NONDAMAGING PHOTOTHERMAL THERAPY FOR THE RETINA: Initial Clinical Experience With Chronic Central Serous Retinopathy

Central serous chorioretinopathy: An evidence-based treatment guideline

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

The effect of nondamaging subthreshold laser therapy in patients with chronic central serous chorioretinopathy

PURPOSE

To evaluate the efficacy of nondamaging subthreshold laser therapy in Korean patients with chronic central serous chorioretinopathy (cCSC).

METHODS

This retrospective interventional case series included 31 patients (31 eyes) with cCSC who underwent nondamaging laser therapy using Endpoint Management (EpM) software. Since a barely visible burn of the test spot was defined as 100% pulse energy, 30% pulse energy with a 200-μm spot was titrated to treat the macular area based on EpM settings. A 30% pulse laser with a spacing of 0.25-beam diameter was applied to cover the macular area where hyperfluorescent leaks were observed on fluorescein angiography. Changes in central macular thickness (CMT), subretinal fluid (SRF) height, subfoveal choroidal thickness (SCT), and logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) were measured at baseline and after 3 and 6 months. If the subretinal fluid persisted for 3 months, retreatment was performed.

RESULTS

At 6 months post-treatment, the complete SRF resolution rate was 48.39% (15/31 eyes), and the partial SRF resolution rate was 12.90% (4/31 eyes). The change in mean BCVA (logMAR) was not significant (0.31 ± 0.29 at the baseline and 0.31 ± 0.40 at month 6) (p = 0.943). At the baseline, the mean CMT (μm) decreased from 350.74 ± 112.76 at baseline to 239.71 ± 130.25 at month 6 (p < 0.001), and the mean SRF height (μm) decreased from 193.16 ± 90.69 at baseline to 70.58 ± 100.00 at month 6 (p < 0.001). However, the change in SCT was not statistically significant (p = 0.516). In 15 patients who were retreated at month 3, the mean SRF height (μm) decreased significantly from 144.67 ± 74.01 at month 3 to 77.13 ± 63.77 at month 6 (p = 0.002). No side effects associated with laser therapy were observed during the 6-month follow-up.

CONCLUSIONS

Nondamaging laser therapy with a modified macular treatment was effective in reducing CMT and SRF and showed favorable visual and anatomical outcomes in patients with cCSC.

Detection sensitivity of fluorescence lifetime imaging ophthalmoscopy for laser-induced selective damage of retinal pigment epithelium

PURPOSE

To investigate the sensitivity of fluorescence lifetime imaging ophthalmoscopy (FLIO) to detect retinal laser spots by comparative analysis with other imaging modalities.

METHODS

A diode laser with a wavelength of 514 nm was applied with pulse durations of 5.2, 12, 20, and 50 µs. The laser pulse energy was increased so that the visibility of the laser spot by slit-lamp fundus examination (SL) under the irradiator's observation covers from the subvisible to visible range immediately after irradiation. The irradiated areas were then examined by fundus color photography (FC), optical coherence tomography (OCT), fundus autofluorescence (AF), FLIO, and fluorescein angiography (FA). The visibility of a total of over 2200 laser spots was evaluated by two independent researchers, and effective dose (ED) 50 laser pulse energy values were calculated for each imaging modality and compared.

RESULTS

Among examined modalities, FA showed the lowest mean of ED50 energy value and SL the highest, that is, they had the highest and lowest sensitivity to detect retinal pigment epithalium (RPE)-selective laser spots, respectively. FLIO also detected spots significantly more sensitively than SL at most laser pulse durations and was not significantly inferior to FA. AF was also often more sensitive than SL, but the difference was slightly less significant than FLIO.

CONCLUSION

Considering its high sensitivity in detecting laser spots and previously reported potential of indicating local wound healing and metabolic changes around laser spots, FLIO may be useful as a non-invasive monitoring tool during and after minimally invasive retinal laser treatment.

Half-dose photodynamic therapy versus 577 nm subthreshold pulse laser therapy in treatment-naive patients with central serous chorioretinopathy

BACKGROUND

To compare real-life anatomical and functional outcomes of half-dose photodynamic therapy (HD-PDT) and 577 nm subthreshold pulse laser therapy (SPL) in treatment-naïve patients with central serous chorioretinopathy (CSC).

