LOW-INTENSITY/HIGH-DENSITY SUBTHRESHOLD DIODE MICROPULSE LASER FOR CENTRAL SEROUS CHORIORETINOPATHY

Subthreshold laser treatment in retinal diseases: a mini review

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Central serous chorioretinopathy: An evidence-based treatment guideline

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

Real-Time Temperature-Controlled Retinal Laser Irradiation in Rabbits

Purpose

Subdamaging thermal retinal laser therapy has the potential to induce regenerative stimuli in retinal diseases, but validated dosimetry is missing. Real-time optoacoustic temperature determination and control could close this gap. This study investigates a first in vivo application.

Methods

Two iterations of a control module that were optically coupled in between a continuous-wave commercial laser source and a commercial slit lamp were evaluated on chinchilla rabbits. The module allows extraction of the temperature rise in real time and can control the power of the therapy laser such that a predefined temperature rise at the retina is quickly achieved and held constant. Irradiations with aim temperatures from 45°C to 69°C were performed on a diameter of 200 µm and a heating time of 100 ms.

Results

We analyzed 424 temperature-guided irradiations in nine eyes of five rabbits. The mean difference between the measured and aim temperature was -0.04°C ± 0.98°C. The following ED50 values for visibility thresholds could be determined: 58.6°C for funduscopic visibility, 57.7°C for fluorescein angiography, and 57.0°C for OCT. In all measurements, the correlation of tissue effect was higher to the temperature than to the average heating laser power used.

Conclusions

The system was able to reliably perform temperature-guided irradiations, which allowed for better tissue effect control than simple power control. This approach could enhance the accuracy, safety, and reproducibility of thermal stimulating laser therapy.

Translational Relevance

This study is a bridge between preclinical ex vivo experiments and a pilot clinical study.

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.

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

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

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.

Central Serous Chorioretinopathy: An Update on the Current State of Management

Central serous chorioretinopathy (CSCR) is a relatively common retinal disorder that leads to central vision impairment, often with a high recurrence rate. The exact etiology and pathogenetic mechanisms have not been fully elucidated but are likely to be associated with hyperpermeability of the choroidal capillaries and failure of the retinal pigment epithelium (RPE), leading to serous detachment of the neurosensory retina. Multimodal imaging plays a critical role in the diagnostic approach and monitoring of CSCR. Fortunately, the natural course of the disease is usually self-limiting, with spontaneous resolution and total fluid reabsorption. However, some patients may exhibit recurrences or persistent subretinal fluid (chronic CSCR), leading to progressive and irreversible RPE atrophy or photoreceptor damage. Thus, to prevent permanent visual loss, individualized treatment should be considered. Recent developments in the diagnostic and therapeutic approach have contributed to better outcomes in patients with CSCR. More studies are required to improve our understanding of epidemiology, pathogenesis, diagnosis, and treatment, with a significant impact on the management of this challenging clinical entity. The purpose of this review is to summarize the current knowledge about the clinical features, diagnostic workup, and therapeutic approach of CSCR.

Role of flavonoids in age-related macular degeneration

A common eye disorder known as age-related macular degeneration (AMD) eventually results in blindness and vision loss. AMD has a complicated and poorly understood aetiology. The main pathological processes associated with AMD include oxidative damage, inflammation, and neovascularization. Flavonoids are naturally occurring bioactive substances with extensive distribution and antioxidant, anti-inflammatory, and neovascularization inhibitory properties. Several in vitro and in vivo AMD-related models pertinent to vision and this ocular ailment have been used to assess the mechanisms of action of various flavonoids. This article will discuss the research progress of flavonoids in AMD, especially the characteristics and mechanism of flavonoids in treating AMD.

Development of the selective micropulse individual retinal therapy depends on age and type on the Fitzpatrick scale

PURPOSE

To develop a selective micropulse individual retinal therapy (SMIRT) based on the age and appearance type of the patient, to derive a formula for calculating power, and evaluate clinical efficacy for the treatment of central serous chorioretinopathy (CSCR).

