Functional and morphological outcome in patients with chronic central serous chorioretinopathy treated by subthreshold micropulse laser

Laser Treatment of Central Serous Chorioretinopathy - An Update

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

Subthreshold laser treatment in retinal diseases: a mini review

PURPOSE

To summarize the mechanism and the clinical applications of subthreshold laser (STL) in retinal practice. Subthreshold or "non-destructive" laser includes all types of laser treatments that produce minimal or no damage to the tissues and no visible signs after application.

METHODS

A descriptive review of articles from literature databases (PubMed, Medline, Embase, Cochrane, Web of Science) published before August 2023, which discuss current STL treatments of retinal diseases.

RESULTS

This review provides evidence for STL as a treatment option for central serous chorioretinopathy, diabetic retinopathy, age-related macular degeneration, macular edema due to retinal vein occlusion, and other maculopathies. In most published reports, STL has shown a therapeutic effect without damage to the underlying tissue.

CONCLUSION

Subthreshold laser treatment has shown safety and efficacy in the management of some retinal and macular diseases. Stimulation of the retinal pigment epithelium without destroying adjacent neuroretina has been shown to be sufficient in inducing retinal repair in many clinical cases. Recent research and clinical studies continue to explore the mechanisms and improving therapeutic benefits of this technology as well as extend the range of retinal disorders treatable by this modality.

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.

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.

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.

Micropulse Laser Therapy as an Integral Part of Eye Disease Management

Ocular diseases can significantly impact vision and quality of life through pathophysiological alterations to the structure of the eye. The management of these conditions often involves a combination of pharmaceutical interventions, surgical procedures, and laser therapy. Laser technology has revolutionized many medical fields, including ophthalmology, offering precise and targeted treatment options that solve some of the unmet needs of other therapeutic strategies. Conventional laser techniques, while effective, can generate excessive thermal energy, leading to collateral tissue damage and potential side effects. Compared to conventional laser techniques, micropulse laser therapy delivers laser energy in a pulsed manner, minimizing collateral damage while effectively treating target tissues. The present paper highlights the advantages of micropulse laser therapy over conventional laser treatments, presents the implications of applying these strategies to some of the most prevalent ocular diseases, and highlights several types and mechanisms of micropulse lasers. Although micropulse laser therapy shows great potential in the management of ocular diseases, further research is needed to optimize treatment protocols, evaluate long-term efficacy, and explore its role in combination therapies.

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

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

Ganglion Cell Loss in the Course of Central Serous Chorioretinopathy

INTRODUCTION

Central serous chorioretinopathy (CSCR) as a clinical entity is potentially damaging and may significantly affect retinal morphology and function, especially in the chronic form. Our study aimed to determine the amount of deficit of best corrected visual acuity (BCVA) and individual retinal layers, including ganglion cells, in different types of CSCR and with reference to its duration.

METHODS

The retrospective analysis included 69 eyes of patients with resolved CSCR managed in Dobry Wzrok Ophthalmological Clinic between 1 January 2019 and 30 June 2022. The diagnosis of CSCR was based on the criteria outlined by the Central Serous Chorioretinopathy International Group. The analysis included data obtained from medical history, BCVA testing, and spectral domain optical coherence tomography (SD-OCT) measurements, with specific thickness values for individual retinal layers. The results were compared among affected eyes, unaffected fellow eyes, and healthy controls.

RESULTS

BCVA values were significantly lower in acute (0.08 ± 0.12 logMAR) and chronic (0.26 ± 0.19 logMAR) cases versus controls (0.0 logMAR). The thickness of all retinal layers (central subfoveal thickness, CST; inner retina with ganglion cell complex, GC; outer retina, ORT; and photoreceptor outer segments, POS) and macular volume (MV) were significantly decreased in chronic eyes versus controls (p < 0.01). Acute eyes had significant thinning of the outer retina and POS only compared to control eyes (p < 0.01). The amount of deficit in CST, ORT, GC, and MV was strongly correlated with poorer BCVA (p < 0.001), and the deficit of CST, ORT, and GC was correlated with disease duration (p < 0.05). The subfoveal choroidal thickness was significantly greater in affected and fellow eyes versus controls (p < 0.001).

CONCLUSION

Damage to the outer retina and photoreceptors occurs early in the course of CSCR, with a deficit in ganglion cells noted adjunctively in chronic forms of the disease. Further studies are required to precisely determine correlation between visual loss in CSCR and deficits in individual retinal layers.

