09; worsening: RR 0.93, 95% CI 0.15 to 5.76; very low-certainty evidence). All studies reported on continuous BCVA at one year; there was low-certainty evidence of no important difference between subthreshold and standard photocoagulation (mean difference (MD) in logMAR BCVA -0.02, 95% CI -0.07 to 0.03; 385 eyes; 7 studies; I² = 42%), and were possibly different for different techniques (P = 0.07 and I² = 61.5% for subgroup heterogeneity), with better results achieved with micropulse photocoagulation (MD -0.08 logMAR, 95% CI -0.16 to 0.0) as compared to the results achieved with nanopulse (MD 0.0 logMAR, 95% CI -0.06 to 0.06) and non-visible conventional (MD 0.04 logMAR, 95% CI -0.03 to 0.11), all of them compared to the standard lasers. One study reported partial to complete resolution of macular oedema at one year. There was low-certainty evidence of some benefit with standard photocoagulation, but estimates of effect were imprecise (RR 0.47, 95% CI 0.21 to 1.03; 29 eyes; 1 study). Studies also reported on the change in central macular thickness at one year and found moderate-certainty evidence of no important difference between subthreshold and standard photocoagulation (MD -9.1 μm, 95% CI -26.2 to 8.0; 385 eyes; 7 studies; I² = 0%). There were no important adverse effects recorded in the studies.Nine studies compared argon laser versus another type of laser (997 eyes). There was moderate-certainty evidence of a small reduction or no difference between the interventions, with respect to improvement (RR 0.87, 95% CI 0.62 to 1.22; 773 eyes; 6 studies) and worsening of BCVA (RR 0.83, 95% CI 0.57 to 1.21; 773 eyes; 6 studies). Three studies reported few cases of subretinal fibrosis and neovascularization with argon laser and one study found subretinal fibrosis in the krypton group.One study (323 eyes) compared the modified ETDRS (mETDRS) grid technique with the mild macular grid (MMG), which uses mild, widely spaced burns throughout the macula. There was low-certainty evidence of an increased chance of visual improvement with MMG, but the estimate was imprecisely measured and the CIs include an increased risk or decreased risk of visual improvement at one year (RR 1.43, 95% CI 0.56 to 3.65; visual worsening: RR 1.40, 95% CI 0.64 to 3.05; change of logMAR visual acuity: MD -0.04 logMAR, 95% CI -0.01 to 0.09). There was a more significant reduction of central macular thickness with the mETDRS compared to the MMG technique (MD -34.0 µm, -59.8 to -8.3) in the MMG group. The study did not record important adverse effects.

AUTHORS' CONCLUSIONS

Laser photocoagulation reduces the chances of visual loss and increases those of partial to complete resolution of DMO compared to no intervention at one to three years. Subthreshold photocoagulation, particularly the micropulse technique, may be as effective as standard photocoagulation and RCTs are ongoing to assess whether this minimally invasive technique is preferable to treat milder or non-central cases of DMO.

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

Purpose

To determine the incidence of new choroidal neovascularization (CNV) in eyes with dry age-related macular degeneration (AMD) following subthreshold diode micropulse laser (SDM).

Method

In 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.

Results

The 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.

Summary

In 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.

Subthreshold micropulse laser reduces anti-VEGF injection burden in patients with diabetic macular edema

PURPOSE

To evaluate the efficacy of micropulse laser in the early treatment of diabetic macular edema (DME) and its associated burden of anti-vascular endothelial growth factor (VEGF) injections.

METHODS

This retrospective comparative study compared a group of 19 eyes with DME treated with micropulse laser to a matched control group of 19 eyes with DME treated with ranibizumab injections without micropulse laser. Recorded parameters included previous medical and ocular history, previous and subsequent ranibizumab injections administered for DME, visual acuity (VA), central macular thickness throughout the follow-up period, and the occurrence of any complications.

RESULTS

The improvement in VA was comparable in both groups, at 12 months and at the final follow-up. Patients treated with micropulse laser required significantly fewer ranibizumab injections than their controls, both at 12 months (1.7 ± 2.3 vs 5.6 ± 2.1) and by the end of the follow-up (2.6 ± 3.3 vs 9.3 ± 5.1) (p<0.001 for both). No complications related to the micropulse laser were encountered.

