Widefield Choroidal Thickness of Eyes with Central Serous Chorioretinopathy Examined by Swept-Source OCT

Comparisons of choroidal thickness and volume in eyes with central serous chorioretinopathy to that of control eyes determined by ultra-widefield optical coherence tomography

PURPOSE

To compare choroidal thickness and volume in eyes with central serous chorioretinopathy (CSC) and healthy control eyes over a wide area of the fundus using ultra-widefield optical coherence tomography (UWF-OCT).

METHODS

Thirty-three eyes of 29 patients with CSC and 36 eyes of 21 healthy controls were examined retrospectively. Choroidal images were obtained with a prototype UWF-OCT device with a field of view of 105° or approximately 31.5-mm wide by 10.9-mm deep. Choroidal thickness and volume were measured in the images of 12 radial scans (every 15°) from the horizontal scan. The "new index" of the extent of focal choroidal protrusion was defined as the maximum steepness of choroidal thickness (MSCT).

RESULTS

Choroidal volume in CSC eyes was significantly larger than in control eyes within the central 50° (P < 0.001). However, there was no significant difference in choroidal volume in the peripheral 50 to 105° (P = 0.071). The MSCTs were significantly steeper in CSC eyes than in control eyes at scan lines 1, 6, 7, 8, and 10 (P < 0.01, P < 0.001, P < 0.05, P < 0.01, P < 0.05).

CONCLUSIONS

The choroid in CSC eyes was thickened only at the posterior pole, and its protrusion was significant mainly in the vertical direction. Focal choroidal thickening at the posterior pole, which we speculate includes congenital scleral changes, may affect the pathophysiology of CSC.

Pigment Epithelial Detachment and Leak Point Locations in Central Serous Chorioretinopathy

PURPOSE

To examine the associations between the vortex vein characteristics and locations of the pigment epithelial detachment (PED) and leak point in patients with central serous chorioretinopathy (CSC).

DESIGN

Observational case series.

METHODS

We evaluated 116 eyes of 104 patients with CSC. The PED and leak point locations were superimposed over the choroidal en face images using widefield swept-source optical coherence tomography and fluorescein angiography. We defined the draining areas of the superior and inferior vortex veins and analyzed their associations with the PED and leak point locations.

RESULTS

One of the 116 eyes with a unique irrigation pattern dominated by the nasal vortex vein was excluded from the analysis. Sixty-nine (60%) of the remaining 115 eyes exhibited asymmetry between the superior and inferior vortex veins. PEDs and leak points were in the vortex vein draining area with greater dilation in 66 (96%) of 69 eyes with asymmetry, and none (0%) were in the opposite areas. Both the PEDs and leak points showed significant differences in their distributions (P < .001, respectively). Additionally, 74% of PEDs and 84% of leak points were located upstream of the vortex vein draining areas, whose frequency was significantly higher compared to other areas (P < .001, respectively).

CONCLUSION

PED and leak point spatial distributions corresponded with the most terminal part of the dilated vortex veins, suggesting that blood flow disturbances, such as stasis within the affected vortex veins, may be essential in the pathogenesis of CSC.

Diurnal Variation in Choroidal Parameters Among Healthy Subjects Using Wide-Field Swept-Source Optical Coherence Tomography Angiography

Purpose

The purpose of this study was to evaluate the diurnal variation in choroidal parameters in a wide field area among healthy subjects and to identify correlations between choroidal luminal area and stromal area and various systemic factors.

Methods

In this cross-sectional study, 42 eyes from 21 healthy participants (mean age = 32.4 ± 8.8 years) were examined using wide-field swept-source optical coherence tomography angiography (WF SS-OCTA, 24 mm × 20 mm). Measurements of choroidal parameters, including choroidal volume (CV), choroidal thickness (CT), choroidal vessel volume (CVV), and choroidal stromal volume (CSV), were taken at 8:00, 12:00, 18:00, and 22:00. Systemic factors, such as blood pressure and heart rate, were concurrently monitored.

