Comparison of photodynamic therapy and navigated microsecond laser for chronic central serous chorioretinopathy

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.

Central serous chorioretinopathy: An evidence-based treatment guideline

Central serous chorioretinopathy (CSC) is a relatively common disease that causes vision loss due to macular subretinal fluid leakage and it is often associated with reduced vision-related quality of life. In CSC, the leakage of subretinal fluid through defects in the retinal pigment epithelial layer's outer blood-retina barrier appears to occur secondary to choroidal abnormalities and dysfunction. The treatment of CSC is currently the subject of controversy, although recent data obtained from several large randomized controlled trials provide a wealth of new information that can be used to establish a treatment algorithm. Here, we provide a comprehensive overview of our current understanding regarding the pathogenesis of CSC, current therapeutic strategies, and an evidence-based treatment guideline for CSC. In acute CSC, treatment can often be deferred for up to 3-4 months after diagnosis; however, early treatment with either half-dose or half-fluence photodynamic therapy (PDT) with the photosensitive dye verteporfin may be beneficial in selected cases. In chronic CSC, half-dose or half-fluence PDT, which targets the abnormal choroid, should be considered the preferred treatment. If PDT is unavailable, chronic CSC with focal, non-central leakage on angiography may be treated using conventional laser photocoagulation. CSC with concurrent macular neovascularization should be treated with half-dose/half-fluence PDT and/or intravitreal injections of an anti-vascular endothelial growth factor compound. Given the current shortage of verteporfin and the paucity of evidence supporting the efficacy of other treatment options, future studies-ideally, well-designed randomized controlled trials-are needed in order to evaluate new treatment options for CSC.

Comparing Half-Dose Photodynamic Therapy with Subthreshold Micropulse Laser for the Treatment of Central Serous Chorioretinopathy

PURPOSE

To compare the anatomic and functional outcomes of half-dose photodynamic therapy (PDT) and yellow 577-nm subthreshold micropulse laser (SMLT) in treating patients with chronic central serous chorioretinopathy (CSCR).

DESIGN

Prospective, double-masked, randomized, controlled clinical trial.

PARTICIPANTS

Patients with chronic CSCR confirmed by clinical features and multimodal imaging.

METHODS

Eligible patients were randomized (1:1) to receive half-dose PDT or SMLT. The same treatment was repeated if persistent subretinal fluid (SRF) was observed. Treatment responses were evaluated 1 month after treatment and every 3 months until the end point at 12 months.

MAIN OUTCOME MEASURES

The primary outcome measure was the complete resolution of SRF on OCT scan at month 12. Secondary outcomes included the changes in best-corrected visual acuity (BCVA), central macular thickness (CMT) as measured by OCT, retinal sensitivity as measured by microperimetry, and vision-related quality of life using the National Eye Institute 25-Item Visual Function Questionnaire.

RESULTS

Between April 2017 and October 2020, 68 patients were recruited. At 1 month after treatment, SRF resolved in 8 (24.2%) of 33 patients receiving SMLT and in 20 (58.8%) of 34 patients receiving half-dose PDT. This increased to 23 (82.1%) of 28 patients in the SMLT group and 30 (90.9%) of 33 patients in the half-dose PDT group at 12 months of follow-up. Kaplan-Meier survival curves showed significantly faster resolution of SRF in the half-dose PDT group than the SMLT group (P = 0.016). Both groups showed significant improvement in BCVA (-0.12 ± 0.21, P = 0.005 for SMLT; -0.13 ± 0.12, P < 0.001 for half-dose PDT), CMT (-154.2 ± 105.6, P < 0.001 for SMLT; -140.8 ± 94.0, P < 0.001 for half-dose PDT), and retinal sensitivity (5.70 ± 5.02, P < 0.001 for SMLT; 6.05 ± 3.83, P < 0.001 for half-dose PDT) at 12 months compared with baseline. There was no significant difference between the 2 treatment groups at each time point in all investigations except BCVA at 3 months (P = 0.03).

CONCLUSIONS

When comparing half-dose PDT to subthreshold SMLT, this study has shown both treatments to be viable options, with half-dose PDT achieving faster anatomic success and functional improvement.

