Subthreshold Micropulse Laser (577 nm) Treatment in Chronic Central Serous Chorioretinopathy

Micropulse Laser versus Eplerenone for Chronic Central Serous Chorioretinopathy: A 12-Month Comparison

INTRODUCTION

To compare the long-term efficacy of navigated subthreshold micropulse laser (NSML) and continuous oral eplerenone (EPL) in chronic central serous chorioretinopathy (cCSC).

METHODS

This retrospective observational study included 44 eyes with cCSC (EPL: n = 26; NSML: n = 18). Best-corrected visual acuity (BCVA), central macular thickness (CMT), subretinal fluid (SRF) height, and subfoveal choroidal thickness (SFCT) were evaluated over 12 months.

RESULTS

Both groups showed significant improvements in BCVA and CMT (p < 0.05). Complete SRF resolution was achieved in both groups by 12 months, with NSML showing faster resolution (2.77 ± 1.43 vs. 6.34 ± 2.17 months, p < 0.001). The EPL group demonstrated significant SFCT reduction at 6 and 12 months (p = 0.001), while the NSML group showed no significant SFCT changes (p > 0.05).

CONCLUSIONS

Both NSML and EPL improved retinal morphology and visual function in patients with cCSC. NSML achieved faster SRF resolution, while EPL resulted in more significant choroidal thickness reduction. These findings suggest distinct mechanisms of action: NSML primarily affects the retinal pigment epithelium, while EPL modulates choroidal vasculature. Treatment choice may depend on individual patient characteristics and treatment goals.

Crossover to 689 nm laser therapy after poor responsiveness to subthreshold micropulse laser for chronic central serous chorioretinopathy

PURPOSE

To compare the visual and anatomical outcomes of 689 nm laser therapy (689-LT) and continued subthreshold micropulse laser (SML) therapy, for chronic central serous chorioretinopathy (cCSC) eyes after poor responsiveness to initial SML treatment.

METHODS

The retrospective study included 32 cCSC patients, of which 15 patients received continued SML, and 17 patients received 689-LT. Best corrected visual acuity (BCVA), central retinal thickness (CRT), the maximum height of subretinal fluid (mSRF), subfoveal choroidal thickness (SFCT), three-dimensional choroidal vascularity index (CVI), and the vascular density of choriocapillaris (CCVD) of two groups were evaluated and compared at baseline, one-month and three-month follow-up after treatment.

RESULTS

Thirty-two cCSC eyes of 32 patients (7 female, 25 male) were included in our study, with a mean age of 46.69 ± 6.56 years. Three months after treatment, complete resolution of SRF was achieved in four eyes in the 689-LT group, whereas no eyes displayed complete resolution in the SML group. There were no significant improvements in BCVA and CCVD at the three-month follow-up in both groups. In the 689-LT group, at one-month and three-month follow-ups, there was a significant reduction in CRT, mSRF, SFCT and CVI, compared to the baseline (p < 0.001 in all analyses). There were no statistically significant changes in CRT, mSRF, SFCT and CVI in the SML group (p > 0.05 in all analyses). The ANOVA test for repeated measures showed the changes in the measurements over time were significantly different between the two groups (P value using Greenhouse-Geisser test < 0.05).

CONCLUSION

689 nm laser therapy provides the opportunity for cCSC eyes with poor responsiveness to SML treatment, especially when verteporfin is unavailable. There was also a notable recovery in the abnormal dilatation of choroidal vessels in the 689-LT group. Further studies are warranted to investigate the long-term efficacy and safety of 689 nm laser therapy in the management of cCSC.

Subthreshold Micropulse Laser (577 nm) Therapy with an Individual Approach for Power Titration in Patients with Chronic Central Serous Chorioretinopathy (Pilot Study)

Purpose

To study the safety and effectiveness of subthreshold micropulse (SML) 577 nm laser therapy with an individual power titration in treating patients with chronic central serous chorioretinopathy (CSC).

Methods

The study was a prospective, single-centre observation of 30 patients (30 eyes) with chronic CSC. All patients with chronic CSC were treated with a 577 nm micropulse laser. Individual power parameters for each patient were titrated in a micropulse mode. The primary outcome measure was best-corrected visual acuity (BCVA) at 6-month follow-up. The secondary outcome measures were as follows: central retinal thickness (CRT) and maximum subretinal fluid height (SRFH) according to optical coherence tomography, number of laser sessions, and treatment safety at 6-month follow-up.

Results

Before treatment, the mean BCVA was 0.35 ± 0.16, the mean CRT was 285 ± 76 µm, and the mean SRFH was 311 ± 85 µm. Six months after 577 nm SML therapy, there was a statistically significant increase in the mean BCVA with the maximum correction to 0.45 ± 0.15 (p = 0.001). The mean CRT and SRFH decreased significantly to 236 ± 45 μm (p = 0.003) and 45 ± 25 μm (p = 0.001), respectively. At the end of the follow-up, complete resorption of the subretinal fluid was noted in 50% (15 eyes), and in 43% (13 eyes), a decrease in the SRFH was observed. During the entire observation period, 25 patients underwent 1 session of 577 nm SML therapy, 2 patients underwent 2 sessions, and 3 patients underwent the intervention three times.

Conclusion

SML 577 nm therapy with individual selection of laser power in a micropulse mode is a safe and effective method of treating patients with chronic CSC. Further studies are needed to test the long-term safety and efficacy of 577 nm SML therapy with individual power settings in chronic CSC.

Settings and Clinical Applications of Subthreshold Micropulse Laser Therapy: A Review

Subthreshold lasers operate below the threshold of visible tissue damage, thereby preventing ophthalmoscopically visible thermal damage to the chorio-retinal layers. They could represent a safe and effective alternative and/or adjunctive procedure to conventional lasers in treating diabetic macula edema (DME), central serous chorioretinopathy (CSCR), and branch retina vein occlusion (BRVO). This review focuses on the use of subthreshold micropulse laser (SMPL), its settings, and clinical applications. Despite their widespread use, a standardized protocol for sub-threshold laser settings has not been established yet, and thus, there is uncertainty in selecting effective and safe parameters for any specific situation. We conducted a comprehensive overview of the existing indications for subthreshold laser therapy and their settings for different retinal diseases. The debate revolves around which parameters could guarantee the safety of the procedure for each case, depending on the duty cycle, the laser wavelength, the spot duration, and the power, with laser power titration on one side or choosing a fixed lowered power value on the other side. SMPL therapy for DME, CSCR, and BRVO-associated macular edema has shown significant effectiveness in reducing the macular thickness, facilitating subretinal fluid absorptions, increasing the best corrected visual acuity (BCVA) and reducing the number of intravitreal injections (IVI) required annually. We presented a broad list of the laser parameters reported in the literature, organized into different tables divided based on the specific pathology, with the aim of providing a useful tool for future studies.

