The role of ultra-widefield imaging with navigated central and peripheral cross-sectional and three-dimensional swept source optical coherence tomography in ophthalmology: Clinical applications.

PURPOSE: To assess central and peripheral retinal and choroidal diseases using ultra-widefield (UWF) fundus imaging in combination with navigated central and peripheral cross-sectional and three-dimensional (3D) swept source optical coherence tomography (SS-OCT) scans. METHODS: Retrospective study involving 332 consecutive patients, with a nearly equal distribution of males and females. The mean age of patients was 52 years (range 18-92 years). Average refractive error was -3.80 D (range +7.75 to -20.75 D). RESULTS: The observations in this study demonstrate the efficacy of peripheral navigated SS-OCT in assessing various ocular conditions. The technology provides high-quality images of the peripheral vitreous, vitreoretinal interface, retina, and choroid, enabling visualization of vitreous floaters and opacities, retinal holes and tears, pigmented lesions, and peripheral retinal degenerations. 3D OCT scans enhance the visualization of these abnormalities and improve diagnostic and therapeutic decisions. CONCLUSION: Navigated central and peripheral cross-sectional and 3D SS-OCT scans offer significant complementary benefits in the assessment and management of retinal diseases. Their addition to UWF imaging provides a comprehensive view of central and peripheral ocular structures, aiding in early detection, precise anatomical measurements, and objective monitoring of disease progression. In addition, this technology serves as a valuable tool for patient education, a teaching tool for trainees, and documentation for medico-legal purposes.

Coefficient of spatial variance of choroidal thickness on swept-source optical coherence tomography in healthy eyes.

PURPOSE: This study aims to introduce the coefficient of spatial variance of choroidal thickness to describe the choroidal variation and investigate its associated factors in healthy eyes. METHODS: This retrospective cross-sectional study included 1031 eyes from 1031 subjects who received a swept-source optical coherence tomography examination. The mean choroidal thickness in the macular 6 × 6 mm region and 900 subregions of 0.2 × 0.2 mm were computed using the embedded algorithm. Before analysis, potential segmentation and magnification errors were corrected. The coefficient of spatial variance was defined as the standard deviation divided by the mean (multiplied by 100%) of the choroidal thicknesses across 900 grids. Potential factors associated with the coefficient of spatial variance were assessed using multiple linear regression. RESULTS: The mean choroidal thickness of the entire 6 × 6 mm macular region was 204.50 ± 72.88 µm. The mean coefficient of spatial variance was 26.58 ± 8.24%, ranging from 11.00 to 61.58%. Statistical analysis revealed that the means choroidal thickness (ß = - 0.08, R2 = 0.42, p < 0.001) and anterior chamber depth (ß = - 2.39, R2 = 0.05, p = 0.06) were associated with the coefficient of spatial variance. CONCLUSION: Our study first incorporated the coefficient of spatial variance to represent the spatial variation of the choroidal thickness and observed that the greater thinning of the choroid is correlated with a more pronounced spatial variation.

Anterior chamber and angle characteristics in Chinese children (6-11 years old) with different refractive status using swept-source optical coherence tomography.

BACKGROUND: The anatomic structure of the anterior chamber (AC) helps to explain differences in refractive status in school-aged children and is closely associated with primary angle closure (PAC). The aim of this study was to quantify and analyze the anterior chamber and angle (ACA) characteristics in Chinese children with different refractive status by swept-source optical coherence tomography (SS-OCT). METHODS: In a cross-sectional observational study, 383 children from two primary schools in Shandong Province, China, underwent a complete ophthalmic examination. First, the anterior chamber depth (ACD), anterior chamber width (ACW), angle-opening distance (AOD), and trabecular-iris space area (TISA) were evaluated automatically using a CASIA2 imaging device. AOD and TISA were measured at 500, 750 µm nasal (N1 and N2, respectively), and temporal (T1 and T2, respectively) to the scleral spur (SS). Cycloplegic refraction and axial length (AL) were then measured. According to spherical equivalent refraction (SER), the children were assigned to hyperopic (SER > 0.50D), emmetropic (-0.50D < SER ≤ 0.50D), and myopic groups (SER ≤ -0.50D). RESULTS: Out of the 383 children, 349 healthy children (160 girls) with a mean age of 8.23 ± 1.06 years (range: 6-11 years) were included. The mean SER and AL were - 0.10 ± 1.57D and 23.44 ± 0.95 mm, respectively. The mean ACD and ACW were 3.17 ± 0.24 mm and 11.69 ± 0.43 mm. The mean AOD were 0.72 ± 0.25, 0.63 ± 0.22 mm at N1, T1, and 0.98 ± 0.30, 0.84 ± 0.27 mm at N2, T2. The mean TISA were 0.24 ± 0.09, 0.22 ± 0.09mm2 at N1, T1, and 0.46 ± 0.16, 0.40 ± 0.14mm2 at N2, T2. The myopic group had the deepest AC and the widest angle. Compared with boys, girls had shorter AL, shallower ACD, narrower ACW, and ACA (all p < 0.05). By Pearson's correlation analysis, SER was negatively associated with ACD, AOD, and TISA. AL was positively associated with ACD, ACW, AOD, and TISA. In the multiple regression analysis, AOD and TISA were associated with deeper ACD, narrower ACW, and longer AL. CONCLUSION: In primary school students, the myopic eyes have deeper AC and wider angle. ACD, ACW, AOD, and TISA all increase with axial elongation. ACA is highly correlated with deeper ACD.

