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

Interventions for central serous chorioretinopathy: a network meta-analysis

BACKGROUND

Central serous chorioretinopathy (CSC) is characterized by a thickened and dysfunctional choroid which is accompanied by a serous detachment of the neural retina. The effects on the retina are usually self-limiting, although some people are left with irreversible vision loss due to progressive and permanent photoreceptor damage or atrophy of the retinal pigment epithelium (RPE). There has been a variety of interventions used in CSC, including, but not limited to, laser treatment, photodynamic therapy (PDT), and drug therapy with mineralocorticoid receptor antagonists or intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) agents. However, it is not known whether these treatments offer significant long-term advantages over observation or each other. At present, there is no evidence-based consensus on the management of CSC.

OBJECTIVES

This is an update of a Cochrane review first published in 2015 where 25 studies with 1098 participants were included. Since then, many trials have been conducted and reports published. Our primary objective was to assess the comparative effectiveness of multiple interventions for CSC. The secondary objective was to provide the relative ranking of the interventions for CSC using network meta-analysis.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and three trial registries in 29 March 2024, together with reference checking.

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 (CL, LP) independently selected studies and extracted data. Our outcomes of interest were best corrected visual acuity (BCVA), recurrence of CSC, persistent CSC, contrast sensitivity, central retinal subfield thickness, quality of life, and adverse events. We used standard methodological procedures expected by Cochrane. We used Cochrane's statistical software, Review Manager, to perform pairwise analyses and Stata to perform network meta-analysis (NMA). For pairwise comparisons, we pooled data from studies using fixed or random-effects models if there were fewer or more than three studies, respectively. We conducted NMAs using a multivariate meta-analyses approach and ranked interventions using the surface under the cumulative ranking (SUCRA). We used the Confidence in Network Meta-Analysis (CINeMA) approach to assess and present the certainty of evidence for NMA results.

MAIN RESULTS

This review includes 4015 participants from 67 RCTs in total. Additionally, we identified 31 ongoing clinical trials. Trials compared aflibercept, crocin, lutein, eplerenone, spironolactone, prednisolone eye drops, PDT, subthreshold micropulse laser (SML) (577 nm) between each other or respective control groups (e.g. observation, sham injection, or placebo). Studies were conducted in Europe, North and South America, the Middle East, and Asia. Most of the trials were small, enrolling fewer than 50 participants, and poorly reported. A substantial proportion of trials were not masked, and it remained unclear whether key aspects of the trial, such as allocation concealment, had been done. Eight (13%) studies were funded by industry and 21 (31%) by non-industry sources. Overall, 23 (34%), 34 (51%), and 10 (15%) studies were rated at high, moderate, and low risk of bias. Twenty-two studies were included in the pairwise meta-analyses, contributing data to at least one prespecified outcome (change in best corrected visual acuity, recurrence or persistence of CSC, change in contrast sensitivity or central retinal thickness, quality of life, or adverse events) with a follow-up of six to 18 months. These RCTs assessed the effect of oral medication treatments (such as antioxidants, beta-blockers, carbonic anhydrase inhibitors and mineralocorticoid receptor antagonists), intravitreal anti-VEGF injections, laser-assisted treatments (such as pulsed and non-pulsed laser approaches), PDT, and meditation. Most studies had a moderate risk of bias. Pairwise meta-analyses mostly failed to find evidence of differences in effect. We did not have any comparisons with more than 10 studies per analysis to assess the risk of publication biases. Regarding harms, most studies did not report harms in a standardized way and reported no treatment-related harms. Specific harms reported included significant RPE damage among those receiving conventional SML and Grade 1 choroidal ischemia in 3/51 eyes receiving PDT, but the evidence is very uncertain. We were unable to conduct an NMA of recurrence or harms due to sparse data. To enable fuller data for our network of change in BCVA, we classified the interventions into seven unique groups by the types of pharmacologics, laser treatments, and levels of PDT. We excluded interventions for which the assumption of transitivity was not met (i.e. focal unpulsed laser treatment, H. pylori eradication therapy), and performed a NMA with 17 trials of the seven treatment groups (21 comparisons). The NMA did not find any evidence of differences between the treatments that were analyzed. The SUCRA analysis for BCVA suggested the following order for the highest ranking treatments: < 50% PDT (SUCRA = 81.1), supplement (59.0), eplenerone (57.7), anti-VEGF (50.3), control (47.9), ≥ 50% PDT (36.5), and pulsed laser (17.5). SUCRA also suggested low-dose PDT, eplenerone, and supplement had the highest probabilities of being the best (≥ 19.6%), compared to the others (≤ 6.3%). However, the reliability of these SUCRA estimates is limited due to poor overall connectivity in the network, leading to an increased risk of inconsistency between direct and indirect comparisons and increased influence of individual studies. We judged most comparisons as being at moderate (13/21) or low (7/21) confidence, mostly because of imprecision and within-study bias. No comparisons had high certainty.