[Subthreshold micropulse laser treatment of the foveal region in chronic central serous chorioretinopathy (case study)]

The article presents a clinical case of subthreshold micropulse laser (SML) treatment of chronic central serous chorioretinopathy (CSC) in the left eye of a 44-year-old female patient K. with dye allergy. The patient first noticed a gray spot, distortion of objects in February, 2018. During 2018-2020 she suffered 5 relapses, repeated unsuccessful conservative treatment, and completed a course of antiangiogenic therapy in the form of three monthly intravitreal injections of ranibizumab. After experiencing stress on 11.08.20 she noted acute deterioration. Laser treatment was carried out on 20.09.20 with the Navilas 577s navigation system (wavelength 577 nm). After the power titration and calculation, the contact-free subthreshold micropulse laser treatment was carried out without anesthesia in three zones: 200 mW for fovea, 240 mW for parafovea and 340 mW for periphovea. Other settings: pulse duration - 200 ms, spot diameter - 100 µm, duty cycle - 5%. Total number of laser pulses - 1000. The retina reattached completely despite the patient having previously recovered from the coronavirus infection and the use of corticosteroids.

Electrophysiological and anatomical outcomes of subthreshold micropulse laser therapy in chronic central serous chorioretinopathy

BACKGROUND

To evaluate short-term efficacy of subthreshold micropulse laser therapy on chronic central serous chorioretinopathy (CSC) electrophysiologically and anatomically.

METHODS

This prospective study included 18 eyes with chronic CSC. Subthreshold micropulse laser therapy was applied to the eyes using Endpoint Management System (EpM). The efficacy of the treatment was evaluated with optical coherence tomography (OCT) and multifocal electroretinography (mfERG) measurements before and after one month of the treatment.

RESULTS

The mean patient age was 47.3 ± 5.7 years (ranged between 36 and 56). The mean symptomatic time of the disease was 12.7 ± 3.33 months. Central macular thickness, choroidal thickness, subretinal fluid height and width showed statistically significant decreases after EpM treatment (p < 0.05). P 1 amplitude of ring 1, 3, 4, and 5 in mfERG increased significantly (p <  0.05).

CONCLUSIONS

The study demonstrated that, in both OCT and electrophysiological evaluations, EpM subthreshold laser therapy resulted in anatomical and functional improvements in chronic CSC.

Central serous chorioretinopathy: Treatment

Central serous chorioretinopathy (CSC) is a pachychoroid spectrum disease characterized by serous detachment of the neurosensory retina with subretinal fluid in young and middle-aged adults. The pathogenesis of CSC is not yet fully understood. However, it is considered a multifactorial disease that is strongly associated with choroidal dysfunction or vascular engorgement. Although there is no consensus on the treatment of CSC, photodynamic therapy has been effectively used to manage serous retinal detachment (SRD) in CSC. Moreover, micropulse diode laser photocoagulation and focal laser treatment have also been used. Recently, oral medications, including mineralocorticoid receptor antagonists, have been proposed for the management of CSC. Multimodal imaging plays a significant role in the diagnosis and treatment of CSC. Optical coherence tomography angiography (OCTA) has the advantage of detecting vascular flow in the retina and choroid layer, allowing for a better understanding of the pathology, severity, prognosis, and chronicity of CSC. In addition, early detection of choroidal neovascularization in CSC is possible using OCTA. This review article aims to provide a comprehensive and updated understanding of CSC, focusing on treatment.

Scanning Laser Ophthalmoscopy Retromode Imaging Compared to Fundus Autofluorescence in Detecting Outer Retinal Features in Central Serous Chorioretinopathy

Central serous chorioretinopathy (CSCR) is a retinal disease characterized by a heterogeneous clinical phenotype, depending on the influence of different factors in its pathogenesis, including the presence of subretinal fluid (SRF), trophism of the retinal pigmented epithelium (RPE) and choroidal hyper-permeability. Our study has the purpose of assessing the ability of scanning laser ophthalmoscopy (SLO) retromode imaging, compared to fundus autofluorescence (FAF), to identify outer retinal features in a cohort of patients with a diagnosis of CSCR. A total of 27 eyes of 21 patients were enrolled in our study. All patients underwent full ophthalmological examination, including fundus retinography, fundus fluorescein angiography, optical coherence tomography (OCT), FAF and SLO retromode imaging. For each patient, the following features were evaluated: SRF, the presence of pigmented epithelium detachment (PED), RPE dystrophy, and RPE atrophy. RPE dystrophy was further characterized according to the appearance in FAF of iso-, hyper- and hypo-autofluorescent dystrophy. The ability to identify each feature was evaluated for FAF and SLO retromode alone, compared to a multimodal imaging approach. FAF identified SRF in 11/14 eyes (78%), PED in 14/19 (74%), RPE dystrophy with iso-autofluorescence in 0/13 (0%), hyper-autofluorescence in 18/19 (95%), hypo-autofluorescence in 20/20 (100%), and RPE atrophy in 7/7 (100%). SLO retromode imaging identified SRF in 13/14 eyes (93%), PED in 15/19 (79%), RPE dystrophy with iso-autofluorescence in 13/13 (100%), hyper-autofluorescence in 13/19 (68%), hypo-autofluorescent in 18/20 (90%), and RPE atrophy in 4/7 (57%). SLO retromode imaging is able to detect retinal and RPE changes in CSCR patients with a higher sensitivity than FAF, while it is not able to identify the depth of lesions or supply qualitative information about RPE cells' health status, meaning that it is less specific. SLO retromode imaging may have a promising role in the assessment of patients with CSCR, but always combined with other imaging modalities such as OCT and FAF.