Analysis of cariogenic biofilms by using a swept-source optical coherence tomography in vitro.

OBJECTIVE: The objective was to measure the thickness of Streptococcus mutans (S. mutans) biofilms forming in an oral biofilm reactor (OBR) by using a noninvasive swept-source optical coherence tomography (SS-OCT) system at every 4 h time interval until 20 h and analyze the correlations with the amounts of biofilms. METHODS: S. mutans biofilms were formed on square-shaped bovine enamel blocks inside an OBR. Biofilms were analyzed at every 4 h stage (4 h, 8 h, 12 h, 16 h and 20 h) using a SS-OCT system and a laser scanning confocal microscope (LSCM). The amounts of biofilms were measured at each stage by separating the water insoluble glucan (WIG) and bacterial cells. Co-relationships between the SS-OCT measured biofilm thickness and the amounts of adhered biofilms were analyzed. RESULTS: The thickness of biofilms detected on SS-OCT images at 4 h stage was 0.059 ± 0.029 (Av ± SD) mm which increased time-dependently in a linear fashion after 8 h stage and reached to 0.435 ± 0.159 mm at 20 h stage and the correlation coefficient was about 0.89. The amounts of biofilms; bacterial optical density (OD) and WIG concentration increased time-dependently were 0.035 ± 0.008 / mm2 and 10.328 ± 2.492 µg/ mm2 respectively at 20 h stage. Correlation coefficients of 0.66 between 'the amounts of bacteria' and 'biofilm thickness on OCT' and 0.67 between 'the amounts of WIG' and 'biofilm thickness on OCT' were obtained, suggesting that there was a relatively positive correlation between them. CONCLUSION: The SS-OCT can be a useful tool to measure time-dependent growth of biofilms. Further studies are needed in order to assess biofilms using SS-OCT more accurately.

Swept-source optical coherence tomography and swept-source optical coherence tomography angiography findings in circumscribed choroidal hemangioma before and after transpupillary thermotherapy.

PURPOSE: To investigate the swept-source optical coherence tomography (SS-OCT) and SS-OCT angiography (SS-OCTA) findings in circumscribed choroidal hemangioma (CCH) before and after treatment with transpupillary thermotherapy (TTT). METHODS: The clinical records of 21 eyes having CCH imaged with SS-OCT/SS-OCTA between September 2018 and December 2022 were evaluated. RESULTS: SS-OCT examination in CCH showed dome-shaped appearance (100%), choroidal shadowing (100%), expansion of choroidal structures (100%), subretinal fluid (66.7%), intraretinal edema/schisis (33.3%), retinal pigment epithelium (RPE) atrophy (19.0%), hyperreflective dots (19.0%), and epiretinal membrane (4.8%). Internal arborizing tumor vessels showing hyperreflectivity were observed in the choriocapillaris slab on SS-OCTA in all eyes. In the deep capillary plexus (DCP), flow void changes were seen in 7 eyes with intraretinal schisis/cystoid macular edema. Four CCHs > 2 mm in thickness showed outer retinal involvement due to unmasking of flow in intratumoral vessels related to RPE atrophy. Following TTT/indocyanine green-enhanced TTT (ICG-TTT) of CCH, SS-OCT findings included total/partial resolution of subretinal fluid (57.1%), complete/partial regression of the tumor (52.4%), and RPE atrophy (33.3%). After treatment; loss of choriocapillaris, decrease in tumor vascularity together with increase in the fibrous component and flow void areas were detected on SS-OCTA. CONCLUSIONS: SS-OCT/SS-OCTA are useful non-invasive tools for imaging the structural/vascular changes in CCHs managed with TTT or ICG-TTT. On SS-OCTA, hyporeflective spaces localizing to edema/schisis in the DCP and arborizing tumor vessels within a hyporeflective stromal background in the choriocapillaris slab were observed. After TTT/ICG-TTT, a decrease in tumor vessels and an increase in the fibrous component and flow-void areas inside the CCH were detected on SS-OCTA.