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 risks of biases and the relatively small number of participants enrolled and successfully followed limit the utility of existing data. Our results did not show the superiority of any treatment option over another. Low-dose photodynamic therapy, supplements, and eplenerone had the greatest SUCRA values and probabilities of being the best treatments for improving visual acuity, although our confidence in the evidence for these interventions is very low to moderate. Larger and high-quality RCTs comparing these treatments are warranted.

Comparative efficacy of subthreshold micropulse laser versus conventional laser therapy in central serous chorioretinopathy

Subthreshold micropulse laser (SML) and conventional laser photocoagulation (CLP) have established efficacy in treating central serous chorioretinopathy (CSC), but systematic comparisons of their effectiveness, safety, and long-term outcomes remain lacking.We carried out this retrospective study. A total of 109 eyes from 109 CSC patients were included, with 53 eyes in the conventional laser group and 56 eyes in the SML group. The SML group was treated with a 577-nm wavelength laser, targeting areas of leakage and subretinal fluid (SRF). For patients without identifiable leakage points, the treatment area covered the SRF region. The conventional laser group received single-spot laser treatment with a laser spot reaction of ≤ grade 1, targeting leakage points identified by early-phase fluorescein angiography (FFA). Disease duration, leakage points on FFA, best-corrected visual acuity (BCVA) during follow-up, central macular thickness (CMT), SRF resolution, and safety were analyzed. The mean follow-up duration was 6.90 ± 2.77 months. The conventional laser group had a shorter mean disease duration compared to the SML group (P = 0.002), and there was a significant difference in the distribution of leakage points between the two groups (P = 0.000). At 6 months post-treatment, compared to baseline, the BCVA change was 0.24 ± 0.28 in the CL group (P = 0.02) and 0.19 ± 0.18 in the SML group (P = 0.04). There were no significant differences in BCVA between the two groups at any follow-up time point, though. CMT changes from baseline to final follow-up demonstrated a mean reduction of 228.00 ± 181.01 μm in the CL group versus 176.97 ± 143.39 μm in the SML group (both P < 0.001). No significant differences were observed in mean CMT or final OCT changes between the two groups at any follow-up time point. The complete SRF resolution rates were 83.01% in the conventional laser group and 87.50% in the SML group (P = 0.59).Both SML and CL treatments are safe and effective for CSC. CL therapy is a safe and effective option for patients with acute disease, clearly identifiable leakage points located > 250 μm from the foveal center, while SML is preferable for patients with longer disease duration, unclear leakage points, or leakage points located within 250 μm of the foveal center. Clinical trial number: Not applicable.

Evaluating Photodynamic Therapy vs. Subthreshold Micropulse Laser for Central Serous Chorioretinopathy: A Retrospective Study

BACKGROUND

Our study aims to compare the efficacy of half-dose photodynamic therapy with verteporfin (PDT) and subthreshold micropulse laser (SML) in patients with central serous chorioretinopathy (CSCR) with regards to subretinal fluid (SRF) resorption, visual acuity (VA), and central subfield thickness (CST).

