Indocyanine green dye-enhanced micropulsed diode laser: a novel approach to subthreshold RPE treatment in a case of central serous chorioretinopathy

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.

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.

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.

Design of a Surgical Pen-Type Probe for Real-Time Indocyanine Green Fluorescence Emission Diagnosis

The advantage of handheld type surgical microscope is that the size of the probe is small and light, and that both the working distance (15–30 cm) and field of view (30 deg) can be adjusted. The shortness working distance will minimize the loss of light source energy. However, the currently developed handheld type surgical microscope is still large, heavy, and uses relatively high energy (600 mW/cm2). To address the aforementioned problems, this study aimed to develop a pen-type surgical fluorescence microscope that is compact, portable, and has an adjustable beam angle and working distance. These features enable real-time diagnosis. The pen-type probe consists of a laser diode, CMOS camera, light source brightness control device, filter, and power switch. The IR-cut filter inside the CMOS camera was removed to facilitate transmission of the fluorescence emission wavelength. In addition, a long-pass filter was attached to the camera so that the external light source was blocked and only the fluorescence emission wavelength was allowed to pass through. The performance of the pen-type probe was tested through a large animal experiment. Indocyanine green (2.5 mg/kg) was injected into a pig's vein. Fluorescence emission of 805-830 nm was achieved by irradiating an external light source (785 nm and 4 mW/cm2), and liver-uptake occurred after 2.4 min. The designed pen-type probe was capable of sufficiently fluorescence expression through low-energy irradiation, and the pen-type probe is small and light and easy to handle by hand because both the pen-based laser device and the camera device are integrated. In addition, it is easy to adjust the working distance and field of view.

A Surgical Pen-Type Probe Design for Real-Time Optical Diagnosis of Tumor Status Using 5-Aminolevulinic Acid

A surgical microscope is large in size, which makes it impossible to be portable. The distance between the surgical microscope and the observation tissue is 15–30 cm, and the adjustment range of the right and left of the camera is a maximum of 30°. Therefore, the surgical microscope generates an attenuation (above 58%) of irradiation of the optical source owing to the long working distance (WD). Moreover, the observation of tissue is affected because of dazzling by ambient light as the optical source power is strong (55 to 160 mW/cm²). Further, observation blind spot phenomena will occur due to the limitations in adjusting the right and left of the camera. Therefore, it is difficult to clearly observe the tumor. To overcome these problems, several studies on the handheld surgical microscope have been reported. In this study, a compact pen-type probe with a portable surgical microscope is presented. The proposed surgical microscope comprises a small and portable pen-type probe that can adjust the WD between the probe and the observed tissue. In addition, it allows the adjustment of the viewing angle and fluorescence brightness. The proposed probe has no blind spots or optical density loss.

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.

An international collaborative evaluation of central serous chorioretinopathy: different therapeutic approaches and review of literature. The European Vitreoretinal Society central serous chorioretinopathy study

PURPOSE

To study and compare the efficacy of different therapeutic options for the treatment of central serous chorioretinopathy (CSCR).

METHODS

This is a nonrandomized, international multicentre study on 1719 patients (1861 eyes) diagnosed with CSCR, from 63 centres (24 countries). Reported data included different methods of treatment and both results of diagnostic examinations [fluorescein angiography and/or optical coherent tomography (OCT)] and best-corrected visual acuity (BCVA) before and after therapy. The duration of observation had a mean of 11 months but was extended in a minority of cases up to 7 years. The aim of this study is to evaluate the efficacy of the different therapeutic options of CSCR in terms of both visual (BCVA) and anatomic (OCT) improvement.