METHODS

73 patients (aged 30-65 years) with acute CSCR and types 1-4 on the Fitzpatrick scale were divided into 2 groups. In the first group (33 patients), the testing of the micropulse mode (50 µs, 2.4%, 10 ms, 100 µm, 0.4-1.9 W) on the Navilas 577 s laser system defined as selective by computer modeling was performed. A logistic regression function based on probability damage detection (PDD) of the 1584 laser spots from power, age, and type on the Fitzpatrick scale was constructed. PDD is the probability of detecting the laser spots using the autofluorescence method. The second group was divided into 4 subgroups of 10 eyes each. Groups 2.1, 2.2, and 2.3 were treated without preliminary testing. The power for Groups 2.1, 2.2, and 2.3 was obtained with the inverse PDD function, so that PDD was 50%, 70%, and 90%, respectively. Control group 2.4 went without treatment.

RESULTS

The transmission and absorption coefficients of laser radiation of the eye depend on the age and the Fitzpatrick scale type. In Groups 2.1-2.3, complete resorption of subretinal fluid was observed 3 months after CSCR treatment in 5 (P < 0.35), 8 (P < 0.023), and 10 eyes (P < 0.0008) out of 10, respectively.

CONCLUSION

The developed SMIRT is effective for CSCR treatment with PDD 90%.

Photodynamic Therapy with Chlorin e6 Derivative for Chronic Central Serous Chorioretinopathy (Pilot Study)

Purpose: To evaluate the use of photodynamic therapy (PDT) with chlorin e6 (Ce6) derivative in patients with chronic central serous chorioretinopathy (CSC). Methods: Participants in this interventional, single-center clinical pilot study included 39 patients (39 eyes) with chronic CSC. Primary objectives were to assess safety and change in decimal best-corrected visual acuity (BCVA) during the 12-month follow-up. Secondary objectives were to evaluate change in central retinal thickness (CRT) in fovea area, maximal height of subretinal fluid (SRF), subfoveal choroidal thickness (SFCT) on spectral-domain optical coherence tomography, and number of treatments. Results: There were no systemic adverse events and ocular side effects. Mean decimal BCVA showed a significant increase from 0.49 ± 0.25 to 0.63 ± 0.28 (P = 0.001), mean CRT and maximal height of SRF decreased significantly from 335 ± 95 to 219 ± 69 μm and from 149 ± 84 to 32 ± 86 μm respectively (P = 0.001), comparing baseline and month 12. There was no significant difference between mean SFCT before PDT and at month 12. During all follow-up periods mean number of PDT treatments was 1.3 ± 0.7. Complete SRF resolution was observed in 82% (32 eyes) during observation period. Conclusion: Results of this pilot study demonstrate that PDT with Ce6 derivative is a safe method to treat eyes with chronic CSC. PDT with Ce6 derivative is the treatment option for chronic CSC. Further randomized controlled studies with a larger sample size and longer periods of follow-up are needed to assess the effectivity and safety of PDT with Ce6 derivative in chronic CSC.

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.

Mineralocorticoid receptor antagonists for chronic central serous chorioretinopathy: systematic review and meta-analyses

BACKGROUND

Mineralocorticoid receptor antagonists (MRAs) are widely used for chronic central serous chorioretinopathy (cCSCR), but their effectiveness remains unclear. This research was conducted to evaluate the efficacy of this drugs for cCSCR.

METHODS

This is a review of randomized clinical trials (RCT) comparing MRAs to placebo in adults with cCSCR, using the effects of MRAs on best-corrected visual acuity (BCVA) and adverse events as primary outcomes and the effects of MRAs on anatomical parameters as secondary outcomes: central subfield thickness (CST), subretinal fluid height (SFH) and central choroidal thickness (CCT). Our all-language online search included Medline (via PubMed), Central, Embase, Lilacs, Ibecs, and RCT registers platforms, as late as May 2021. We used the Cochrane risk-of-bias tool (version 2) to assess the methodological quality of each study and synthesized the results in meta-analyses using a random-effects model.