Analysis of intraocular lens decentration and tilt after femtosecond laser-assisted cataract surgery using swept-source anterior optical coherence tomography.

Objective: To evaluate and compare the magnitude of intraocular lens (IOL) decentration and tilt following conventional and femtosecond laser-assisted cataract surgery (FLACS) using swept-source anterior optical coherence tomography (SS-OCT). Methods: In this retrospective observational study, we enrolled patients who underwent conventional cataract surgery or FLACS with the implantation of hydrophobic 1-piece monofocal IOL. The magnitude of IOL decentration and tilt were measured using SS-OCT. Visual acuity, intraocular pressure, spherical equivalent, axial length, contrast sensitivity, and satisfaction questionnaire were evaluated before and one-month post-surgery. Additionally, postoperative internal cylinder measurements were obtained using a wavefront aberrometer. Correlation factors between each parameter and IOL decentration or tilt were analyzed. Results: This study included 100 eyes from 100 patients. Mean IOL decentration and tilt were 0.21 ± 0.13 mm and 5.01 ± 1.49°, respectively. Conventional cataract surgery (versus FLACS, P = 0.001) and male sex (versus female, P = 0.047) were significantly correlated with higher postoperative decentration. Preoperative lens diameter (P < 0.001), preoperative lens tilt (P = 0.007), and preoperative intraocular pressure (P = 0.027) were correlated with higher postoperative tilt. Fifty eyes that underwent FLACS demonstrated mean postoperative decentration of 0.21 ± 0.13 mm and tilt of 4.64 ± 1.48°. Compared with the conventional surgery group, the FLACS group significantly differed in postoperative decentration (0.30 ± 0.12 mm, P < 0.001) but not in tilt (5.03 ± 1.35°, P = 0.173). Postoperative visual acuity did not significantly differ between the two groups. Conclusion: Patients who underwent FLACS demonstrated better IOL decentration and tilt than those who underwent conventional cataract surgery one-month post-surgery. However, differences in IOL decentration and tilt did not affect postoperative visual acuity.

Case report: Intraretinal hyperflow microinfiltration lesions on swept-source optical coherence tomography angiography as a potential biomarker of primary vitreoretinal lymphoma.

Primary vitreoretinal lymphoma (PVRL) is often associated with central nervous system involvement, contributing to a heightened mortality rate, thus imaging features that are characteristic enough to be potential biomarkers of PVRL are important, either in diagnosis or in assessment of disease activity. This report details the case of a 68-year-old male who presented with blurred vision in both eyes persisting for 2 months. Fundus examination demonstrated vitreous opacity and multiple subretinal yellow nodular lesions of varying sizes in the peripheral fundus of both eyes. Multiple vertical hyperreflective lesions in the neural retina of posterior pole, indistinct outer retina borders in the fovea, and hyperreflective lesions in the sub-retinal pigment epithelium (RPE) space of the peripheral retina were demonstrated on swept-source optical coherence tomography (SS-OCT) of the left eye. Hyperflow signals corresponding to the vertical hyperreflective lesions were detected on swept-source optical coherence tomography angiography (SS-OCTA) images of retinal deep capillary plexus (DCP) layer. Notably, the hyperflow signals, precisely located around retinal vessels from the nerve fiber layer to the outer plexiform layer, were postulated to stem from the dilation of infiltrated retinal vessels. Vitreous pathological results of the left eye confirmed the diagnosis of PVRL. Treatments with intravitreal methotrexate injections led to a marked improvement of best-corrected visual acuity (BCVA) and regression of the hyperflow microinfiltration lesions demonstrated on SS-OCTA. In conclusion, SS-OCTA effectively delineated the vertical hyperreflective lesions and corresponding hyperflow signals in the posterior pole macular region of a patient with PVRL. These lesions significantly diminished following intravitreal methotrexate injections. We speculated that the specific hyperflow signals on SS-OCTA could act as a potential biomarker of PVRL, and SS-OCTA holds promise in facilitating early diagnosis and monitoring therapeutic responses in PVRL cases.

