Comparing Half-Dose Photodynamic Therapy with Subthreshold Micropulse Laser for the Treatment of Central Serous Chorioretinopathy

PURPOSE

To compare the anatomic and functional outcomes of half-dose photodynamic therapy (PDT) and yellow 577-nm subthreshold micropulse laser (SMLT) in treating patients with chronic central serous chorioretinopathy (CSCR).

DESIGN

Prospective, double-masked, randomized, controlled clinical trial.

PARTICIPANTS

Patients with chronic CSCR confirmed by clinical features and multimodal imaging.

METHODS

Eligible patients were randomized (1:1) to receive half-dose PDT or SMLT. The same treatment was repeated if persistent subretinal fluid (SRF) was observed. Treatment responses were evaluated 1 month after treatment and every 3 months until the end point at 12 months.

MAIN OUTCOME MEASURES

The primary outcome measure was the complete resolution of SRF on OCT scan at month 12. Secondary outcomes included the changes in best-corrected visual acuity (BCVA), central macular thickness (CMT) as measured by OCT, retinal sensitivity as measured by microperimetry, and vision-related quality of life using the National Eye Institute 25-Item Visual Function Questionnaire.

RESULTS

Between April 2017 and October 2020, 68 patients were recruited. At 1 month after treatment, SRF resolved in 8 (24.2%) of 33 patients receiving SMLT and in 20 (58.8%) of 34 patients receiving half-dose PDT. This increased to 23 (82.1%) of 28 patients in the SMLT group and 30 (90.9%) of 33 patients in the half-dose PDT group at 12 months of follow-up. Kaplan-Meier survival curves showed significantly faster resolution of SRF in the half-dose PDT group than the SMLT group (P = 0.016). Both groups showed significant improvement in BCVA (-0.12 ± 0.21, P = 0.005 for SMLT; -0.13 ± 0.12, P < 0.001 for half-dose PDT), CMT (-154.2 ± 105.6, P < 0.001 for SMLT; -140.8 ± 94.0, P < 0.001 for half-dose PDT), and retinal sensitivity (5.70 ± 5.02, P < 0.001 for SMLT; 6.05 ± 3.83, P < 0.001 for half-dose PDT) at 12 months compared with baseline. There was no significant difference between the 2 treatment groups at each time point in all investigations except BCVA at 3 months (P = 0.03).

CONCLUSIONS

When comparing half-dose PDT to subthreshold SMLT, this study has shown both treatments to be viable options, with half-dose PDT achieving faster anatomic success and functional improvement.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Subthreshold micropulse laser combined with anti-vascular endothelial growth factor therapy for diabetic macular edema: a systematic review and meta-analysis

PURPOSE

To evaluate the effects of subthreshold micropulse laser (SML) in addition to anti-vascular endothelial growth factor (VEGF) therapy for diabetic macular edema (DME).

METHODS

MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were systematically searched for studies that compared anti-VEGF with SML and anti-VEGF monotherapy for DME. Outcome measures were best-corrected visual acuity (BCVA), central macular thickness (CMT), and the number of anti-VEGF injections.

RESULTS

Eight studies including 493 eyes were selected. Four studies were randomized controlled, and the other four were retrospective. Meta-analysis showed that there was no significant difference in BCVA (mean difference [MD] -0.04; 95%CI -0.09 to 0.01 logMAR; P = 0.13;). CMT was thinner in the group of anti-VEGF with SML (MD -11.08; 95%CI -21.04 to -1.12 µm; P = 0.03); however, it was due to a single study that weighed higher, and the sensitivity and subcategory analyses did not support the finding. The number of anti-VEGF injections was significantly decreased in the group of anti-VEGF with SML (MD -2.22; 95%CI -3.02 to -1.42; P < 0.0001).

CONCLUSION

Current evidence indicates that adding SML to anti-VEGF therapy could significantly reduce the number of anti-VEGF injections compared to anti-VEGF monotherapy, while achieve similar BCVA and CMT.

Subthreshold micropulse laser therapy for early postoperative macular thickening following surgical removal of epiretinal membrane

BACKGROUND

This study aimed to investigate the functional and anatomical outcomes of subthreshold micropulse laser (SMPL) therapy in eyes with early postoperative macular thickening after idiopathic epiretinal membrane (iERM) removal.

