SS OCT Research Articles

Artificial intelligence-based prediction of neurocardiovascular risk score from retinal swept-source optical coherence tomography–angiography

The recent rise of artificial intelligence represents a revolutionary way of improving current medical practices, including cardiovascular (CV) assessment scores. Retinal vascular alterations may reflect systemic processes such as the presence of CV risk factors. The value of swept-source retinal optical coherence tomography–angiography (SS OCT-A) imaging is significantly enhanced by image analysis tools that provide rapid and accurate quantification of vascular features. We report on the interest of using machine-learning (ML) and deep-learning (DL) models for CV assessment from SS OCT-A microvasculature imaging. We assessed the accuracy of ML and DL algorithms in predicting the CHA2DS2-VASc neurocardiovascular score based on SS OCT-A retinal images of patients from the open-source RASTA dataset. The ML and DL models were trained on data from 491 patients. The ML models tested here achieved good performance with area under the curve (AUC) values ranging from 0.71 to 0.96. According to a classification into two neurocardiovascular risk groups, the EfficientNetV2-B3, a well suited DL model for retinal OCT-A images, predicted risk correctly in 68% of cases, with a mean absolute error (MAE) of approximately 0.697. Our models enable a confident prediction of the CHA2DS2-VASc score from SS OCT-A imaging, which could be a useful tool contributing to the assessment of neurocardiovascular profiles in the future.

Optical coherence tomography angiography of the foveal avascular zone after successful macula‐off rhegmatogenous retinal detachment repair

Aims/Purpose: To investigate the size and shape of the foveal avascular zone (FAZ) after successful macula‐off rhegmatogenous retinal detachment (RRD) repair using swept source OCT angiography (SS OCTA).Methods: A prospective comparative cross‐sectional study including 21 eyes of 21 patients with macula‐off RRD that were successfully repaired. The size of the superficial FAZ was assessed by its area, length of perimeter, and Feret's diameter, and the shape by the circularity, axial ratio, roundness and solidity. The correlations between each parameter and the clinical and OCT findings were statistically determined. The unaffected fellow eyes were used as controls.Results: The mean initial BCVA was 1.92 ± 0.41 Log MAR (20/2000 Snellen's equivalent). The mean BCVA at OCTA acquisition (3 months) was 0.78 ± 0.39 Log MAR (20/100 Snellen's equivalent) (p < 0.001). FAZ was significantly larger (323.09 ± 129.03 μm2 vs. 245.27 ± 93.15 μm2; p = 0.038), with longer perimeter (2.31 ± 0.35 mm vs. 2.07 ± 0.31 mm; p = 0.048), and irregular shaped (mean circularity: 0.73 ± 0.72 vs. 0.78 ± 0.5; p = 0.019 and mean solidity: 0.90 ± 0.02 vs. 0.93 ± 0.02; p = 0.002) in operated eyes than in the control group. The average Feret's diameter was 0.77 ± 0.10 mm versus 0.71 ± 0.88 mm (p = 0.076). The average axial ratio was 1.25 ± 0.20 versus 1.22 ± 0.22 (p = 0.531), and the average roundness was 0.81 ± 0.11 versus 0.83 ± 0.11 (p = 0.531). Mean central foveal thickness (CFT) was significantly lower in operated eyes than in control eyes (178.23 ± 40.59 μm vs. 247.44 ± 38.2 μm (p < 0.001)). There was a significant inverse correlation between FAZ area and post‐operative outer nuclear layer thickness (r = −0.520, p = 0.016) and CFT (r = −0.571, p = 0.007) in operated eyes. There was no significant correlation between the post‐operative visual acuity and FAZ parameters.Conclusions: Enlargement and irregularities of FAZ after successful macula‐off RRD repair, as demonstrated by SS OCTA, might suggest an ischaemic macular damage caused by RRD that may affect post‐operative functional outcome.