Quantitative assessment of choroidal parameters and retinal thickness in central serous chorioretinopathy using ultra-widefield swept-source optical coherence tomography: a cross-sectional study.

OBJECTIVE: In this study, we used ultra-wide field swept-source optical coherence tomography angiography (UWF SS-OCTA) to assess changes in retinal thickness (RT) and choroidal parameters in individuals who had received a diagnosis of central serous chorioretinopathy (CSC). METHODS: The study encompassed the evaluation of 59 eyes from 47 patients with a diagnosis of CSC, alongside 33 fellow eyes and 31 eyes from healthy individuals (controls). The parameters assessed included RT, choroidal thickness (CT), choriocapillaris density, vascular density of the large choroidal vessel layer, three-dimensional choroidal vascularity index (3D-CVI), choroidal vessel volume per unit area (mCVV/a), and choroidal stroma volume per unit area (mCSV/a). RESULTS: Metrics including mCVV/a, mCSV/a, 3D-CVI, CT, and RT exhibited significantly elevated values in the eyes affected by CSC compared to those of the control group across nine subfields. Moreover, a substantial number of the subfields in both CSC-affected and fellow eyes exhibited increased values for mCVV/a, mCSV/a, 3D-CVI, CT, and RT when compared with the control group. Additionally, acute and chronic CSC subfields demonstrated significantly elevated values for mCVV/a, mCSV/a, 3D-CVI, CT, and RT in comparison to healthy control eyes. Notably, specific subfields associated with complex and atypical forms of CSC revealed higher metrics compared to those of the control group. CONCLUSION: In conclusion, the UWF SS-OCTA proved to be a valuable tool for exploring the anatomical etiology and clinical classification and diagnosis of CSC.

Implantation of Hydrophobic Acrylic Toric Intraocular Lens with High-Water Contents Using Swept-Source Optical Coherence Tomography Biometer Integrated with a Surgical Guiding System.

Purpose: To evaluate postoperative outcomes after implantation of toric intraocular lenses (IOLs) made of high-water-content hydrophobic acrylic material in Japanese patients using a swept-source optical coherence tomography (SS-OCT) biometer integrated with a surgical guiding system. Patients and Methods: In this prospective observational study, toric IOL models CNW0T3 to CNW0T9 (Alcon) were implanted in 33 eyes of 33 patients and followed-up for one month. Powers and toric models were determined using an SS-OCT biometer ARGOS® Ver 1.5 (Alcon), and the IOLs were aligned using surgical guidance. Differences between planned and actual axis positions at the end of the surgery (misalignment) and rotations from the end of surgery to one month postoperatively were measured. Additionally, postoperative uncorrected visual acuity, refraction, and residual astigmatism were evaluated. Results: Mean and median misalignments were 2.3° (standard deviation [SD]: 1.6, 95% confidence interval [CI]: 1.7-2.9) and 2°, and those of postoperative rotation were 2.4° (SD: 2.6, 95% CI: 1.5-3.4) and 2°, respectively. Mean postoperative refraction was 0.06 D (SD: 0.62). Prediction errors within ±0.5 and ±1.0 D were 69.7% and 93.9%, respectively. Mean residual astigmatisms were 0.19 D (SD: 0.41), and mean uncorrected visual acuity was 0.00 logMAR (SD: 0.11), and 64% of the eyes scored 20/20 or better. Conclusion: Implantation of high-water-content hydrophobic acrylic toric IOLs using SS-OCT biometry integrated with a surgical guiding system effectively corrected corneal astigmatism with accurate IOL alignment in Japanese patients.

Delineation of three-dimensional tumor margins based on normalized absolute difference mapping via volumetric optical coherence tomography.

The extent of surgical resection is an important prognostic factor in the treatment of patients with glioblastoma. Optical coherence tomography (OCT) imaging is one of the adjunctive methods available to achieve the maximal surgical resection. In this study, the tumor margins were visualized with the OCT image obtained from a murine glioma model. A commercialized human glioblastoma cell line (U-87) was employed to develop the orthotopic murine glioma model. A swept-source OCT (SS-OCT) system of 1300 nm was used for three-dimensional imaging. Based on the OCT intensity signal, which was obtained via accumulation of each A-scan data, an en-face optical attenuation coefficient (OAC) map was drawn. Due to the limited working distance of the focused beam, OAC values decrease with depth, and using the OAC difference in the superficial area was chosen to outline the tumor boundary, presenting a challenge in analyzing the tumor margin along the depth direction. To overcome this and enable three-dimensional tumor margin detection, we converted the en-face OAC map into an en-face difference map with x- and y-directions and computed the normalized absolute difference (NAD) at each depth to construct a volumetric NAD map, which was compared with the corresponding H&E-stained image. The proposed method successfully revealed the tumor margin along the peripheral boundaries as well as the margin depth. We believe this method can serve as a useful adjunct in glioma surgery, with further studies necessary for real-world practical applications.