METHODS

This was a prospective and interventional study. Forty-eight eyes from 48 patients with macular edema at 1 month after iERM removal were randomly divided into two groups. Patients in the SMPL group (n = 24) received SMPL therapy while no special intervention was used for the observation group (n = 24). Baseline demographic data and clinical findings before and at 1 and 3 months after SMPL treatment or observation, including best-corrected visual acuity (BCVA) and the changes in central subfield thickness (CST) and average macular thickness (AMT), were analyzed.

RESULTS

An improvement in BCVA with a decrease in CST and AMT from baseline to the 3-month follow-ups were observed in both SMPL and observation groups. No significant difference in BCVA was observed between the SMPL group and observation group either in the 1-month (0.26 [0.15, 0.52] vs. 0.26 [0.15, 0.39], P = 0.852) or the 3-month (0.15 [0.10, 0.30] vs. 0.23 [0.15, 0.30], P = 0.329) follow-up. There was a greater reduction in CST in the SMPL group versus observation group between baseline and the 3-month follow-up (-77.8 ± 72.3 μm vs. -45.0 ± 46.9 μm, P = 0.049). The alteration in AMT did not differ between the two groups in either 1-month (-16.5 ± 20.1 μm vs. -19.7 ± 16.3 μm, P = 0.547) or 3-month (-36.9 ± 26.9 μm vs. -34.0 ± 20.1 μm, P = 0.678) follow-up.

CONCLUSIONS

SMPL therapy led to a significant decrease in CST at the 3-month follow-up while did not significantly improve the visual acuity in patients with postoperative macular thickening following iERM surgery.

TRIAL REGISTRATION

The study was registered on Aug 27, 2020 (Trial Registration Number: ChiCTR 2000037227).

Evaluation of changes in macular structures after subthreshold micropulse laser therapy on chronic central serous chorioretinopathy

PURPOSE

To evaluate the changes in macular structures following subthreshold micropulse laser (SHML) treatment for chronic central serous chorioretinopathy (cCSC).

METHODS

Data of 33 eyes from 31 cCSC patients treated with SHML and followed up for at least 6 months has been included in this retrospective study. Main outcome measurements include resolution of subretinal fluid (SRF) and pigment epithelial detachment (PED), the recovery of ellipsoid zone (EZ) continuity, and the foveal outer nuclear layer (ONL) thickness along with its ratio.

RESULTS

Mean observation period is 7.355 months (ranging from 6 to 24 months) and mean number of treatments administered is 1.839 (ranging from 1 to 5). 6 months after SHML treatment, there is a significant decrease in the area of SRF and PED (P < 0.001, P = 0.010, respectively). Additionally, the frequency of continuous EZ and the foveal ONL thickness reveal a significant increase (P<0.001, P = 0.005, respectively). The ratio of foveal ONL thickness is significantly higher after laser treatment, particularly in patients with a disease duration of ≤12 months (p = 0.022, P=0.036, respectively).

CONCLUSION

SHML treatment proves to be effective in cCSC eyes, leading to satisfactory recovery of macular structures, especially the photoreceptor layer.

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

Purpose

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

Methods

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

Results

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

Conclusions

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

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

OCT biomarkers related to subthreshold micropulse laser treatment effect in central serous chorioretinopathy

Background

To identify the OCT biomarkers related to the anatomical outcomes in eyes with central serous chorioretinopathy (CSCR) after subthreshold micropulse laser (SML) treatment.

Methods

Patients with CSCR underwent SML were enrolled in this retrospective study. Only patients who underwent enhanced depth imaging optical coherence tomography (EDI-OCT) examination before and after SML were selected. Patients were divided into two groups based on whether subretinal fluid (SRF) absorbed or not after SML. Group 1 was the SRF resolved group, and Group 2 was the SRF non-resolved group. Factors including age and gender, duration of symptoms, CSCR history, the height of SRF at baseline, retinal pigment epithelium (RPE) /inner choroid alterations, as well as subfoveal choroidal thickness (SFCT) of the affected eye and the fellow eye before and after SML were recorded and compared between two groups. Longitudinal change of SFCT of a subgroup of patients were analyzed.