METHODS

We retrospectively reviewed consecutive treatment-naïve CSC patients with non-resolving subretinal fluid (SRF) for more than 2 months who received either HD-PDT or SPL treatment. One repetition of the same treatment was allowed in patients with persistent SRF after first treatment. Functional and anatomical outcomes were assessed after first treatment and at final visit.

RESULTS

We included 95 patients (HD-PDT group, n = 49; SPL group, n = 46). Complete resolution of SRF after a single treatment was observed in 42.9% of HD-PDT-treated patients (n = 21; median time to resolution 7.1 weeks) and in 41.3% of SPL-treated patients (n = 19; median time to resolution 7.0 weeks). In the HD-PDT-group, 44.9% of patients (n = 22) and in the SPL-group, 43.5% (n = 20) of patients, received a second treatment due to persistent SRF, while 12.2% (n = 6) and 15.2% (n = 7), respectively, opted against a second treatment despite persistent SRF. After the final treatment, complete SRF resolution was observed in 61.2% of all HD-PDT-treated patients (n = 30; median time to resolution 8.8 weeks) and 60.9% of all SPL-treated patients (n = 28; median time to resolution 13.7 weeks, p = 0.876). In the final visit, both groups showed significant improvement of BCVA in comparison to baseline (p < 0.001 for all). The change in BCVA from baseline to final visit was similar for the two groups (HD-PDT, median BCVA change 0.10 logMAR (IQR: 0.0-0.2); in SPL group, median BCVA change 0.10 logMAR (IQR: 0.0-0.2), P = 0.344). The CSC subclassification (simple versus complex) had no influence on the anatomical or functional outcome.

CONCLUSIONS

High-density 577 nm SPL resulted in as good anatomical and functional treatment as HD-PDT and may thus represent a treatment alternative to HD-PDT in CSC.

Retinal and Choroidal Alterations in Diabetic Retinopathy Treatment using Subthreshold Panretinal Photocoagulation with Endpoint Management Algorithm: A Secondary Analysis of a Randomized Clinical Trial

INTRODUCTION

The aim of this study was to compare retinal and choroidal alterations in eyes with severe nonproliferative diabetic retinopathy (NPDR) after panretinal photocoagulation (PRP), using conventional pattern scan laser (PASCAL) and PASCAL with endpoint management (EPM).

METHODS

This was a post hoc analysis of a paired randomized clinical trial. Bilateral treatment-naïve eyes of an individual with symmetric severe NPDR were randomly allocated into the threshold PRP group and subthreshold EPM PRP group. Patients had follow-up visits at 1, 3, 6, 9, and 12 months post-treatment. The retinal thickness (RT), choroidal thickness (CT), choroidal area, and choroidal vascularity index (CVI) were compared between the two groups and among different time points within the same group.

RESULTS

Seventy eyes of 35 patients with diabetes mellitus (DM) were finally included for analysis at the 6- and 12-month visits, respectively. At 3 and 6 months post-treatment, the RT in the subthreshold EPM PRP group was significantly thinner than that in the threshold PRP group. CT, stromal area, and luminal area were reduced earlier in the threshold PRP group than in the subthreshold EPM PRP group. CVI was not significantly different within the same group or between groups at most time points.

CONCLUSION

At 12 months post-treatment, retinal thickening and choroidal disturbance may be slightly less severe and more delayed in eyes receiving PRP using PASCAL with EPM than in those receiving PRP using conventional PASCAL. The EPM algorithm may be a good alternative in PRP when treating severe NPDR.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT01759121.

Interferometric thermometry of ocular tissues for retinal laser therapy

Controlling the tissue temperature rise during retinal laser therapy is highly desirable for predictable and reproducible outcomes of the procedure, especially with non-damaging settings. In this work, we demonstrate a method for determining the optical absorption, the thermal conductivity, and the thermal expansion coefficients of RPE and choroid using phase-resolved optical coherence tomography (pOCT). These parameters are extracted from the measured changes in the optical path length (ΔOPL) using an axisymmetric thermo-mechanical model. This allows the calculation of the temperature rise during hyperthermia, which was further validated by imaging the temperature-sensitive fluorescence at the same location. We demonstrate that, with a temperature uncertainty of ±0.9°C and a peak heating of about 17°C following a laser pulse of 20 ms, this methodology is expected to be safe and sufficiently precise for calibration of the non-damaging retinal laser therapy. The method is directly translatable to in-vivo studies, where we expect a similar precision.