SS OCT and OCT-A Findings in Convalescent Inactive Vogt-Koyanagi-Harada Disease

ABSTRACT Purpose This study aimed to determine predictive factors for low final visual acuity in patients with inactive Vogt-Koyanagi-Harada (VKH) disease using Swept-source OCT and OCT-angiography (OCT-A). Methods We conducted a prospective longitudinal study, including 21 patients (42 eyes), who were followed up for the first 24 months after disease onset. Patients were included at the acute phase and subsequently treated. Sequential qualitative and quantitative changes in OCT and OCT-A were assessed. Analytical statistical methods were employed to determine predictive factors for final visual acuity. Results Structural alterations including focal parafoveal outer nuclear layer atrophy, ellipsoid zone disruption, interdigitation zone disruption, and irregular and thickened retinal pigment epithelium line were observed in 57.1% of eyes at month 3, with no significant improvement over time. The presence of flow voids at months 6, 12, and 24 was significantly associated with low final visual acuity. Serous retnal detachment at presentation emerged as an independent risk factor for structural changes detected by SS-OCT during the first 2 years of the disease. Optic disc edema was predictive factor for both structural SS-OCT and OCT-A changes. Conclusion This study underscores the importance of monitoring flow voids to predict final visual acuity and highlights the impact of serous retinal detachment at presentation on structural changes in patients with inactive VKH disease.

Swept-Source OCT Mid-Peripheral Retinal Irregularity in Retinal Detachment and Posterior Vitreous Detachment Eyes.

Irregularities in retinal shape have been shown to correlate with axial length, a major risk factor for retinal detachment. To further investigate this association, a comparison was performed of the swept-source optical coherence tomography (SS OCT) peripheral retinal shape of eyes that had either a posterior vitreous detachment (PVD) or vitrectomy for retinal detachment. The objective was to identify a biomarker that can be tested as a predictor for retinal detachment. Eyes with a PVD (N = 88), treated retinal detachment (N = 67), or retinal tear (N = 53) were recruited between July 2020 and January 2022 from hospital retinal clinics in South Australia. The mid-peripheral retina was imaged in four quadrants with SS OCT. The features explored were patient age, eye axial length, and retinal shape irregularity quantified in the frequency domain. A discriminant analysis classifier to identify retinal detachment eyes was trained with two-thirds and tested with one-third of the sample. Retinal detachment eyes had greater irregularity than PVD eyes. A classifier trained using shape features from the superior and temporal retina had a specificity of 84% and a sensitivity of 48%. Models incorporating axial length were less successful, suggesting peripheral retinal irregularity is a better biomarker for retinal detachment than axial length. Mid-peripheral retinal irregularity can identify eyes that have experienced a retinal detachment.

Healing features of outer retinal layers on SS OCT in VKH disease

AbstractPurpose: To describe restoration of outer retinal layers on Swept‐Source OCT (SS OCT) in Vogt Koyanagi Harada (VKH) disease over a year after the disease onset.Methods: Prospective longitudinal study carried out at the department of Ophthalmology of Fattouma Bourguiba University Hospital of Monastir. Twenty‐one patients (42 eyes) were followed‐up for 12 months after the disease onset. The patients were included at the acute phase and subsequently treated. Sequential SS OCT changes were assessed.Results: Structural SS OCT changes occurred in 24 eyes (57.1%) on month 3 (M3), in 23 eyes (54.8%) on month 6 (M6), and in 19 eyes (45.2%) on month 12 (M12). They included external nuclear layer atrophy (14.3% on M3; 11.9% on M6; and 9.5% on M12); ellipsoid zone disruption (40.5% on M3; 38.1% on M6; and 33.3% on M12); interdigitation zone disruption (42.9% on M3; 40.5% on M6; and 33.3% on M12); and multifocal retinal pigment epithelium thickening (50% on M3; 45.2% on M6; and 31% on M12). No significant association between final visual acuity and external retinal layers alterations at any stage of the study was found. Stepwise analysis showed that the presence of serous retinal detachment at presentation was an independent factor for structural SS OCT changes on M3.Conclusions: After initial onset, SS OCT shows thinning of the outer nuclear layer, disruption of the ellipsoid and interdigitation zones, and multifocal retinal pigment epithelium thickening. Serous retinal detachment at presentation is an independent factor for structural SS OCT changes during the first year of the disease.