Significant Visual Impairment after Short-Lasting Central Serous Chorioretinopathy

A 37-year-old man experienced two episodes of central serous chorioretinopathy (CSCR) with the onset within a 7-month period, one in each eye. The diagnosis was made based on spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF), and fluorescein angiography. The presence of subretinal neovascularization and polypoidal choroidal vasculopathy were excluded. Each CSCR episode lasted for approximately 6 months and resolved completely after laser photocoagulation (left eye) and photodynamic therapy (right eye). In the right eye, subthreshold micropulse laser treatment and oral eplerenone were initially administered because of a verteporfin shortage, but they were not effective. Final best-corrected visual acuity was 0.8 logMAR in the left eye and "counting fingers" in the right. SD-OCT revealed significant retinal thinning in both eyes despite FAF, showing no major loss of retinal pigment epithelial cells. A significant reduction of ganglion cell complex thickness occurred in the right eye. Acute CSCR can result in significant visual impairment, even when short-lasting.

Short-term comparison between navigated subthreshold microsecond pulse laser and oral eplerenone for chronic central serous chorioretinopathy

To compare the anatomical/functional changes after navigated subthreshold pulse laser (SML) and oral eplerenone therapy for chronic central serous chorioretinopathy (cCSC). A total of 36 eyes of 36 patients suffering from cCSC treated with navigated SML (Navilas® 577s; OD-OS GmbH, near Berlin, Germany) (18 eyes, SML group) and oral eplerenone (18 eyes, eplerenone group) were enrolled in this retrospective study. Main outcome measures during a 3-month follow up period included changes of best corrected visual acuity (BCVA), central macular thickness (CMT), foveal subretinal fluid thickness (FSRFT), and subfoveal choroidal thickness (SFCT). At baseline average duration of symptoms was 6.8 ± 0.6 months in SML group and 6.4 ± 0.9 months in eplerenone group (p = 0.127). Mean BCVA, CMT and FSRFT changed significantly over time (p < 0.001). From baseline to 90 days the BCVA improved from 0.3 ± 0.1 to 0.1 ± 0.1 logMAR in SML group and from 0.3 ± 0. to 0.2 ± 0.1 logMAR in eplerenone group, CMT reduced from 357.1 ± 104.3 to 210.6 ± 46.7 μm and from 428.7 ± 107.7 to 332.5 ± 27.5 μm in SML group and eplerenone group respectively, FSRFT reduced from 144.4 ± 108.2 to 22.6 ± 37.2 μm and from 217.1 ± 105.9 to 54.4 ± 86.2 μm in SML group and eplerenone group. 55.6% of patients in SML group and 66.7% in eplerenone group showed a complete resolution of FSRFT during follow up. The interaction between group and time was statistically significant with greater absolute variation for CMT and FSRFT in SML group compared to eplerenone group (p < 0.001 and p = 0.043). SFCT did not change significantly during follow up (p = 0.083) for both groups. Both navigated SML and oral eplerenone were effective treatments showing recovery of retinal morphology and related visual acuity improvement in cCSC.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Micropulse Transscleral Cyclophotocoagulation as Primary Surgical Treatment for Primary Open Angle Glaucoma in Taiwan during the COVID-19 Pandemic

Glaucoma is the leading cause of irreversible blindness worldwide, with primary open angle glaucoma (POAG) accounting for the greatest number of total glaucoma cases. This study aimed to evaluate the efficacy and safety of micropulse transscleral cyclophotocoagulation (MP-TSCPC) as a primary procedure in POAG during the COVID-19 pandemic. We retrospectively analyzed 60 eyes of 52 patients, who were diagnosed with mild-to-end-stage POAG without previous glaucoma surgery and received MP-TSCPC between 1 January 2020 and 31 August 2020. The mean preoperative intraocular pressure (IOP) significantly decreased from 27.8 mm Hg to 19.8, 20.1, 20.3, 20.4, and 20.2 mm Hg at 1, 3, 6, 9, and 12 months, respectively (all p < 0.05). The mean number of IOP-lowering medications used significantly decreased from 3.3 at the baseline to 1.6, 1.8, 1.8, 1.9, and 1.9 at 1, 3, 6, 9, and 12 months, respectively (all p < 0.001). Total withdrawal of antiglaucoma medications was fulfilled in five patients. The main outcome was achieved in 81.7% at postoperative month 12. The most common adverse effect was transient mydriasis (28.3%). No major complications were encountered. MP-TSCPC seems to be an effective and safe treatment to reduce IOP and the medication burden with minimal vision-threatening complications in mild-to-end-stage POAG patients without previous glaucoma surgery.