532 nm versus 810 nm subthreshold micropulse laser in treatment of non-resolving central serous chorioretinopathy: A randomized controlled trial

Background

The relative efficacy of 532 nm subthreshold micropulse laser in comparison to the 810 nm subthreshold micropulse laser, in the treatment of central serous chorioretinopathy is not known.

Methods

This randomized controlled trial included 99 eyes each in groups A and B. Key inclusion criteria were: (i) vision loss for minimum three months due to persistent central serous chorioretinopathy; (ii) focal leaks (upto two leaks) on fundus fluorescein angiography. Key exclusion criteria were: (i) history of prior treatment for central serous chorioretinopathy; (ii) absence of any leak/ presence of diffuse leaks/ >2 leaks on fundus fluorescein angiography; (iii) chronic central serous chorioretinopathy. All eyes were treated with subthreshold micropulse laser (group A: 532 nm green laser; group B: 810 nm diode laser). Best-corrected visual acuity, autofluorescence, spectral domain optical coherence tomography, and fundus fluorescein angiography, were evaluated at baseline and at 1, 3, and 6 months. Laser was repeated in nor-responders at 3 months.

Results

There was a statistically significant improvement in BCVA in both groups six months post laser. Between the two groups, a comparable proportion of eyes showed complete resolution of subretinal fluid at one month, three months and at six months. No adverse effect of laser was observed in either group.

Conclusion

Both 532 nm STMP laser and 810 nm STMP laser have comparable structural and functional outcomes in the treatment of non-resolving CSC. There are no adverse effects related to either of the two wavelengths.

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.

The effect of nondamaging subthreshold laser therapy in patients with chronic central serous chorioretinopathy

PURPOSE

To evaluate the efficacy of nondamaging subthreshold laser therapy in Korean patients with chronic central serous chorioretinopathy (cCSC).

METHODS

This retrospective interventional case series included 31 patients (31 eyes) with cCSC who underwent nondamaging laser therapy using Endpoint Management (EpM) software. Since a barely visible burn of the test spot was defined as 100% pulse energy, 30% pulse energy with a 200-μm spot was titrated to treat the macular area based on EpM settings. A 30% pulse laser with a spacing of 0.25-beam diameter was applied to cover the macular area where hyperfluorescent leaks were observed on fluorescein angiography. Changes in central macular thickness (CMT), subretinal fluid (SRF) height, subfoveal choroidal thickness (SCT), and logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) were measured at baseline and after 3 and 6 months. If the subretinal fluid persisted for 3 months, retreatment was performed.

RESULTS

At 6 months post-treatment, the complete SRF resolution rate was 48.39% (15/31 eyes), and the partial SRF resolution rate was 12.90% (4/31 eyes). The change in mean BCVA (logMAR) was not significant (0.31 ± 0.29 at the baseline and 0.31 ± 0.40 at month 6) (p = 0.943). At the baseline, the mean CMT (μm) decreased from 350.74 ± 112.76 at baseline to 239.71 ± 130.25 at month 6 (p < 0.001), and the mean SRF height (μm) decreased from 193.16 ± 90.69 at baseline to 70.58 ± 100.00 at month 6 (p < 0.001). However, the change in SCT was not statistically significant (p = 0.516). In 15 patients who were retreated at month 3, the mean SRF height (μm) decreased significantly from 144.67 ± 74.01 at month 3 to 77.13 ± 63.77 at month 6 (p = 0.002). No side effects associated with laser therapy were observed during the 6-month follow-up.

CONCLUSIONS

Nondamaging laser therapy with a modified macular treatment was effective in reducing CMT and SRF and showed favorable visual and anatomical outcomes in patients with cCSC.

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).

Crossover to PDT after the unsuccessful micropulse laser treatment of central serous chorioretinopathy

Purpose

Subthreshold micropulse laser (SML) and photodynamic therapy (PDT) are among the most effective therapeutic modalities applied to central serous chorioretinopathy (CSCR). This study aimed to evaluate the efficacy and durability of PDT in CSCR cases unresponsive to at least two SML treatments.

Methods

The study included 26 consecutive eyes of 24 patients (21 males and three females) with chronic CSCR. In all cases, a lack of reduction in subretinal fluid (SRF) levels was noted after at least two consecutive SML sessions. The parameters of best corrected visual acuity (BCVA) and spectral domain optical coherence tomography (SD-OCT) were evaluated at baseline and 1, 3 and 12 months post-PDT.

Results

The mean duration of symptoms in the group was 53.81 ± 39.48 months, the mean age of the patients was 49.26 ± 12.91 years, and the mean subfoveal choroidal thickness (SFCT) was 572.11 ± 116.21 mm. Complete resorption of SRF was observed in 21 out of 26 eyes (80.77%) at 1 month and sustained in 18 cases (69.23%) at 12 months. At 12 months, in the sustained group, BCVA improved significantly from 0.39 ± 0.18 to 0.19 ± 0.2 logMAR (P = 0.01), central subfoveal thickness (CST) reduced from 316.44 ± 75.83 mm to 197.67 ± 22.99 mm (P < 0.0001), and SFCT reduced from 579.28 mm to 446.78 mm (P < 0.0001).

Conclusions

PDT provides the opportunity for the successful treatment of CSCR unresponsive to SML treatment. Improvements are possible even in cases with a long duration of symptoms and significant alterations in retinal morphology. Thus, PDT should be considered for patients with prominently increased choroidal thickness.

Half-dose photodynamic therapy versus 577 nm subthreshold pulse laser therapy in treatment-naive patients with central serous chorioretinopathy

BACKGROUND

To compare real-life anatomical and functional outcomes of half-dose photodynamic therapy (HD-PDT) and 577 nm subthreshold pulse laser therapy (SPL) in treatment-naïve patients with central serous chorioretinopathy (CSC).

METHODS

We retrospectively reviewed consecutive treatment-naïve CSC patients with non-resolving subretinal fluid (SRF) for more than 2 months who received either HD-PDT or SPL treatment. One repetition of the same treatment was allowed in patients with persistent SRF after first treatment. Functional and anatomical outcomes were assessed after first treatment and at final visit.

RESULTS

We included 95 patients (HD-PDT group, n = 49; SPL group, n = 46). Complete resolution of SRF after a single treatment was observed in 42.9% of HD-PDT-treated patients (n = 21; median time to resolution 7.1 weeks) and in 41.3% of SPL-treated patients (n = 19; median time to resolution 7.0 weeks). In the HD-PDT-group, 44.9% of patients (n = 22) and in the SPL-group, 43.5% (n = 20) of patients, received a second treatment due to persistent SRF, while 12.2% (n = 6) and 15.2% (n = 7), respectively, opted against a second treatment despite persistent SRF. After the final treatment, complete SRF resolution was observed in 61.2% of all HD-PDT-treated patients (n = 30; median time to resolution 8.8 weeks) and 60.9% of all SPL-treated patients (n = 28; median time to resolution 13.7 weeks, p = 0.876). In the final visit, both groups showed significant improvement of BCVA in comparison to baseline (p < 0.001 for all). The change in BCVA from baseline to final visit was similar for the two groups (HD-PDT, median BCVA change 0.10 logMAR (IQR: 0.0-0.2); in SPL group, median BCVA change 0.10 logMAR (IQR: 0.0-0.2), P = 0.344). The CSC subclassification (simple versus complex) had no influence on the anatomical or functional outcome.