Evaluation of retinal and choroidal thickness changes in overweight and obese adults without ocular symptoms by swept-source optical coherence tomography.

AIM: To evaluate the relationship of overweight and obesity with retinal and choroidal thickness in adults without ocular symptoms by swept-source optical coherence tomography (SS-OCT). METHODS: According to the body mass index (BMI) results, the adults enrolled in the cross-sectional study were divided into the normal group (18.50≤BMI<25.00 kg/m2), the overweight group (25.00≤BMI<30.00 kg/m2), and the obesity group (BMI≥30.00 kg/m2). The one-way ANOVA and the Chi-square test were used for comparisons. Pearson's correlation analysis was used to evaluate the relationships between the measured variables. RESULTS: This research covered the left eyes of 3 groups of 434 age- and sex-matched subjects each: normal, overweight, and obesity. The mean BMI was 22.20±1.67, 26.82±1.38, and 32.21±2.35 kg/m2 in normal, overweight and obesity groups, respectively. The choroid was significantly thinner in both the overweight and obesity groups compared to the normal group (P<0.05 for all), while the retinal thickness of the three groups did not differ significantly. Pearson's correlation analysis showed that BMI was significantly negatively correlated with choroidal thickness, but no significant correlation was observed between BMI and retinal thickness. CONCLUSION: Choroidal thickness is decreased in people with overweight or obesity. Research on changes in choroidal thickness contributes to the understanding of the mechanisms of certain ocular disorders in overweight and obese adults.

Effect of mydriasis on macular and peripapillary metrics in swept-source optical coherence tomography angiography.

Introduction: The study aimed to evaluate the effect of mydriasis on macular and peripapillary metrics with swept-source optical coherence tomography angiography (SS-OCTA) in healthy subjects. Methods: Thirty-five healthy subjects were included. The macular region was scanned by the 3×3mm mode and 6×6mm mode, and the peripapillary region was scanned by the 4.5×4.5mm mode on both eyes with SS-OCTA before and after mydriasis. Macular and peripapillary metrics, including retinal vessel density (VD) and fundus thickness were measured by the built-in program. Data of the right eye were analyzed. Results: The signal strength of the scans was comparable before and after mydriasis (all P>0.05). There were no significant differences in foveal avascular zone (FAZ) parameters and retinal VD of most sectors in both macular and peripapillary areas (all P>0.05). Choroidal thickness was decreased, outer and whole retinal thickness was increased in most of the macular sectors after mydriasis (all P<0.05). Choroidal thickness was decreased in all the peripapillary sectors, but whole retinal thickness and GCC thickness were increased in some peripapillary sectors after mydriasis (all P<0.05). Conclusions: FAZ parameters and retinal VD in the most macular and peripapillary regions are not affected by mydriasis. The thickness of the choroid is decreased after mydriasis, while the thickness of retinal layers in some sectors may be increased after mydriasis.

Clinical Evaluation of a New Spectral-Domain Optical Coherence Tomography-Based Biometer.

The VEMoS-AXL system is a new optical biometer based on spectral domain optical coherence tomography (SD-OCT) that has been tested in terms of intrasession repeatability and compared with a swept-source optical coherence tomography biometer (SS-OCT), which is recognized as the gold standard for the performance of an agreement analysis. A biometric analysis was performed three consecutive times in 120 healthy eyes of 120 patients aged between 18 and 40 years with the SD-OCT system, and afterwards, a single measurement was obtained with the SS-OCT system. Within-subject standard deviations were 0.004 mm, 4.394 µm, and 0.017 mm for axial length (AL), central corneal thickness (CCT), and anterior chamber depth (ACD) measures obtained with the SD-OCT biometer, respectively. The agreement between devices was good for AL (limits of agreement, LoA: -0.04 to 0.03 mm) and CCT (LoA: -4.36 to 14.38 µm), whereas differences between devices were clinically relevant for ACD (LoA: 0.03 to 0.21 mm). In conclusion, the VEMoS-AXL system provides consistent measures of anatomical parameters, being most of them interchangeable with those provided by the SS-OCT-based gold standard.

Evaluation of a new dynamic real-time visualization 25 kHz swept-source optical coherence tomography based biometer.