Results

A total of 58 eyes of 58 patients were involved in this study. SRF of 31 eyes got completely absorbed, and SRF of 27 eyes was retained after SML. Logistic regression analysis revealed baseline SFCT of the affected eye (OR = 1.007, 95% CI: 1.001–1.012, P = 0.019) and RPE/inner choroid alterations (OR = 25.229, 95% CI: 2.890–220.281, P = 0.004) were correlated with SML efficacy. Thirty-three eyes of 33 patients were enrolled in the subgroup analysis. A significant difference of SFCT changes between two groups were demonstrated (P = 0.001). The difference of SFCT between baseline and three months after SML was also related to SRF resolution (OR = 0.952, 95% CI: 0.915–0.990, P = 0.014).

Conclusion

Baseline SFCT, change of SFCT at 3-month after treatment, and RPE/inner choroid alterations were the OCT biomarkers related to SRF resolution after SML treatment.

Differential gene expression analysis using RNA sequencing: retinal pigment epithelial cells after exposure to continuous-wave and subthreshold micropulse laser

PURPOSE

Subthreshold micropulse laser (SMPL) is more clinically efficient for the treatment of diabetic macular edema (DME) than the conventional continuous-wave (CW) laser. We aimed to characterize transcriptome changes after the application of these lasers and to compare the transcripts.

METHODS

Human pluripotent stem cell-derived retinal pigment epithelial cells were exposed to laser irradiation. Differentially expressed genes (DEGs), distribution of heat shock protein (Hsp) family, gene expression profile, and gene ontology (GO) enrichment analysis based on RNA sequencing data were investigated at 3 h and 24 h after irradiation.

RESULTS

CW laser induced more DEGs than SMPL (1771 vs. 520 genes). The expression of the Hsp family was confirmed in both groups: however, the induction patterns was different for different genes. GO enrichment analysis revealed that CW laser upregulated the expression of DEGs involved in vasculature development (GO: 0001944), related to apoptosis and repair after cell injury whereas SMPL upregulated the expression of DEGs involved in photoreceptor cell maintenance (GO: 0045494), photoreceptor cell development (GO: 0042461), and sensory perception of light stimuli (GO: 0050953).

CONCLUSIONS

The results provide insights into the genetic responses and may contribute to the understanding of the molecular mechanisms of laser-induced thermal effects.

Morphological parameters predicting subthreshold micropulse laser effectiveness in central serous chorioretinopathy

PURPOSE

The purpose of this prospective study was to predict the effectiveness of subthreshold micropulse laser (SML) based on morphological parameters in patients with central serous chorioretinopathy (CSC).

METHODS

Thirty-one patients were examined at presentation, 3 months, and 6 months after the disease onset. In patients with persistent subretinal fluid (SRF) at 3 months, SML was performed. The following morphological parameters were observed just before treatment: central retinal thickness (CRT), maximal SRF, choroidal thickness (CT), pigment epithelial detachment (PED) height and width, number of hyperreflective foci (HF) at fovea and leakage site, secondary choroidal neovascularization (CNV), and severity of retinal pigment epithelium (RPE) alterations using multimodal imaging.

RESULTS

Good response was associated with lower SRF (p = 0.038), narrower PED (p = 0.078), and decreasing number of HF at fovea (difHFf) (p = 0 .016) just before the treatment. From a bivariate and multivariate point of view, the two groups differed significantly in the pair (SRF, PED width) (p = 0.048) and in the triple (SRF, PED width, difHFf) (p = 0.026).

CONCLUSION

Lower SRF, narrower PED, and decreasing HF could be associated with good response to SML in CSC patients.

Factors affecting the response to subthreshold micropulse laser therapy used in center-involved diabetic macular edema