Longitudinal analysis of Irvine‐Gass syndrome using swept source optical coherence tomography

AbstractPurpose: To monitor macular edema in Irvine‐Gass (IG) syndrome using Swept source optical coherence tomography (SS OCT) and describe different features.Methods: A prospective longitudinal study carried out at the Ophthalmology department of Habib Thameur University Hospital of Tunis between January 1st 2020 and December 30th 2021. Patients with pseudophakic macular edema were included. Patients with ocular or systemic diseases that may interfere with ocular imaging (Age‐related macular degeneration, diabetes and central venous occlusion) were excluded. All patients underwent complete ophthalmic examination and SS OCT at first presentation (M1) and 2 months (M2) after treatment with topical nonsteroidal anti‐inflammatory drugs. Central retinal thickness (CRT), central choroidal thickness (CCT), serous retinal detachment thickness (SRDT) and diameter of the largest cystic intraretinal space (DCS) were measured and compared. Paired samples T‐test and McNemar test were performed using 21.0 SPSS.Results: Fourteen eyes of 14 patients (5 males and 9 females) were eligible for the study. The median age was 69 years ±8 years. Pseudophakic macular edema interested the right eye in 12 eyes. Qualitative analysis of SS OCT revealed serous retinal detachment in 11 eyes (73%) on M1 and 9 eyes (60%) on M2. Cystic intraretinal spaces were present in 14 eyes (100%) on M1 and 10 eyes (66%) on M2. CRT decreased significantly from 505.73 μm on M1 to 342.93 μm on M2 (p = 0.000), it affected the four macular quadrants significatively (p = 0.004). SRDT decreased from 134.80 μm on M1 to 56.33 μm on M2 (p = 0.03) and DCS from 287.93 μm on M1 to 104.93 μm on M2 (p = 0.000). Mean CCT was 205.60 μm on M1 and 210.20 μm on M2 with no significant difference (p = 0.90).Conclusions: SS OCT provides qualitative and quantitative analysis for the monitoring of the IG syndrome. It demonstrated improvement of the retinal measurements during the first 2 months with significant regression of the CRT, the SRDT and the DCS. Therefore, the choroid seems to be spared in the regeneration process.

Characterising collateral vessels in eyes with branch retinal vein occlusions using widefield swept-source optical coherence tomography angiography

Background/aimsTo characterise the morphology, location and functional significance of both macular and extramacular collateral vessels (CVs) in patients with a history of branch retinal vein occlusion (BRVO) using widefield swept-source...

Nodular Posterior Scleritis Masquerading as Amelanotic Choroidal Melanoma

We report a patient of choroidal mass, masquerading as amelanotic choroidal melanoma. A 48 years old male presented in outpatient department (OPD) with painless decrease in vision of left eye. Fundus examination revealed a two disc diameter, non-pigmented, sub-retinal lesion with approximately 3mm basal diameter, superior to the disc with no choroidal folds, retinal detachment or pigmentation over the lesion. B scan revealed a small nodular thickening superior to the optic nerve head with moderate to low internal reflectively and no choroidal excavation. Swept-Source optical coherence tomography (SS OCT) showed massive elevation of retina due to underlying scleral thickening. He was diagnosed as nodular posterior scleritis (NPS). The lesion regressed completely after treatment with topical and systemic Non-steroidal anti-inflammatory drugs (NSAIDs). Despite its low prevalence, NPS should be kept in differential diagnosis of an amelanotic choroidal mass.