Results

Our study observed significant diurnal variations in the mean total CV, CT, CVV, and CSV, with minimum measurements around 12:00 (P < 0.001) and peak values at 22:00 (P < 0.001). Furthermore, changes in CV in specific regions were more closely associated with fluctuations in CVV than CSV in the same regions. No significant diurnal variations were found in systolic (P = 0.137) or diastolic blood pressure (P = 0.236), whereas significant variations were observed in the heart rate (P = 0.001).

Conclusions

Our study reveals diurnal variations in choroidal parameters and their associations, emphasizing that changes in choroidal volume relate more to the luminal than the stromal area in vessel-rich regions. This enhances our understanding of choroidal-related ocular diseases.

Translational Relevance

Regions with higher choroidal vasculature observed greater choroidal volume changes.

Attenuation of irradiated choroid and its regional vortex veins in central serous chorioretinopathy after photodynamic therapy

We retrospectively studied 12 eyes of 12 patients with central serous chorioretinopathy (CSC) to investigate choroidal thickness changes following half-fluence photodynamic therapy (PDT) using widefield choroidal thickness maps obtained by optical coherence tomography (OCT). Additionally, we assessed the relationship between choroidal thickness changes and the regional vortex veins as visualized on widefield en face OCT of the choroid. Pre-treatment en face images of the choroidal vasculature were superimposed on subtracted choroidal thickness maps before and 3 months after half-fluence PDT. The choroidal thickness decreased mainly in the irradiated macular area and in the region of vortex veins which function as drainage for the macula in all eyes. Eleven eyes (91.7%) showed choroidal thinning in the nasal area which overlapped with the nasal vortex vein distribution. Moreover, in 10 (90.9%) of those eyes, we observed intervortex venous anastomosis across the vertical watershed zone. Quantitative analysis revealed that the reduction in choroidal thickness was most pronounced in the macular area. Furthermore, the choroidal thickness reduction in the area with macular drainage vortex veins was significantly greater than that in the area without such vortex veins. These results suggest that half-fluence PDT might decrease choroidal thickness due to choriocapillaris occlusion in the irradiated macula, possibly leading to diminished venous drainage from the macula to regional vortex veins. Moreover, venous blood flow through the anastomotic vessels from the macular drainage vortex veins into the nasal vortex veins might be reduced post-treatment.

Macular retinal circulation in healthy eyes examined by optical coherence tomography angiography extended interscan time analysis

PURPOSE

To examine whether extended interscan time (IST) on optical coherence tomography angiography (OCTA) can detect slow retinal blood flow, which is undetectable on default IST, in the healthy macula.

METHODS

OCTA (OCT-A1, Canon Inc.) scanning of a macular area measuring 4 × 4 mm2 of 14 healthy eyes of 14 healthy volunteers with no history or evidence of systemic and macular diseases was performed. ISTs were set at 7.6 (IST7.6, default setting), 12.0 (IST12.0), and 20.6 msec (IST20.6). Ten OCTA images were acquired at each IST, and an averaged image was created. For each averaged OCTA image obtained at IST7.6, IST12.0, and IST20.6, we defined the area surrounded by the innermost capillary ring as the foveal avascular zone (FAZ). We qualitatively evaluated the delineation of the capillaries consisting of the FAZ and quantitatively measured the FAZ area at each IST.

RESULTS

Extensions from IST7.6 to IST12.0 and IST20.6 could newly delineated retinal capillaries that were undetectable at the default IST; new capillaries were detected in 10 (71%) eyes at IST12.0 and 11 (78%) eyes at IST20.0. The FAZ areas were 0.334 ± 0.137 mm2, 0.320 ± 0.132 mm2, and 0.319 ± 0.129 mm2 for IST7.6, IST12.0, and IST20.0, respectively; the FAZ areas at IST12.0 and IST20.0 were significantly decreased compared with that at IST7.6 (p = 0.004 and 0.002, respectively).