RESULTS

The search identified 302 records, five of which were eligible, totaling 225 cCSCR patients (aged 45-62 years; M/F ratio 3.1:1) treated for 1 to 12 months with spironolactone (50 mg/day) or eplerenone (50 mg/day) vs. placebo. Moderate-certainty evidence suggests MRAs result in little to no improvement in BCVA compared to placebo (SMD 0.22; 95% CI - 0.04 to 0.48; studies = 5; comparisons = 6; participants = 218; I2 = 0%). Very low-certainty evidence suggests that, when compared to placebo, MRAs have a very uncertain impact on adverse effects (no meta-analysis was performed), and CST (MD 18.1; 95% CI - 113.04 to 76.84; participants = 145; studies = 2; I2 = 68%). MRAs also result in little to no difference in SFH (SMD - 0.35; 95% CI - 0.95 to 0.26; studies = 5; comparisons = 6; participants = 221; I2 = 76%; moderate certainty) and CCT (MD - 21.23; 95% CI - 64.69 to 22.24; participants = 206; studies = 4; comparisons = 5; I2 = 85%; low certainty).

CONCLUSION

MRAs have little to no effect on BCVA. Evidence for adverse events and CST is very uncertain. MRAs also have little to no effect on SFH and CCT. These findings should be considered when prescribing MRAs for cCSCR. This research was previous registration in the PROSPERO platform (CRD42020182601).

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

Purpose

To access the impact of regular periodic subthreshold diode micropulse laser (SDM) as Vision Protection Therapy on the rate of neovascular conversion of dry age-related macular degeneration (AMD).

Methods

Patient unidentified clinical data aggregated by Vestrum Health, LLC (VH) from 300 retina specialists across the United States was analyzed to examine the effect of a program of regular periodic panmacular low-intensity/high-density subthreshold diode micropulse laser as vision protection therapy (VPT) compared to standard care alone, on the incidence of neovascular conversion in patients with dry age-related macular degeneration (AMD), between January 4, 2016, and September 30, 2020, producing 392,250 eyes for study.

Results

After applying inclusion and exclusion criteria, eyes were matched by propensity scoring for key risk factors. This produced 830 eyes managed by standard care plus VPT, performed on average every 108 days per eye; and 8300 eyes managed with standard care alone (SCA) in a 1/10 ratio for comparison. Comparison found that VPT eyes had a markedly lower rate of neovascular conversion than SCA eyes (hazard ratio 13.04) overall, and for each propensity score matched quintile. VA worsened over time in the SCA group but improved in the VPT group.

Conclusion

Our findings suggest that, compared to standard care alone, VPT may markedly reduce the rate of neovascular conversion in AMD, the main cause of irreversible visual loss worldwide.

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.

Factors Predicting Response to Selective Retina Therapy in Patients with Chronic Central Serous Chorioretinopathy

This retrospective study aimed to assess the safety and efficacy of selective retina therapy (SRT) with real-time feedback-controlled dosimetry (RFD) for chronic central serous chorioretinopathy (CSC) and to evaluate factors predictive of treatment response. We included 137 eyes of 135 patients with chronic CSC. SRT was performed to cover each of the leakage areas on fundus fluorescein angiography. Changes in mean best-corrected visual acuity (BCVA), central macular thickness (CMT), and subretinal fluid (SRF) height were evaluated at baseline and at 3 and 6 months after treatment. Complete SRF resolution was observed in 52.6% (72/137 eyes) and 90.5% (124/137 eyes) at 3 and 6 months, respectively. Mean BCVA (logMAR) significantly improved from 0.41 ± 0.31 at baseline to 0.33 ± 0.31 at month 6 (p < 0.001). Mean CMT significantly decreased from 347.67 ± 97.38 μm at baseline to 173.42 ± 30.95 μm at month 6 (p < 0.001). Mean SRF height significantly decreased from 187.85 ± 97.56 µm at baseline to 8.60 ± 31.29 µm after 6 months (p < 0.001). Baseline SRF height was a significant predictive factor for retreatment requirement (p = 0.008). In conclusion, SRT showed favorable anatomical outcomes in patients with chronic CSC. A higher baseline SRF height was a risk factor for retreatment.

Characteristics of Central Serous Chorioretinopathy without Leakage

Purpose:

To describe optical coherence tomography (OCT) characteristics of central serous chorioretinopathy (CSCR) without any hyperfluorescent leakage on fundus fluorescein angiography (FFA).