RESULTS

One thousand seven hundred nineteen patients (1861 eyes) diagnosed with CSCR were included. Treatments performed were nonsteroidal anti-inflammatory eye drops, laser photocoagulation, micropulse diode laser photocoagulation, photodynamic therapy (PDT; Standard PDT, Reduced-dose PDT, Reduced-fluence PDT), intravitreal (IVT) antivascular endothelial growth factor injection (VEGF), observation and other treatments. The list of the OTHERS included both combinations of the main proposed treatments or a variety of other treatments such as eplerenone, spironolactone, acetazolamide, beta-blockers, anti-anxiety drugs, aspirin, folic acid, methotrexate, statins, vitis vinifera extract medication and pars plana vitrectomy. The majority of the patients were men with a prevalence of 77%. The odds ratio (OR) showed a partial or complete resolution of fluid on OCT with any treatment as compared with observation. In univariate analysis, the anatomical result (improvement in subretinal fluid using OCT at 1 month) was favoured by age <60 years (p < 0.005), no previous observation (p < 0.0002), duration less than 3 months (p < 0.0001), absence of CSCR in the fellow eye (p = 0.04), leakage outside of the arcade (p = 0.05) and fluid height >500 μm (p = 0.03). The OR for obtaining partial or complete resolution showed that anti-VEGF and eyedrops were not statistically significant; whereas PDT (8.5), thermal laser (11.3) and micropulse laser (8.9) lead to better anatomical results with less variability. In univariate analysis, the functional result at 1 month was favoured by first episode (p = 0.04), height of subretinal fluid >500 μm (p < 0.0001) and short duration of observation (p = 0.02). Finally, there was no statistically significant difference among the treatments at 12 months.

CONCLUSION

Spontaneous resolution has been described in a high percentage of patients. Laser (micropulse and thermal) and PDT seem to lead to significant early anatomical improvement; however, there is little change beyond the first month of treatment. The real visual benefit needs further clarification.

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.

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.

Central serous chorioretinopathy: Current update on management

Central serous chorioretinopathy (CSC), the fourth most common nonsurgical retinopathy with a usual self-limiting course, is known to present with persistent or recurrent form with distressing visual loss. Evolution of newer mutimodal imaging techniques have revolutionized the understanding about the pathophysiology of CSC, and hence the diagnosis and management. Multifactorial etiopathology of CSC promotes the use of multiple treatment modalities. With advances in investigative options, treatment options including conventional focal laser, micropulse laser, photodynamic therapy, and transpupillary thermotherapy are also advancing and refining. Medical management for CSC is also under evaluation with a wide spectrum of new drugs in vogue. However, standard of treatment is yet to be established through randomized clinical trials. This review article discusses the current approach to multimodal treatment options for CSC including conventional as well as newer therapeutic modalities.

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.

Fluorescent property of indocyanine green (ICG) rubber ring using LED and laser light sources

Fluorescent properties of ICG depends on solvent. Fluorescent characteristics of ICG rubber rings and optimized detection system condition were identified. The fluorescent rubber rings are produced by drying mixture of ICG solution and liquid rubber. LED and laser light sources were used to test differences between them. Other variables are ICG molar concentration (100, 80, 60, 40, 20, 10μM), excitation light spectrum (740, 760, 785nm) and angle of view (0~80°). We observed that ICG ring emitted fluorescence at longer wavelength than in blood and aqueous state. Observation angle between 0 and 50 provided similar brightness of images, while others are significantly less luminous. Excitation light between 740~760nm ensured non-overlapping spectrums of excitation light and fluorescence emission.

Interventions for central serous chorioretinopathy: a network meta-analysis

BACKGROUND

Central serous chorioretinopathy (CSC) is characterized by serous detachment of the neural retina with dysfunction of the choroid and retinal pigment epithelium (RPE). The effects on the retina are usually self limited, although some people are left with irreversible vision loss due to progressive and permanent photoreceptor damage or RPE atrophy. There have been a variety of interventions used in CSC, including, but not limited to, laser treatment, photodynamic therapy (PDT), and intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents. However, it is not known whether these or other treatments offer significant advantages over observation or other interventions. At present there is no evidence-based consensus on the management of CSC. Due in large part to the propensity for CSC to resolve spontaneously or to follow a waxing and waning course, the most common initial approach to treatment is observation. It remains unclear whether this is the best approach with regard to safety and efficacy.