CONCLUSION

In OCTA for healthy participants, extensions of the ISTs newly detected retinal capillaries with slow blood flow around FAZ. The FAZ shapes varied with different ISTs. Thus, the blood flow dynamics are not physiologically uniform around FAZ. Compared with conventional OCTA, this protocol enables a more detailed evaluation of retinal circulation and provides a better understanding of the physiological circulatory status of the healthy retina, and may enable the assessment of circulation in the very early stages in diseased eyes.

Differences in Central and Peripheral Choroidal Thickness among the Subtypes of Age-Related Macular Degeneration in an Asian Population

Age-related macular degeneration (AMD) causes visual impairment in individuals who are >50 years of age. However, no study has investigated AMD when using ultra-wide-field swept-source optical coherence tomography (UWF SS-OCT). We aimed to evaluate central and peripheral choroidal thicknesses using UWF SS-OCT, and to compare these across the AMD subtypes. We included 75 eyes of patients with typical AMD (tAMD), 56 with polypoidal choroidal vasculopathy (PCV), 29 with pachychoroid neovasculopathy (PNV), and 12 with retinal angiomatous proliferation (RAP). To compare choroidal thicknesses in the central and peripheral choroids, we established subfields of <3 mm, <9 mm, and 9-18 mm from the fovea. PNV patients were significantly younger than those with tAMD (p = 0.01). The choroidal thicknesses of PNV were significantly greater than that of tAMD in all subfields (p < 0.01), and choroidal thickness significantly correlated with age and axial length in all subfields (p < 0.05). Even after adjusting for age and axial length, the choroidal thickness in PNV was significantly greater than that in tAMD (p < 0.05). In addition, the ratio of the posterior <9 mm to a peripheral 9-18 mm choroidal thickness in PNV was significantly greater than that in tAMD (p < 0.01). A thickened choroid in PNV was more pronounced in the posterior choroid than in the periphery.

Widefield choroidal vasculature associated with future condition of subretinal fluid in central serous chorioretinopathy

Purpose

To examine choroidal angiographic features in the posterior pole associated with resolution or persistency of subretinal fluid (SRF) in eyes with central serous chorioretinopathy (CSC).

Design

Observational case series.

Methods

Twenty-nine patients with treatment-naïve CSC were divided into two groups based on the presence or absence of SRF 3 months after the initial visit (month 3) without any treatment. Using enhanced depth imaging of widefield swept-source optical coherence tomography, the choroidal thickness (CT), vessel density (VD), and vessel diameter index (VDI) in the superotemporal and inferotemporal subfields on the temporal side of the 18-mm circle from the disc were measured at the initial visit. We calculated the vertical difference in CT and other choroidal angiographic parameters and evaluated their association with the SRF condition at 3 months.

Results

The SRF-resolved and SRF-persistent groups included 10 and 19 patients, respectively. At the initial visit, sex, age, axial length, symptom duration, the logarithm of the minimum angle of resolution visual acuity, and foveal thickness were not significantly different between the two groups. The SRF status at month 3 was not associated with the vertical difference in CT and choroidal VD (P = .614, .065, respectively). However, the vertical difference in choroidal VDI was positively associated with the future presence of SRF (P = .017).

Conclusions

Vertically asymmetric dilation of choroidal vessels in the posterior pole may be a vasculature feature associated with SRF from CSC and may be a good predictor of future SRF status.

Choroidal vascularity index in different types of central serous chorioretinopathy: A meta-analysis

PURPOSE

To evaluate the choroidal vascularity index (CVI) in different types of central serous chorioretinopathy (CSC), healthy control eyes, and fellow eyes.