CONCLUSIONS

High-density 577 nm SPL resulted in as good anatomical and functional treatment as HD-PDT and may thus represent a treatment alternative to HD-PDT in CSC.

Micropulse Laser Therapy as an Integral Part of Eye Disease Management

Ocular diseases can significantly impact vision and quality of life through pathophysiological alterations to the structure of the eye. The management of these conditions often involves a combination of pharmaceutical interventions, surgical procedures, and laser therapy. Laser technology has revolutionized many medical fields, including ophthalmology, offering precise and targeted treatment options that solve some of the unmet needs of other therapeutic strategies. Conventional laser techniques, while effective, can generate excessive thermal energy, leading to collateral tissue damage and potential side effects. Compared to conventional laser techniques, micropulse laser therapy delivers laser energy in a pulsed manner, minimizing collateral damage while effectively treating target tissues. The present paper highlights the advantages of micropulse laser therapy over conventional laser treatments, presents the implications of applying these strategies to some of the most prevalent ocular diseases, and highlights several types and mechanisms of micropulse lasers. Although micropulse laser therapy shows great potential in the management of ocular diseases, further research is needed to optimize treatment protocols, evaluate long-term efficacy, and explore its role in combination therapies.

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.

Tb3+-Tb3+ cross-relaxation study under novel experimental technique: Simultaneous laser excitation at UV-Vis

Tb³⁺ doped GeO₂-Na₂O glasses have been fabricated by conventional melt quenching technique using 0.3, 1, 3, and 5 %mol of terbium ions. The optical properties were studied by means of steady-state photoluminescence (excitation and emission spectra), and emission decay time. Under excitation of 355 nm and as the concentration of dopant increases, the glasses show an enhancement of the emission intensity from ⁵D₄ level accompanied by a decrease on the emission intensity from ⁵D₃ level. This phenomenon can be attributed to an energy transfer process that occurs through cross-relaxation mechanisms between Tb³⁺ ions. The aim of this study is to report an experimental technique to study the cross-relaxation of ⁵D₃ level decay curves of Tb³⁺ ions under simultaneous temporal and spatial pulsed excitation using UV and visible light (355 nm + 488 nm), allowing to limit the occurrence of cross-relaxation mechanisms and increase luminescent efficiency. Upon simultaneous UV + Vis excitation, the emission from ⁵D₃ level in enhanced, as the energy of the 488 nm pulse is increased. Additionally, the energy transfer efficiency between Tb³⁺ ions was analyzed with the Inokuti-Hirayama (IH) model, as function of the excitation pulse energy at 488 nm, keeping fixed the energy of the 355 nm pulse, determining a dipole-dipole interaction as the dominant interaction mechanism.

Central serous chorioretinopathy: Treatment

Central serous chorioretinopathy (CSC) is a pachychoroid spectrum disease characterized by serous detachment of the neurosensory retina with subretinal fluid in young and middle-aged adults. The pathogenesis of CSC is not yet fully understood. However, it is considered a multifactorial disease that is strongly associated with choroidal dysfunction or vascular engorgement. Although there is no consensus on the treatment of CSC, photodynamic therapy has been effectively used to manage serous retinal detachment (SRD) in CSC. Moreover, micropulse diode laser photocoagulation and focal laser treatment have also been used. Recently, oral medications, including mineralocorticoid receptor antagonists, have been proposed for the management of CSC. Multimodal imaging plays a significant role in the diagnosis and treatment of CSC. Optical coherence tomography angiography (OCTA) has the advantage of detecting vascular flow in the retina and choroid layer, allowing for a better understanding of the pathology, severity, prognosis, and chronicity of CSC. In addition, early detection of choroidal neovascularization in CSC is possible using OCTA. This review article aims to provide a comprehensive and updated understanding of CSC, focusing on treatment.

Temperature Increase and Damage Extent at Retinal Pigment Epithelium Compared between Continuous Wave and Micropulse Laser Application

Continuous wave (CW) and microsecond pulse (MP) laser irradiations were compared regarding cell damage and laser-induced temperature rise at retinal pigment epithelium (RPE). The RPE of porcine RPE-choroid-sclera explants was irradiated with a 577 nm laser in CW or MP mode (5% or 15% duty cycle (DC)) for 20 ms or 200 ms at an average laser power of 20−90 mW. Cell viability was investigated with calcein-AM staining. Optoacoustic (OA) technique was employed for temperature measurement during irradiation. For 200 ms irradiation, the dead cell area (DCA) increased linearly (≈1600 µm2/mW) up to the average power of 40 mW for all modes without significant difference. From 50 mW, the increase of DCA of MP-5% significantly dropped to 610 µm2/mW (p < 0.05), likely due to the detected microbubble formation. OA temperature measurement showed a monotonic temperature increase in CW mode and a stepwise increase in MP mode, but no significant difference in the average temperature increase at the same average power, consistent with the temperature modeling. In conclusion, there is no difference in the average temperature rise between CW and MP modes at the same average power regardless of DC. At lower DC, however, more caution is required regarding mechanical damage due to microbubble formation.

Subthreshold Micropulse Treatment Laser versus Half-Dose Photo Dynamic Therapy for the Chronic Central Serous Chorioretinopathy with Parafoveal or Subfoveal Leakage STML versus PDT for Treatment of Chronic CSC

Purpose. The study aimed to compare the efficacy and safety outcomes of a subthreshold micropulse treatment laser (SMTL) versus half-dose photodynamic therapy (PDT) for treatment of chronic central serous chorioretinopathy (cCSC) with parafoveal or subfoveal leakage to persistent subretinal fluid. Methods. One hundred and forty-eight patients (148 eyes) with persistent cCSC were enrolled in this retrospective study and treated with SMTL or half-dose PDT. All patients were diagnosed according to clinical characteristics and findings on multimodal imaging. The medical records including patients with a minimum follow-up period of 3 months were reviewed. The patients were divided into two groups according to the application of the SMTL or PDT. The group of the SMTL or PDT was also divided into two subgroups according to parafoveal or subfoveal leakage. The primary outcomes included best-corrected visual acuity (BCVA) and central retinal thickness (CRT) before and 1, 2, and 3 months after treatment. The repeat treatment and resolution of subretinal fluid were also collected. Results. Seventy-nine patients (79 eyes) treated with half-dose PDT and 69 Patients (69 eyes) treated with the STML were included. The mean age was 44.20 ± 7.42 years and 80% were male. No significant difference in age, gender, baseline logMAR BCVA or CRT between the half-dose PDT group and the SMTL group ( $P=0.201$ ; 0.051) can be defined. The BCVA of the SMTL group improved at 1, 2, and 3 months after treatment, while that of the half-dose PDT group improved like the SMTL group. There were no significant differences between the SMTL and the PDT group at 1, 2, and 3 months ( $P=0.723$ ; 0.139; 0.896). The CRT for the SMTL group decreased at 1, 2, and 3 months after treatment, while that of the half-dose PDT group changed like the SMTL group. However, there were significant differences between the SMTL group and the PDT group at 1and 3 months ( $P=0.010$ ; 0.009). 13/69 (18.84%) and 9/79 (11.39%) patients underwent treatment at least twice in the SMTL and half-dose PDT group, respectively, and achieved resolution of SRF after treatment. The results of subgroups analysis showed no significant differences between the logMAR BCVA of the SMTL and PDT group which were divided into parafoveal and subfoveal leakage groups after treatment, but significant difference in CRT between subgroups can be found after treatment at 1and 3 months ( $P=0.003$ ; 0.04). Conclusions. The SMTL can be an effective candidate for the treatment of persistent cCSC where leakage occurred at parafoveal or subfoveal and improvement of logMAR BCVA, but half-dose PDT has been more effective for resolution of SRF.