OBJECTIVES

To compare the relative effectiveness of interventions for central serous chorioretinopathy.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2015, Issue 9), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to February 2014), EMBASE (January 1980 to October 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 5 October 2015.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that compared any intervention for CSC with any other intervention for CSC or control.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies and extracted data. We pooled data from all studies using a fixed-effect model. For interventions applied to the eye (i.e. not systemic interventions), we synthesized direct and indirect evidence in a network meta-analysis model.

MAIN RESULTS

We included 25 studies with 1098 participants (1098 eyes) and follow-up from 16 weeks to 12 years. Studies were conducted in Europe, North and South America, Middle East, and Asia. The trials were small (most trials enrolled fewer than 50 participants) and poorly reported; often it was unclear whether key aspects of the trial, such as allocation concealment, had been done. A substantial proportion of the trials were not masked.The studies considered a variety of treatments: anti-VEGF (ranibizumab, bevacizumab), PDT (full-dose, half-dose, 30%, low-fluence), laser treatment (argon, krypton and micropulse laser), beta-blockers, carbonic anhydrase inhibitors, Helicobactor pylori treatment, and nutritional supplements (Icaps, lutein); there were only one or two trials contributing data for each comparison. We downgraded for risk of bias and imprecision for most analyses, reflecting study limitations and imprecise estimates. Network meta-analysis (as planned in our protocol) did not help to resolve this uncertainty due to a lack of trials, and problems with intransitivity, particularly with respect to acute or chronic CSC.Low quality evidence from two trials suggested little difference in the effect of anti-VEGF (ranibizumab or bevacizumab) or observation on change in visual acuity at six months in acute CSC (mean difference (MD) 0.01 LogMAR (logarithm of the minimal angle of resolution), 95% confidence interval (CI) -0.02 to 0.03; 64 participants). CSC had resolved in all participants by six months. There were no significant adverse effects noted.Low quality evidence from one study (58 participants) suggested that half-dose PDT treatment of acute CSC probably results in a small improvement in vision (MD -0.10 logMAR, 95% CI -0.18 to -0.02), less recurrence (risk ratio (RR) 0.10, 95% CI 0.01 to 0.81) and less persistent CSC (RR 0.12, 95% CI 0.01 to 1.02) at 12 months compared to sham treatment. There were no significant adverse events noted.Low quality evidence from two trials (56 participants) comparing anti-VEGF to low-fluence PDT in chronic CSC found little evidence for any difference in visual acuity at 12 months (MD 0.03 logMAR, 95% CI -0.08 to 0.15). There was some evidence that more people in the anti-VEGF group had recurrent CSC compared to people treated with PDT but, due to inconsistency between trials, it was difficult to estimate an effect. More people in the anti-VEGF group had persistent CSC at 12 months (RR 6.19, 95% CI 1.61 to 23.81; 34 participants).Two small trials of micropulse laser, one in people with acute CSC and one in people with chronic CSC, provided low quality evidence that laser treatment may lead to better visual acuity (MD -0.20 logMAR, 95% CI -0.30 to -0.11; 45 participants). There were no significant adverse effects noted.Other comparisons were largely inconclusive.We identified 12 ongoing trials covering the following interventions: aflibercept and eplerenone in acute CSC; spironolactone, eplerenone, lutein, PDT, and micropulse laser in chronic CSC; and micropulse laser and oral mifepristone in two trials where type of CSC not clearly specified.

AUTHORS' CONCLUSIONS

CSC remains an enigmatic condition in large part due to a natural history of spontaneous improvement in a high proportion of people and also because no single treatment has provided overwhelming evidence of efficacy in published RCTs. While a number of interventions have been proposed as potentially efficacious, the quality of study design, execution of the study and the relatively small number of participants enrolled and followed to revealing endpoints limits the utility of existing data. 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. RCTs comparing individual treatments to the natural history would be valuable in identifying potential treatment groups for head-to-head comparison. Of the interventions studied to date, PDT or micropulse laser treatment appear the most promising for study in future trials.