METHODS

Relevant studies published up to January 2023 were identified by searching multiple databases, including PubMed, Embase, Web of Science, Cochrane Library, and China National Knowledge Infrastructure (CNKI). Studies investigating the difference in CVI between CSC and control eyes were included. Data from these studies were analyzed using Stata (version 17) software. Weighted mean difference (WMD) and 95% confidence interval (95%CI) were calculated for the CVI in CSC eyes, control eyes, and fellow eyes.

RESULTS

The meta-analysis included 15 studies, with 213 acute CSC eyes, 153 chronic CSC eyes, 92 uncategorized CSC eyes, 40 resolved CSC eyes, 409 eyes of normal healthy controls, and 318 fellow eyes. The result revealed that CVI was higher in acute CSC eyes (WMD = 5.40, 95%CI = 2.36-8.44, P = 0.001) compared to control eyes. Also, CVI in chronic CSC eyes was higher than in control eyes (WMD = 1.26, 95%CI = 0.03-2.49, p = 0.046). The fellow eyes of acute CSC had a higher CVI when compared to control eyes (WMD = 2.53, 95%CI = 0.78-4.28, p = 0.005). There was no significant difference in CVI between acute and chronic CSC eyes (WMD = 0.75, 95%CI = -0.31-1.82, P = 0.167). In the sub-analysis based on the area selected for CVI calculation, the WMDs in the whole image subgroups were lower than the main analysis for the comparisons of fellow eyes of acute CSC and control eyes, acute CSC eyes and control eyes, and acute CSC eyes and fellow eyes. In the macular area subgroups, the WMDs were higher than in the whole image subgroups, suggesting a potential regional variation of CVI in CSC eyes.

CONCLUSIONS

The results demonstrated that CVI is increased in CSC eyes and fellow eyes of acute CSC. There is no significant difference in CVI between acute and chronic CSC eyes. The area selected for CVI calculation can influence the outcome, which requires further clinical research to clarify.

Analysis of widefield choroidal thickness maps of healthy eyes using swept source optical coherence tomography

We aimed to obtain widefield (WF) swept source optical coherence tomography (SS-OCT) data and examine the features of choroidal thickness maps in healthy eyes. The posterior pole choroidal thickness was examined in 127 eyes using enhanced depth imaging of SS-OCT with a viewing angle of 20 (vertical) × 23 (horizontal) mm, and choroidal thickness maps were generated. For SS-OCT image analysis, we developed a grid with inner and outer rings, each divided into superotemporal, inferotemporal, superonasal, and inferonasal quadrants, comprising a total of nine subfields, including the central 3-mm ring. The posterior pole choroidal thicknesses were significantly lower at the periphery than in the central area, in the inferior field than in the superior field, and in the nasal field than in the temporal field (p < 0.001 for all). We also evaluated the effects of age and axial length (AL) on the WF choroidal thickness. The choroidal thickness in all subfields was negatively associated with advanced age (p < 0.05). The choroidal thicknesses in the central and inferonasal inner and outer subfields were negatively associated with AL (p = 0.042, 0.034, and 0.022, respectively). These findings provide insights into the two-dimensional characteristics of choroidal thickness and its association with age and AL.

Extensive reduction in choroidal thickness after photodynamic therapy in eyes with central serous chorioretinopathy

We examined the effect of reduced fluence (rf)-photodynamic therapy (PDT) of the macular area on the wide-field choroidal thickness in 20 eyes with central serous chorioretinopathy (CSC) and 20 age- and sex-matched control eyes. The choroidal thickness at the posterior pole was measured before and after rf-PDT, using a grid with inner and outer rings, each divided into superotemporal, inferotemporal, superonasal, and inferonasal quadrants, respectively, making up a total of nine subfields including the central 3 mm ring. Before treatment, all eyes showed wide-field choroidal thickening from the dilated vortex vein ampulla to the fovea, along the course of the vein. After rf-PDT of the macular area, the choroidal thickness significantly decreased, not only in the irradiated macular area but also outside the arcade vessels in all quadrants (p < 0.001 for all inner subfields; p = 0.035 and p = 0.024 for the outer superonasal and inferonasal subfields, respectively; p < 0.001 and p = 0.004 for the outer superotemporal and inferotemporal subfields, respectively). For control eyes, the choroidal thickness did not differ between the initial visit and follow-up 1.2 ± 0.7 months after the initial visit (p > 0.05 for all subfields). These findings provide new insights into the pathogenesis of CSC and explain the reasons for the effectiveness of rf-PDT for this condition.