PATIENTS AND METHODS

We conducted a retrospective multicentre clinical study at the Departments of Ophthalmology at the University Hospital Zurich and Stadtspital Zürich, Switzerland. The study included patients with acute and chronic CSCR who underwent PDT, SML, or both sequentially between June 1, 2020 and December 31, 2023. The primary outcome was the reduction in SRF at three and six months post-treatment. The secondary outcomes included change in CST VA at the same intervals.

RESULTS

A total of eighty-one eyes were analysed (33 PDT, 35 SML, thirteen combined). SRF reduction was statistically significant at both three and six months in the PDT (p < 0.001) and SML groups (p < 0.001). The combined treatment group showed a significant reduction in SRF only at six months (p = 0.001). At three months, PDT resulted in a significantly greater SRF reduction than the combined group.

CONCLUSIONS

Both PDT and SML demonstrated improvements in SRF, CST and VA, with SML presenting as a comparable alternative, particularly in cases where access to verteporfin is limited.

Short-term effectiveness of intelligent navigated laser photocoagulation versus subthreshold micropulse laser in patients with chronic central serous chorioretinopathy

AIM

To compare the short-term effectiveness of intelligent navigated laser photocoagulation and 577-nm subthreshold micropulse laser (SML) treatment in patients with chronic central serous chorioretinopathy (cCSC).

METHODS

This observational retrospective cohort study included 60 consecutive patients who underwent intelligent navigated laser photocoagulation (n=30) or 577-nm SML treatment (n=30) for cCSC between Jan. 2021 and Oct. 2022. During 3mo follow-up, all patients underwent assessments of best correct visual acuity (BCVA) and optical coherence tomography (OCT).

RESULTS

The operation of laser treatment was successful in all cases. At 1mo, BCVA improved significantly more in the intelligent navigated laser photocoagulation group compared to the SML group (P<0.05). The change was not significantly different at 3mo (P>0.05). Central macular thickness (CMT) in the intelligent navigated laser photocoagulation group was lower than in the SML group at 1mo (P<0.05). The subfoveal choroidal thickness (SFCT) in two groups were all significantly improved at 3mo (all P<0.05). The change between two groups was not significantly different at 1mo or at 3mo (P>0.05).

CONCLUSION

Intelligent navigated laser photocoagulation is superior to SML for treating cCSC, leading to better improvements in vision and CMT for short term.

A clinical study on the therapeutic effects of 577 nm micropulse laser photocoagulation treatment in early-stage CSCR patients

PURPOSE

To research the therapeutic effects of 577 nm micropulse laser photocoagulation (MLP) treatment in early-stage central serous chorioretinopathy (CSCR) patients.

METHODS

Twenty-two CSCR patients with 24 CSCR eyes were examined prior to MLP treatment. The examinations included best-corrected visual acuity (BCVA), fluorescein fundus angiography (FFA), indocyanine green angiography (ICGA), optical coherence tomography (OCT), optical coherence tomography angiography (OCTA) and microperimetry. After MLP treatment, all the subjects were reviewed at 30 days. The BCVA, macular function on microperimetry, subretinal fluid (SRF) height of the macula on OCT, and choroid vascular density (VD) of the macular area on OCTA were compared before and after MLP treatment. The correlations between SRF height and visual function, choroid VD was analyzed separately.

RESULTS

BCVA and macular function significantly increased and the SRF height of the macula significantly decreased after MLP treatment. BCVA and macular function were significantly negatively correlated with SRF height. The choroid VD was significantly increased after MLP treatment, and choroid VD in the leakage site part of the macula were significantly negatively correlated with the height of the SRF. A recurrent patient who received two MLP treatments also had a negative correlation between SRF and choroid VD during the course of disease.

CONCLUSIONS

577 nm MLP is safe and effective for early-stage CSCR patients, and treatment can restore macular structure and function. The increase in choroid VD of leakage site part after treatment is one of the key effects of MLP treatment for early-stage CSCR patients.