Short-term comparison between navigated subthreshold microsecond pulse laser and oral eplerenone for chronic central serous chorioretinopathy

To compare the anatomical/functional changes after navigated subthreshold pulse laser (SML) and oral eplerenone therapy for chronic central serous chorioretinopathy (cCSC). A total of 36 eyes of 36 patients suffering from cCSC treated with navigated SML (Navilas® 577s; OD-OS GmbH, near Berlin, Germany) (18 eyes, SML group) and oral eplerenone (18 eyes, eplerenone group) were enrolled in this retrospective study. Main outcome measures during a 3-month follow up period included changes of best corrected visual acuity (BCVA), central macular thickness (CMT), foveal subretinal fluid thickness (FSRFT), and subfoveal choroidal thickness (SFCT). At baseline average duration of symptoms was 6.8 ± 0.6 months in SML group and 6.4 ± 0.9 months in eplerenone group (p = 0.127). Mean BCVA, CMT and FSRFT changed significantly over time (p < 0.001). From baseline to 90 days the BCVA improved from 0.3 ± 0.1 to 0.1 ± 0.1 logMAR in SML group and from 0.3 ± 0. to 0.2 ± 0.1 logMAR in eplerenone group, CMT reduced from 357.1 ± 104.3 to 210.6 ± 46.7 μm and from 428.7 ± 107.7 to 332.5 ± 27.5 μm in SML group and eplerenone group respectively, FSRFT reduced from 144.4 ± 108.2 to 22.6 ± 37.2 μm and from 217.1 ± 105.9 to 54.4 ± 86.2 μm in SML group and eplerenone group. 55.6% of patients in SML group and 66.7% in eplerenone group showed a complete resolution of FSRFT during follow up. The interaction between group and time was statistically significant with greater absolute variation for CMT and FSRFT in SML group compared to eplerenone group (p < 0.001 and p = 0.043). SFCT did not change significantly during follow up (p = 0.083) for both groups. Both navigated SML and oral eplerenone were effective treatments showing recovery of retinal morphology and related visual acuity improvement in cCSC.

Long-term follow-up of chronic central serous chorioretinopathy after successful treatment with photodynamic therapy or micropulse laser

PURPOSE

To describe the treatment outcomes and recurrence risk of chronic central serous chorioretinopathy (cCSC) in patients who had complete resolution of subretinal fluid (SRF) after either primary half-dose photodynamic therapy (PDT) or high-density subthreshold micropulse laser (HSML) in the PLACE trial.

METHODS

This multicentre prospective follow-up study evaluated cCSC patients at 1 year after completion of the PLACE trial. Outcomes included: complete resolution of SRF on OCT, best-corrected visual acuity (BCVA) in Early Treatment of Diabetic Retinopathy Study (ETDRS) letters, retinal sensitivity on microperimetry and a visual function questionnaire (NEI-VFQ25).

RESULTS

Twenty-nine out of 37 patients who received half-dose PDT and 15 out of 17 patients who received HSML could be evaluated at final visit. At final visit, 93% of the patients treated with half-dose PDT had complete resolution of SRF, compared with 53% of HSML-treated patients (p = 0.006). At final visit, the mean estimate increase in the PDT group compared with the HSML group was + 2.1 ETDRS letters, +0.15 dB for the retinal sensitivity and + 5.1 NEI-VFQ25 points (p = 0.103, p = 0.784 and p = 0.071, respectively). The mean estimated central retinal thickness in the half-dose PDT group was -7.0 µm compared with the HSML group (p = 0.566). The mean estimated subfoveal choroidal thickness in the half-dose PDT group was -16.6 µm compared with the HSML group (p = 0.359).

CONCLUSION

At 20 months after treatment, cCSC patients successfully treated with half-dose PDT are less likely to have recurrences of SRF compared with those successfully treated with HSML. However, functional outcomes did not differ.

Subthreshold Micropulse Laser vs. Conventional Laser for Central Serous Chorioretinopathy: A Randomized Controlled Clinical Trial

Purpose: To investigate the effectiveness and safety of 577-nm subthreshold micropulse laser (SML) on acute central serous chorioretinopathy (CSC). Methods: One hundred and ten patients with acute CSC were randomized to receive SML or 577-nm conventional laser (CL) treatment. Optical coherence tomography and best-corrected visual acuity (BCVA) were performed before and after treatment. Results: At 3 months, the complete resolution of subretinal fluid (SRF) in 577-nm SML group (72.7%) was lower than that in CL group (89.1%) (Unadjusted RR, 0.82; P = 0.029), but it was 85.5 vs. 92.7% at 6 months (unadjusted RR, 0.92; P = 0.221). The mean LogMAR BCVA significantly improved, and the mean central foveal thickness (CFT) significantly decreased in the SML group and CL group (all P < 0.001) at 6 months. But there was no statistical difference between the two groups (all P > 0.05). In the SML group, obvious retinal pigment epithelium (RPE) damage was shown only in 3.64% at 1 month but 92.7% in the CL group (P < 0.001). Conclusions: Although 577-nm SML has a lower complete absorption of SRF compared with 577-nm CL for acute CSC at 3 months, it is similarly effective as 577-nm CL on improving retinal anatomy and function at 6 months. Importantly, 577-nm SML causes less damage to the retina.

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

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

Comparison of the efficacy and safety between subthreshold micropulse laser, standard-fluence and low-fluence photodynamic therapy for chronic central serous chorioretinopathy

PURPOSE

To compare the efficacy and safety of subthreshold micropulse laser treatment (SML), standard-fluence photodynamic therapy (PDT) and low-fluence PDT in patients with chronic central serous chorioretinopathy (cCSC).