Methods:

This was a multicentric, retrospective, observational study of ten eyes of ten patients with CSCR without any hyperfluorescence leakage on FFA. Baseline patient characteristics, best corrected visual acuity, and OCT parameters like relative retinal pigment epithelium (RPE) reflectivity at the presumed leak site and control site were measured.

Results:

Increased macular thickness, neurosensory detachment, and choroidal thickness were seen at the site of maximum subretinal fluid (SRF). Out of ten eyes, nine had photoreceptor outer segment (PROS) disruption (46% ± 26.33%) at the site of SRF pocket, and five had presumed former leak site characterized by PROS thinning. The presumed leak site demonstrated higher RPE reflectivity compared to the control site (0.92 ± 0.04 vs. 0.87 ± 0.04; P = 0.0058).

Conclusion:

CSCR without hyperfluorescent leakage on FFA may have PROS damage and changes in RPE hyperreflectivity.

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.

Serous business: Delineating the broad spectrum of diseases with subretinal fluid in the macula

A wide range of ocular diseases can present with serous subretinal fluid in the macula and therefore clinically mimic central serous chorioretinopathy (CSC). In this manuscript, we categorise the diseases and conditions that are part of the differential diagnosis into 12 main pathogenic subgroups: neovascular diseases, vitelliform lesions, inflammatory diseases, ocular tumours, haematological malignancies, paraneoplastic syndromes, genetic diseases, ocular developmental anomalies, medication-related conditions and toxicity-related diseases, rhegmatogenous retinal detachment and tractional retinal detachment, retinal vascular diseases, and miscellaneous diseases. In addition, we describe 2 new clinical pictures associated with macular subretinal fluid accumulation, namely serous maculopathy with absence of retinal pigment epithelium (SMARPE) and serous maculopathy due to aspecific choroidopathy (SMACH). Differentiating between these various diseases and CSC can be challenging, and obtaining the correct diagnosis can have immediate therapeutic and prognostic consequences. Here, we describe the key differential diagnostic features of each disease within this clinical spectrum, including representative case examples. Moreover, we discuss the pathogenesis of each disease in order to facilitate the differentiation from typical CSC.

The Role of Imaging in Planning Treatment for Central Serous Chorioretinopathy

Central serous chorioretinopathy (CSC) is a controversial disease both in terms of clinical classification and choice of therapeutic strategy. Choroidal layers, retinal pigment epithelium (RPE), photoreceptors, and retina are involved to varying degrees. Beyond well-known symptoms raising the clinical suspect of CSC and slit-lamp fundus examination, multimodal imaging plays a key role in assessing the extent of chorioretinal structural involvement. Subretinal fluid (SRF) originating from the choroid leaks through one or multiple RPE defects and spreads into the subretinal space. Spontaneous fluid reabsorption is quite common, but in some eyes, resolution can be obtained only after treatment. Multiple therapeutic strategies are available, and extensive research identified the most effective procedures. Imaging has carved a significant role in guiding the choice of the most appropriate strategy for each single CSC eye. Multiple biomarkers have been identified, and all of them represent a diagnostic and prognostic reference point. This review aims to provide an updated and comprehensive analysis of the current scientific knowledge about the role of imaging in planning the treatment in eyes affected by CSC.

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.

Short Term Presence of Subretinal Fluid in Central Serous Chorioretinopathy Affects Retinal Thickness and Function