Evaluation of the choroidal vascularity index after subthreshold yellow laser treatment in the patients with chronic central serous chorioretinopathy

PURPOSE

To assess the choroidal vascularity index (CVI) after subthreshold laser treatment in patients with central serous chorioretinopathy (CSC).

METHOD

A total of 32 eyes with CSC were included in this study. In group 1, 14 eyes with persistent CSC were treated with the PASCAL (Endpoint Management Software) at 577-nm wavelength and in group 2, 18 eyes without treatment. The luminal area (LA), stromal area (SA), total area of choroid (TA), and CVI were measured by binarization (ImageJ) of optical coherence tomography images. Changes of choroidal structure parameters were evaluated over 3 months.

RESULT

A significant decrease was observed in LA, TA, and CVI at the third month after the laser treatment (p = 0.018, p = 0.024, p = 0.046). The best-corrected visual acuity (BCVA) and choriocapillaris plexus (CCP) flow area values were increased after treatment in group 1 (p < 0.001, p = 0.002). The final subfoveal fluid height, and CVI were lower in group 1 (p = 0.003, p = 0.011). The visual acuity and CCP flow area were higher in group 1 at the third month (p < 0.001, p = 0.003). A positive correlation between the final BCVA and CVI was observed (r = 0.539, p = 0.01).

DISCUSSION

Decreased CVI was observed in CSC eyes after subthreshold yellow laser treatment. The CVI may be a useful index to evaluate the response to treatment.

Interferometric imaging of thermal expansion for temperature control in retinal laser therapy

Precise control of the temperature rise is a prerequisite for proper photothermal therapy. In retinal laser therapy, the heat deposition is primarily governed by the melanin concentration, which can significantly vary across the retina and from patient to patient. In this work, we present a method for determining the optical and thermal properties of layered materials, directly applicable to the retina, using low-energy laser heating and phase-resolved optical coherence tomography (pOCT). The method is demonstrated on a polymer-based tissue phantom heated with a laser pulse focused onto an absorbing layer buried below the phantom's surface. Using a line-scan spectral-domain pOCT, optical path length changes induced by the thermal expansion were extracted from sequential B-scans. The material properties were then determined by matching the optical path length changes to a thermo-mechanical model developed for fast computation. This method determined the absorption coefficient with a precision of 2.5% and the temperature rise with a precision of about 0.2°C from a single laser exposure, while the peak did not exceed 8°C during 1 ms pulse, which is well within the tissue safety range and significantly more precise than other methods.

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

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

Recent advances in ocular drug delivery systems and targeting VEGF receptors for management of ocular angiogenesis: A comprehensive review

Background

Angiogenic ocular diseases address the main source of vision impairment or irreversible vision loss. The angiogenesis process depends on the balance between the pro-angiogenic and anti-angiogenic factors. An imbalance between these factors leads to pathological conditions in the body. The vascular endothelial growth factor is the main cause of pathological conditions in the ocular region. Intravitreal injections of anti-angiogenic drugs are selective, safe, specific and revolutionized treatment for ocular angiogenesis. But intravitreal injections are invasive techniques with other severe complications. The area of targeting vascular endothelial growth factor receptors progresses with novel approaches and therapeutically based hope for best clinical outcomes for patients through the developments in anti-angiogenic therapy.

Main text

The present review article gathers prior knowledge about the vascular endothelial growth factor and associated receptors with other angiogenic and anti-angiogenic factors involved in ocular angiogenesis. A focus on the brief mechanism of vascular endothelial growth factor inhibitors in the treatment of ocular angiogenesis is elaborated. The review also covers various recent novel approaches available for ocular drug delivery by comprising a substantial amount of research works. Besides this, we have also discussed in detail the adoption of nanotechnology-based drug delivery systems in ocular angiogenesis by comprising literature having recent advancements. The clinical applications of nanotechnology in terms of ocular drug delivery, risk analysis and future perspectives relating to the treatment approaches for ocular angiogenesis have also been presented.

Conclusion

The novel ocular drug delivery systems involving nanotechnologies are of great importance in the ophthalmological sector to overcome traditional treatments with many drawbacks. This article gives a detailed insight into the various approaches that are currently available to be a road map for future research in the field of ocular angiogenesis disease management.