The purpose of this study was to investigate the effect of the status of retinal pigment epithelium (RPE) and HbA1c levels on the efficacy of the subthreshold micropulse laser (SMPL) in the treatment of center-involving diabetic macular edema (DME). A total of 20 eyes of 20 patients (mean age 57.9 ± 9.7 years) who were diagnosed with center-involving DME and treated with SMPL for refusing intravitreal injection and 20 eyes of 20 age- and sex-matched healthy participants were enrolled. All patients were followed up in the 1st and 3rd months after SMPL. For measurement of RPE area central 1000 microns, macular EDI-OCT scans were binarized by using the public domain software ImageJ, with a semi-automated technique. There was a significant increase in BCVA values and a significant decrease in CMT values during follow-up. The area of RPE before SMPL was significantly thinner in the patient group (p: 0.004). When the areas of RPE before and 3 months after SMPL were compared, no significant change was observed (p: 0.437). When the relationship between pre-treatment area of RPE and HbA1c was examined, an inverse correlation was observed (p: 0.018). The patients were evaluated by dividing them into 2 groups as 2nd session SMPL required and not required, and the area of RPE was smaller in the group requiring 2nd session SMPL (p: 0.030). The status of central RPE may be a determining factor on the response to treatment. Additionally, HbA1c levels may have an impact on treatment efficacy.

Comparison of the efficacy and safety of anti-VEGF monotherapy versus anti-VEGF therapy combined with subthreshold micropulse laser therapy for diabetic macular edema

The purpose of this study is to compare the efficacy and safety of 577-nm subthreshold micropulse laser (SML) and intravitreal bevacizumab injection (IVB) combined therapy with IVB monotherapy in the treatment of diabetic macular edema (DME). This retrospective study included 80 eyes of 80 patients; 40 eyes were treated with IVB monotherapy, and 40 eyes were treated with SML-IVB combined therapy. The mean number of required IVB injections and changes of best corrected visual acuity (BCVA) and central macular thickness (CMT) values were compared between the groups. The mean age of the patients was 60.19±7.43 years. The baseline characteristics of the patients were similar between the groups. In the SML-IVB combined group, the mean number of required SML sessions was 2.1±0.81. The mean number of required IVB injections was 4.38±0.81 in the SML-IVB combined group and 5.65±1.51 in the IVB monotherapy group (p<0.05). The increase of the BCVA was significant in the SML-IVB combined group at the 3rd, 6th, 9th, and 12th months; however, in the IVB monotherapy group, it was only significant at the 3rd month (p<0.05). The mean CMT values of the 3rd, 9th, and 12th months were similar between the groups (p>0.05); only at the 6th month was it significantly lower in the SML-IVB combined group (p<0.05). When compared with baseline, the decrease of the CMT was statistically significant in both groups at the 3rd, 6th, 9th, and 12th months (p<0.05). In this study, a significant benefit of adding SML to IVB therapy was found with less IVB need, although a very significant increase in BCVA could not be achieved. The use of SML-IVB combined treatment may be an effective and safe alternative for DME.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Real-life outcomes of subthreshold laser therapy for diabetic macular edema

BACKGROUND

Diabetic macular edema (DME) is a major cause of visual impairment and its treatment is a public health challenge. Even though anti-angiogenic drugs are the gold-standard treatment, they are not ideal and subthreshold laser (SL) remains a viable and promising therapy in selected cases. The aim of this study was to evaluate its efficacy in a real-life setting.

METHODS

Retrospective case series of 56 eyes of 36 patients with center-involving DME treated with SL monotherapy. Treatment was performed in a single session with the EasyRet® photocoagulator with the following parameters: 5% duty cycle, 200-ms pulse duration, 160-µm spot size and 50% power of the barely visible threshold. A high-density pattern was then applied to the whole edematous area, using multispot mode. Best corrected visual acuity (BCVA) and optical coherence tomography (OCT) data were obtained at baseline and around 3 months after treatment.

RESULTS

Fifty-six eyes of 36 patients were included (39% women, mean age 64.8 years old); mean time between treatment day and follow-up visit was 14 ± 6 weeks. BCVA (Snellen converted to logMAR) was 0.59 ± 0.32 and 0.43 ± 0.25 at baseline and follow-up, respectively (p = 0.002). Thirty-two percent had prior panretinal photocoagulation (p = 0.011). Mean laser power was 555 ± 150 mW and number of spots was 1,109 ± 580. Intraretinal and subretinal fluid (SRF) was seen in 96 and 41% of eyes at baseline and improved in 35 and 74% of those after treatment, respectively. Quantitative analysis of central macular thickness (CMT) change was performed in a subset of 23 eyes, 43% of which exhibited > 10% CMT reduction post-treatment.