METHODS

This retrospective study included 52 eyes of 46 patients with chronic CSC who were treated with 577nm SML (n=23), standard-fluence PDT (verteporfin 6mg/m² and light energy 50J/cm²) (n=13), or low-fluence PDT (verteporfin 6mg/m² and light energy 25J/cm²) (n=16). The mean changes in best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) parameters, including central retinal thickness (CRT), subretinal fluid (SRF) height, and ellipsoid zone (EZ) disruption, over the follow-up period were evaluated.

RESULTS

The mean follow-up period was 8.42±3.34 months. In the SML group, the SRF resolution time was longer than the other groups. At 1 month, the SML group's mean CRT was higher than the other groups. The BCVA improvement was statistically significant in all groups (P<0.05), but in the SML group, it was slower than the other groups. Three eyes in the low-fluence and one eye in the standard-fluence PDT group received a second PDT treatment. The mean number of SML treatments was 2.48±1.08. If the EZ was intact, the rate of complete resolution of SRF was higher than if the EZ was disrupted or lost.

CONCLUSION

SML, standard-fluence PDT, and low-fluence PDT can all improve visual acuity in cCSC. Standard-fluence and low-fluence PDT induced a more rapid reabsorption of the fluid, improvement of BCVA, and equal safety compared with SML. More treatment sessions of SML were required than with the other treatment modalities.

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.

Role of 532 nm transfoveal subthreshold micropulse laser in non-resolving central serous chorioretinopathy with subfoveal leaks

Purpose:

The purpose of this study was to evaluate the role of 532 nm transfoveal subthreshold micropulse laser in non-resolving central serous chorioretinopathy with subfoveal leak.

Methods:

A retrospective chart analysis of 23 eyes of 21 patients with central serous chorioretinopathy was performed. Inclusion criteria include vision loss ⩾3 months and focal subfoveal leak on fluorescein angiography. Exclusion criteria include prior treatment for central serous chorioretinopathy and chronic central serous chorioretinopathy. All eyes were treated with 532 nm subthreshold micropulse laser (5% duty cycle). Visual acuity score, contrast sensitivity, autofluorescence, spectral domain optical coherence tomography, and fundus fluorescein angiography were assessed at baseline, 1, 3, 6 months.

Results:

Average visual acuity score (letters) improved from 66.0 ± 8.51 (baseline) to 71.35 ± 8.48 (1 month, p < 0.01), 77.30 ± 11.34 (3 months, p < 0.01), 80.17 ± 9.30 (6 months, p < 0.01). Contrast sensitivity improved from 0.75 ± 0.30 to 1.30 ± 0.37 (p < 0.01) at 6 months. Two eyes needed rescue laser at 3 months followed by photodynamic therapy at 6 months; two eyes needed rescue laser at 6 months.

Conclusion:

The 532 nm subthreshold micropulse laser is safe in non-resolving central serous chorioretinopathy with subfoveal leaks.

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

AIM

To evaluate the efficacy and safety of subthreshold micropulse yellow laser (SMYL) in the treatment of chronic central serous chorioretinopathy (CCSC).

METHODS

The medical records of 58 eyes of 58 patients with CCSC were reviewed. A 577-nm SMYL system was used for the treatment. Fundus fluorescein angiography was used as the primary method of identifying CCSC, and resolution of subretinal fluid (SRF) evaluated by optical coherence tomography (OCT) and fundus autofluorescence. Central macular thickness (CMT), central macular volume (CMV), total macular volume (TMV), subfoveal choroidal thickness (SFCT), subretinal fluid height (SRFH), and subfoveal fluid basement diameter values were measured by spectral domain-OCT (SD-OCT) for all eyes.

RESULTS

The mean age of the patients was 42.4±9.9 (range: 20-72)y. The mean follow-up was 11.4±8.5 (range: 6-37)mo. Median BCVA at at the final follow up after treatment was statistically significant from the baseline. Complete SRF resolution was 12.1% of the eyes in the 1^st month, 67.2% of the eyes in the 3^rd month and 67.2% of the eyes in the last follow up. The initial median CMT, CMV, TMV, and SFCT values before treatment was significantly higher than 3^rd month visit values (P<0.001). In the multivariate analysis performed, age and disease duration were found to be a risk factor for persistent SRF (P=0.017, P=0.016, respectively).

CONCLUSION

SMYL treatment provides a significant anatomical and functional improvement and is effective in eliminating SRF in eyes with CCSC.

Efficacy and safety of subthreshold micropulse laser compared with threshold conventional laser in central serous chorioretinopathy

PURPOSE

To compare the efficacy and safety of subthreshold micropulse laser (SML) with threshold conventional laser (TCL) in central serous chorioretinopathy (CSC).

METHODS

Prospective, randomized, double-masked, non-inferiority, 12-week clinical trial. Patients were randomly assigned 1:1 to SML group or TCL group. Patients in the SML group were treated with 577 nm micropulse laser. The spot size was 160 µm, the duty cycle was 5% and exposure time was 0.2 s. The power was 50% threshold tested. Patients in the TCL group were treated with 577 nm continuous laser. The power was 100% threshold tested. The primary outcome was the mean change in best-corrected visual acuity (BCVA) at week 12, with a non-inferiority limit of five letters on the Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity charts.

RESULTS

Eighty-eight patients were enroled. Seventy-seven patients were male. Forty-four patients were in SML group and 44 in TCL group. At week 12, SML was equivalent to TCL with a gain of 6.23 ± 8.59 and 6.61 ± 6.35 letters, respectively, (SML-TCL difference: -0.38 letters; 95% confidence interval (CI):-3.58-2.81; Pnon-inferiority = 0.0026). There was no statistically significant difference between the two groups (t = 0.240, P = 0.811). At week 12, the proportion of patients whose SRF had been totally absorbed was 63.63 and 81.82% respectively for SML and TCL groups. There was no statistically significant difference between the two groups (χ2 = 3.67, P = 0.056).

CONCLUSIONS

Both SML and TCL can improve visual acuity in CSC. SML was non-inferior to TCL in the improvement of BCVA.

The efficacy of subthreshold micropulse yellow laser (577 nm) in chronic central serous chorioretinopathy

Central serous chorioretinopathy (CSC) is a disease characterized by a well-defined serous detachment of the neurosensory retina. Therapeutic options in chronic cases are limited, and side effects can result in a limited response. The aim of this article is to assess the efficacy of subthreshold micropulse laser therapy in patients with chronic central serous chorioretinopathy. The study included 20 eyes of 19 patients who had a history of chronic or chronic recurrent CSC and who underwent subthreshold micropulse laser therapy between January 2015 and June 2018. Twenty eyes of 19 patients with a mean age of 48.9 ± 9.40 years were included. The mean visual acuity was 0.24 ± 0.28 logMAR before laser, 0.19 ± 0.25 logMAR 3 months after laser, and 0.18 ± 0.27 logMAR after 6 months. A statistically significant difference was determined in terms of visual acuity before and after treatment (p = 0.0001). The mean central retinal thickness was 308.10 ± 95.25 μm before laser, 233.65 ± 81.17 μm 3 months after laser, and 203.88 ± 72.79 μm at 6 months. A statistically significant relationship was present between visual acuity and the duration of disease (p = 0.001), between visual acuity and the outer nuclear layer thickness (p = 0.005), and between the outer nuclear layer thickness and the duration of disease in chronic cases (p = 0.008). There was no evidence of retinal pigment epithelium or retinal damage on optical coherence tomography or fundus autofluorescence secondary to subthreshold micropulse laser therapy. Visual acuity appears to be more associated with the duration of disease and with changes in the outer nuclear layer thickness in chronic CSC. Subthreshold micropulse laser therapy seems to be effective at treating chronic CSC, while it increases success during early period of the disease before the development of permanent retinal damage.