Central serous chorioretinopathy: update on pathophysiology and treatment

Recent technological advances--new pathophysiological insights, new imaging techniques for diagnosis and management, and new treatments--have led to an improved understanding of central serous chorioretinopathy (CSC). The primary role of the choroid has become more widely accepted with widespread use of indocyanine green angiography. Optical coherence tomography (OCT), and particularly enhanced depth imaging OCT, demonstrate a thickened and engorged choroid. Adaptive optics, fundus autofluorescence, multifocal electroretinography, microperimetry, and contrast sensitivity testing reveal that patients with even a mild course suffer previously undetected anatomic and functional loss. Although focal laser and photodynamic therapy are the current standard of care for persistent subretinal fluid in CSC, they are not appropriate in all cases, and the optimal timing of intervention remains unclear.

Subthreshold diode laser micropulse photocoagulation for the treatment of diabetic macular edema

Diabetic macular edema (DME) is a sight-threatening complication of diabetic retinopathy, the leading cause of visual loss in the working-age population in the industrialized and emerging world. The standard of care for DME is focal/grid laser photocoagulation, which is proven effective in reducing the risk of vision loss, but inherently destructive and associated with tissue damage and collateral effects. Subthreshold diode laser micropulse photocoagulation is a nondestructive tissue-sparing laser procedure, which, in randomized controlled trials for the treatment of DME, has been found equally effective as conventional photocoagulation. Functional and anatomical outcomes from four independent randomized controlled trials provide level one evidence that vision stabilization/improvement and edema resolution/reduction can be elicited with less or no retinal damage, and with fewer or no complications. This review describes the principles of subthreshold diode laser micropulse photocoagulation, its treatment modalities and clinical outcomes in the context of standard laser treatments and of emerging nonlaser therapies for DME.

Review and update of central serous chorioretinopathy

PURPOSE OF REVIEW

Greater understanding of central serous chorioretinopathy (CSCR) has changed initial beliefs that CSCR is a benign condition affecting young men with almost complete resolution. CSCR has a spectrum of presentations with more diffuse retinal dysfunction and variations between races. CSCR can affect older individuals and in a subset of patients may lead to significant ocular morbidity.

RECENT FINDINGS

Advances in imaging, particularly in indocyanine green angiography and optical coherence tomography, have led to a greater understanding of the pathophysiology of this condition. Treatments for CSCR are still evolving, in particular photodynamic dynamic therapy using lower doses and reduced fluence showing promising results. More research is required on ideal dosage. Anti-vascular endothelial growth factor treatment offers a new medical treatment modality with promising results.

SUMMARY

There have been recent imaging developments in addition to therapeutic advances for refractory CSCR.

Micropulsed diode laser therapy: evolution and clinical applications

Many clinical trials have demonstrated the clinical efficacy of laser photocoagulation in the treatment of retinal vascular diseases, including diabetic retinopathy. There is, however, collateral iatrogenic retinal damage and functional loss after conventional laser treatment. Such side effects may occur even when the treatment is appropriately performed because of morphological damage caused by the visible endpoint, typically a whitening burn. The development of the diode laser with micropulsed emission has allowed subthreshold therapy without a visible burn endpoint. This greatly reduces the risk of structural and functional retinal damage, while retaining the therapeutic efficacy of conventional laser treatment. Studies using subthreshold micropulse laser protocols have reported successful outcomes for diabetic macular edema, central serous chorioretinopathy, macular edema secondary to retinal vein occlusion, and primary open angle glaucoma. The report includes the rationale and basic principles underlying micropulse diode laser therapy, together with a review of its current clinical applications.

Transpupillary Thermotherapy for Juxtafoveal Leak in Central Serous Chorioretinopathy

The authors describe the use of transpupillary thermotherapy (TTT) for juxtafoveal central serous chorioretinopathy (CSC) leak. A 45-year-old man with juxtafoveal leak developed fibrinous exudate in the macular area, demonstrated on optical coherence tomography. After one session of TTT, fibrinous exudate totally disappeared with improvement in vision to 20/40 from counting finger. Subretinal fluid got absorbed with obliteration of leak on fluorescein angiogram. TTT may be useful as a treatment option in juxtafoveal leak of CSC.