NORMAL PERIPHERAL CHOROIDAL THICKNESS MEASURED BY WIDEFIELD OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

Choroidal stasis plays an important role in the pathogenesis of many conditions and leads to choroidal thickening. However, the normal peripheral choroidal thickness (PCT) pattern remains unknown. This study investigated PCT and associated factors using ultrawidefield optical coherence tomography in healthy eyes.

METHODS

This cross-sectional study included 120 healthy eyes (57 males; age, 52.0 ± 20.5 years). We used choroidal thickness maps created by ultrawidefield optical coherence tomography (viewing angle, 200°) with real-shape correction. The peripheral area was defined from 60° to 100° and further separated vertically and horizontally. The PCT and the correlations between PCT and subjects' characteristics were examined.

RESULTS

The PCT were 227.1 ± 57.0 µ m, 199.6 ± 53.9 µ m, 196.6 ± 57.1 µ m, and 148.0 ± 38.2 µ m in supratemporal, infratemporal, supranasal, and infranasal areas, respectively. The thickest peripheral sector was most frequently observed in supratemporal (69.2%). The PCT negatively correlated with age in all regions ( P -values < 0.001) and axial length in supratemporal, supranasal, and infranasal areas ( P -values ≤ 0.003). The temporal PCT was thicker on the side contiguous with the posterior pole Haller's vessels ( P -values ≤ 0.020).

CONCLUSION

The PCT is associated with age, axial length, and the running pattern of Haller's vessels.

Quantitative analysis of choroidal vasculature in central serous chorioretinopathy using ultra-widefield swept-source optical coherence tomography angiography

We aimed to quantitatively compare the choroid blood flow and choroid thickness at the periphery among eyes with central serous chorioretinopathy (CSC), fellow eyes and healthy eyes using ultra-widefield swept-source optical coherence tomography angiography (UWF SS-OCTA). Retrospective analysis of 49 patients with CSC (98 eyes, including unaffected fellow eyes) and 49 age and sex matched controls were included. We obtained 3-dimensional data of vertical 20 mm × horizontal 24 mm × scan depth 6 mm, comprising 9 subfields (superotemporal, upper, superonasal, temporal, central, nasal, inferotemporal, lower, inferonasal regions). CSC eyes presented with greater density of large-vessel choroidal layer in all the 9 subfields compared with controls. Compared with normal eyes, CSC eyes had greater choroidal thickness (superotemporal, upper, superonasal, temporal, central, nasal, inferotemporal, and inferonasal subfields) and choroidal volume (superotemporal, upper, superonasal, temporal, central, and nasal subfields). Compared with control eyes, the choriocapillaris density in the superotemporal, inferotemporal and inferonasal subfields was greater in patients with CSC. Our study may provide further evidence for the congestion of vortex vein in the pathogenesis of CSC. UWF SS-OCTA can be used to evaluate the abnormalities of the choroidal structures even at the periphery in eyes with CSC.

Wide-field OCT-angiography assessment of choroidal thickness and choriocapillaris in eyes with central serous chorioretinopathy

Purpose: To assess wide-field changes in choroidal thickness and choriocapillaris in eyes with central serous chorioretinopathy (CSC) compared with the fellow eyes and eyes from healthy individuals using wide-field swept-source (SS) OCT-Angiography (OCTA).

