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

Microsecond Pulsing Laser for Choroidal Neovascularization Associated with Central Serous Chorioretinopathy

PURPOSE

To analyze the efficacy and safety of microsecond pulsing laser therapy (MLT) in the management of central serous chorioretinopathy (CSCR) complicated by choroidal neovascularization (CNV).

METHODS

Patients with CSCR complicated by CNV defined as the presence of characteristic OCT angiography features were randomly assigned to either study or control group. All patients of the study group underwent MLT targeting CNV area using navigated laser system followed by at least 6-month follow-up. Sham treatment was performed in the control group. No other treatment or anti-VEGF therapy was used during the follow-up. Main outcome measure was complete resolution of subretinal fluid at the end of follow-up.

RESULTS

Twenty-three eyes (13 males and 10 females, mean age 58.2 ± 8.0 years) with a mean CNV area 0.62 ± 0.77 mm2 were included in the study group. Fourteen (60.9%) patients achieved complete resolution of SRF, five (21.7%) patients demonstrated some reduction of SRF, and four (17.4%) patients demonstrated no improvement after MLT in the study group. Twelve eyes (8 males and 4 females, mean age 59.8 ± 4.6 years) were included in the control group where none of them demonstrated resolution of SRF at the end of the follow-up (p = 0.0018 compared to the study group). No adverse effects, such as changes of CNV size, deterioration of exudation, or decline in visual acuity were observed in the study group.

CONCLUSION

Microsecond pulsing laser is an effective and safe option for the treatment of CSCR complicated by relatively small CNV and achieves complete resolution of SRF in 61% of cases.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Safety and efficacy of the yellow sub-threshold micropulse laser for uveitic macular edema: A pilot study

PURPOSE

To assess the safety and efficacy of the yellow sub-threshold micropulse laser (YSML) in eyes with uveitic macula edema (UME).

METHODS

A prospective interventional study. Eyes with non-infectious UME and an unsatisfactory response to prior conventional treatments underwent navigated YSML (NAVILAS®). The treatment was planned on an imported macular OCT scan. The central macular thickness (CMT) and best-corrected visual acuity (BCVA) were recorded immediately before the treatment (baseline) and again after 1 and 3 months. The end of the follow up (FU) was the last available evaluation in the case of no UME recurrence; or when the CMT increase required rescue therapy.

RESULTS

Eight eyes of as many patients were included. The mean duration of the FU was 252 days (range: 170-398 days). No adverse events were observed. In the whole cohort the mean values improvement over time was significant for both CMT (p = 0.011) and BCVA (p < 0.001). The indication for a new treatment was stated in 4 eyes (50%) after a mean FU of 277 ± 43 days. This time was statistically comparable with the mean FU of eyes without UME recurrence. At the baseline the non-UME recurrence eyes had a significantly lower mean CMT (326 ± 80 vs 485 ± 112 μm, p = 0.03).

CONCLUSIONS

The application of YSLM for UME has not previously been mentioned in literature. Our results were promising in terms of both safety and efficacy. This would authorize further studies on the procedure, also as a first line treatment in naif UME cases.

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.

Intravitreal Dexamethasone Implant Switch after Anti-VEGF Treatment in Patients Affected by Retinal Vein Occlusion: A Review of the Literature

Nowadays, retinal vein occlusion (RVO) is the second most prevalent cause of vision loss associated with retinal vascular disease. Intravitreal injections are currently known as a major advancement in ophthalmology, particularly in the treatment of RVO and other retinal disorders. Particularly, the first line of therapy is usually anti-vascular endothelial growth factor (VEGF) drugs. Notably, for RVO eyes that have not responded to anti-VEGF therapy, an intravitreal dexamethasone (DEX) implant 0.7 mg (Ozurdex®, AbbVie Inc., North Chicago, IL, USA) is considered a suitable therapeutical substitute. Actually, investigations carried out in the real world and clinical trials have shown the safety and the efficacy of intravitreal DEX implants for treating this retinal disease. For this reason, choosing patients carefully may thus be essential to reduce the number of injections that clinics and hospitals have to do to manage RVO and its complications. The primary aim of this review is to summarize the pathophysiology of this retinal vascular disease, as well as the clinical and ocular imaging features that may support a switch from prior anti-VEGF treatment to intravitreal DEX implant, to provide the RVO patients with the best possible treatment to ensure maximum visual recovery.

Current management options for the treatment of refractory postoperative cystoid macular edema: A systematic review

Post-operative cystoid macular edema (PCME) is an important complication following intraocular surgery that often resolves spontaneously without treatment. In some cases, PCME may persist despite initial medical therapy, which can adversely impact visual outcomes. Various topical, intraocular and systemic treatments exist for the prevention and management of cystoid macular edema; however, there is no consensus on treatment of refractory cases in the postoperative setting. In accordance with the PRISMA guidelines, we systematically reviewed 68 articles describing management options and their outcomes for treatment-resistant cases of PCME. The most commonly reported treatments included steroid (39 studies) and biological-based (17 studies) therapies. We provide an overview of the treatment options for refractory PCME.