Crossover to Photodynamic Therapy or Micropulse Laser After Failure of Primary Treatment of Chronic Central Serous Chorioretinopathy: The REPLACE Trial

PURPOSE

To assess whether chronic central serous chorioretinopathy (cCSC) patients without a complete resolution of subretinal fluid (SRF) after either half-dose photodynamic therapy (PDT) or high-density subthreshold micropulse laser (HSML) treatment may benefit from crossover treatment.

DESIGN

Multicenter prospective interventional case series.

METHODS

cCSC patients with persistent SRF at the final visit of the PLACE trial were included. Patients received crossover treatment with either half-dose PDT or HSML.

RESULTS

Thirty-two patients received PDT and 10 patients received HSML. At the first evaluation visit (6-8 weeks after treatment), 81% of patients in the PDT group had complete resolution of SRF, while none of the HSML-treated patients had complete resolution of SRF. At final visit (1 year after baseline), 78% (P = .030) and 67% (P = .109) of the patients, respectively, had a complete resolution of SRF. The mean retinal sensitivity in the PDT group increased from 21.7 dB (standard error [SE]: 0.9) to 23.4 dB (SE: 0.8) at evaluation visit 1 (P = .003), to 24.7dB (SE: 0.8) at final visit (P < .001), while there were no significant changes in the HSML group (23.7 dB [SE: 1.6] at baseline, 23.8 dB [SE: 1.4] at evaluation 1, and 23.3 dB [SE: 1.4] at final visit). The mean visual acuity and mean visual quality-of-life questionnaire score did not change significantly in both groups.

CONCLUSIONS

Crossover to half-dose PDT after previous unsuccessful HSML treatment for cCSC may lead to improved anatomic and functional endpoints, while crossover to HSML after half-dose PDT does not seem to significantly affect these endpoints.

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.

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.

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.

Pharmacotherapy of Central Serous Chorioretinopathy: A Review of the Current Treatments

BACKGROUND

Central serous chorioretinopathy (CSC) is the fourth most frequent retinal disorder in terms of prevalence. It typically occurs in young subjects and affects men more often than women. CSC is characterized by serous retinal detachment (SRD) involving mainly the macular area. The clinical course is usually selflimited, with spontaneous resolution within 3 months. The persistence of SRD or multiple relapse may result in a chronic form of CSC distinguished by permanent retinal pigment epithelium (RPE) and photoreceptor damage. As the pathogenetic mechanism of CSC primarily involves RPE and choroidal vascularization, the current therapeutic approaches aim to restore the normal functions of RPE and normal choroidal vascular permeability. In this review, the authors aim to summarize the current therapeutic approach to CSC.

METHODS

A comprehensive review of the literature was conducted in PubMed by searching for relevant studies on the current therapeutic options for CSC, including simple observation, conventional laser treatment, subthreshold laser treatment (SLT), photodynamic therapy (PDT) with verteporfin, treatment with mineralocorticoid receptor (MR) antagonists and treatment with anti-vascular endothelial growth factor drugs.

RESULTS

Since most cases resolve spontaneously, the most common initial CSC treatment is observation. Current evidence suggests that PDT and SLT are valuable in improving visual acuity, reducing subretinal fluid and maintaining long-term effectiveness. No clear evidence of efficacy has been achieved for anti-VEGF. MR antagonists might be a viable choice for the treatment of chronic CSC.

CONCLUSION

The pathophysiology of CSC remains poorly understood and as a consequence, the gold standard of care for CSC is yet to be defined. To date, PDT and SLT continue to offer good clinical outcomes. Positive preliminary results seem to emerge from the studies of MR antagonists.

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.

Transfoveal Micropulse Laser Treatment of Central Serous Chorioretinopathy within Six Months of Disease Onset

Background: It has been recommended that any invasive treatment performed in patients with central serous chorioretinopathy (CSCR) not be initiated earlier than four months after disease onset due to the potential for spontaneous remission of symptoms. The goal of this study was to examine the outcome of transfoveal subthreshold micropulse laser treatment (SMPLT) of CSCR performed at six months or less after disease onset. Materials and methods: The study included 32 cases of CSCR lasting between three weeks and six months (mean: 3.4 ± 2.3 months). All patients had transfoveal SMPLT applied and were followed for at least three months after each session of SMPLT. Two sessions of SMPLT in total were planned in case of an insufficient response to the first instance of treatment. Evaluation parameters included any change in best-corrected visual acuity (BCVA) and retinal morphology. Results: Total resolution of subretinal fluid (SRF) was noted in 26 cases (81.25%). Final BCVA improved significantly from 0.37 ± 0.22 logMAR to 0.22 ± 0.20 logMAR after treatment. Overall, early SMPLT correlated with better final BCVA (p = 0.0005, Spearman rank correlation). For eyes achieving a total resolution of SRF, BCVA improved from 0.33 ± 0.21 logMAR to 0.17 ± 0.14 logMAR (p = 0.004, Spearman rank correlation). The analysis of SMPLT nonresponders revealed a tendency for poorer baseline visual acuity. Conclusions: Patients with CSCR lasting six months or less treated with transfoveal SMPLT achieve better functional results with early application of this procedure. As baseline BCVA predicts final visual acuity, earlier treatment, permitted by the safety of SMPLT, may improve final visual outcomes.

Focal and Diffuse Chronic Central Serous Chorioretinopathy Treated With Half-Dose Photodynamic Therapy or Subthreshold Micropulse Laser: PLACE Trial Report No. 3

PURPOSE

To compare the outcome between high-density subthreshold micropulse laser (HSML) treatment and half-dose photodynamic therapy (PDT) in chronic central serous chorioretinopathy (cCSC) patients, subdivided based on either focal or diffuse leakage on fluorescein angiography (FA).

DESIGN

Retrospective analysis of multicenter randomized controlled trial data.

METHODS

Patients were treated with either half-dose PDT or HSML (both indocyanine green angiography-guided) and categorized in 2 groups, based on focal or diffuse leakage on FA. Clinical outcomes were evaluated at baseline and during follow-up.