FINANCIAL DISCLOSURE(S)

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

Yellow Subthreshold Micropulse Laser in Retinal Diseases: An In-Depth Analysis and Review of the Literature

Yellow subthreshold micropulse laser (YSML) is a retinal laser capable of inducing a biologic response without causing thermal damage to the targeted tissue. The 577-nm YSML is delivered to the retina abiding by different protocols in which wavelength, power, duration, spot size and number of spots can be properly set to achieve the most effective and safe treatment response in various chorioretinal disorders. The ultrashort trains of power modulate the activation of the retinal pigment epithelium cells and intraretinal cells, such as Müller cells, causing no visible retinal scars. Subthreshold energy delivered by YSML stimulates the production of the heat-shock proteins, highly conserved molecules that protect cells against any sort of stress by blocking apoptotic and inflammatory pathways that cause cell damage. YSML treatment allows resorption of the subretinal fluid in central serous chorioretinopathy and intraretinal fluid in various conditions including diabetic macular edema, postoperative cystoid macular edema and other miscellaneous conditions. YSML also seems to modulate the development and progression of reticular pseudodrusen in dry age-related macular degeneration. The aim of this review is to discuss and summarize the safety and efficacy of YSML treatment in retinal diseases.

577 nm subthreshold micropulse laser treatment for acute central serous chorioretinopathy: a comparative study

BACKGROUND

To assess the efficacy of 577 nm subthreshold micropulse laser (SML) treatment for acute central serous chorioretinopathy (CSC).

METHODS

This retrospective comparative case-series included 34 eyes of 34 patients with acute CSC who received either 577 nm SML treatment (SML group, n = 16 eyes) or were only monitored (observation group, n = 18 eyes). Acute CSC was defined as disease course < 3 months. Eyes with any history of treatment in the past were excluded. Data were collected over a period of 6 months. The best corrected visual acuity (BCVA), central macular thickness (CMT), and subfoveal choroidal thickness (SFCT) were observed.

RESULTS

SML group showed significantly greater improvement in the BCVA (logMAR) compared to observation group at 1 month (0.20 ± 0.10 vs 0.30 ± 0.12, P < 0.01), 3 months (0.13 ± 0.06 vs 0.21 ± 0.06, P < 0.01) and 6 months (0.01 ± 0.06 vs 0.09 ± 0.66, P < 0.01). The CMT reduction was significantly greater in the SML group at 1 month (337.19 ± 62.96 µm vs 395.11 ± 91.30 µm, P < 0.05), 3 months (312.94 ± 49.50 µm vs 364.50 ± 70.30 µm, P < 0.05) and 6 months (291.38 ± 26.46 µm vs 348.56 ± 54.65 µm, P < 0.05). In the SML group, the SFCT did not show a significant decrease at 1 month (468.88 ± 42.19 µm, P > 0.05) but showed a significant reduction at 3 months (451.75 ± 39.36 µm, P < 0.05) and 6 months (450.50 ± 34.24 µm, P < 0.05) from baseline (489.94 ± 45.86 µm). In the observation group, there was no significant change in SFCF during follow-up. No adverse events occurred in the SML group.

CONCLUSIONS

Although some patients with acute CSC show spontaneous healing, timely intervention with 577 nm SML can shorten the disease course, improve visual acuity, and reduce the risk of chronic transformation without adverse events.

Navigated micropulse laser for central serous chorioretinopathy: Efficacy, safety, and predictive factors of treatment response

PURPOSE

There is no widely accepted treatment for persistent/chronic central serous chorioretinopathy. The present study aimed to evaluate the efficacy, safety, and factors associated to treatment response to navigated micropulse laser in chorioretinopathy.

METHODS

Retrospective observational case series including consecutive patients presenting with symptomatic persistent and chronic chorioretinopathy. All patients were treated with 5% navigated micropulse laser with the Navilas system (Navilas®, OD-OS GmBH, Teltwo, Germany), by overlying fluorescein angiography, indocyanine green angiography and/or spectral domain-optical coherence tomography images of visible leaking points and/or choroidal hyperpermeability/subretinal fluid to plan the laser treatment.