Methods: A cross-sectional study in which 68 eyes from 34 individual patients affected by unilateral CSC and 32 eyes of 32 age- and sex-matched healthy subjects were evaluated. All subjects underwent wide-field SS-OCTA examination to quantify choroidal thickness and vascular density of the choriocapillaris. To assess the wide-field changes, we developed five 4-by-4 mm square regions located in the posterior pole and in the four quadrants of the peripheral retina (superotemporal, inferotemporal, superonasal, and inferonasal subfields, respectively).

Results: The choroidal thickness of eyes with CSC was greater than that of the fellow eyes in the central and inferonasal subfields (p < 0.001 for the central subfield and p = 0.006 for the inferonasal subfield, respectively). Compared with the choroidal thickness of healthy eyes, that of patients with CSC were significantly greater in all the subfields (p < 0.05 for the fellow eyes and p < 0.05 for eyes with CSC, respectively). Compared with that of healthy eyes, the vascular density of choriocapillaris in eyes of patients with CSC were significantly greater in the central and superotemporal subfields (p < 0.05 for the fellow eyes and p < 0.05 for eyes with CSC, respectively). In the central region, the vascular density of choriocapillaris of the fellow eyes was greater than eyes with CSC (p = 0.023).

Conclusion: CSC appears to be a bilateral disease with asymmetric manifestations. Local factors of the diseased eyes may play an important role in the development of CSC, during which dynamic and regional changes in the choriocapillaris may have happened. Wide-field swept-source OCTA provided a useful tool to study the pathogenesis of CSC.

Three-dimensional choroidal vascularity index in central serous chorioretinopathy using ultra-widefield swept-source optical coherence tomography angiography

Background

To map and compare the three-dimensional choroidal vascularity index (3D-CVI) in eyes with unilateral central serous chorioretinopathy (CSC), fellow eyes and control eyes using ultra-widefield swept source optical coherence tomography (UWF SS-OCTA).

Methods

In this prospective observational study, the 3D-CVIs were measured in 9 subfields or 1 × 1 mm grids by the UWF SS-OCTA with a viewing angle of horizontal 24 × vertical 20 mm. The proportions of vortex vein anastomoses and their corresponding CVI in the central regions were compared among the CSC, fellow and control eyes. Correlations of CVI and vascular density of the large choroidal vessel layer/choriocapillaris layer/choroidal thickness (CT) were also assessed.

Results

Thirty-two eyes in 32 patients with unilateral CSC and 32 normal eyes were included in the study. The mean CVI in the eyes with CSC was significantly greater than that in the fellow eyes of CSC and control eyes (41.99 ± 3.56% vs. 40.38 ± 3.855%, P = 0.003; 41.99 ± 3.56% vs. 38.93 ± 4.067%, P = 0.004, respectively). The CVIs in superotemporal, inferotemporal and inferonasal regions were significantly higher in CSC eyes than control eyes (P = 0.03, P = 0.02, P = 0.008). In CSC eyes, there was a linear positive correlation between 3D-CVI and vascular density of the large choroidal vessel layer and CT in all subfields. The proportion of vortex vein anastomoses in CSC was 25/32 (78.1%), and significantly higher in fellow and control eyes (P < 0.001). The average central CVI was significantly higher in CSC eyes with anastomoses than in CSC eyes without anastomoses (42.8 ± 5.1% vs. 38.4 ± 2.7%, P = 0.039). CVIs in superior, central, inferior, superonasal, nasal and inferonasal regions were significantly correlated with vortex vein anastomoses (P < 0.05), regardless of CSC, fellow or healthy eyes. In addition, whether there were vortex vein anastomoses, CVI in superotemporal region was significantly higher in eyes with CSC (P = 0.002) and fellow eyes (P = 0.014), compared to control eyes. No significant correlation was found between hypertension and CVIs in the three groups.

Conclusion

Remodeling of choroidal drainage routes by venous anastomosis between superior and inferior vortex veins may be common in CSC. The 3D-CVI could be a comprehensive parameter to evaluate the choroid vasculature and help understand the pathogenesis of pachychoroid spectrum disease.