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

Purpose: To investigate the effectiveness and safety of 577-nm subthreshold micropulse laser (SML) on acute central serous chorioretinopathy (CSC). Methods: One hundred and ten patients with acute CSC were randomized to receive SML or 577-nm conventional laser (CL) treatment. Optical coherence tomography and best-corrected visual acuity (BCVA) were performed before and after treatment. Results: At 3 months, the complete resolution of subretinal fluid (SRF) in 577-nm SML group (72.7%) was lower than that in CL group (89.1%) (Unadjusted RR, 0.82; P = 0.029), but it was 85.5 vs. 92.7% at 6 months (unadjusted RR, 0.92; P = 0.221). The mean LogMAR BCVA significantly improved, and the mean central foveal thickness (CFT) significantly decreased in the SML group and CL group (all P < 0.001) at 6 months. But there was no statistical difference between the two groups (all P > 0.05). In the SML group, obvious retinal pigment epithelium (RPE) damage was shown only in 3.64% at 1 month but 92.7% in the CL group (P < 0.001). Conclusions: Although 577-nm SML has a lower complete absorption of SRF compared with 577-nm CL for acute CSC at 3 months, it is similarly effective as 577-nm CL on improving retinal anatomy and function at 6 months. Importantly, 577-nm SML causes less damage to the retina.

Subthreshold Pan-Retinal Photocoagulation Using Endpoint Management Algorithm for Severe Nonproliferative Diabetic Retinopathy: A Paired Controlled Pilot Prospective Study

PURPOSE

The aim of this study was to report the efficacy and safety profile of subthreshold pan-retinal photocoagulation (PRP) using endpoint management (EPM) algorithm compared with conventional threshold PASCAL PRP for the treatment of severe nonproliferative diabetic retinopathy (NPDR).

METHODS

This was a prospective, single-center, paired randomized controlled trial of 56 eyes of 28 participants with bilateral symmetric severe NPDR. One eye of the participant was randomly assigned to receive the subthreshold EPM PRP, while the other eye of the same participant received the threshold PASCAL PRP. The primary outcome measures included the difference in the 1-year risk of progression to PDR between 2 groups, and mean changes of the logarithm of the minimal angle of resolution (logMAR) visual acuity (VA). The second outcome measures included central foveal thickness (CFT), 1-year risk of progression to PDR, and visual field (VF) parameters.

RESULTS

The subthreshold EPM PRP group and the threshold PASCAL PRP group had similar 1-year risk of progression to PDR during the 12-month follow-up visits (17.86 vs. 14.29%, p > 0.05). Slightly decreased VA was found in both groups (0.08 vs. 0.09 logMAR VA); however, no statistical difference was found for neither group (p > 0.05). Similar results were found for thickened CFT for both groups (23.59 vs. 28.34 μm, p > 0.05). Specifically, although substantial loss of VF was found in the threshold PASCAL PRP group (p < 0.05), no obvious damage to VF was seen in the subthreshold EPM PRP group (p > 0.05).

CONCLUSION

The subthreshold EPM PRP is noninferior to the conventional threshold PASCAL PRP in the treatment of severe NPDR during 12-month follow-up and could be an alternative treatment option for patients with severe NPDR.

Response of Retinal Pigment Epithelium (RPE)-Choroid Explants to Thermal Stimulation Therapy of the RPE (TSR)

BACKGROUND AND OBJECTIVES

The thermal stimulation therapy of the retinal pigment epithelium (TSR) is a sublethal laser technique for thermal stimulation of the retinal pigment epithelium (RPE)-Bruch's membrane (BrM)-complex. The aim of this study was to investigate the influence of TSR on the release of age-related macular degeneration (AMD)-relevant cell mediators.

STUDY DESIGN/MATERIALS AND METHODS

Porcine RPE-BrM-choroid explants were irradiated with a 532 nm continuous wave laser using different spot sizes (100-300 µm, duration 100 milliseconds, 15-100 mW). Cell death was investigated by calcein staining. Explants were treated with grids of sublethal spots and cultivated in modified Ussing chambers. The effect on matrix metalloproteinase-2 (MMP-2) and -9 was investigated by zymography and quantitative reverse transcription polymerase chain reaction. Secretion of vascular endothelial growth factor (VEGF), pigment epithelium derived factor (PEDF), and transforming growth factor-β (TGF-β) was analyzed by enzyme-linked immunosorbent assay and expression of HSP70 was examined by western blot. Integrity of the RPE/BrM-complex was analyzed by scanning electron microscopy.