Safety of various parameter sets with navigated microsecond pulsing laser in central serous chorioretinopathy

Background

Subthreshold microsecond pulsing laser is an increasingly common treatment approach for central serous chorioretinopathy. However, there is no literature available on the safety of microsecond laser using different fluence settings in this disease. While many publications can be obtained from conventional microsecond pulsing lasers, few parameter sets are published with the navigated microsecond pulsing laser. Therefore, this study aims to investigate the safety of different parameter sets in subthreshold microsecond pulsing laser treatments.

Methods

In this retrospective chart review, consecutive patients with central serous chorioretinopathy (> 3 months duration of symptoms) treated with navigated subthreshold microsecond pulsing laser and a follow up of at least five months after microsecond laser application were included. For each patient, the treatment parameters, plan layout, and adverse events related to laser were evaluated. Secondary outcomes included best-corrected visual acuity and anatomical improvements (central retinal thickness).

Results

One hundred and one eyes were included in the observation and followed for a mean of 10 months (range 5–36). Although a larger range of parameter sets and fluence settings have been used, no patient demonstrated adverse events from navigated microsecond pulsing laser. While 88% of the cases demonstrated stability, 13 cases lost five or more letters due to the persistence of the subretinal fluid. In mean, a best-corrected visual acuity improvement of 0.07logMar (± 0.2) was seen (p = 0.02). In 51% of the patients, a statistically significant improvement of the central retinal thickness was noted at the last follow-up with a mean thickness reduction of 70 µm (± 143) (p < 0.01).

Conclusion

In conclusion, none of the used parameter sets lead to tissue damage (when using a cautious titration) and, in summary, lead to an improvement in subretinal fluid and improvement in visual acuity. However, further prospective studies are needed to correctly identify the dependency of the treatment strategy on the outcome criteria.

Clinical Evaluation of Individualized and Navigated Microsecond Pulsing Laser for Acute Central Serous Chorioretinopathy

BACKGROUND AND OBJECTIVE

A computational model has predicted parameters for using a navigated microsecond pulsing laser system to treat central serous chorioretinopathy (CSC).

PATIENTS AND METHODS

A prospective, single-center, interventional case series was conducted for patients with acute CSC who were enrolled following screening and informed consent. Treatment involved laser pulse duration of 50 μs, 2.4% Duty Cycle, 100 μm spot size, and 10 ms pulse duration.

RESULTS

Average best-corrected visual acuity (decimal) of 12 patients improved from 0.86 ± 0.03 at baseline to 0.97 ± 0.01 at 3 months. Baseline central retinal thickness decreased from 452.58 μm ± 24.53 μm at baseline to 249.25 μm ± 2.92 μm at 3 months. Retinal sensitivity improved from 24.1 dB ± 1.09 dB at baseline to 28.98 dB ± 0.23 dB at 3 months. In all cases, subretinal fluid was resorbed.

CONCLUSION

The parameter sets derived from the computer model can be applied safely and effectively for CSC treatment using the navigated microsecond pulsing laser system. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:512-520.].

Central Serous Chorioretinopathy Classification

Central serous chorioretinopathy is characterized by an idiopathic neurosensory detachment of the retina. This narrative review aims to discuss the classification system used for central serous chorioretinopathy. Based on our current knowledge, there is no universally adopted classification system. This is the result of the unknown aspects related to pathogenesis and clinical spectrum and evolution. The best option could be to aggregate multimodal pieces of information alongside temporal and phenotypic characteristics.

Short Term Presence of Subretinal Fluid in Central Serous Chorioretinopathy Affects Retinal Thickness and Function

Background: Acute central serous chorioretinopathy (CSCR), with subretinal fluid (SRF) resolving spontaneously within a few months from disease onset, has been considered as a benign and self-limiting disease for many years. This study sought to discover if a short presence of SRF can result in morphological and functional damage to the retina. Materials and methods: The study included patients treated by subthreshold diode micropulse laser (SDM) application for acute CSCR at the Dobry Wzrok Ophthalmological Clinic between January 2018 and November 2019. Inclusion criteria were: first episode of CSCR; duration of symptoms of two months or less; complete resolution of subretinal fluid (SRF) after a single session of SDM; and a lack of any retinal pathology, previous CSCR episode, significant anisometropia or amblyopia in the collateral eye. Fifteen patients fulfilled the inclusion criteria, including 13 males and two females aged 42.3 ± 9.5 years. The mean duration of symptoms before treatment was 4.7 ± 1.3 weeks on average. Baseline and follow-up examinations were performed in both the affected and collateral eyes and included best-corrected visual acuity (BCVA); spectral-domain optical coherent tomography measurements such as central retinal thickness (CRT) and minimal foveal thickness (MFT) (at the follow-up visit only); fluorescein angiography (at presentation only) and fundus autofluorescence. The first follow-up visit, when the total resolution of SRF was noted, was conducted between 8 and 12 weeks after SDM. Results: Resolved CSCR eyes had significantly poorer BCVA, CRT, and MFT findings in comparison with healthy collateral eyes (respectively, 0.11 +/− 0.1 vs. 0.01 +/− 0.04 logMAR; 238.80 +/− 23.39 vs. 264.87 +/− 21.22 µm and 178.93 +/− 16.88 vs. 199.47 +/− 17.87 µm) despite the short period of CSCR duration (maximum of 14 ± 2.15 weeks on average). Conclusion: Short presence of SRF typical for acute CSCR can affect retinal function and morphology resulting in poorer visual outcome.