Early laser photocoagulation treatment as an option in central serous chorioretinopathy

BACKGROUND AND OBJECTIVE

To investigate the effect of early photocoagulation in central serous chorioretinopathy.

PATIENTS AND METHODS

In a prospective study, 15 consecutive patients with central serous chorioretinopathy and single leakage points were treated with photocoagulation between 2 days and 8 weeks after onset of symptoms. The main outcome measures were best-corrected visual acuity and metamorphopsias (Amsler grid) at months 1 and 4 compared with baseline.

RESULTS

Mean visual acuity improved by 1.53 lines 1 month after treatment. The mean squares involved in the Amsler grid were reduced by 2.07 squares. No relapse occurred during the follow-up period.

CONCLUSION

Considering the characteristics of individuals affected by central serous chorioretinopathy, a fast recovery would be advantageous. This study identified early laser photocoagulation in central serous chorioretinopathy as an effective treatment regarding resorption of subretinal fluid, recovery of visual acuity, and improvement of metamorphopsia.

Indocyanine green enhanced subthreshold diode-laser micropulse photocoagulation treatment of chronic central serous chorioretinopathy

PURPOSE

To assess the efficacy and safety of indocyanine green (ICG) dye-enhanced subthreshold diode-laser micropulse (SDM) photocoagulation in patients with chronic central serous chorioretinopathy (CCSC) with no spontaneous resolution 6 months after the onset of the disease.

STUDY DESIGN

Interventional prospective non-comparative case series of seven patients presenting with CCSC with well-defined active leaking sites (ALS) suitable for laser treatment and with serous neuroepithelial detachment persisting for 6 or more months.

METHODS

SDM treatment was performed 15 minutes after the injection of 25 mg of ICG in 2 cc of 5% glucose solution. ALS were treated with a series of 50 500-ms exposures separated by 500-ms pauses. Each 500-ms exposure delivered a train of 250 micropulses at 10% duty cycle and 500 mW power. ICG angiographic images were taken after the treatment without new ICG injection, to check for the presence of laser-induced spots of background hypofluorescence at the treated leakage sites.

RESULTS

Within 7-14 days after treatment, all the patients showed improved visual acuity and reduction of serous neuroepithelial detachment on OCT. No signs of laser lesions were visible at fundus examination and on fluorescein angiography. In a period ranging from 4 to 8 weeks, the neuroepithelial detachment was completely resolved in five patients and reduced in two patients. At the 12-month follow-up visits, no recurrence had occurred in the patients, with resolution of the serous neuro-epithelial detachment, and no worsening of the serous detachment or of VA was noted in the patients with incomplete recovery.

CONCLUSIONS

These preliminary results suggest that ICG dye-enhanced SMD photocoagulation appears to be an effective treatment, and can represent a viable approach for the management of CSCC with persistent serous neuroepithelial detachment. Post-treatment ICG angiography, without new ICG dye injection, can be used to verify the placement of the SDM laser applications.

Evolution of retinal laser therapy: minimum intensity photocoagulation (MIP). Can the laser heal the retina without harming it?

Laser photocoagulation is a photo-thermal therapy validated by landmark studies and commonly accepted as the standard of care for various retinal diseases. Although its mechanism of action is still not completely understood, it is normally administered with visible endpoints, true intra-retinal burns that cause chorioretinal scars, which, with time, evolve into expanding areas of atrophy. New hypotheses on the mechanism of action of laser photocoagulation suggest that its therapeutic benefits derive from biologic activities that cannot be inducted within the "burned" area of photocoagulation necrosis, but that occur in the adjacent surrounding areas affected by a lower, sub-lethal, photo-thermal elevation. Thus, the iatrogenic chorioretinal damage caused by visible endpoint photocoagulation may be redundant and an equally effective laser therapy could be administered with minimum intensity photocoagulation (MIP) using laser protocols aiming to create only non-lethal photo-thermal elevations with no intraoperative visible endpoint. It is the purpose of this paper to review laser techniques and clinical protocols that have been utilized to administer retina-sparing MIP treatments that hold the promise of healing the retina while minimizing the iatrogenic harm.