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

Therapeutic interventions for chronic central serous chorioretinopathy: a comprehensive assessment of systematic reviews

BACKGROUND

A variety of different treatments have been proposed to effectively treat chronic central serous chorioretinopathy but there remains uncertainty regarding the efficacy of a number of treatment options. We aim to evaluate the efficacy of several therapeutic options for chronic central serous chorioretinopathy including photodynamic therapy, conventional laser photocoagulation, subthreshold micropulse laser, selective retina therapy, vascular endothelial growth factor (VEGF) antagonists, and mineralocorticoid receptor antagonists.

METHODS

Pubmed, Embase, and Cochrane databases were searched for systematic reviews and meta-analyses evaluating treatment modalities for chronic central serous chorioretinopathy. Primary outcome measures included improvement in best corrected visual acuity (BCVA) and resolution of subretinal fluid (SRF). Conclusions regarding the efficacy of each modality were summarized and compared to findings of several key randomized controlled trials.

RESULTS

Ten systematic reviews and meta-analyses that incorporated 58 unique randomized controlled trials and observational studies were identified. Treatments that were shown to improve BCVA and promote SRF resolution included half-fluence and half-dose photodynamic therapy, conventional laser therapy, and subthreshold micropulse laser therapy. Evidence regarding selective retina therapy was limited and inconclusive. VEGF antagonists were not effective in the absence of choroidal neovascularization and mineralocorticoid receptor antagonists were not effective.

CONCLUSION

The most effective therapeutic option for chronic central serous chorioretinopathy is half-dose or half-fluence photodynamic therapy, however, conventional laser therapy is an acceptable alternative in cases when photodynamic therapy is unavailable and when fluid leakage sites are not subfoveal or juxtafoveal. Subthreshold micropulse laser is less effective but can be considered when other options are unavailable.

Efficacy and safety of subthreshold micropulse laser in the treatment of central serous chorioretinopathy accompanied by choroidal hemangioma: a case report

BACKGROUND

Circumscribed choroidal hemangioma (CCH) is a benign vascular hamartoma caused by congenital vascular malformation. And, central serous chorioretinopathy (CSCR) is a chorioretinal disease characterized by pachychoroid, RPE irregularities, and subretinal fluid (SRF) accumulation. Some literature has indicated a potential correlation between the occurrences of CCH and CSCR.

CASE PRESENTATION

A 59-year-old man presented with blurred vision in his right eye for six months, with an unremarkable history. Multimodal imaging techniques including color fundus photography, fundus autofluorescence (FAF), B-scan ultrasonography (USG), fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), and optical coherence tomography (OCT), revealed the presence of CCH accompanying CSCR in the right eye. The patient received treatment with SML for CSCR, while no specific treatment was administered for CCH. The SRF was fully resolved one month after the treatment. At the 3- and 6-month follow-up, SRF resolved, and best-corrected visual acuity (BCVA) improved from 0.6 to 0.9 in the decimal format in the right eye, without notable changes in subfoveal choroidal thickness (SFCT) or the size of CCH.

CONCLUSION

This case reported the coexistence of CCH and CSCR in the right eye, both characterized by choroidal vascular abnormalities. Further research is necessary to determine the favorable effect of SML in patients with CSCR and concurrent CCH.

Subthreshold Laser Titration Database in a Population with Central Serous Chorioretinopathy and Dome-Shaped Macula

Objectives: This study aimed to describe the laser titration needed to create a safe and effective subthreshold laser (STL) for use in patients with chronic central serous chorioretinopathy (CSCR) and dome-shaped macula (DSM) and to investigate the possible factors influencing titration. Methods: This was a prospective single-center study that recruited 92 eyes of 87 patients that presented with CSCR (84.8%) and DSM (15.2%) for a 577 nm STL treatment for persistent subretinal fluid. Age, sex, and the spherical equivalent (SE) were collected. Titration was performed by applying various impacts, beginning at 800 mW and increasing in 100 mW steps. The photocoagulation threshold (PT) was assessed as the minimum power at which faint whitening was observed in fundus retinography. Results: The mean age was 53.5 ± 10.3 years and 78.3% of patients were male. The mean SE was 0.3 ± 3.0 D (range -9.5-+11.0). The overall mean power to reach PT was 1102.7 ± 183.0 mW (range 800-1600). In the multivariate analysis, age and SE were associated with PT (p = 0.022 and 0.011, respectively). On the contrary, no association was observed between PT and sex (p = 0.924), macular disease (CSCR vs. DSM, p = 0.416), or central macular thickness (CMT) (p = 0.667). Conclusions: This study highlights the broad power range required for effective subthreshold laser (STL) titration and emphasizes the need for individualized treatment parameters to optimize outcomes. No significant differences in titration power were found regarding macular disease type, CMT, or sex. However, a mild correlation between PT, SE, and age was observed.