BACKGROUND: To evaluate the intraobserver repeatability and interobserver reproducibility of a newly developed dynamic real-time visualization 25 kHz swept-source optical coherence tomography (SS-OCT) based biometer (ZW-30, TowardPi Medical Technology Ltd, China) and compare its agreement with another SS-OCT based biometer (IOLMaster 700, Carl Zeiss Meditec AG, Jena, Germany). METHODS: Eighty-two healthy right eyes were enrolled in this prospective observational study. Measurements were repeated for three times using the ZW-30 and IOLMaster 700 in a random order. Obtained parameters included axial length (AL), central corneal thickness (CCT), aqueous depth (AQD), anterior chamber depth (ACD), lens thickness (LT), mean keratometry (Km), astigmatism magnitude (AST), vector J0, vector J45, and corneal diameter (CD). The within-subject standard deviation (Sw), test-retest (TRT) variability, coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were adopted to assess the intraobserver repeatability and interobserver reproducibility. The double-angle plot was also used to display the distribution of AST. To estimate agreement, Bland-Altman plots were used. RESULTS: For the intraobserver repeatability and interobserver reproducibility, the Sw, TRT and CoV for all parameters were low. Meanwhile, the ICC values were all close to 1.000, except for the J45 (ICC = 0.887 for the intraobserver repeatability). The double-angle plot showed that the distribution of AST measured by these two devices was similar. For agreement, the Bland-Altman plots showed narrow 95% limits of agreements (LoAs) for AL, CCT, AQD, ACD, LT, Km AST, J0, J45, and CD (- 0.02 mm to 0.02 mm, - 7.49 µm to 8.08 µm, - 0.07 mm to 0.04 mm, - 0.07 mm to 0.04 mm, - 0.07 mm to 0.08 mm, - 0.16 D to 0.30 D, - 0.30 D to 0.29 D, - 0.16 D to 0.16 D, - 0.23 D to 0.13 D, and - 0.39 mm to 0.10 mm, respectively). CONCLUSIONS: The newly dynamic real-time visualization biometer exhibited excellent intraobserver repeatability and interobserver reproducibility. The two devices both based on the SS-OCT principle had similar ocular parameters measurement values and can be interchanged in clinical practice.

Assessment of Schlemm's canal with swept-source optical coherence tomography in Graves' ophthalmopathy.

PURPOSE: To evaluate the Schlemm's canal (SC) parameters obtained by swept-source optical coherence tomography (OCT) different in Graves' ophthalmopathy (GO) eyes compared to healthy eyes. METHODS: This cross-sectional observational study evaluated 64 eyes of 32 GO cases and 56 eyes of 28 healthy controls. The study was conducted between October 2020 and June 2021. SC images were obtained from the temporal limbus of individuals using swept-source OCT. SC length (SCL) and SC area (SCA) were measured. The relationship between SC parameters in the patient group and intraocular pressure (IOP), retinal nerve fiber layer (RNFL) thickness, Graves' disease (GD) duration, and clinical activity score (CAS) was evaluated. RESULTS: In the GO group, 64 eyes of 32 patients were evaluated, and in the age and gender-matched healthy control group, 56 eyes of 28 individuals were assessed. SC images from 4 eyes of 4 patients in the patient group and 1 eye of 1 patient in the control group were not clear, preventing SCL and SCA measurements for these eyes. SCL and SCA measurements were found to be lower, and IOP and Hertel values were higher in the GO group compared to the healthy controls. However, no significant correlation was observed between SCL and SCA with IOP, RNFL thickness, GD duration, GO duration, or CAS in the GO group. In the GO group, the mean value of SCA was found to be higher in eyes with glaucoma or OHT compared to those without. CONCLUSION: These findings indicate that SC in GO-affected eyes is shorter and has a smaller area than in healthy individuals. Additionally, higher IOP and Hertel values were observed in the GO group compared to healthy controls. This study suggests that assessing SC using anterior segment OCT could provide valuable insights into the regulation of IOP and the development of glaucoma in GO-affected eyes.

Using choroidal thickness to detect myopic macular degeneration.