CONCLUSIONS

Subthreshold laser therapy is known to have RPE function as its main target, modulating the activation of heat-shock proteins and normalizing cytokine expression. In the present study, the DME cases associated with SRF had the best anatomical response, while intraretinal edema responded poorly to laser monotherapy. BCVA and macular thickness exhibited a mild response, suggesting the need for combined treatment in most patients. Given the effect on SRF reabsorption, subthreshold laser therapy could be a viable treatment option in selected cases.

Optical coherence tomography parameters as predictors of treatment response to a 577-nm subthreshold micropulse laser in chronic central serous chorioretinopathy

To determine the relation between retinal microstructural changes and the response to 577-nm subthreshold micropulse laser (SML) treatment in chronic central serous chorioretinopathy (cCSC). This retrospective study included 39 eyes of 39 patients with cCSC, treated with the 577-nm SML. The eyes were evaluated in three groups: complete remission, partial remission, and failure groups. The presence of some baseline retinal microstructural changes, thickness of the outer nuclear layer (ONL), status of the ellipsoid zone (EZ), and retinal pigment epithelium (RPE) were evaluated. The changes in central macular thickness (CMT), subretinal fluid (SRF) height, and best-corrected visual acuity (BCVA) were calculated. There were 14, 13, and 12 eyes in the complete remission, partial remission, and failure group, respectively. The baseline EZ and RPE were found intact in 71.4% and 64.3% of the eyes in the complete remission group, respectively; however, these rates were respectively 25% and 16.7% in the failure group (p < 0.05). Extrafoveal foci were present in 35.7% of the eyes in the complete remission group, but none was found in the failure group (p < 0.05). Although there was no statistically significant difference, the baseline ONL thickness was higher, and the hyperreflective dots, retinal bumps, subretinal fibrinous exudates, and PEDs were seen less in the complete remission group. The changes of the BCVA were not significant in any of the groups at the last visit (p > 0.05). The presence of baseline intact EZ and RPE, and extrafoveal foci can potentially be used as predictors of the SML treatment success in cCSC.

Evaluation of the Safety and Efficacy of Selective Retina Therapy Laser Treatment in Patients with Central Serous Chorioretinopathy

Purpose

To assess the safety and efficacy of selective retina therapy (SRT) using a Q-switched neodymium-doped yttrium lithium fluoride laser with feedback systems in patients with idiopathic central serous chorioretinopathy (CSC).

Methods

This randomized clinical trial enrolled patients having at least 3-month symptom of CSC. From month 3 visit, all subjects in both groups were eligible for SRT retreatment if they showed persistent or recurrent subretinal fluid (SRF). The primary outcome was complete resolution of SRF by optical coherence tomography at 3 months after treatment. The secondary outcomes were changes in SRF, central macular thickness (CMT) and best-corrected visual acuity at the 1-, 3-, and 6-month examinations.

Results

Sixty-eight CSC patients were included (SRT, 31; control, 37). After 1 and 3 months, complete resolution of SRF was achieved in 25.8% and 54.8% of SRT group and 17.6% and 35.1% of controls. The differences were not statistically significant (p = 0.424 and p = 0.142, respectively). However, mixed model for repeated measures analyses showed that the reduction of SRF and CMT were observed earlier in SRT group than in the sham group (least squares mean difference, −59.7 μm; 95% confidence interval, −98.2 to −21.2; p = 0.0029; least squares mean difference −67.0 μm; 95% confidence interval, −104.8 to −29.2; p = 0.0007, respectively). Significant reduction of SRF (≥50% reduction from baseline) was more frequently observed in SRT group (80.6%) than the sham group (44.1%) at month 1 (p = 0.007). Early reduction of SRF and CMT was more abundant in SRT group with symptom duration less than 6 months. Treatment related serious adverse events were not observed.

Conclusions

SRT using a Q-switched neodymium-doped yttrium lithium fluoride laser with feedback system was safe in this trial and effective for early resolution of SRF in the CSC patients. Early intervention with SRT can be a safe alternative for patients with acute symptomatic CSC.

Investigation of the therapeutic mechanism of subthreshold micropulse laser irradiation in retina

PURPOSE

Subthreshold micropulse laser irradiation has been used for the treatment of retinal edema; however, there are few reports about the mechanism of its therapeutic effect. In this study, we compared threshold short pulse and subthreshold micropulse laser irradiation in mice and investigated their mechanism.