Swept-source OCT for corneal graft quantitative evaluation in the eye bank and the correlation of the measurements to pre-excision values

Quantitative evaluation of the human corneal grafts stored in the tissue banks is usually limited to endothelial cell density and central thickness. Swept-source OCT (SS-OCT) is capable of measuring the central curvatures of the corneal tissue prepared for transplantation without loss of sterileness, providing insights on its refractive state. The aim of the paper is to compare in vitro SS-OCT measurements with pre-excision values. Hand-held keratometry and ultrasound pachymetry was performed on 22 corneas before excision of corneoscleral button and insertion in the vial with Eusol-C solution (AlchimiaS.r.l, Nicolò, Italy). After 12 to 36 h of hypothermic storage the corneas were examined within the vials with custom built SS-OCT system maintaining a sterile environment. The anterior and posterior central curvatures, and central corneal thickness (CCT) were measured. Rotation of the corneoscleral button was controlled by making a 6-o'clock mark during excision. Mean pre-excision CCT was 626.45 ± 28.71 µm and 468.05 ± 52.96 µm when measured with SS OCT (r = 0.55; p < 0.001). Respective values for average keratometry were 7.74 ± 0.39 mm and 7.92 ± 0.57 mm (r = 0.6; p = 0.22). Although high differences were observed in corneal thickness, keratometric radius of curvature at the flat (r = 0.42; p < 0.001) and steep (r = 0.62; p = 0.014) meridian of the anterior corneal surface, as well as corneal anterior astigmatism (r = 0.3; p < 0.001), showed good correlation with pre-excision values. SS-OCT is capable of providing quantitative evaluation of the human corneal grafts in hypothermic storage. Good correlation between curvature measurements before excision and during banking in the vial indicates its clinical utility.

Retinal Microvascular Changes in Familial Hypercholesterolemia: Analysis with Swept-Source Optical Coherence Tomography Angiography.

Familial hypercholesterolemia (FH) is a common but underdiagnosed genetic disorder affecting cholesterol metabolism, leading to atherosclerotic disease. The relationship between retinal microvascular changes and the presence of atheroma in patients with FH (FH group), and in comparison to volunteers without FH (CT group), needs further investigation. This cross-sectional study was conducted in a university hospital between October 1, 2020 and May 31, 2021. Cardiovascular data, including the Coronary Artery Calcium (CAC) score, were recorded for FH patients. Macula angiograms were acquired using swept-source optical coherence tomography angiography (SS OCT-A) to analyze both the superficial capillary plexus (SCP) and deep capillary plexus (DCP). A total of 162 eyes of 83 patients were enrolled in the FH group and 121 eyes of 78 volunteers in the CT group. A statistically significant association was found between the CAC score and both vessel density (β = −0.002 [95% CI, −0.004; −0.0005], p = 0.010) and vessel length (β = −0.00005 [95% CI, −0.00008; −0.00001], p = 0.010) in the DCP. The FH group had a significantly lower foveal avascular zone circularity index than the CT group in multivariate analysis (0.67 ± 0.16 in the FH group vs. 0.72 ± 0.10 in the CT group, β = 0.04 [95% CI, 0.002; 0.07], p = 0.037). Retinal microvascularization is altered in FH and retinal vascular densities are modified according to the CAC score.

A pediatric case of West Nile virus chorioretinitis associated with unilateral acute idiopathic maculopathy

We report a pediatric case of unilateral acute idiopathic maculopathy (UAIM) associated with West Nile virus (WNV) infection. A 10-year-old child with a 15-day history of presumed acute viral encephalitis, complained of blurred vision in the right eye. Clinical and multimodal imaging findings, including disruption of the foveal ellipsoid zone (EZ) with preservation of the external limiting membrane on Swept Source OCT (SS OCT), were consistent with UAIM. The finding of associated curvilinear chorioretinal lesions in the setting of encephalitis led a diagnosis of WNV infection to be considered and subsequently confirmed by serology. The EZ spontaneously restored over a few weeks with near complete visual recovery. This is a unique pediatric case of UAIM associated with serologically proven WNV infection.