AIM: To explore the usage of choroidal thickness measured by swept-source optical coherence tomography (SS-OCT) to detect myopic macular degeneration (MMD) in high myopic participants. METHODS: Participants with bilateral high myopia (≤-6 diopters) were recruited from a subset of the Guangzhou Zhongshan Ophthalmic Center-Brien Holden Vision Institute High Myopia Cohort Study. SS-OCT was performed to determine the choroidal thickness, and myopic maculopathy was graded by the International Meta-Analysis for Pathologic Myopia (META-PM) Classification. Presence of MMD was defined as META-PM category 2 or above. RESULTS: A total of 568 right eyes were included for analysis. Eyes with MMD (n=106, 18.7%) were found to have older age, longer axial lengths (AL), higher myopic spherical equivalents (SE), and reduced choroidal thickness in each Early Treatment Diabetic Retinopathy Study (ETDRS) grid sector (P<0.001). The area under the receiver operating characteristic (ROC) curves (AUC) for subfoveal choroidal thickness (0.907) was greater than that of the model, including age, AL, and SE at 0.6249, 0.8208, and 0.8205, respectively. The choroidal thickness of the inner and outer nasal sectors was the most accurate indicator of MMD (AUC of 0.928 and 0.923, respectively). An outer nasal sector choroidal thickness of less than 74 µm demonstrated the highest odds of predicting MMD (OR=33.8). CONCLUSION: Choroidal thickness detects the presence of MMD with high agreement, particularly of the inner and outer nasal sectors of the posterior pole, which appears to be a biometric parameter more precise than age, AL, or SE.

Association of refractive outcome with postoperative anterior chamber depth measured with 3 optical biometers.

PURPOSE: This study evaluated the relationship between refractive outcomes and postoperative anterior chamber depth (ACD, measured from corneal epithelium to lens) measured by swept-source optical coherence tomography (SS-OCT), optical low-coherence reflectometry (OLCR), and Scheimpflug devices under the undilated pupil. METHODS: Patients undergoing cataract phacoemulsification with intraocular lens (IOL) implantation in a hospital setting were enrolled. Postoperative ACD (postACD) was performed with an SS-OCT device, an OLCR device, and a Scheimpflug device at least 1 month after cataract surgery. After adjusting the mean predicted error to 0, differences in refractive outcomes were calculated with the Olsen formula using actual postACD measured from 3 devices and predicted value. RESULTS: Overall, this comparative case study included 69 eyes of 69 patients, and postACD measurements were successfully taken using all 3 devices. The postACD measured with the SS-OCT, OLCR, and Scheimpflug devices was 4.59 ± 0.30, 4.50 ± 0.30, and 4.54 ± 0.32 mm, respectively. Statistically significant differences in postACD were found among 3 devices (P < 0.001), with intraclass correlation coefficients (ICCs) and Bland-Altman showing good agreement. No significant difference in median absolute error was found with the Olsen formula using actual postACD obtained with 3 devices. Percentage prediction errors were within ± 0.50 D in 65% (OLCR), 70% (Scheimpflug), and 67% (SS-OCT) calculated by actual postACD versus 64% by predicted value. CONCLUSION: Substantial agreement was found in postACD measurements obtained from the SS-OCT, OLCR, and Scheimpflug devices, with a trend toward comparable refractive outcomes in the Olsen formula. Meanwhile, postACD measurements may be potentially superior for the additional enhancement of refractive outcomes.

El espacio supracoroideo en pacientes afectados por retinosis pigmentaria / The suprachoroidal space in patients affected by retinitis pigmentosa

Antecedentes y objetivo: El espacio supracoroideo (SCS) es una estructura teórica que se sitúa entre el borde interno de la esclera y el límite externo del coroides. El SCS está siendo estudiado por sus posibles usos como vía para la administración de medicamentos y por técnicas quirúrgicas innovadoras para el tratamiento de muchas enfermedades retinianas. La retinitis pigmentosa (RP) es un grupo de trastornos hereditarios y progresivos caracterizados por el detrimento gradual de fotorreceptores que conduce a una discapacidad visual que se manifiesta típicamente como hemeralopía y pérdida progresiva del campo visual. El objetivo del estudio fue definir la morfología de los márgenes coroideos externos mediante el uso de tomografía de coherencia óptica de barrido (SS-OCT) en la RP.Materiales y métodosEstudio observacional retrospectivo diseñado para evaluar la presencia del ESC en la RP. Realizamos SS-OCT en un grupo de 55 pacientes afectados por RP (26 hombres y 29 mujeres, 110 ojos) con una edad media de 51,8±13,7 años. En el grupo de control incluimos a 28 sujetos sanos (6 hombres y 22 mujeres, 56 ojos) con una edad media de 48,8±16,6 años.ResultadosLas imágenes OCT permitieron delinear de manera precisa el margen coroideo externo y el margen escleral interno en los 110 ojos. En el grupo RP se detectó el ESC en 47 de los 110 ojos (42,7%), en el grupo de control se detectó el ESC en 11 ojos (19,6%).Los sujetos del grupo RP con SCS visibles presentaron un menor grosor retiniano (168,4 micrones) en comparación con aquellos con SCS visibles (211,2 micrones, p=0,007). (AU)