The efficacy of subthreshold micropulse yellow laser (577 nm) in chronic central serous chorioretinopathy

Central serous chorioretinopathy (CSC) is a disease characterized by a well-defined serous detachment of the neurosensory retina. Therapeutic options in chronic cases are limited, and side effects can result in a limited response. The aim of this article is to assess the efficacy of subthreshold micropulse laser therapy in patients with chronic central serous chorioretinopathy. The study included 20 eyes of 19 patients who had a history of chronic or chronic recurrent CSC and who underwent subthreshold micropulse laser therapy between January 2015 and June 2018. Twenty eyes of 19 patients with a mean age of 48.9 ± 9.40 years were included. The mean visual acuity was 0.24 ± 0.28 logMAR before laser, 0.19 ± 0.25 logMAR 3 months after laser, and 0.18 ± 0.27 logMAR after 6 months. A statistically significant difference was determined in terms of visual acuity before and after treatment (p = 0.0001). The mean central retinal thickness was 308.10 ± 95.25 μm before laser, 233.65 ± 81.17 μm 3 months after laser, and 203.88 ± 72.79 μm at 6 months. A statistically significant relationship was present between visual acuity and the duration of disease (p = 0.001), between visual acuity and the outer nuclear layer thickness (p = 0.005), and between the outer nuclear layer thickness and the duration of disease in chronic cases (p = 0.008). There was no evidence of retinal pigment epithelium or retinal damage on optical coherence tomography or fundus autofluorescence secondary to subthreshold micropulse laser therapy. Visual acuity appears to be more associated with the duration of disease and with changes in the outer nuclear layer thickness in chronic CSC. Subthreshold micropulse laser therapy seems to be effective at treating chronic CSC, while it increases success during early period of the disease before the development of permanent retinal damage.

Efficacy of nanosecond laser treatment in central serous chorioretinopathy with and without atrophy of retinal pigment epithelium

Background

To evaluate the outcomes of subthreshold nanosecond laser treatment of chronic central serous chorioretinopathy (CSC) as a function of the severity of concomitant of retinal pigment epithelium (RPE) defects.

Methods

This retrospective study compares data from 23 CSC diagnosed eyes with only mild RPE defects (group 1), 16 CSC eyes with moderate RPE defects (group 2), and 17 CSC eyes having severe RPE defects (group 3). After subthreshold treatment with the standard Ellex 2RT™ nanosecond laser (Ellex Medical Lasers Ltd, Australia), changes in macular structure and levels of subretinal fluid (SRF) were assessed by OCT-SD, OCT-A, functional integrity of the retina was assessed by corrected distance visual acuity (CDVA) and microperimetry, each at baseline and 1, 3, 6, and 12 months after initial treatment; re-treatment took place in cases of persistent SRF pro re nata.

Results

During the 12 months observation period, group 1 and 2 mostly required on initial and one re-treatment (1.9 ± 1.0 treatments; 1.9 ± 1.3 treatments). In contrast, group 3 was subject to three to four treatments (3.7 ± 1.5 treatments). 6 to 12 months after treatment, subretinal fluid (SRF) disappeared in 100% of the eyes of group 1 and in 76.9%, and 42.9% of the eyes of group 2 and group 3, respectively. Retinal sensitivity and CDVA improved in group 1 and 2, but did not change significantly in group 3 during the 12 months period.

Conclusions

Subthreshold nanosecond laser treatment is an effective and safe method for the restoration of macular anatomy and sensitivity in acute and chronic CSC cases with only mild or moderate RPE defects. However, this laser treatment has very limited outcome in CSC eyes with more severe RPE defects.

532-nm Subthreshold Micropulse Laser for the Treatment of Chronic Central Serous Retinopathy

Introduction

Subthreshold micropulse laser treatment with a 532 nm (532-SML) wavelength has been suggested as a treatment option for the treatment of chronic central serous retinopathy (cCSR). The objective is to present its effects and complications.

Methods

We present a retrospective cohort study of cCSR patients submitted to 532-SML. Best-corrected visual acuity (BCVA) and spectral-domain optical coherence tomography (SD-OCT) parameters – central macular thickness, subfoveal outer nuclear layer, external limiting membrane, ellipsoid band, interdigitation band, subretinal fluid and choroidal thickness – were evaluated before and 12 weeks after treatment. A power of 50%, a duty cycle of 5%, exposure time of 200 ms and a spot size of 160 µm were the applied laser parameters.