RESULTS

Laser powers of 15 mW (100 µm) and 45 mW (300 µm) did not induce RPE cell death. The integrity of the RPE/BrM-complex was not impaired after TSR. After TSR with 300 µm spot size, we observed a significant increase of active MMP-2 in the basal compartments. The content of PEDF significantly increased in treated explants in both compartments with 100 and 300 µm spot sizes. VEGF and TGF-β secretion was not triggered by TSR.

CONCLUSIONS

TSR represents a possible RPE stimulating treatment for dry AMD. TSR increases the basal release of active MMP-2, which might reverse age-related thickening of BrM. VEGF secretion was not triggered by TSR while anti-angiogenic PEDF was increased, indicating an induction of an anti-angiogenic and neuroprotective environment. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Induction of Heat Shock Protein 70 in Mouse RPE as an In Vivo Model of Transpupillary Thermal Stimulation

The induction of heat shock response in the macula has been proposed as a useful therapeutic strategy for retinal neurodegenerative diseases by promoting proteostasis and enhancing protective chaperone mechanisms. We applied transpupillary 1064 nm long-duration laser heating to the mouse (C57Bl/6J) fundus to examine the heat shock response in vivo. The intensity and spatial distribution of heat shock protein (HSP) 70 expression along with the concomitant probability for damage were measured 24 h after laser irradiation in the mouse retinal pigment epithelium (RPE) as a function of laser power. Our results show that the range of heating powers for producing heat shock response while avoiding damage in the mouse RPE is narrow. At powers of 64 and 70 mW, HSP70 immunostaining indicates 90 and 100% probability for clearly elevated HSP expression while the corresponding probability for damage is 20 and 33%, respectively. Tunel staining identified the apoptotic regions, and the estimated 50% damaging threshold probability for the heating (ED50) was ~72 mW. The staining with Bestrophin1 (BEST1) demonstrated RPE cell atrophy with the most intense powers. Consequently, fundus heating with a long-duration laser provides an approachable method to develop heat shock-based therapies for the RPE of retinal disease model mice.

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.

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.

Blood platelet and serum bilirubin in the diagnosis of central serous chorioretinopathy

Diagnostic value of blood platelet (PLT) and serum total bilirubin (TBIL) for central serous chorioretinopathy (CSC) was investigated. A total of 537 patients with CSC and 182 people with normal physical conditions were selected from June 2012 to August 2016. The 537 patients included 294 males and 243 females with an average age of 45.5±17.8 years, and all patients were treated in the Department of Ophthalmology of Yantai Hospital of Traditional Chinese Medicine and the Department of Ophthalmology of Yantai Liuhuangding Hospital. Clinical data of the patients were retrospectively analyzed. The 182 people with normal physical conditions included 103 males and 79 females with an average age of 43.6±15.2 years, and they were set as the control group. PLT and TBIL tests at admission and after treatment were collected and compared between CSC and the control group to analyze the diagnostic values of PLT and TBIL for CSC. PLT level in the CSC group was significantly higher than that in the control group, but TBIL level in the CSC group was significantly lower than that in the control group (p<0.05). Linear correlation analysis showed that PLT was a risk factor for CSC, and TBIL was a protective factor for CSC. The sensitivity of PLT and TBIL in diagnosis of CSC was 75.2 and 72.7%, respectively, and the specificity of PLT and TBIL in diagnosis of CSC was 65.8 and 63.3%, respectively. PLT of CSC patients was significantly higher than that of the control group, and TBIL of CSC patients was significantly lower than that of the control group, but they both gradually reduced to normal levels after treatment, which can be regarded as the index for the clinical diagnosis of CSC in the future.

Comparison of different settings for yellow subthreshold laser treatment in diabetic macular edema

BACKGROUND

To assess the safety and efficacy of two subthreshold parameters (5 and 15% duty cycle (DC)) compared to standard ETDRS (early treatment of diabetic retinopathy study) continuous wave (CW) laser.