Retinal microvascular changes in white matter hyperintensities investigated by swept source optical coherence tomography angiography

BackgroTo assess the microvascular changes in the macular region and the foveal avascular zone (FAZ) area in participants with white matter hyperintensities (WMHs) using swept source optical coherence tomography angiography (SS OCTA).MethodsThis cross-sectional study included a total of 23 WMH participants (45 eyes) and 20 age-matched healthy participants (40 eyes). SS OCTA (VG200; SVision Imaging, Ltd., Luoyang, China) was used to assess the retinal vessel density (VD) and the FAZ area. VD was measured in the superficial vascular plexus (SVP), intermediate capillary plexus (ICP) and deep capillary plexus (DCP) within a 6 × 6-mm scan centred on the macula using a 5-mm Macula circle. The FAZ area was automatically measured on the inner retina layer within a 3 × 3-mm scan in the macular region.ResultsThere was no significant difference in VD in the SVP between the two groups. However, VD in both the ICP and DCP was significantly decreased in WMH participants (P = 0.028, P = 0.016). The FAZ area was significantly enlarged in WMH participants (P = 0.030). The signal quality was significantly lower in WMH participants (P < 0.001).ConclusionsThis study suggested that WMH participants have retinal microvascular and foveal avascular zone area changes compared with healthy controls. Further longitudinal studies with larger sample sizes are warranted to identify the value of our findings in the early evaluation of WMHs.

Wide-field swept source optical coherence tomography evaluation of posterior segment changes in highly myopic eyes.

To investigate the features in the posterior pole of highly myopic (HM) eyes using a wide-field high-resolution swept source optical coherence tomography (SS OCT). This observational cross-sectional study involved 262 eyes of 139 patients, who were diagnosed as HM and had consecutively been examined by SS OCT in the Ophthalmology Department of the Peking Union Medical College Hospital between March 2019 and December 2019. The characteristics of OCT images were documented and analyzed. In our study, SS OCT could demonstrate the entire layer of the choroid and detect the sclera in all eyes. The mean subfoveal retinal/choroidal/scleral thickness were 204.84 ± 119.86 μm, 92.80 ± 75.78 μm and 394.734 ± 123.09 μm, respectively. 138 eyes (52.67%) had posterior precortical vitreous pocket. Myopic foveoschisis was detected in 110 eyes (41.98%), and significantly associated with the presence of posterior staphyloma. 36 eyes (13.74%) had DSM in our study, of which 8 eyes (22.22%) showed a round dome, 16 (44.44%) were horizontal oval-shaped, 9 (25%) were vertical oval-shaped and 3 (8.34%) were oblique oval-shaped. Both SFCT and SFST were inversely and significantly associated with age and refractive errors. Macular neovascularization was significantly correlated with intrascleral vessels. Different deformation of the sclera and posterior staphyloma were vividly identified on SS OCT images. This study provided a relatively comprehensive picture of posterior pole in HM eyes. Such good visualization of ocular fundus provided by wide-field SS OCT could be useful for the therapy option, disease condition monitoring and pathogenesis investigation.

Ultra-wide field swept-source optical coherence tomography angiography in patients with diabetes without clinically detectable retinopathy

BackgroundTo investigate alterations in retinal microvasculature in eyes with preclinical diabetic retinopathy (DR) using ultra-wide field swept-source optical coherence tomography angiography (UWF SS OCTA).MethodsProspective cross-sectional study. Fifty-five eyes of 30 diabetic patients without clinical retinal signs were included. All subjects underwent OCTA examination with a 12 × 12 mm2 field of view of 5 visual fixations (1 central fixation and 4 peripheral fixations) to compose a UWF OCTA image. In the UWF images, the central area corresponded to the original central image obtained using central fixation, and the peripheral area was the remaining area. Lesions, including nonperfusion areas (NPAs), microvascular dilation and tortuosity, and neovascularization (NV), were recorded in different areas. Diabetes history was also recorded.ResultsPeripheral areas presented significantly more microvascular dilation and tortuosity than central areas (P = 0.024) and more NPAs than central areas, with borderline significance (P = 0.085). The number of lesion types was associated with HbA1c levels in the peripheral and overall areas (all P values < 0.001).ConclusionsUWF SS OCTA is a promising imaging method for detecting vascular alterations in diabetic eyes without clinical signs to reveal retinal microvascular alterations. These alterations were correlated with systemic conditions.