Laser Treatment of Central Serous Chorioretinopathy - An Update

Laser treatment has been a mainstay for management of central serous chorioretinopathy for a few decades. Different types of lasers have been used and non-damaging retinal laser is the most recent option. The aim of this review is to provide an update on this form of treatment, based on the research published during last 5 years, in comparison with earlier studies published. A MEDLINE database search was performed with a combination of the following terms: central serous chorioretinopathy and laser photocoagulation or subthreshold laser or subthreshold micropulse laser or nanosecond laser or microsecond laser or end-point management or photodynamic therapy. Results were analyzed separately for each modality of laser treatment. Reports published in recent years confirm findings of previous research and do not distinguish treatments of this clinical entity. Among all analyzed laser options, photodynamic therapy provides the fastest and most prominent morphological improvements, including subretinal fluid resorption and reduction of choroidal thickness. This modality is also associated with fewer recurrences than with other treatments. Subthreshold micropulse laser allows the physician to maintain and, in selected cases, improve the patient's vision. Conventional photocoagulation is still effective, especially with the introduction of navigated laser systems. Despite the availability of variable laser treatment options, long-term functional improvements in chronic cases are minor for each modality. Long-lasting central serous chorioretinopathy cases with significantly altered retinal morphology do not usually present with functional improvement, despite satisfactory morphological outcomes. Early initiation of treatment has the potential to prevent visual loss and to improve the patient's quality of life.

Prognostic factors of visual outcome in central serous chorioretinopathy treated with subthreshold micropulse laser therapy

Analyze the prognostic factors of visual outcome in central serous choriretinopathy (CSC) treated with subthreshold micropulse laser (SML) therapy through the most fundamental medical history and clinical examinations. It was a retrospective clinical study. We collected the most fundamental medical history and clinical examinations of CSC patients who received SML treatment, including visual acuity (VA) and spectral-domain optical coherence tomography (SD-OCT) of macular. Eyes were divided into two groups according the change of central macular thickness (CMT) before and one month after SML: CMT improvement and CMT deterioration group; divided into three groups according the change of VA: VA improvement, VA stability and VA decline group. Seventy-eight patients (eighty-three eyes) were enrolled. The baseline CMT was 339.83 ± 115.72 μm, and the baseline VA was 0.43 ± 0.36. One month after SML, CMT was 281.13 ± 121.48 μm, had a significant statistical improvement (p = 0.000); and VA was 0.46 + 0.42, had no significant statistical difference compared to baseline VA (p = 0.114). CMT of sixty-three eyes (75.90%) declined, and twenty eyes (24.10%) increased; VA of thirty-one eyes (37.35%) improved, fourteen eyes (16.87%) remained unchanged, and thirty-eight eyes (45.78%) declined. CMT and VA of twenty-seven eyes (32.53%) were both improved, and eleven eyes (13.25%) were both deteriorated. VA one month after SML was statistically correlated with age (p = 0.000), baseline VA (p = 0.000), and baseline CMT (P = 0.002). CMT and VA both improved one month after SML, and the improvement of CMT was more significant than VA. Elder age and poorer baseline vision indicated poorer VA one month after SML, while higher baseline CMT indicated better VA one month after SML.

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

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

Efficacy of Subthreshold Micropulse Laser for Central Serous Chorioretinopathy

PURPOSE

To evaluate the efficacy of a subthreshold micropulse laser (SML) in patients with central serous chorioretinopathy (CSCR).

METHODS

Retrospective clinical study conducted at the Departments of Ophthalmology at a university and a municipal hospital in Zurich, Switzerland. We enrolled acute and chronic CSCR patients with persistent subretinal fluid (SRF) treated with SML. Two treatment protocols (fluorescein/indocyanine green angiography or optical coherence tomography guided) were evaluated for efficacy after 3 and 6 months. The primary outcomes of the study were reduction and percentage of eyes with complete resolution of SRF 3 and 6 months after SML treatment. Secondary endpoints included changes in central subfield thickness (CST) and visual acuity (VA) after 3 and 6 months.