Background: Acute central serous chorioretinopathy (CSCR), with subretinal fluid (SRF) resolving spontaneously within a few months from disease onset, has been considered as a benign and self-limiting disease for many years. This study sought to discover if a short presence of SRF can result in morphological and functional damage to the retina. Materials and methods: The study included patients treated by subthreshold diode micropulse laser (SDM) application for acute CSCR at the Dobry Wzrok Ophthalmological Clinic between January 2018 and November 2019. Inclusion criteria were: first episode of CSCR; duration of symptoms of two months or less; complete resolution of subretinal fluid (SRF) after a single session of SDM; and a lack of any retinal pathology, previous CSCR episode, significant anisometropia or amblyopia in the collateral eye. Fifteen patients fulfilled the inclusion criteria, including 13 males and two females aged 42.3 ± 9.5 years. The mean duration of symptoms before treatment was 4.7 ± 1.3 weeks on average. Baseline and follow-up examinations were performed in both the affected and collateral eyes and included best-corrected visual acuity (BCVA); spectral-domain optical coherent tomography measurements such as central retinal thickness (CRT) and minimal foveal thickness (MFT) (at the follow-up visit only); fluorescein angiography (at presentation only) and fundus autofluorescence. The first follow-up visit, when the total resolution of SRF was noted, was conducted between 8 and 12 weeks after SDM. Results: Resolved CSCR eyes had significantly poorer BCVA, CRT, and MFT findings in comparison with healthy collateral eyes (respectively, 0.11 +/− 0.1 vs. 0.01 +/− 0.04 logMAR; 238.80 +/− 23.39 vs. 264.87 +/− 21.22 µm and 178.93 +/− 16.88 vs. 199.47 +/− 17.87 µm) despite the short period of CSCR duration (maximum of 14 ± 2.15 weeks on average). Conclusion: Short presence of SRF typical for acute CSCR can affect retinal function and morphology resulting in poorer visual outcome.

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.

Update on the management of chronic central serous chorioretinopathy

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

Subthreshold Micro-Pulse Yellow Laser and Eplerenone Drug Therapy in Chronic Central Serous Chorio-Retinopathy Patients: A Comparative Study

PURPOSE

To study the outcomes of subthreshold micropulse yellow laser (SML) and eplerenone (EP) therapy in central serous chorio-retinopathy (cCSCR).

METHODS

Retrospective study of 28 eyes of 27 patients undergoing SML and 20 eyes of 19 patients undergoing EP therapy.

RESULTS

Median duration of follow-up was 8 months for SML and 4.5 months for EP group. Complete SRF resolution was seen in 12/28 (42.8%) eyes in SML and 4/20 (20%) in EP group. Six eyes in SML group and two eyes in EP group needed additional SML. No EP patients demonstrated hyperkalemia warranting stopping of therapy. Baseline visual acuity (VA) was correlated positively with final VA in both groups. Presence/absence of focal leaks had differing outcomes in both treatment groups in terms of anatomical resolution.

CONCLUSION

Both treatment modalities were effective in the management of cCSCR showing comparable favorable anatomical outcomes, but visual outcomes were not significant, probably due to chronicity of the pathology.

Subthreshold yellow laser for fovea-involving diabetic macular edema in a series of patients with good vision: effectiveness and safety of a fovea-sparing technique

PURPOSE

Patients with center-involved diabetic macular edema (CI-DME) with good visual acuity (VA) represent a controversial clinical scenario in which a subthreshold laser might be a reasonable approach. We report a case series of patients with CI-DME with VA better than 20/32 who were treated with a subthreshold 577 nm (yellow) laser.

METHODS

The area of retinal thickening on OCT was treated with confluent laser spots at individually titrated power. The fovea was spared from treatment. Effectiveness and safety were evaluated through OCT and autofluorescence (AF) as well as BCVA.

RESULTS

A total of 23 eyes from 19 patients were treated. VA ranged from 20/20 to 20/30. The follow-up period ranged from 6 to 18 months. Edema in OCT resolved completely at the end of follow-up in 56.5% (13/23) of the cases. Central retinal thickness was reduced at 12 weeks and at the end of follow-up, with a mean reduction of 16.9 μm and 22 μm, respectively (paired t-test p = 0.001 and 0.0003). VA remained stable. The laser was invisible (OCT, AF, Fundoscopy) in 91,3% (21/23) of eyes.