Corneal Analysis with Swept Source Optical Coherence Tomography in Patients with Coexisting Cataract and Fuchs Endothelial Corneal Dystrophy

This study focused on defining the characteristic features of keratometry and pachymetry elevation maps based on swept source optical coherence tomography (SS OCT) in Fuchs endothelial corneal dystrophy (FECD) eyes with a coexisting cataract. 70 eyes of 35 patients diagnosed with FECD and a coexisting cataract and 70 control eyes were included in this prospective, controlled, observational, cross-sectional study. Features characteristic of intermediately affected eyes included an increased corneal thinnest thickness (CTT) (p = 0.01), 3 and 6 mm asymmetry (p < 0.0001), higher order Fourier indices (p < 0.05 and p ≤ 0.0001, respectively), chord µ, and a posterior Ectasia Screening Index (pESI) (p < 0.01). The lack of agreement between the anterior and posterior elevation map and a significant area of negative values in the posterior map were detected. In advanced FECD eyes, our study additionally revealed decreased posterior keratometry steep (Ks), keratometry flat (Kf), keratometry average (AvgK), eccentricity (Ecc), an increased corneal apex thickness (CAT), and decreased 3 and 6 mm posterior spherical indices (p < 0.0001 for all of the above). Characteristic features of subclinical FECD, independent of the corneal thickness, can be detected by SS OCT and should be considered during the preoperative assessment of patients with a coexisting cataract.

Macular fibrosis in Coats' disease demonstrated by Optical Coherence Tomography Angiography - new data toward pathophysiology.

To analyze if Segmented Swept-Source Optical Coherence Tomography Angiography (SS OCT-A) can provide additional information on morphology and pathophysiology of macular fibrosis in Coats' patients. A consecutive case series of three male patients (5, 7 and 15 years old), with Coats' disease-related macular fibrosis (stage 2b-2 patients, 3b-1 patient). SS OCT-A 3×3 mm macular scans of affected eyes were performed. In all three cases the inner portion of macular fibrosis displayed a dense network of vessels, continuing into deeper layers. This structure was similar to that observed in retinal angiomatous proliferations (RAP). There was associated loss of the foveal avascular zone. In one case we observed evolution of the lesion. SS-OCT imaging of macular fibrosis in Coats' disease reveals a distinct intralesional vascular structure with elements resembling RAP, probably developing as a secondary process.

Evaluation of the effect of high-intensity interval training on macular microcirculation via swept-source optical coherence tomography angiography in young football players.

Purpose:This study was conducted to evaluate the effect of high intensity interval training (HIIT) on macular microcirculation, measured by swept source optical coherence tomography angiography (ss OCTA) in young football players.Methods:Football players between 18–20 years old were included. After a detailed ophthalmological examination, physiological parameters, including height, body weight, body fat, systemic blood pressure, hematocrit values, oxygen saturation, and heart rate, were recorded. Intraocular pressure and ss OCTA parameters were measured one day before and the day after the high intensity interval training program using DRI OCT Triton (Topcon, Tokyo, Japan) between 11:00 am and 1:00 pm.Results:Fifteen participants completed the study. All were males with a mean age of 18.1 ± 0.4 years. Systolic and diastolic blood pressure and oxygen saturation did not change significantly (P > 0.05), while hematocrit levels increased remarkably (P = 0.049) after the HIIT program. Heart rates and intraocular pressure decreased (P = 0.003, P = 0.017, respectively). There was a significant increase in the central vessel density in deep capillary plexus (before: 18.7 ± 3.8%, after: 21.1 ± 4.5%) and central vessel density in choriocapillaris (before: 54.5 ± 2.8%, after 56.9 ± 2.2%) (P = 0.02, P = 0.02, respectively), although no changes were observed in other ss OCTA or in the central macular thickness and subfoveal choroidal thickness.Conclusion:A 6 week, high intensity interval training program with three exercise sessions per week seems not to alter mean superficial vascular densities, deep foveal avascular zone, and superficial foveal avascular zones, central macular thickness, or subfoveal choroidal thickness, while the central deep vascular density and central choriocapillaris vascular density increased remarkably among ss OCTA parameters.