Visual and anatomical evaluation of navigated subthreshold micropulse laser versus photodynamic therapy in managing chronic central serous chorioretinopathy

PURPOSE

To compare the visual and anatomical results of navigated subthreshold micropulse laser (nSML) and photodynamic therapy (PDT) in the treatment of chronic central serous chorioretinopathy (CSCR).

METHODS

Patients who underwent either half-dose PDT or nSML for the management of chronic CSCR were included in this study. Comprehensive ophthalmic examination, fundus autofluorescence, and spectral domain optical coherence tomography (SD-OCT) were performed at baseline and at 1-, 3-, and 6-month follow-up visits after nSML or PDT. Fluorescein angiography and indocyanine green angiography were performed only at baseline. Main outcome measures were best corrected visual acuity (BCVA), central macular thickness (CMT), subretinal fluid (SRF), subfoveal choroidal thickness (SFCT), and choroidal vascularization index (CVI) that were collected at baseline and at each follow-up visit for up to 6 months.

RESULTS

Forty-two eyes of 42 patients (PDT group-20 eyes, nSML group-22 eyes) affected by chronic CSCR were enrolled. At 6-month follow-up, no significant differences were observed between the nSML group compared to the PDT group in BCVA (0.10 [0.00; 0.20]) and 0.10 [0.10; 0.10], respectively, p=0.69, and between some OCT parameters, namely CMT and CVI. SFCT was significantly reduced in the PDT group more than in the nSML group (p=0.01). Twelve eyes (60%) in the PDT group had complete resolution of the SRF at 6 months compared to 8 eyes (36.4%) in the nSML group, but the difference was not statistically significant (p=0.14).

CONCLUSION

Results from patients treated with PDT and nSML showed that, at 6 months, no significant differences except for choroidal thickness. nSML is less invasive than PDT and can be used as an effective alternative to PDT.

KEY MESSAGES

WHAT IS KNOWN : Treating chronic CSCR is a therapeutic conundrum for clinicians because of a lack of definitive consensus over remediation options, two of which are photodynamic therapy (PDT) and navigated subthreshold micropulse laser (nSML) therapy.

THIS STUDY SHOWS

Results from patients treated with PDT and nSML showed no significant differences except for choroidal thickness. Even though patients treated with PDT recovered more quickly, retreatment was necessary due to fluid recollection. Although patients treated with nSML also needed retreatment, nSML is less invasive than PDT and can be used as an effective alternative to PDT.

Fluorescein angiography patterns and subretinal hyperreflective material predict subthreshold micropulse laser response in chronic central serous chorioretinopathy

BACKGROUND

To investigate predictors of navigated subthreshold micropulse laser (SML) treatment in chronic central serous chorioretinopathy (cCSC).

METHODS

In this single-center prospective consecutive case series, patients with cCSC were treated with 577 nm SML and followed up for 12 months. A complete ophthalmological evaluation including spectral optical coherence tomography (SD-OCT), fluorescein angiography (FA) and microperimetry (MP) was performed. FA hyperfluorescence patterns and SD-OCT features were investigated.

RESULTS

Overall, 38 eyes from 38 patients affected by cCSC with a mean age of 48.20 ± 5.95 years were included. Thirty-one eyes (81.6%) demonstrated a significant subretinal fluid (SRF) reduction after treatment at 3 months. Complete SRF resolution was achieved by twenty-three patients (60.5%) at 3 months and attained by an additional patient (24 in total, 63.2%) at 6 months. Twenty-two (57.9%) of such individuals were confirmed with no SRF at the end of the follow-up. Best-corrected visual acuity improved significantly and progressively at all timepoints from baseline, in parallel with macular sensitivity (all p: <0.005). Logistic regression analysis revealed that the presence of subretinal hyperreflective material (SHRM, p: 0.044; OR: -0.225; 95% CI: -0.448 - -0.003) and focal hyperfluorescence pattern on FA (p < 0.001; OR: 0.438; 95% CI: 0.196-0.632) predicted poorer and better treatment response, respectively.