Results

We included 26 eyes. Overall there were no significant changes in visual acuity (median 0.20 (IQR 0) logMAR before and after treatment) or SD-OCT parameters. However, visual benefits occurred in 42.3% (n=11) of the patients and in half of the cases, subretinal fluid was completely reabsorbed. There were no complications.

Conclusion

In this study, 532-SML was overall ineffective on cCSR as it did not lead to significant changes in the overall median visual acuity and SD-OCT parameters. However, some patients may have benefited functionally and anatomically from the treatment; further investigation is necessary to understand the potential of 532-SML.

Pharmacotherapy of Central Serous Chorioretinopathy: A Review of the Current Treatments

BACKGROUND

Central serous chorioretinopathy (CSC) is the fourth most frequent retinal disorder in terms of prevalence. It typically occurs in young subjects and affects men more often than women. CSC is characterized by serous retinal detachment (SRD) involving mainly the macular area. The clinical course is usually selflimited, with spontaneous resolution within 3 months. The persistence of SRD or multiple relapse may result in a chronic form of CSC distinguished by permanent retinal pigment epithelium (RPE) and photoreceptor damage. As the pathogenetic mechanism of CSC primarily involves RPE and choroidal vascularization, the current therapeutic approaches aim to restore the normal functions of RPE and normal choroidal vascular permeability. In this review, the authors aim to summarize the current therapeutic approach to CSC.

METHODS

A comprehensive review of the literature was conducted in PubMed by searching for relevant studies on the current therapeutic options for CSC, including simple observation, conventional laser treatment, subthreshold laser treatment (SLT), photodynamic therapy (PDT) with verteporfin, treatment with mineralocorticoid receptor (MR) antagonists and treatment with anti-vascular endothelial growth factor drugs.

RESULTS

Since most cases resolve spontaneously, the most common initial CSC treatment is observation. Current evidence suggests that PDT and SLT are valuable in improving visual acuity, reducing subretinal fluid and maintaining long-term effectiveness. No clear evidence of efficacy has been achieved for anti-VEGF. MR antagonists might be a viable choice for the treatment of chronic CSC.

CONCLUSION

The pathophysiology of CSC remains poorly understood and as a consequence, the gold standard of care for CSC is yet to be defined. To date, PDT and SLT continue to offer good clinical outcomes. Positive preliminary results seem to emerge from the studies of MR antagonists.

Central serous chorioretinopathy: Towards an evidence-based treatment guideline

Central serous chorioretinopathy (CSC) is a common cause of central vision loss, primarily affecting men 20-60 years of age. To date, no consensus has been reached regarding the classification of CSC, and a wide variety of interventions have been proposed, reflecting the controversy associated with treating this disease. The recent publication of appropriately powered randomised controlled trials such as the PLACE trial, as well as large retrospective, non-randomised treatment studies regarding the treatment of CSC suggest the feasibility of a more evidence-based approach when considering treatment options. The aim of this review is to provide a comprehensive overview of the current rationale and evidence with respect to the variety of interventions available for treating CSC, including pharmacology, laser treatment, and photodynamic therapy. In addition, we describe the complexity of CSC, the challenges associated with treating CSC, and currently ongoing studies. Many treatment strategies such as photodynamic therapy using verteporfin, oral mineralocorticoid antagonists, and micropulse laser treatment have been reported as being effective. Currently, however, the available evidence suggests that half-dose (or half-fluence) photodynamic therapy should be the treatment of choice in chronic CSC, whereas observation may be the preferred approach in acute CSC. Nevertheless, exceptions can be considered based upon patient-specific characteristics.

Transfoveal Micropulse Laser Treatment of Central Serous Chorioretinopathy within Six Months of Disease Onset

Background: It has been recommended that any invasive treatment performed in patients with central serous chorioretinopathy (CSCR) not be initiated earlier than four months after disease onset due to the potential for spontaneous remission of symptoms. The goal of this study was to examine the outcome of transfoveal subthreshold micropulse laser treatment (SMPLT) of CSCR performed at six months or less after disease onset. Materials and methods: The study included 32 cases of CSCR lasting between three weeks and six months (mean: 3.4 ± 2.3 months). All patients had transfoveal SMPLT applied and were followed for at least three months after each session of SMPLT. Two sessions of SMPLT in total were planned in case of an insufficient response to the first instance of treatment. Evaluation parameters included any change in best-corrected visual acuity (BCVA) and retinal morphology. Results: Total resolution of subretinal fluid (SRF) was noted in 26 cases (81.25%). Final BCVA improved significantly from 0.37 ± 0.22 logMAR to 0.22 ± 0.20 logMAR after treatment. Overall, early SMPLT correlated with better final BCVA (p = 0.0005, Spearman rank correlation). For eyes achieving a total resolution of SRF, BCVA improved from 0.33 ± 0.21 logMAR to 0.17 ± 0.14 logMAR (p = 0.004, Spearman rank correlation). The analysis of SMPLT nonresponders revealed a tendency for poorer baseline visual acuity. Conclusions: Patients with CSCR lasting six months or less treated with transfoveal SMPLT achieve better functional results with early application of this procedure. As baseline BCVA predicts final visual acuity, earlier treatment, permitted by the safety of SMPLT, may improve final visual outcomes.