Background and objective: The suprachoroidal space (SCS) is a theoretical structure which can be demonstrated between the inner border of the sclera and the outer boundary of the choroid. SCS is being studied for its potential uses as a route for drug delivery and innovative surgical techniques for the treatment of many retinal diseases. Retinitis pigmentosa (RP) is a group of inherited eye disorders characterized by a gradual loss of photoreceptors, resulting in vision impairment, which typically presents as night blindness and progressive visual field loss. The purpose of the study is to define the morphology of outer choroidal margins by means of SS-OCT in RP.Material and methodThis is a retrospective observational study designed to evaluate the presence of SCS in RP. We performed swept source optical coherence tomography (SS-OCT) in a group of 55 patients affected by RP (26 males and 29 females, 110 eyes) with a mean age of 51.8±13.7 years. In the control group, we included 28 healthy subjects (6 males and 22 females, 56 eyes) with a mean age of 48.8±16.6 years.ResultsOCT scans allowed the outer choroidal margin and inner scleral margin to be delineated with certainty in all 110 eyes. In the RP group SCS was detected in 47 of 110 eyes (42.7%), in the control group SCS was detected in 11 eyes (19.6%).Subjects with SCS visible (RP group) had reduced retinal thickness (168.4μm) compared to those with not visible SCS (211.2μm, p=0.007). (AU)

Study of ischemic progression in different intestinal tissue layers during acute intestinal ischemia using swept-source optical coherence tomography angiography.

In acute intestinal ischemia, the progression of ischemia varies across different layers of intestinal tissue. We established a mouse model and used swept-source optical coherence tomography (OCT) to observe the intestinal ischemic process longitudinally in different tissue layers. Employing a method that combines asymmetric gradient filtering with adaptive weighting, we eliminated the vessel trailing phenomenon in OCT angiograms, reducing the confounding effects of superficial vessels on the imaging of deeper vasculature. We quantitatively assessed changes in vascular perfusion density (VPD), vessel length, and vessel average diameter across various intestinal layers. Our results showed a significant reduction in VPD in all layers during ischemia. The mucosa layer experienced the most significant impact, primarily due to disrupted capillary blood flow, followed by the submucosa layer, where vascular constriction or decreased velocity was the primary factor.

Comparison of Pre- and Post-DMEK Keratometry and Total Keratometry Values for IOL Power Calculations in Eyes Undergoing Triple DMEK.

PURPOSE: To evaluate prediction accuracy of pre- and post-DMEK keratometry (K) and total keratometry (TK) values for IOL power calculations in Fuchs endothelial corneal dystrophy (FECD) eyes undergoing DMEK with cataract surgery (triple DMEK). METHODS: Retrospective cross-sectional multicenter study of 55 FECD eyes (44 patients) that underwent triple DMEK between 2019 and 2022 between two centers in USA and Europe. Swept-source optical coherence tomography biometry (IOLMaster 700) was used for pre- and post-DMEK measurements. K and TK values were used for power calculations with ten formulae (Barrett Universal II (BUII), Castrop, Cooke K6, EVO 2.0, Haigis, Hoffer Q, Hoffer QST, Holladay I, Kane, and SRK/T). Mean error, mean absolute error (MAE), standard deviation, and percentage of eyes within ±0.50/±1.00 diopters (D) were calculated. Studied formulae were additionally adjusted using a method published previously (IOLup1D Method), which increases the IOL power by 1D. While both eyes from the same patient were considered for descriptive statistics, we restricted to one eye per individual (44 eyes for statistical comparisons. RESULTS: MAEs for all formulae were lower for post-DMEK K and TK than pre-DMEK K and TK by an average of 0.24 and 0.47 D, respectively. The lowest MAE was 0.49 D for Kane using post-DMEK TK, and the highest MAE was 1.05 D for BUII using pre-DMEK TK. Most IOLup1D formulae had lower MAEs than pre-DMEK K and TK formulae. CONCLUSIONS: The IOLup1D Method should be used instead of pre-DMEK K and TK values for triple DMEK in FECD eyes. Using post-DMEK TK values for cataract surgery after DMEK provides better refractive accuracy than any of the three studied methods used for triple DMEK procedures.