CONCLUSIONS

FA hyperfluorescence pattern and presence of SHRM may predict SML treatment response in cCSC patients.

Variability of thermal subthreshold retinal laser treatment plans

To investigate the variability in subthreshold laser treatment plans for patients with diabetic macular edema or central serous chorioretinopathy. Diagnostic images from 20 patients were utilized, and 25 retina specialists generated subthreshold treatment plans along with a self-rated experience level. Evaluation comprised of i) Area Variability (AV): quantifies the consensus regarding the covered area and is the difference between the areas planned by 75% and 25% of the participants ii) mean Centroid Distance (CD): level of agreement on the localization of a treatment. Subgroup analysis investigated the impact of participants' experience levels, utilizing the Mann-Whitney-Wilcoxon test. The predominant plan style is a targeted treatment approach (92%) and avoidance of subfoveal region (89%). Mean CD is 71.0 ± 37.5 pixels (≈half disc diameter) and mean AV is 9.8%±8.9%. A slight difference is observed between the 50-75% areas, but a notable distinction exists between the 25-50% areas. Subgroup analysis revealed CD and AV value of 75.9 pixels and 24% in the lower experience level group as opposed to 55.9 pixels and 8.6% in the higher experience level group. There is significant variability in treatment planning which reduces with increased experience of retina specialists. While consensus is observed around focal points, differences in the surrounding extents persist.

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.

A randomized non-inferiority trial of 577nm subthreshold micropulse laser versus half-dose photodynamic therapy for acute central serous chorioretinopathy

PURPOSE

To compare the effectiveness of 577nm subthreshold micropulse laser (SML) with half-dose photodynamic therapy (Hd-PDT) for acute central serous chorioretinopathy (CSC).

METHOD

A non-inferiority clinical trial was performed with a non-inferiority margin of eight letters. Sixty-eight eyes of 68 patients with acute CSC were randomized to the Hd-PDT group or 577 nm SML group. Best-corrected visual acuity (BCVA ), the subretinal fluid (SRF), and the central foveal thickness (CFT) were evaluated at 6 months.

RESULTS

The visual acuity significantly improved from 70.38 ± 10.37 at baseline to 83.24 ± 3.03 at 6 months after treatment in the SML group (P < 0.001), from 71.09 ± 10.50 to 84.35 ± 2.09 in the PDT group (P < 0.001). SML was non-inferior to the PDT (mean difference: -0.41, 95% CI: -5.51 - 4.68, P = 0.0021). At the endpoint, CFT was significantly reduced in the two groups, but no statistical difference (P = 0.7694). The complete resolution of SRF reached 82.35% (28/34) in the SML group and 91.18% (31/34) in the PDT group, respectively,but no statistical difference (P = 0.3724).

CONCLUSIONS

SML was non-inferiority to half-dose PDT in improving the visual acuity for CSC, and it is a viable alternative, especially when the verteporfin in PDT is unavailable.

Hyperplasia of the retinal pigment epithelium secondary to subthreshold laser treatment in chronic central serous chorioretinopathy

PURPOSE

To assess the development of hyperplasia of the retinal pigment epithelium (HRPE) secondary to subthreshold laser treatment (STL) in chronic central serous chorioretinopathy (CSCR).

METHODS

Prospective study including 149 eyes of 146 patients with CSCR with persistent subretinal fluid (SRF) that have undergone STL using the Navilas® device. Visual acuity (VA) optical coherence tomography (OCT) and fundus autofluorescence (FAF) were performed before and after the treatment. The HRPE was identified on OCT as a hyperreflective and dense material at the expense of the RPE that did not exist prior to the treatment. The demographics of the patients as well as the parameters of the STL treatments employed were registered.