RESULTS

In the focal leakage group (63 patients), both at first evaluation and at final visit, more PDT-treated than HSML-treated patients demonstrated a resolution of subretinal fluid (evaluation visit 1: 57% in the PDT group and 17% in the HSML group, P = .007; final visit: 75% and 38%, P = .012). In the diffuse leakage group (93 patients), both at first evaluation and at final visit, more PDT-treated than HSML-treated patients showed a resolution of subretinal fluid (evaluation visit: 1:48% in the PDT group and 16% in the HSML group, P = .002; final visit: 67% and 21%, P = .002). PDT-treated patients in the focal and diffuse leakage group had a higher retinal sensitivity increase, comparing baseline and final visit (+3.1 ± 3.1 dB vs +1.2 ± 4.0 dB, P = .048, and +2.7 ± 3.3 dB vs +1.0 ± 3.8 dB, P = .036, respectively). Only in the diffuse leakage group, the increase in ETDRS letters was higher in the PDT-treated group when comparing baseline and first evaluation visit (+4.4 ± 6.1 vs +0.9 ± 10.0, P = .049).

CONCLUSIONS

Half-dose PDT is superior to HSML treatment in cCSC patients, regardless of the presence of focal or diffuse leakage on FA.

Impairment of visual acuity and retinal morphology following resolved chronic central serous chorioretinopathy

Purpose

Central serous chorioretinopathy (CSCR) is a complex ocular entity that, in its chronic form, can lead to serious visual impairment and morphological damage to the retina.

The aim of the current retrospective study was to evaluate the damage present after long-standing but resolved central serous chorioretinopathy and refer it to healthy individuals. Correlations between measurable factors—for example, duration of the disease, baseline retinal morphological parameters, or patient age and/or their degree of impairment—were also assessed.

Materials and methods

The study group consisted of thirty-two eyes (13 female and 19 male, mean age 49.6 years SD +/− 10.5) with chronic central serous chorioretinopathy (mean duration 18.9 months SD +/− 15.4) in which complete resolution of subretinal fluid was achieved after subthreshold micropulse laser treatment. Inclusion criterion was a lack of subretinal fluid within the whole area of the central retina scanned by the spectral domain optical coherence tomography. The group was extracted out of 51 cases of chronic CSCR that were treated with that method. They were analyzed according to final best-corrected visual acuity and retinal morphological parameters as measured by spectral optical coherence tomography with angiography option (OCTA). Results were compared with the outcomes of a control group, which consisted of 40 eyes of healthy individuals with full distance visual acuity (0.0 logMAR, 1.0 Snellen) never treated with subthreshold micropulse laser. Statistical analysis included regarding correlation between final visual acuity and final central retinal thickness and retinal and functional parameters prior to treatment.

Results

Final best-corrected visual acuity after chronic central serous chorioretinopathy was 0.23 logMAR (0.6 Snellen) and central retinal thickness was 39.32 μm smaller than in controls. No correlation was found between final visual acuity and retinal thickness and duration of the disease, patient age, and baseline morphological retinal parameters. OCTA scans revealed impaired choriocapillaries flow signal even following resolution of the disease.

Conclusion

Chronic central serous chorioretinopathy is a potentially damaging clinical entity that results in serious visual impairment, retinal thinning, and choroidal flow defects. Further research is needed to determine precisely the timepoint of this damage.

Micropulse Laser Treatment of Retinal Diseases

Subthreshold micropulse laser treatment has been intensively used for selected retinal diseases in the last decade; however, the exact mechanism of the action of lasers in the subthreshold micropulse mode is not yet fully understood. This kind of treatment is safe and cheap, and contrary to classic laser photocoagulation, it leaves the retinal cells intact. A modern theory of micropulse laser interaction with retinal tissue and a possible explanation of this mechanism are presented in this review. The authors present all the relevant literature on the application of micropulse lasers in different retinal disorders. The efficacy of this treatment is analyzed on the basis of available studies and then placed in the perspective of other therapeutic methods that are used in retinal diseases.

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.

Half-Dose Photodynamic Therapy versus High-Density Subthreshold Micropulse Laser Treatment in Patients with Chronic Central Serous Chorioretinopathy: The PLACE Trial

PURPOSE

To compare the anatomic and functional efficacy and safety of half-dose photodynamic therapy (PDT) versus high-density subthreshold micropulse laser (HSML) treatment in patients with chronic central serous chorioretinopathy (cCSC).

DESIGN

Open-label, multicenter, randomized controlled clinical trial.

PARTICIPANTS

Patients with cCSC whose disease had to be confirmed by both clinical characteristics and findings on multimodal imaging.

METHODS

Eligible patients were randomized in a 1:1 allocation ratio. Treatment was evaluated during a follow-up visit, and the same treatment was repeated in patients who still demonstrated subretinal fluid (SRF).

MAIN OUTCOME MEASURES

The primary end point was the complete disappearance of SRF at the first evaluation visit at 6 to 8 weeks after treatment. As a secondary outcome measure, we assessed this anatomic result at the final evaluation visit at 7 to 8 months after treatment. Other secondary outcomes covered functional improvement and included change in best-corrected visual acuity (BCVA; measured in Early Treatment Diabetic Retinopathy Study [ETDRS] letters), retinal sensitivity (measured using microperimetry), and vision-related quality of life using a validated questionnaire.

RESULTS

Between November 2013 and September 2016, 179 patients were included: 89 patients were assigned randomly to half-dose PDT, and 90 were assigned randomly to HSML treatment. At their first evaluation visit, SRF had resolved in 51.2% and 13.8% of patients, respectively (P < 0.001). At their final evaluation visit, a significantly higher percentage of PDT-treated patients demonstrated no SRF (67.2% vs. 28.8%; P < 0.001). Moreover, at the first evaluation visit, the PDT-treated patients showed a significantly higher increase in BCVA (+4.60±6.62 ETDRS letters vs. +1.39±8.99 ETDRS letters; P = 0.011), and a significantly higher increase in retinal sensitivity on microperimetry (+2.01±3.04 dB vs. +0.92±3.65 dB; P = 0.046); however, the improvement in vision-related quality of life was similar (score of +2.87±8.35 vs. +2.56±7.36, respectively; P = 0.800).

CONCLUSIONS

Half-dose PDT is superior to HSML for treating cCSC, leading to a significantly higher proportion of patients with complete resolution of SRF and functional improvement.

Subthreshold diode micropulse laser versus observation in acute central serous chorioretinopathy

BACKGROUND

The purpose of this study was to evaluate subthreshold diode micropulse (SDM) laser as a treatment modality in acute central serous chorioretinopathy (CSC) and compare it with the current standard of care (observation).

METHODS

A randomised controlled trial was conducted on 68 eyes (34 eyes in SDM laser group and 34 eyes in observation group) with acute CSC, with a single angiographic leak and duration of complaints less than two months. Detailed history, examination and investigations were performed at the baseline and at regular intervals until six months.