METHODS

In this prospective randomized study, 30 eyes from 20 patients with non-center involving macular edema were randomized into 3 different groups: 5% DC, 15% DC and CW navigated modified ETDRS laser treatment. Titration in subthreshold groups was performed with 30% of the threshold power, decided with microsecond pulses. CW laser was titrated to a barely visible burn. All patients underwent microperimetry, thickness measurements and visual acuity examinations at baseline, 6 weeks and 12 weeks post treatment.

RESULTS

At three months follow up, retinal sensitivity was significantly reduced in the CW group by - 2.2 dB whereas in both subthreshold groups, retinal sensitivity increased by 2.4 dB for 5% and 1.9 dB for 15% DC with no significant difference. Retinal volume (mm³) decreased in both subthreshold groups by 0.08 ± 0.3 and 0.12 ± 0.11 in 5 and 15% DC group respectively. Whereas the CW group showed volume increase of 0.55 ± 0.92 (p = 0.02 and 0.01 for 5 and 15% DC groups). Visual acuity remained stable in all 3 groups (- 0.7 letter in 5% DC; 2.11 letters in 15% DC and 0.88 in CW with no significant difference).

CONCLUSION

Subthreshold microsecond laser was shown to be safe and effective with both 5 and 15% DC as compared to conventional photocoagulation with ETDRS parameters. The 15% DC setting trended to achieve better anatomical, visual and functional outcomes.

TRIAL REGISTRATION

Retrospectively registered ( NCT03571659 , 06/26/2018).

Thermal Stimulation of the Retina Reduces Bruch's Membrane Thickness in Age Related Macular Degeneration Mouse Models

Purpose

To investigate the effect of thermal stimulation of the retina (TS-R) on Bruch's membrane (BrM) thickness in age-related macular degeneration (AMD) mouse models as a novel concept for the prophylaxis and treatment of dry AMD.

Methods

Two knockout AMD mouse models, B6.129P2-Apoe^tm1Unc/J (ApoE−/−) and B6.129X1-Nfe2I2^tm1Ywk/J (NRF2−/−), were chosen. One randomized eye of each mouse in four different groups (two of different age, two of different genotype) of five mice was treated by TS-R (532 nm, 10-ms duration, 50-μm spot size), the fellow eye served as control. Laser power was titrated to barely visible laser burns, then reduced by 70% to guarantee for thermal elevation without damage to the neuroretina, then applied uniformly to the murine retina. Fundus, optical coherence tomography (OCT), and fluorescein angiography (FLA) images were obtained at the day of treatment and 1 month after treatment. Eyes were enucleated thereafter to analyze BrM thickness by transmission electron microscopy (TEM) in a standardized blinded manner.

Results

Fundus images revealed that all ApoE−/− and NRF2−/− mice had AMD associated retinal alterations. BrM thickness was increased in untreated controls of both mouse models. Subvisible TS-R laser spots were not detectable by fundus imaging, OCT, or FLA 2 hours or 1 month after laser treatment. TEM revealed a significant reduction of BrM thickness in laser-treated eyes of all four groups compared to their fellow control eyes.

Conclusions

TS-R reduces BrM thickness in AMD mouse models ApoE−/− and NRF2−/− without damage to the neuroretina. It may become a prophylactic or even therapeutic treatment option for dry AMD.

Translational Relevance

TS-R may become a prophylactic or even therapeutic treatment option for dry AMD.

Evolution of Concepts and Technologies in Ophthalmic Laser Therapy

Ophthalmology was the first medical specialty to adopt lasers right after their invention more than 50 years ago, and they gradually revolutionized ocular imaging, diagnostics, therapy, and surgery. Challenging precision, safety, and selectivity requirements for ocular therapeutic and surgical procedures keep advancing the laser technologies, which in turn continue enabling novel applications for the preservation and restoration of sight. Modern lasers can provide single-cell-layer selectivity in therapy, submicrometer precision in three-dimensional image-guided surgery, and nondamaging retinal therapy under optoacoustic temperature control. This article reviews the evolution of laser technologies; progress in understanding of the laser-tissue interactions; and concepts, misconceptions, and accidental discoveries that led to modern therapeutic and surgical applications of lasers in ophthalmology. It begins with a brief historical overview, followed by a description of the laser-tissue interactions and corresponding ophthalmic applications.