Impairment of visual acuity and retinal morphology following resolved chronic central serous chorioretinopathy

Purpose

Central serous chorioretinopathy (CSCR) is a complex ocular entity that, in its chronic form, can lead to serious visual impairment and morphological damage to the retina.

The aim of the current retrospective study was to evaluate the damage present after long-standing but resolved central serous chorioretinopathy and refer it to healthy individuals. Correlations between measurable factors—for example, duration of the disease, baseline retinal morphological parameters, or patient age and/or their degree of impairment—were also assessed.

Materials and methods

The study group consisted of thirty-two eyes (13 female and 19 male, mean age 49.6 years SD +/− 10.5) with chronic central serous chorioretinopathy (mean duration 18.9 months SD +/− 15.4) in which complete resolution of subretinal fluid was achieved after subthreshold micropulse laser treatment. Inclusion criterion was a lack of subretinal fluid within the whole area of the central retina scanned by the spectral domain optical coherence tomography. The group was extracted out of 51 cases of chronic CSCR that were treated with that method. They were analyzed according to final best-corrected visual acuity and retinal morphological parameters as measured by spectral optical coherence tomography with angiography option (OCTA). Results were compared with the outcomes of a control group, which consisted of 40 eyes of healthy individuals with full distance visual acuity (0.0 logMAR, 1.0 Snellen) never treated with subthreshold micropulse laser. Statistical analysis included regarding correlation between final visual acuity and final central retinal thickness and retinal and functional parameters prior to treatment.

Results

Final best-corrected visual acuity after chronic central serous chorioretinopathy was 0.23 logMAR (0.6 Snellen) and central retinal thickness was 39.32 μm smaller than in controls. No correlation was found between final visual acuity and retinal thickness and duration of the disease, patient age, and baseline morphological retinal parameters. OCTA scans revealed impaired choriocapillaries flow signal even following resolution of the disease.

Conclusion

Chronic central serous chorioretinopathy is a potentially damaging clinical entity that results in serious visual impairment, retinal thinning, and choroidal flow defects. Further research is needed to determine precisely the timepoint of this damage.

Micropulse Laser Treatment of Retinal Diseases

Subthreshold micropulse laser treatment has been intensively used for selected retinal diseases in the last decade; however, the exact mechanism of the action of lasers in the subthreshold micropulse mode is not yet fully understood. This kind of treatment is safe and cheap, and contrary to classic laser photocoagulation, it leaves the retinal cells intact. A modern theory of micropulse laser interaction with retinal tissue and a possible explanation of this mechanism are presented in this review. The authors present all the relevant literature on the application of micropulse lasers in different retinal disorders. The efficacy of this treatment is analyzed on the basis of available studies and then placed in the perspective of other therapeutic methods that are used in retinal diseases.

Management of chronic central serous chorioretinopathy

New treatment modalities for the management of central serous chorioretinopathy (CSC) now exist. While acute CSC generally resolves without the requirement for intervention, chronic CSC has been associated with persistent disruption in visual function. Current treatment approaches include photodynamic therapy, oral aldosterone antagonism and subthreshold multifocal laser. There has also been further investigation into a number of new treatments including antivascular endothelial growth factor treatment. Further investigation using developing optical coherence tomography imaging is helping to determine biomarkers of CSC activity, potential indicators of treatment response and indications of chronicity of disease activity. Further comparative study is required to determine the effectiveness of different forms of treatment in a range of patients with varied demographics, aetiology and chronicity of disease.

Application of subthreshold laser therapy in retinal diseases: a review

Introduction

Laser photocoagulation has been a valuable tool in the ophthalmologist's armamentarium for decades. Conventional laser photocoagulation relies on visible retinal burns as a treatment endpoint, which is thought to result in photocoagulative necrosis of retinal tissue. Recent studies have suggested that using subthreshold (ST) laser, which does not cause detectable damage to the retina may also have therapeutic effects in a variety of retinal diseases. Areas covered: We review the proposed biological mechanisms mediating the therapeutic effects of subthreshold laser on the retina, followed by the evidence for ST laser efficacy in retinal diseases such as diabetic macular edema, central serous chorioretinopathy, age-related macular degeneration, and retinal vein occlusion.