Subfoveal Choroidal Thickness Measured By Swept Source OCT in Retinitis Pigmentosa Patients

Abstract Background Retinitis pigmentosa (RP) encompasses a group of hereditary retinal diseases that result in progressive loss of rod and cone photoreceptors. It occurs in approximately one in 4000 individuals, with a worldwide prevalence of 1.5 million affected individuals. Aim of the Work This study aimed measure the subfoveal choroidal thickness and outer retinal layer thickness in patients with Retinitis Pigmentosa and correlate them with visual acuity. Methods Fifty eyes of clinically and electrophysiologically confirmed retinitis pigmentosa patients compare to fifty eyes of normal healthy individuals of the same age group as controls. Both groups were investigated for best corrected visual acuity (BCVA)(LogMAR) and Swept Source optical coherence tomography (SS-OCT) evaluating outer retinal layer thickness (ORL), central foveal thickness and subfoveal thickness (SFCT) and the integrity of inner segment-outer segment junction IS/OS as being (Intact (+) or disrupted (-)), Results Mean ages were 34.5 ± 11.3 years for controls versus 38.8 ±12.8 years for RP patients (p &amp;gt; 0.05). Mean BCVA (logMAR) was 0.86 for RP group vesus 0.02 for control group. Mean subfoveal choroidal thickness (SFCT) measurements were significantly lower in RP group (288.4 µm) than control group (333.7µm) (P value = 0.008). Significant difference was found between choroidal thickness and BCVA (logMAR) (p-value &amp;lt;0.001). Presence of IS/OS was significantly correlated with BCVA (log MAR) (p value=0.0001). And finally, there was moderate negative correlation between central foveal thickness and BCVA (logMAR) (r = -0.414, p-value = 0.012). Conclusion Submacular choroidal thickness as measured by SS–OCT, is significantly reduced in patients with RP and significantly correlated to BCVA and IS/OS integrity.

Analysis of performance improvement in a swept source for optical coherence tomography applications

This study explores the development of high-speed swept source with a wide imaging range and instantaneous line width. For the swept source in the 1.3 μm band, the sweep rate is 193.25 kHz through the sampling buffer structure, the maximum tuning range is 142.34 nm. Meanwhile, the numerical model of the SS–OCT system is established and the signal in the OCT imaging process is numerically simulated. The influence of the dispersion mismatch point diffusion function on the imaging system is studied. Simulation results provide valuable guidance for the selection of optical components in the SS–OCT systems.

Highly Stable All-Fiber-Ring Short-Cavity Continuously Tuned Swept Source

In this study, we present a swept source that can intelligently control its sweeping speed while satisfying the commercial stability and miniaturization standards. The source’s central wavelength of the output spectrum is 1300 nm and spectral width is greater than 100 nm. Meanwhile, the scan frequency can be adjusted to range from 20 to 100 kHz, and the stability degree of the optical capacity is less than 0.34%. Additionally, this study establishes a numerical model for the swept-source optical coherence tomography (SS–OCT) system and introduces a numerical simulation of the signal produced during the OCT imaging process. The simulation results are helpful to guide the design and construction of the future OCT systems.