Power-controlled temperature guided retinal laser therapy

Laser photocoagulation has been a treatment method for retinal diseases for decades. Recently, studies have demonstrated therapeutic benefits for subvisible effects. A treatment mode based on an automatic feedback algorithm to reliably generate subvisible and visible irradiations within a constant irradiation time is introduced. The method uses a site-individual adaptation of the laser power by monitoring the retinal temperature rise during the treatment using optoacoustics. This provides feedback to adjust the therapy laser power during the irradiation. The technique was demonstrated on rabbits in vivo using a 532-nm continuous wave Nd:YAG laser. The temperature measurement was performed with 523-nm Q-switched Nd:YLF laser pulses with 75-ns pulse duration at 1-kHz repetition rate. The beam diameter on the fundus was 200  μm for both lasers, respectively. The aim temperatures ranged from 50°C to 75°C in 11 eyes of 7 rabbits. The results showed ophthalmoscopically invisible effects below 55°C with therapy laser powers over a wide range. The standard deviation for the measured temperatures ranged from 2.1°C for an aim temperature of 50°C to 4.7°C for 75°C. The ED50 temperature value for ophthalmoscopically visible lesions in rabbits was determined as 65.3°C. The introduced method can be used for retinal irradiations with adjustable temperature elevations.

A Novel Method for Mouse Retinal Temperature Determination Based on ERG Photoresponses

This study introduces a novel retinal temperature determination method based on the temperature dependent properties of photoresponses recorded by electroretinography (ERG). The kinetics and amplitudes of ERG photoresponses depend on retinal temperature. Additionally, raising retinal temperature increases the probability of long-wavelength photon absorption, which manifests as temperature dependence of photoreceptor sensitivity. In this study we extract a number of features that represent these properties from the a- and b-waves of mouse ex vivo ERG flash responses and construct three multivariable regression models between temperature and the selected features. The performance of these models was evaluated against a separate test dataset and for two of the models, an RMS temperature determination error of less than 0.50 °C could be reached. Our results demonstrate that the method can be successfully used for reliable retinal temperature determination ex vivo. The method, reflecting the temperature of distal retina, can be applied also in the estimation of retinal pigment epithelium temperature.

Diagnosed a Patient with Central Serous Chorioretinopathy? Now What?: Management of Central Serous Chorioretinopathy

PURPOSE OF REVIEW WHAT IS THE GOAL OF YOUR PAPER? WHAT QUESTIONS DID YOU SEEK TO ANSWER?

The goal of this paper is to provide a comprehensive review of the management options for central serous chorioretinopathy (CSCR).

RECENT FINDINGS SUMMARIZE THE LATEST RESEARCH ON YOUR TOPIC

The majority of cases of acute CSCR may be managed with observation and cessation of corticosteroids, if possible, as well as life-style modifications including stress reduction and control of hypertension. The management of chronic disease is more challenging and may include either medication or laser-based treatment.

SUMMARY WHAT ANSWERS DID YOU FIND? WHAT ARE THE MAJOR TAKEAWAYS/CONCLUSIONS OF YOUR EXAMINATION? WHAT’S THE IMPACT ON FUTURE RESEARCH?

Management of CSCR necessitates an individualized and selective treatment approach. There is overall poor evidence for the use of systemic and intravitreal medications. From this class of treatments, mineralocorticoid receptor antagonists appear to have the greatest potential. Although conventional thermal photocoagulation may be used in select cases, the most promising treatment options at this time for chronic CSCR are photodynamic therapy, either half-dose or half-fluence, and non-damaging (subthreshold) retinal laser therapy.

Comparison of subthreshold micropulse laser (577 nm) treatment and half-dose photodynamic therapy in patients with chronic central serous chorioretinopathy

PurposeTo compare the short-term treatment outcome of the 577 nm subthreshold micropulse laser (SML) and half-dose photodynamic therapy (PDT) in patients with chronic central serous chorioretinopathy (cCSC) and persistent subretinal fluid (SRF).MethodsThis retrospective study included 100 eyes of 100 consecutive patients who were treated with the 577 nm SML (Supra Scan, Quantel Medical) (n=42) or half-dose PDT (n=58) for cCSC. The treatment was applied at the leakage sites in the fluorescein and indocyanine green angiography. The treatment success was evaluated 6 weeks after treatment using best-corrected visual acuity, central retinal thickness, and resolution of SRF in spectral domain optical coherence tomography.ResultsPatients showed treatment response more often in the SML group compared with the PDT group (treatment response after SML: 33 eyes (79%), PDT: 34 eyes (59%), P=0.036, χ² test). The CRT decreased significantly after both treatments (mean CRT before SML: 445±153 μm, after SML: 297±95, P<0.001; mean CRT before PDT: 398±88 μm, after PDT: 322±93 μm, P<0.001, Wilcoxon's signed-rank test). The decrease in CRT was statistically significantly higher in the SML group (decrease in CRT after SML: -148±163 μm, after PDT: -76±104 μm, P=0.041, Mann-Whitney U-test).ConclusionsBoth the half-dose PDT and the 577 nm SML are potent treatments for cCSC with persistent SRF. More patients showed treatment response to the SML treatment and SML leads to a greater decrease in CRT.