RESULTS

Thirty-nine eyes of 36 consecutive patients (29 men and 7 women, with a mean age of 51.87 years) were included. Logarithm of the minimum angle of resolution (LogMar) best-corrected visual acuity increased from 0.39 ± 0.24 at baseline to 0.24 ± 0.22 at 3 months (p < 0.0001) and to 0.20 ± 0.07 at 6 months (p < 0.0001). Subretinal fluid decreased from 166.82 ± 111.11 micron at baseline to 52.33 ± 78.97 micron (p < 0.0001) at 3 months and 34.12 ± 67.56 micron at 6 months (p < 0.0001). The presence of a hot spot on fluorescein angiography and a focal choroidal hyperpermeability on indocyanine green angiography, but not the duration of symptoms correlated significantly with the resolution of subretinal fluid at month 3 (p = 0.023 and p = 0.001).

CONCLUSION

Navigated micropulse laser laser treatment was found to be effective and safe for the treatment of chorioretinopathy, with significant improvement in visual and anatomical outcomes, unaccompanied by any adverse event at 3 and 6 months follow-up. Factors associated to subretinal fluid resolution may allow a better selection of likely responders to navigated micropulse laser treatment.

Clinical Evaluation of Individualized and Navigated Microsecond Pulsing Laser for Acute Central Serous Chorioretinopathy

BACKGROUND AND OBJECTIVE

A computational model has predicted parameters for using a navigated microsecond pulsing laser system to treat central serous chorioretinopathy (CSC).

PATIENTS AND METHODS

A prospective, single-center, interventional case series was conducted for patients with acute CSC who were enrolled following screening and informed consent. Treatment involved laser pulse duration of 50 μs, 2.4% Duty Cycle, 100 μm spot size, and 10 ms pulse duration.

RESULTS

Average best-corrected visual acuity (decimal) of 12 patients improved from 0.86 ± 0.03 at baseline to 0.97 ± 0.01 at 3 months. Baseline central retinal thickness decreased from 452.58 μm ± 24.53 μm at baseline to 249.25 μm ± 2.92 μm at 3 months. Retinal sensitivity improved from 24.1 dB ± 1.09 dB at baseline to 28.98 dB ± 0.23 dB at 3 months. In all cases, subretinal fluid was resorbed.

CONCLUSION

The parameter sets derived from the computer model can be applied safely and effectively for CSC treatment using the navigated microsecond pulsing laser system. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:512-520.].

Comparison of the efficacy and safety of subthreshold micropulse laser with photodynamic therapy for the treatment of chronic central serous chorioretinopathy: A meta-analysis

BACKGROUND

This meta-analysis was conducted to compare the therapeutic effect and safety of subthreshold micropulse laser (SML) vs photodynamic therapy (PDT) in treatment of chronic central serous chorioretinopathy (cCSC).

METHODS

PubMed, EMBASE, and the Cochrane Library were searched for all relevant studies published up to August 17, 2020. Data of interest were analyzed by STATA (version 14.0) software.

RESULTS

Four randomized clinical trials (RCTs) and 5 retrospective studies with 790 eyes were included in this meta-analysis after study selection. The results showed that SML significantly improved the best-corrected visual acuity (BCVA) compared with PDT at 6 to 8 weeks, 6 months, and 7 to 8 months in patients with cCSC (weighted mean difference (WMD) = -0.15, 95% confidence intervals (CI): -0.23 to -0.07, P < .01; WMD = -2.83, 95% CI: -4.79 to -0.87, P < .01; and WMD = -2.61, 95% CI: -4.23 to -1.24, P = .026, respectively). There was also a statistically significant difference between SML and PDT groups in the differences in the complete resolution of subretinal fluid (SRF) (risk radios = 0.388, 95% CI: 0.307 to 0.491, P < .01). There were no significant differences between the SML and PDT in the overall effect with central macular thickness (CMT), adverse events, complete resolution of SRF and treatment response.

CONCLUSIONS

Based on the available evidence, this meta-analysis demonstrated that SML may be considered as a competitive alternative to PDT for treating cCSC, and as the first-line treatment of cCSC.