Expert Commentary

Multiple clinical studies demonstrate that subthreshold laser does not cause structural damage to the retina based on multimodal imaging. Evidence suggests that there is a therapeutic effect on decreasing diabetic macular edema and subretinal fluid in chronic central serous retinopathy; however, the effect may be relatively modest and is not as efficacious as first line treatments for these diseases. Given the repeatability and lack of damage to the retina by this treatment, subthreshold laser deserves further study to determine its place in the retina specialist's armamentarium.

Subthreshold diode micropulse laser versus observation in acute central serous chorioretinopathy

BACKGROUND

The purpose of this study was to evaluate subthreshold diode micropulse (SDM) laser as a treatment modality in acute central serous chorioretinopathy (CSC) and compare it with the current standard of care (observation).

METHODS

A randomised controlled trial was conducted on 68 eyes (34 eyes in SDM laser group and 34 eyes in observation group) with acute CSC, with a single angiographic leak and duration of complaints less than two months. Detailed history, examination and investigations were performed at the baseline and at regular intervals until six months.

RESULTS

Eyes in the laser group had significantly higher best-corrected visual acuity at two weeks (p = 0.002), four weeks (p < 0.001), eight weeks (p < 0.001), 16 weeks (p = 0.042) and six months (p = 0.008), and higher contrast sensitivity at eight weeks (p = 0.008), 16 weeks (p < 0.001) and six months (p < 0.001). A recurrent/persistent neurosensory detachment was observed at the end of six months in 11.76 per cent of SDM laser treated eyes versus 29.41 per cent of eyes in the observation group (p = 0.036).

CONCLUSION

SDM laser produces faster and superior visual rehabilitation without any adverse effects. It also reduces the chances of CSC going into chronicity and recurrence compared to the current standard of care (observation).

Intravitreal aflibercept therapy in eyes with chronic central serous chorioretihopathy: Short term results

OBJECTIVES

To evaluate the short term efficacy and tolerability results of intravitreal aflibercept injection as a treatment option for eyes with chronic central serous chorioretinopathy (CSCR).

MATERIAL AND METHODS

A prospective longitudinal study. Ten eyes of 10 patients with chronic CSCR who had been followed for >6months after the first intravitreal injection of aflibercept were recruited for the study. The best corrected visual acuity (BCVA) and central macular thickness (CMT) values obtained by spectral-domain optical coherence tomography were recorded at baseline and the first, third, and sixth months after the injection.

RESULTS

The mean logMAR BCVA was 0.70±0.25 at baseline. At the first, third, and sixth months after the injection, the mean logMAR BCVA were 0.39±0.36, 0.32±0.39, and 0.29±0.34, respectively. The mean and median BCVA over the entire follow-up period was significantly improved compared with baseline BCVA (P<.05 for each one). The mean CMT was 449.30±142.53μm at baseline. It was measured as 302.60±72.28μm on the first month, 294.30±72.85μm on the third month, and 294.60±83.84μm on the sixth month after the injection. The mean and median CMT during the entire follow-up period was significantly decreased compared with baseline CMT (P<.05 for each one). None of the patients had any serious ocular or systemic side effects over the course of the study.

CONCLUSIONS

Short term results of this study demonstrate that intravitreal aflibercept may be used as a treatment option to improve the BCVA and reduce the CMT in chronic CSCR.

Visual outcomes and anatomic changes after sub-threshold micropulse yellow laser (577-nm) treatment for chronic central serous chorioretinopathy: long-term follow-up

PurposeTo analyze the long-term efficacy of 577 nm sub-threshold micropulse yellow laser (SMYL) in the treatment of chronic central serous chorioretinopathy (CCSC) and to evaluate the anatomic outcome, visual results and safety profile of the treatment.Patients and methodsThis prospective study assessed 39 eyes of 39 patients with non-resolving CCSC lasting more than three months. All eyes were treated by using 577 nm SMYL system with 5% duty cycle (DC) and each patients was monitored monthly. The main outcome measures were best-corrected visual acuity (BCVA), contrast sensitivity (CS) and subretinal fluid (SRF) height, central macular thickness (CMT), central macular volume (CMV), total macular volume (TMV), and subfoveal choroidal thickness (SFCT) measured by spectral domain optical coherence tomography (SD-OCT).ResultsThe median follow-up time period was 17.82±0.42 (13-23 months) months. The BCVA was improved significantly at final follow-up in comparison of baseline visit (P<0.01) in 35 eyes (89.7%) and in 4 eyes (10.3%) was stable. The median CMT, CMV, TMV before treatment was 369 μm, 0.30 mm3, and 9.86 mm3, in comparison to 250 μm, 0.19 mm3, and 8.76 mm3 at final follow-up, respectively (P<0.01 for all these parameters). Initial median SFCT was recorded as 364 μm and 342 μm at the final follow-up (P<0.001).DiscussionResults suggest that SMYL treatment is an effective method as response was rapid and procedure is safe to manage the non-resolving CCSC eyes.