Subthreshold Micropulse Laser (577 nm) Treatment in Chronic Central Serous Chorioretinopathy

PURPOSE

To assess treatment with a 577-nm subthreshold micropulse laser (SML) in patients with chronic central serous chorioretinopathy (cCSC).

METHODS

This retrospective study included 38 patients treated with a 577-nm SML (Supra Scan; Quantel Medical) for cCSC. We included a subgroup of 18 patients with persistent subretinal fluid (SRF) after photodynamic therapy (PDT). Assessment included visual acuity (VA), central retinal thickness (CRT) and resolution of SRF.

RESULTS

At the last follow-up (mean 5 months), 74% of patients responded to therapy. The CRT decreased after treatment (mean CRT -115 µm, p < 0.001) and VA improved (mean logMAR -0.06, p = 0.039). No laser burns were detected with any imaging modality. In the subgroup of patients resistant to PDT, 61% of patients responded to therapy with a decrease in CRT (mean CRT -75 µm, p = 0.019).

CONCLUSIONS

The 577-nm SML is an effective treatment for cCSC even in patients without sufficient improvement after PDT.

Comparing half-dose photodynamic therapy with high-density subthreshold micropulse laser treatment in patients with chronic central serous chorioretinopathy (the PLACE trial): study protocol for a randomized controlled trial

Background

Chronic central serous chorioretinopathy (cCSC) is an eye disease characterized by an accumulation of serous fluid under the retina. It is postulated that this fluid accumulation results from hyperpermeability and swelling of the choroid, the underlying vascular tissue of the eye, causing a dysfunction of the retinal pigment epithelium. This fluid accumulation causes neuroretinal detachment. A prolonged neuroretinal detachment in the macula can lead to permanent vision loss. Therefore, treatment is aimed primarily at achieving resolution of subretinal fluid, preferably within the first 4 months after diagnosis of the disease. A broad spectrum of treatment modalities has been investigated in cCSC, but no consensus exists on the optimal treatment of cCSC. Currently, photodynamic therapy (PDT) and high-density subthreshold micropulse laser treatment (HSML) are among the most frequently cited treatments in obtaining successful neuroretinal reattachment.

Methods/Design

This is a randomized, controlled, open-label, multicenter trial comparing the efficacy of half-dose PDT to HSML in treating patients with cCSC. A total of 156 patients will be recruited, 78 patients in each treatment arm, with a maximum follow-up duration of 8 months after the first treatment. A complete ophthalmological examination with vision-related quality of life (NEI VFQ-25) and stress questionnaires, will be performed at baseline, 6 to 8 weeks after the first treatment, 6 to 8 weeks after a second treatment (if necessary), and at the final follow-up visit at 7 to 8 months after the first treatment. Treatment visits will be scheduled within 3 weeks after the baseline visit, and within 3 weeks after the first control visit, if a second treatment is required.

Discussion

Both half-dose PDT and HSML may be effective treatments in cCSC, but because of the lack of prospective randomized controlled trials, which treatment should be the first choice remains unclear. The aim of this study is to compare the efficacy of half-dose PDT to HSML. The primary endpoint to evaluate efficacy will be a complete absence of subretinal fluid on optical coherence tomography after treatment. Secondary functional endpoints include change in Early Treatment Diabetic Retinopathy Study (ETDRS) best-corrected visual acuity, retinal sensitivity on microperimetry, and NEI VFQ-25 questionnaire of visual functioning.

Registration number Institutional Review Board (CMO Arnhem-Nijmegen, the Netherlands): 2013/203 NL nr.: 41266.091.13

Trial registration

ClinicalTrials.gov identifier: NCT01797861. Date of registration: 21 February 2013.