Central Serous Chorioretinopathy: Treatment with Laser

Currently, no general consensus exists regarding the management of central serous chorioretinopathy (CSC). Laser treatments include three different therapeutic approaches: conventional laser, subthreshold laser and photodynamic therapy. Conventional focal laser, addressed to seal the leaking points, as evidenced on fluorescein angiography, was largely used in the past, but now, it is almost completely abandoned, owing to the potential complications. Several studies confirmed the positive effects achieved by subthreshold laser treatment in CSC, even though its improper application in the PLACE trial has questioned the effectiveness.

Photodynamic Therapy with Verteporfin for Chronic Central Serous Chorioretinopathy: A Review of Data and Efficacy

Central serous chorioretinopathy represents the fourth most frequent retinal disorder, occurring especially in young age. Central serous chorioretinopathy is mainly characterized by macular serous retinal detachment and although the clinical course moves frequently toward a spontaneous resolution, the subretinal fluid may persist for a long time, thus evolving to the chronic form, and leading to a potential damage of the retinal pigment epithelium and to photoreceptors. The photodynamic therapy with verteporfin plays an important role in the armamentarium among the many therapeutic options employed in this complex retinal disorder. In this review, the authors aim to summarize data of efficacy and safety of PDT focusing especially on mechanisms of action of the PDT and providing comparative outcomes with the alternative therapeutic approaches, including especially the subthreshold laser treatment.

Update on the management of chronic central serous chorioretinopathy

Central serous chorioretinopathy (CSC) is one of the main causes of impaired visual acuity in patients younger than 60 years. Its pathophysiology remains partially unknown, although it has been postulated that choroidal hyper-permeability may be involved. This typically produces a neurosensory retinal detachment and/or a detachment of the retinal pigment epithelium in the posterior pole. Although acute CSC generally does not require treatment, when chronic it must be treated to avoid visual impairment. With the development of new imaging techniques, there has been an improvement in diagnosis, and different therapeutic strategies have been proposed. Various treatments for the management of chronic CSC have currently been shown to be useful to improve or stabilise visual acuity, the resolution of subretinal fluid, and to prevent recurrences. The most commonly used treatments today are photodynamic therapy, micropulse subthreshold laser, mineralocorticoid antagonists, or anti-vascular endothelial growth factor drugs. There are also other proposals and new treatments being developed, with promising results. This review aims to provide the reader with an overview of the current scientific evidence of the different treatment options available for CSC in order to help decision-making in clinical practice.

Efficacy of nanosecond laser treatment in central serous chorioretinopathy with and without atrophy of retinal pigment epithelium

Background

To evaluate the outcomes of subthreshold nanosecond laser treatment of chronic central serous chorioretinopathy (CSC) as a function of the severity of concomitant of retinal pigment epithelium (RPE) defects.

Methods

This retrospective study compares data from 23 CSC diagnosed eyes with only mild RPE defects (group 1), 16 CSC eyes with moderate RPE defects (group 2), and 17 CSC eyes having severe RPE defects (group 3). After subthreshold treatment with the standard Ellex 2RT™ nanosecond laser (Ellex Medical Lasers Ltd, Australia), changes in macular structure and levels of subretinal fluid (SRF) were assessed by OCT-SD, OCT-A, functional integrity of the retina was assessed by corrected distance visual acuity (CDVA) and microperimetry, each at baseline and 1, 3, 6, and 12 months after initial treatment; re-treatment took place in cases of persistent SRF pro re nata.

Results

During the 12 months observation period, group 1 and 2 mostly required on initial and one re-treatment (1.9 ± 1.0 treatments; 1.9 ± 1.3 treatments). In contrast, group 3 was subject to three to four treatments (3.7 ± 1.5 treatments). 6 to 12 months after treatment, subretinal fluid (SRF) disappeared in 100% of the eyes of group 1 and in 76.9%, and 42.9% of the eyes of group 2 and group 3, respectively. Retinal sensitivity and CDVA improved in group 1 and 2, but did not change significantly in group 3 during the 12 months period.

Conclusions

Subthreshold nanosecond laser treatment is an effective and safe method for the restoration of macular anatomy and sensitivity in acute and chronic CSC cases with only mild or moderate RPE defects. However, this laser treatment has very limited outcome in CSC eyes with more severe RPE defects.