METHODS

Nine to 12-week-old male C57BL/6J mice were used in this study. After general anesthesia, threshold short pulse or subthreshold micropulse laser irradiation was performed on the right eye using IQ577. Enucleation was performed 24 h after the laser irradiation, and histological and gene expression analyses were carried out.

RESULTS

Coagulation spots and atrophy of the retinal pigment epithelium were observed after threshold short pulse laser irradiation but not after subthreshold micropulse laser irradiation. Twenty-four hours after laser, aquaporin (AQP) 1, 2, 7, and 11 levels were significantly elevated by 1.7- to 3-fold in the threshold short pulse laser group compared with non-treated control group. AQP 3 was increased significantly and prominently by 100-fold. VEGF-A and VEGFR2 were upregulated 1.5- and 2.3-fold, respectively. In the subthreshold micropulse laser group, AQP 3 was increased by 6-fold compared with the non-treated control group. Angiopoietin-1 and the adrenomedullin (AM) receptor CLR were decreased by 0.6-fold and 0.5-fold, respectively.

CONCLUSION

Threshold short pulse laser irradiation caused retinal damage and prominent changes in the expression of various genes. Contrarily, subthreshold micropulse laser irradiation did not induce retinal damage; it upregulated AQP 3, which might have improved retinal edema by drainage of subretinal fluid.

The efficacy of selective retina therapy for diabetic macular edema based on pretreatment central foveal thickness

To evaluate the efficacy of selective retina therapy (SRT) in patients with diabetic macular edema (DME) based on pretreatment central foveal thickness (CFT). Seventy-two eyes of 63 patients with DME who had previously undergone SRT were included. Patients were divided into two groups based on the CFT at baseline. Group 1 was composed of 35 eyes with CFT < 400 μm and group 2 was composed of 37 eyes with CFT ≥ 400 μm. Changes in best corrected visual acuity (BCVA) and CFT were measured at baseline, 3 and 6 months after SRT. A single-session retreatment was performed at 3-month posttreatment if there was no reduction in CFT. Rescue treatment with intravitreal anti-VEGF injections was performed if persistent DME or vision loss of 1 ≥ logMAR VA line was observed by 6 months after initial SRT. Six months after SRT, group 1 showed reduction of 45.9 μm in mean CFT (P < 0.001) and gain of 0.13 logMAR in mean BCVA (P < 0.001), whereas group 2 experienced no significant change in CFT or BCVA. In group 1, retreatments were performed in 6 eyes (17.1%), and rescue treatment was performed in 1 eye (2.9%), whereas in group 2, retreatment was performed in 17 eyes (45.9%), and rescue treatments were administered in 27 eyes (73%) during a 6-month follow-up. Although SRT had limited effects as a treatment for severe DME, SRT monotherapy for mild DME was effective in improving BCVA and reducing CFT during a 6-month follow-up period.

A pilot prospective study of 577-nm yellow subthreshold micropulse laser treatment with two different power settings for acute central serous chorioretinopathy

To compare the efficacy of 50% threshold power with 25% threshold power of 577-nm subthreshold micropulse laser (SMPL) for acute central serous chorioretinopathy (CSC). Prospective, interventional, non-randomized, comparative case series. A total of 54 patients (54 eyes) with acute CSC were enrolled. Twenty-four eyes received 25% threshold power and 30 eyes received 50% threshold power of 577-nm SMPL. Best-corrected visual acuity (BCVA), central macular thickness (CMT), and complete absorption of subretinal fluid (SRF) were evaluated at 1 month and 3 months. The complete absorption rate of SRF in the 50% power group was significantly greater than that in the 25% power group at 1 month (70.0% vs 25.0%, p < 0.001) and at 3 months (83.3% vs 54.2%, p < 0.001). Mean BCVA improved from 0.34 ± 0.20 LogMAR to 0.02 ± 0.13 LogMAR in the 50% power group and from 0.27 ± 0.15 LogMAR to 0.14 ± 0.21 LogMAR in the 25% power group with a significant difference between the two groups after 3 months (p = 0.027). In the 50% power group, the CMT decreased from 491.6 ± 154.8 μm at baseline to 231.3 ± 92.3 μm at 1 month and 228.2 ± 88.1 μm at 3 months, and in the 25% power group, the CMT decreased from 444.9 ± 164.1 to 306.8 ± 102.6 μm at 1 month and 254.5 ± 101.7 μm at 3 months. There was statistical difference of CMT at 1 month (p = 0.009) but no significant difference at 3 months between the two groups (p = 0.232). SMPL with 50% threshold power may be more effective than 25% threshold power for acute CSC.