CONCLUSIONS

A fovea-sparing yellow subthreshold laser was safe and effective for treating CI-DME patients with good VA in this case series. This technique is of interest to prevent the progression of mild edema and might avoid or reduce the use of more invasive and expensive therapies. Excluding the fovea from the treated area does not seem to affect the results, which is of interest to novel laser practitioners.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

Translational Relevance

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

Central Serous Chorioretinopathy: Pathogenesis and Management

Central serous chorioretinopathy (CSC) is a common retina disease and has a relative high recurrence rate, etiology, and pathogenesis of which remains largely ambiguous. The effects on the retina are usually self-limited, although some people are left with permanent vision loss due to progressive and irreversible photoreceptor damage or retinal pigment epithelium atrophy. There have been a number of interventions used in CSC, including, but not limited to, laser treatment, photodynamic therapy (PDT), intravitreal injection of anti-vascular endothelial growth factor agents, and subthreshold lasers. It is not clear whether there is a clinically important benefit to treating acute CSC, which often resolves spontaneously as part of its natural history. Of the interventions studied to date, PDT and micropulse laser treatment appear the most promising. 

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.

The subthreshold micropulse laser treatment of the retina restores the oxidant/antioxidant balance and counteracts programmed forms of cell death in the mice eyes

PURPOSE

Subthreshold micropulse laser (SMPL) has been increasingly used for the treatment of different retinal and choroidal macular disorders. However, the exact mechanisms of action have not yet been clearly defined. Therefore, we aimed to examine the role of SMPL treatment in the modulation of oxidant/antioxidant systems, apoptosis and autophagy in the mice eyes.

METHODS

A specific laser contact lens for retina was positioned on the cornea of 40 mice (20 young and 20 old) in order to focus the laser on the eye fundus for SMPL treatment. Within 6 months, 20 animals received one treatment only, whereas the others were treated three times. Eye specimens underwent histological analysis and were used for thiobarbituric acid reactive substances (TBARS) and glutathione (GSH) quantification, as well as for the superoxide dismutase 1 (SOD1) and the selenoprotein thioredoxin reductase 1 (TrxR1) expression evaluation. Western blot was performed for nitric oxide synthase (NOS) subtypes detection and to examine changes in apoptotic/autophagy proteins expression.

RESULTS

SMPL treatment reduced TBARS and increased GSH and SOD1 in the mice eyes. It also reduced cytochrome c, caspase 3 expression and activity and cleaved caspase 9, and increased Beclin 1, p62 and LC3β. The effects were more relevant in the elderly animals.

CONCLUSION

Our results showed that SMPL therapy restored the oxidant/antioxidant balance within retinal layers and modulated programmed forms of cell death. Further studies may confirm these data and could evaluate their relevance in clinical practice.

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.

Short-duration multiple-session subthreshold micropulse yellow laser (577 nm) for chronic central serous chorioretinopathy: results at 3 years

OBJECTIVES

To review the 3-year follow-up results of subthreshold micropulse yellow laser (SMYL) delivered by a short-duration multiple-session method for treatment of chronic central serous chorioretinopathy (CSC).

METHODS

A total of 27 eyes from 27 patients with chronic CSC available for 3 years of follow-up were enrolled in this retrospective and interventional study. Patients were treated with 577-nm SMYL photocoagulation at a 15% duty cycle over multiple sessions, with low power ranging from 200 to 400 mW that was increased in 100 mW increments according to resolution of subretinal fluid at monthly follow-up. Laser titration was not performed. A treatment duration of 20 ms rather than the conventional duration (100-300 ms) was applied over the area of retinal pigment epithelium leakage and all areas of serous retinal detachment, including the fovea.

RESULTS

The mean follow-up period was 3.7 ± 0.8 years (range, 3-6 years). A total of 22 out of 27 eyes (81.5%) including six cases of recurrence during the follow-up period exhibited complete resolution of subretinal detachment at final follow-up, whereas only five eyes (15.5%) had either a partial or null response to SMYL treatment. The baseline best-corrected visual acuity was 0.26 ± 0.24 logarithm of the minimum angle of resolution (logMAR), which was improved to 0.08 ± 0.15 logMAR at 1-year (p = 0.005) and 3-year (p = 0.01) follow-up. The central macular thickness at baseline was 389.6 ± 103.4 μm, which was changed to 197.2 ± 40.0 μm (p < 0.001) at 1-year follow-up, 196.4 ± 40.2 μm (p < 0.001) at 3-year follow-up.

CONCLUSION

Short-duration multiple-session SMYL therapy may be effective for long-term treatment of chronic CSC.

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.

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).

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.

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.