532-nm Subthreshold Micropulse Laser for the Treatment of Chronic Central Serous Retinopathy

Introduction

Subthreshold micropulse laser treatment with a 532 nm (532-SML) wavelength has been suggested as a treatment option for the treatment of chronic central serous retinopathy (cCSR). The objective is to present its effects and complications.

Methods

We present a retrospective cohort study of cCSR patients submitted to 532-SML. Best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT) parameters – central macular thickness, subfoveal outer nuclear layer, external limiting membrane, ellipsoid band, interdigitation band, subretinal fluid and choroidal thickness – were evaluated before and 12 weeks after treatment. A power of 50%, a duty cycle of 5%, exposure time of 200 ms and a spot size of 160 µm were the applied laser parameters.

Results

We included 26 eyes. Overall there were no significant changes in visual acuity (median 0.20 (IQR 0) logMAR before and after treatment) or SD-OCT parameters. However, visual benefits occurred in 42.3% (n=11) of the patients and in half of the cases, subretinal fluid was completely reabsorbed. There were no complications.

Conclusion

In this study, 532-SML was overall ineffective on cCSR as it did not lead to significant changes in the overall median visual acuity and SD-OCT parameters. However, some patients may have benefited functionally and anatomically from the treatment; further investigation is necessary to understand the potential of 532-SML.

Central serous chorioretinopathy: Towards an evidence-based treatment guideline

Central serous chorioretinopathy (CSC) is a common cause of central vision loss, primarily affecting men 20-60 years of age. To date, no consensus has been reached regarding the classification of CSC, and a wide variety of interventions have been proposed, reflecting the controversy associated with treating this disease. The recent publication of appropriately powered randomised controlled trials such as the PLACE trial, as well as large retrospective, non-randomised treatment studies regarding the treatment of CSC suggest the feasibility of a more evidence-based approach when considering treatment options. The aim of this review is to provide a comprehensive overview of the current rationale and evidence with respect to the variety of interventions available for treating CSC, including pharmacology, laser treatment, and photodynamic therapy. In addition, we describe the complexity of CSC, the challenges associated with treating CSC, and currently ongoing studies. Many treatment strategies such as photodynamic therapy using verteporfin, oral mineralocorticoid antagonists, and micropulse laser treatment have been reported as being effective. Currently, however, the available evidence suggests that half-dose (or half-fluence) photodynamic therapy should be the treatment of choice in chronic CSC, whereas observation may be the preferred approach in acute CSC. Nevertheless, exceptions can be considered based upon patient-specific characteristics.

Non-resolving, recurrent and chronic central serous chorioretinopathy: available treatment options

Central serous chorioretinopathy is one of the most frequent causes of vision reduction among middle-aged men. This disease usually has a self-limiting course, but sometimes it lasts more than 4-6 months or a second episode follows a complete resolution of the first one. Nevertheless, to date no consensus exists about the duration threshold and therapy protocols for these non-resolving central serous chorioretinopathy. Treatment as half-dose and half-fluence photodynamic therapy, subthreshold micropulse laser treatment, mineralocorticoid receptor antagonists, intravitreal anti-angiogenic drugs, transpupillary thermal therapy, anti-androgenic drugs, methotrexate, Rifampicin and melatonin are described in this review. Complications are very uncommon but end-point results like central macular thickness reduction and best-corrected visual acuity improvement are difficult to compare among different therapeutic modalities due to different duration of follow-up and lack of homogeneity in patient recruitment. The aim of this review is focusing on treatment modalities for these chronic forms with comprehensive recent management updates according to latest clinical trial results.

Management of chronic central serous chorioretinopathy

New treatment modalities for the management of central serous chorioretinopathy (CSC) now exist. While acute CSC generally resolves without the requirement for intervention, chronic CSC has been associated with persistent disruption in visual function. Current treatment approaches include photodynamic therapy, oral aldosterone antagonism and subthreshold multifocal laser. There has also been further investigation into a number of new treatments including antivascular endothelial growth factor treatment. Further investigation using developing optical coherence tomography imaging is helping to determine biomarkers of CSC activity, potential indicators of treatment response and indications of chronicity of disease activity. Further comparative study is required to determine the effectiveness of different forms of treatment in a range of patients with varied demographics, aetiology and chronicity of disease.