RESULTS

The study involved 37 eyes (35 patients, 48.6% chronic). A statistically significant reduction in SRF height and CST could be shown, irrespective of SRF duration, type of CSCR, or chosen guidance after 3 and 6 months: SRF - 40 µm (p < 0.01), CST - 52 µm (p < 0.01). Percentage of eyes with complete resolution of fluid at 3 and 6 months after SML were 24.3 and 21.6%, respectively. No statistically significant functional improvement (VA) could be shown. Multivariable regression and linear mixed regression analyses did not identify statistically significant differences in SRF reduction, CMT change, or VA improvement with respect to the type of CSCR or the treatment plan used (p > 0.05).

CONCLUSION

The effectiveness of SML in CSCR is under continuous debate. Our study findings demonstrate structural but only little functional changes with SML. In view of the shortage of verteporfin for photodynamic therapy, SML remains an important therapeutic option for CSCR patients.

Comparing treatment outcomes in randomized controlled trials of central serous chorioretinopathy

PURPOSE

To perform a qualitative analysis of outcomes published from randomized controlled trials (RCTs) on central serous chorioretinopathy (CSCR) from 1979 to 2022.

DESIGN

Systematic review.

METHODS

All RCTs (including both therapeutic and non-therapeutic interventions) on CSCR available online till July 2022 were included after an electronic search in multiple databases such as PubMed, CENTRAL, MEDLINE, EMBASE, BIOSIS, Scopus, and Cochrane database. We analyzed and compared the inclusion criteria, imaging modalities, study endpoints, duration, and the results of the study.

RESULTS

The literature search yielded 498 potential publications. After excluding duplicate studies and studies that met clear exclusion criteria, 64 were screened for further evaluation, of which 7 were removed due to a lack of necessary inclusion criteria. A total of 57 eligible studies are described in this review.

CONCLUSION

This review provides a comparative overview of key outcomes reported between RCTs investigating CSCR. We describe the current landscape of treatment modalities for CSCR and note the discrepancies between results in these published studies. Challenges arise when attempting to compare similar study designs without comparable outcome measures (i.e., clinical vs. structural) which may limit the overall evidence presented. To mitigate this issue, we present the collected data from each study in tables detailing the measures that are and are not assessed in each publication.

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

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

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%.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Selective retina therapy and thermal stimulation of the retina: different regenerative properties - implications for AMD therapy

BACKGROUND

Selective Retina Therapy (SRT), a photodisruptive micropulsed laser modality that selectively destroys RPE cells followed by regeneration, and Thermal Stimulation of the Retina (TSR), a stimulative photothermal continuous wave laser modality that leads to an instant sublethal temperature increase in RPE cells, have shown therapeutic effects on Age-related Macular Degeneration (AMD) in mice. We investigate the differences between both laser modalities concerning RPE regeneration.

METHODS

For PCR array, 6 eyes of murine AMD models, apolipoprotein E and nuclear factor erythroid-derived 2- like 2 knock out mice respectively, were treated by neuroretina-sparing TSR or SRT. Untreated litter mates were controls. Eyes were enucleated either 1 or 7 days after laser treatment. For morphological analysis, porcine RPE/choroid organ cultures underwent the same laser treatment and were examined by calcein vitality staining 1 h and 1, 3 or 5 days after irradiation.

RESULTS

TSR did not induce the expression of cell-mediators connected to cell death. SRT induced necrosis associated cytokines as well as inflammation 1 but not 7 days after treatment. Morphologically, 1 h after TSR, there was no cell damage. One and 3 days after TSR, dense chromatin and cell destruction of single cells was seen. Five days after TSR, there were signs of migration and proliferation. In contrast, 1 h after SRT a defined necrotic area within the laser spot was seen. This lesion was closed over days by migration and proliferation of adjacent cells.

CONCLUSIONS

SRT induces RPE cell death, followed by regeneration within a few days. It is accompanied by necrosis induced inflammation, RPE proliferation and migration. TSR does not induce immediate RPE cell death; however, migration and mitosis can be seen a few days after laser irradiation, not accompanied by necrosis-associated inflammation. Both might be a therapeutic option for the treatment of AMD.