RESULTS

Eyes in the laser group had significantly higher best-corrected visual acuity at two weeks (p = 0.002), four weeks (p < 0.001), eight weeks (p < 0.001), 16 weeks (p = 0.042) and six months (p = 0.008), and higher contrast sensitivity at eight weeks (p = 0.008), 16 weeks (p < 0.001) and six months (p < 0.001). A recurrent/persistent neurosensory detachment was observed at the end of six months in 11.76 per cent of SDM laser treated eyes versus 29.41 per cent of eyes in the observation group (p = 0.036).

CONCLUSION

SDM laser produces faster and superior visual rehabilitation without any adverse effects. It also reduces the chances of CSC going into chronicity and recurrence compared to the current standard of care (observation).

Visual outcomes and anatomic changes after sub-threshold micropulse yellow laser (577-nm) treatment for chronic central serous chorioretinopathy: long-term follow-up

PurposeTo analyze the long-term efficacy of 577 nm sub-threshold micropulse yellow laser (SMYL) in the treatment of chronic central serous chorioretinopathy (CCSC) and to evaluate the anatomic outcome, visual results and safety profile of the treatment.Patients and methodsThis prospective study assessed 39 eyes of 39 patients with non-resolving CCSC lasting more than three months. All eyes were treated by using 577 nm SMYL system with 5% duty cycle (DC) and each patients was monitored monthly. The main outcome measures were best-corrected visual acuity (BCVA), contrast sensitivity (CS) and subretinal fluid (SRF) height, central macular thickness (CMT), central macular volume (CMV), total macular volume (TMV), and subfoveal choroidal thickness (SFCT) measured by spectral domain optical coherence tomography (SD-OCT).ResultsThe median follow-up time period was 17.82±0.42 (13-23 months) months. The BCVA was improved significantly at final follow-up in comparison of baseline visit (P<0.01) in 35 eyes (89.7%) and in 4 eyes (10.3%) was stable. The median CMT, CMV, TMV before treatment was 369 μm, 0.30 mm3, and 9.86 mm3, in comparison to 250 μm, 0.19 mm3, and 8.76 mm3 at final follow-up, respectively (P<0.01 for all these parameters). Initial median SFCT was recorded as 364 μm and 342 μm at the final follow-up (P<0.001).DiscussionResults suggest that SMYL treatment is an effective method as response was rapid and procedure is safe to manage the non-resolving CCSC eyes.

Yellow (577 nm) micropulse laser versus half-dose verteporfin photodynamic therapy in eyes with chronic central serous chorioretinopathy: results of the Pan-American Collaborative Retina Study (PACORES) Group

PURPOSE

To compare the functional and anatomical outcomes of eyes with chronic central serous chorioretinopathy treated with yellow micropulse (MP) laser versus half-dose verteporfin photodynamic therapy (PDT).

METHODS

This is a multicentre, retrospective comparative study of 92 eyes treated with yellow MP laser (duty cycle of 5%, zero spacing between spots, spot size varied from 100 to 200 µm, power varied from 320 to 660 mW, and the pulse burst duration was 200 ms) and 67 eyes treated with PDT (half-dose verteporfin (3 mg/m²) infused over 10 min), followed by laser activation for 83 s. Spot sizes varied from 400 to 2000 µm.

RESULTS

In the MP group, at 12 months of follow-up, the mean best corrected visual acuity (BCVA) improved from the logarithm of the minimum angle of resolution (logMAR) of 0.41±0.27 at baseline to 0.21±0.26 (P<0.0001), 48.9% (45/92) of eyes had an improvement of ≥3 lines of BCVA from baseline, 48.9% (45/92) of eyes remained within 2 lines of baseline BCVA, and only 2.2% (2/92) of eyes lost ≥3 lines of BCVA from baseline. In the PDT group, at 12 months of follow-up, the mean BCVA changed from logMAR of 0.50±0.34 at baseline to 0.47±0.34 (P=0.89), 19% (13/67) of eyes had an improvement of ≥3 lines of BCVA from baseline, 73% (49/67) of eyes remained within 2 lines of baseline BCVA, and 7% (5/67) of eyes lost ≥3 lines of BCVA from baseline. There were no adverse events attributable to the yellow MP laser treatment. One eye in the PDT group developed choroidal neovascularisation, which was treated with three intravitreal bevacizumab injections.

CONCLUSIONS

Both PDT and MP are effective in restoring the macular anatomy. In places where PDT is not available, yellow MP laser may be an adequate treatment alternative.

Functional and morphological outcome in patients with chronic central serous chorioretinopathy treated by subthreshold micropulse laser

Background

Chronic central serous chorioretinopathy is a serious therapeutic problem as it may lead to significant visual impairment. The aim of this retrospective study is to evaluate functional and morphological effects, as well as factors influencing visual outcome in patients treated by subthreshold micropulse laser.

Methods

Fifty-one eyes with chronic central serous chorioretinopathy lasting longer than 4 months (18 months on average) underwent up to two sessions of subtreshold micropulse laser treatment. Change in best corrected visual acuity, central retinal thickness, central retinal volume, average central retinal thickness and maximum subretinal fluid height were measured. Relation between the effects of the treatment and the initial retinal morphological and functional parameters was then analyzed.

Results

The total resorption of subretinal fluid was achieved in 36 cases (70.6%). There was, however, only a minor improvement in best corrected visual acuity of approximately one line on the Snellen chart. No correlation was observed between the effects of the treatment and the duration of the symptoms, retinal morphology and initial visual acuity. Younger patients responded better to the therapy.

Conclusion

Subthreshold micropulse laser treatment in chronic serous chorioretinopathy provides good morphological results, however significant improvement of visual acuity is not to be expected.

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.

Diagnosed a Patient with Central Serous Chorioretinopathy? Now What?: Management of Central Serous Chorioretinopathy

PURPOSE OF REVIEW WHAT IS THE GOAL OF YOUR PAPER? WHAT QUESTIONS DID YOU SEEK TO ANSWER?

The goal of this paper is to provide a comprehensive review of the management options for central serous chorioretinopathy (CSCR).

RECENT FINDINGS SUMMARIZE THE LATEST RESEARCH ON YOUR TOPIC

The majority of cases of acute CSCR may be managed with observation and cessation of corticosteroids, if possible, as well as life-style modifications including stress reduction and control of hypertension. The management of chronic disease is more challenging and may include either medication or laser-based treatment.

SUMMARY WHAT ANSWERS DID YOU FIND? WHAT ARE THE MAJOR TAKEAWAYS/CONCLUSIONS OF YOUR EXAMINATION? WHAT’S THE IMPACT ON FUTURE RESEARCH?

Management of CSCR necessitates an individualized and selective treatment approach. There is overall poor evidence for the use of systemic and intravitreal medications. From this class of treatments, mineralocorticoid receptor antagonists appear to have the greatest potential. Although conventional thermal photocoagulation may be used in select cases, the most promising treatment options at this time for chronic CSCR are photodynamic therapy, either half-dose or half-fluence, and non-damaging (subthreshold) retinal laser therapy.