Switching to an Intravitreal Dexamethasone Implant after Intravitreal Anti-VEGF Therapy for Diabetic Macular Edema: A Review

Among working-age people, diabetic retinopathy and diabetic macular edema are currently considered the main causes of blindness. Nowadays, intravitreal injections are widely acknowledged as a significant milestone in ophthalmology, especially for the treatment of several retinal diseases, including diabetic macular edema. In particular, anti-vascular endothelial growth factor (VEGF) agents are typically the first line of treatment; however, monthly injections are required, at least, during the loading dosage. Notably, an intravitreal 0.7 mg dexamethasone (DEX) implant (Ozurdex®, AbbVie Inc., North Chicago, IL, USA) is considered a legitimate substitute treatment for diabetic eyes that have not responded to anti-VEGF treatment. In fact, clinical trials and real-life studies have demonstrated the effectiveness and safety of an intravitreal DEX implant in treating such conditions over a period of three to six months. For this reason, wisely selecting diabetic patients might be crucial to decreasing the load of injections in clinics and hospitals. The purpose of this review is to analyze the available scientific literature to highlight the benefits, efficacy, and clinical criteria for choosing whether to switch from intravitreal anti-VEGF therapy to an intravitreal DEX implant in diabetic macular edema.

A Two-Decade Bibliometric Analysis of Laser in Ophthalmology: From Past to Present

Background

Laser therapy has been proven as an effective technique for managing ophthalmological disorders. To guide future research, we conducted a bibliometric analysis of laser applications in eye diseases from 1990 to 2022, aiming to identify key themes and trends.

Methods

We retrieved 3027 publications from the Web of Science Core Collection (WoSCC). Bibliometrix was used for science mapping of the literature, while VOSviewer and CiteSpace were applied to visualize co-authorship, co-citation, co-occurrence, and bibliographic coupling networks.

Results

From a co-citation reference network, we identified 52 distinct clusters. Our analysis uncovered three main research trends. The first trend revolves around the potential evolution of corneal laser surgery techniques, shifting from the treatment of refractive errors to broader applications in biomedical optics. The second trend illustrates the advancement of laser applications in treating a range of disorders, from retinal and ocular surface diseases to glaucoma. The third trend focuses on the innovative uses of established technologies.

Conclusion

This study offers significant insights into the evolution of laser applications in ophthalmology over the past 30 years, which will undoubtedly assist scientists in directing further research in this promising field.

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.

Navigated yellow subthreshold micropulse laser for refractory cystoid macular edema following rhegmatogenous retinal detachment surgery

Purpose

To report the efficacy and safety of navigated 577nm yellow subthreshold micropulse laser (YSML) treatment in a case of refractory cystoid macular edema (CME) following combined phaco-vitrectomy for rhegmatogenous retinal detachment (RRD).

Observations

A 69-year-old male patient complained a slow and progressive visual loss in the right eye (RE) since two months. A complete ophthalmological evaluation was performed. Best corrected visual acuity (BCVA) was hand motion and slit lamp examination revealed a nuclear cataract and a total macula-off RRD in the RE. Patient underwent a combined phaco +25 gauge pars plana vitrectomy (PPV) with 5000 cSt silicon oil (SO) tamponade. At the 3-month follow up BCVA was 20/250, retina was completely flat but a macular proliferative vitreoretinopathy (PVR) was detected with swept source optical coherence tomography (SS-OCT) and a second 23 G PPV with PVR peeling and SO removal was performed. At 1 month visit from the second surgery retina was flat and BCVA was 20/200 due to a persistent CME. Oral carbonic anhydrase inhibitors and topical steroids were administered for 2 months without any improvements. At this point, YSML was applied with a macular grid pattern and at three months follow up visit SS-OCT showed a complete resolution of CME, BCVA was 20/100 and these anatomical and functional outcomes were maintained at 6 months follow-up.

Conclusions and importance

YSML treatment may be considered a safe and effective treatment strategy for the management of refractory CME following complex RRD surgery cases.

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.

Subthreshold Micropulse Laser Acute Exudative Maculopathy in Central Serous Chorioretinopathy

Photodynamic acute exudative maculopathy is a transient increase in subretinal fluid (SRF) within the first days after treatment in different chorioretinal diseases and tumors. Recently, this entity has attracted much attention. However, no cases of acute exudative maculopathy have been described after subthreshold laser (STL). This report presents the case of a 35-year-old male with chronic central serous chorioretinopathy with an extrafoveal serous retinal pigment epithelium detachment (PED) who underwent STL. One day after treatment, the patient noted an acute decrease in visual acuity and abundant SRF. One month after treatment, both the SRF and PED were spontaneously resolved. [Ophthalmic Surg Lasers Imaging Retina 2023;54:540-542.].