RESULTS

Seven HRPE cases after STL were identified, observing an incidence of 4.7% (7 out of 149 eyes). The mean age was 52.1 ± 3.6 years, being 6/7 males. The mean number of STL sessions was 1.3 ± 0.5. The mean total fluence applied was 52.2 ± 12.4 J/cm2 (range 35.37 to 76.39 J/cm2), using a duty cycle of 10% in all cases. The HRPE was subfoveal in 6 of the 7 cases. The SRF was resolved in 6 of the 7 patients. The mean VA loss was -14.1 ± 14.3 ETDRS letters.

CONCLUSION

The development of HRPE secondary to STL in CSCR is an uncommon but severe adverse effect, probably related to the excessive energy employed. Further studies are warranted to minimize the incidence and to know the predictors of this complication after STL treatment to optimize the parameters that should be used.

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.

Effectiveness, Safety and Choroidal Changes of a Fovea-Sparing Technique for the Treatment of Chronic Central Serous Chorioretinopathy with Yellow Subthreshold Laser

The aim of this study was to evaluate the effectiveness and safety of a yellow subthreshold laser (STL) for the treatment of chronic central serous chorioretinopathy delivered in a fovea-sparing pattern and to analyze the post-laser changes in the choroidal structure by Swept-Source Optical Coherence Tomography. This study was a prospective case series of 43 eyes corresponding to 37 patients. Data were recorded at 6, 12 and 24 weeks after the STL treatment. The best-corrected visual acuity improved in 93% of the patients and remained stable in 7%. The subretinal fluid was completely reabsorbed in 27.9%, 32.6% and 69.8% of the patients at 6, 12 and 24 weeks, respectively. There were reductions in the choroidal thickness of 13.1% and 25.3% at 12 and 24 weeks, which corresponded to reductions of 17.5% and 45.9% in the choriocapillaris and Sattler layer and reductions of 12.2% and 21.2% in the Haller layer at 12 and 24 weeks, respectively (p < 0.05). This might account for the effect of the laser on the inner choroidal vasculature, the dysregulation of which is believed to be at the core of central serous chorioretinopathy. No laser-related complications were detected. Overall, the fovea-sparing STL was safe and effective in this series of patients.

Influence of Retinal Microsecond Pulse Laser Treatment in Central Serous Chorioretinopathy: A Short-Term Optical Coherence Tomography Angiography Study

Background: Central serous chorioretinopathy (CSC) is a common macular condition characterized by detachment of the neuroretina and is a frequent cause of central vision loss in adults. Among the various therapeutic strategies, subthreshold microsecond pulsed laser (SML) treatment has become a useful option. Despite the suggested involvement of choroidal circulatory disturbances in CSC, the effects of this treatment on macular microperfusion have not been fully evaluated yet. Herein, we report the impact of SML on retinal and choroidal microvascular flow using non-invasive optical coherence tomography (OCT) angiography (OCTA). Methods: In this study, CSC patients with persistent subretinal fluid (SRF) with or without secondary choroidal neovascularization (CNV) were included (referred to as the pachychoroid neovasculopathy (PNV) group and the CSC group, respectively). SML was conducted using a yellow (577 nm) laser with a duty cycle of 10%, spot size of 200 µm and duration of 200 ms. Best corrected visual acuity (BCVA) as well as OCT and OCTA images were evaluated at baseline and 4 weeks after SML. OCTA parameters of interest included full retinal perfusion (FRP), choriocapillaris perfusion (CCP), Sattler’s layer perfusion (SLP), and Haller’s layer perfusion (HLP), which were evaluated longitudinally and compared to unaffected fellow eyes. Results: 27 affected eyes and 17 fellow eyes from 27 patients were included. Before treatment, central retinal thickness (CRT) and subfoveal choroidal thickness (SFCT) of affected eyes were significantly larger than in fellow eyes. Four weeks after SML, CRT decreased significantly, whereas perfusion parameters did not change. In subgroup analyses, the CSC group showed a significant decrease in SFCT, whereas the PNV group did not despite the decrease in CRT. Conclusion: Our results suggest that the SML may affect the SFCT of the CSC, but not the PNV patients at least within four weeks following treatment. This effect seems to be independent of the change in choroidal perfusion measured with OCTA.