Micropulse laser for persistent optic disc pit maculopathy. A case report

Purpose

Optic disc pits (ODP) are rare and congenital anomalies of the optic disc, sometimes remaining asymptomatic. However, serous macular detachment or optic disc maculopathy is the most common complication, causing significant visual deterioration, without a current consensus about treatment. We describe a case of ODP maculopathy that was treated successfully with micropulse laser.

Observations

A patient with ODP maculopathy remained with macular serous detachment after nine months of follow up after pars plana vitrectomy. Subthreshold micropulse laser was used to treat macular serous detachment, achieving a significant improvement in central macular thickness after one session.

Conclusions and importance

Subthreshold micropulse laser is designed to stimulate the retinal pigment epithelium without damage to the photoreceptors, resulting in absorption of subretinal and intraretinal fluid. Macular serous detachment in patients with ODP requires a prompt diagnosis and treatment to avoid damage to photoreceptors. Subthreshold micropulse laser is a potential treatment for eyes with ODP and macular serous detachment complication.

Advances in Retinal Laser Therapy

Since the 1960s, laser therapies have played a critical role in the treatment of numerous retinal diseases. Significant advances have been made in laser technology and the molecular understanding of laser-tissue interactions over the past 55 years to maximize the therapeutic effect while minimizing side-effects. While pharmacologic therapies (e.g., anti-vascular endothelial growth factor or anti-VEGF) are playing a larger role, laser therapy remains an important treatment modality for proliferative diabetic retinopathy (PDR), diabetic macular edema (DME), sickle cell retinopathy, retinal vein occlusions, central serous chorioretinopathy, tumors, polypoidal choroidal vasculopathy, and retinal tears. With the development new laser technologies such as selective retinal therapy, subthreshold micropulse laser, nanosecond laser, photomediated ultrasound therapy, and navigated laser, the risk of adverse events has been significantly reduced. This review summarizes the latest developments in retinal laser therapy.

Combined Intravitreal Dexamethasone Implant And Micropulse Yellow Laser For Treatment Of Anti-VEGF Resistant Diabetic Macular Edema

Purpose:

To report the efficacy and safety of combined intravitreal dexamethasone implant and micropulse laser for anti-VEGF resistant diabetic macular edema.

Patients and Methods:

Prospective, non-controlled study that was conducted for twenty eyes with center-involved diabetic macular edema not responding to anti-VEGF therapy. Ozurdex intravitreal implant was injected to all eyes with subsequent micropulse yellow laser one month after the injection. All eyes were followed up after one, three, four, six, nine and twelve months. The primary outcome measure is the change in best corrected visual acuity (BCVA) after one year and secondary outcome measures are central macular thickness (CMT) change and safety of both dexamethasone implant and micropulse laser. Reinjection was done for those eyes with recurrent edema.

Results:

The mean age was 58.8 ±7.94 years. The mean BCVA was 0.6± 0.14, 0.57 ±0.12, 0.51±0.15, 0.59±0.12, 0.6± 0.12 and 0.59±0.14 after one, three, four, six, nine and twelve months in comparison to 0.45± 0.14 as initial BCVA [SS,P<0.05]. The CMT was 302.5±30.01, 330.6±20.24, 357.6±32.15, 285.4±19.95, 292.9±25.07 and 285.2±14.99 after one ,three, four ,six , nine and twelve months µm in comparison to initial CMT of 420.7 ±38.74µm [HS, P<0.01]. Cataract occurred in 6 eyes from 14 phakic eyes (42.8%). Transient ocular hypertension occurred in 6 eyes (30%). Reinjection was done for eight eyes (40%).

Conclusion:

Intravitreal dexamethasone implant and micropulse laser are both effective and safe treatment options for anti-VEGF resistant diabetic macular edema.