CONCLUSIONS

Micropulse laser is a safe and effective treatment for DME, which may achieve comparable improvement in VA along with a significant reduction in the burden of anti-VEGF injections. We suggest a treatment approach for its inclusion in the early stages of DME.

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

Objectives

To examine the effect of subthreshold diode micropulse laser (SDM) on pattern electroretinography (PERG) and visual function in retinitis pigmentosa (RP).

Methods

The 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.

Results

All 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.

Conclusions

SDM 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.

Subthreshold Photocoagulation Using Endpoint Management in the PASCAL® System for Diffuse Diabetic Macular Edema

We evaluated subthreshold photocoagulation using endpoint management (EPM) for the treatment of diabetic macular edema (DME). The study enrolled 10 eyes from 10 patients (6 men and 4 women) with DME. The entry criteria included central macular thickness (CMT) ≥ 300 μm and decimal visual acuity (VA) ≤ 0.5. The primary endpoints were VA (logMAR) and CMT at 6 months follow-up. Secondary endpoints included fundus autofluorescence, macular volume (MV), and macular sensitivity (MS). We used the PASCAL Streamline Yellow® (wavelength, 577 nm) system to perform grid pattern laser photocoagulation at 50% of the threshold (size, 100 μm; duration, 0.015 s; spacing, 0.5; and energy, 4.5-7.8 mJ). At 6 months posttreatment, CMT was significantly decreased, while there were no significant changes in macular sensitivity, mean BCVA (logMAR), or macular volume. Autofluorescence imaging revealed no changes after treatment in 6 of 10 eyes. No eyes exhibited subjective symptoms of scotoma after photocoagulation. Optical coherence tomography showed the complete resolution of macular edema in 4 eyes (40%) after a single treatment; MS was increased in all 4 of these eyes at 6 months posttreatment. In conclusion, subthreshold photocoagulation using EPM is safe and effective for DME treatment and preserves MS. This trial is registered with UMIN000012401.

Recent advances in the management and understanding of diabetic retinopathy

Despite recent advances in the diagnosis and treatment of diabetic retinopathy, this complication remains a steadfast challenge to patients and physicians. This review summarizes recent progress in the diagnosis and management of diabetic retinopathy, including automated screening, optical coherence tomography, control of systemic risk factors, surgical techniques, laser treatment, and pharmaceutical treatment, including vascular endothelial growth factor inhibitors. Recent advances in pharmaceutical treatments, in particular, hold strong promise of halting and sometimes reversing the disease process. Clinicians nevertheless must remain vigilant in their efforts to diagnose and treat this disease early in its course.

Panretinal Photocoagulation: A Review of Complications

Panretinal photocoagulation (PRP) is a mainstay of therapy for retinal ischemic disease. The procedure involves creating thermal burns in the peripheral retina leading to tissue coagulation, the overall consequence of which is improved retinal oxygenation. While highly effective, there have been concerns historically regarding the anatomic effects and visual complications following PRP, the most common of which include choroidal effusions, exudative retinal detachments, macular edema, visual field deficits, and night vision defects. The occurrence of these complications is closely tied to laser parameters such as increased duration and power and intensive treatment in a single sitting, all of which cause increased dispersion of thermal energy within the retina and choroid. The advent of newer laser delivery systems, such as the multispot pattern laser, has greatly mitigated but not eliminated these issues. The following article reviews the most common complications following PRP treatment, including reported occurrences, inciting factors, and underlying pathophysiology.

A Review of Subthreshold Micropulse Laser for Treatment of Macular Disorders

Micropulse laser treatment is an alternative to the conventional continuous-wave laser for the treatment of retinal or macular diseases. In contrast to the conventional laser, the therapeutic effect of the subthreshold micropulse laser is not accompanied by thermal retinal damage. This fact is of particular importance when a treatment near the fovea is required. Micropulse treatment is applied in indications such as central serous chorioretinopathy (CSC), diabetic macular edema (DME), or macular edema due to retinal vein occlusion (RVO). This review outlines and discusses the published literature of subthreshold micropulse laser treatment for CSC, DME, and macular edema after RVO.