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Purpose: To describe optical coherence tomography angiography (OCTA)-guided navigated laser photocoagulation (LP) using the Navilas Laser System for treating retinal hemangioblastomas (RHs) associated with von Hippel-Lindau disease (VHLD). Methods: Patients with VHLD were screened using ophthalmoscopy and widefield OCTA. Detected RHs were classified with regard to tumor morphology (endophytic, sessile, exophytic, recurrent) and size. Then, 6 × 6- or 3 × 3-mm2 en face OCTA scans of the RHs were uploaded to the Navilas system, generating a merged image combining the scan and Navilas fundus photography. LP was planned by placing laser spots in the OCTA scan and executed with the Navilas system. Treatment efficacy was assessed by conducting OCTA scans immediately after LP and at follow-up visits. Results: Fifteen RHs were detected in 10 patients (median, one RH; range, one to four). Twelve RHs were treatment naive (exophytic [3], sessile [3], and endophytic [6]), and there were three recurrent RHs in pretreated areas. Total applied energy per tumor correlated with tumor size (P < 0.001). After a mean first follow-up of 3.6 ± 1.5 months (range, 0.9-5.3), nine RHs exhibited complete regression (60%), five partial regression (33.3%), and one no regression (6.7%). No correlation between tumor morphology and treatment success was observed (P = 0.32). However, a correlation between treatment success and tumor size trended toward significance (P = 0.08), with a 100% success rate observed for small RHs. Conclusions: OCTA-guided LP via the Navilas Laser System is a promising technique, especially beneficial for targeting small RHs. Combining OCTA and ophthalmoscopy improves tumor detection, underscoring the utility of this approach. Translational Relevance: OCTA-guided LP enables highly precise and safe treatment of early-stage RHs, minimizing possible complications caused by LP or the tumor itself.
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Hemangioblastoma , Coagulación con Láser , Neoplasias de la Retina , Tomografía de Coherencia Óptica , Enfermedad de von Hippel-Lindau , Humanos , Hemangioblastoma/cirugía , Hemangioblastoma/diagnóstico por imagen , Masculino , Femenino , Enfermedad de von Hippel-Lindau/complicaciones , Enfermedad de von Hippel-Lindau/cirugía , Coagulación con Láser/métodos , Adulto , Tomografía de Coherencia Óptica/métodos , Neoplasias de la Retina/cirugía , Neoplasias de la Retina/diagnóstico por imagen , Neoplasias de la Retina/patología , Persona de Mediana Edad , Angiografía con Fluoresceína/métodos , Adulto Joven , Resultado del Tratamiento , Cirugía Asistida por Computador/métodosRESUMEN
Purpose: Optical coherence tomography (OCT) representations in clinical practice are static and do not allow for a dynamic visualization and quantification of blood flow. This study aims to present a method to analyze retinal blood flow dynamics using time-resolved structural OCT. Methods: We developed novel imaging protocols to acquire video-rate time-resolved OCT B-scans (1024 × 496 pixels, 10 degrees field of view) at four different sensor integration times (integration time of 44.8 µs at a nominal A-scan rate of 20 kHz, 22.4 µs at 40 kHz, 11.2 µs at 85 kHz, and 7.24 µs at 125 kHz). The vessel centers were manually annotated for each B-scan and surrounding subvolumes were extracted. We used a velocity model based on signal-to-noise ratio (SNR) drops due to fringe washout to calculate blood flow velocity profiles in vessels within five optic disc diameters of the optic disc rim. Results: Time-resolved dynamic structural OCT revealed pulsatile SNR changes in the analyzed vessels and allowed the calculation of potential blood flow velocities at all integration times. Fringe washout was stronger in acquisitions with longer integration times; however, the ratio of the average SNR to the peak SNR inside the vessel was similar across all integration times. Conclusions: We demonstrated the feasibility of estimating blood flow profiles based on fringe washout analysis, showing pulsatile dynamics in vessels close to the optic nerve head using structural OCT. Time-resolved dynamic OCT has the potential to uncover valuable blood flow information in clinical settings.
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Flujo Sanguíneo Regional , Vasos Retinianos , Tomografía de Coherencia Óptica , Tomografía de Coherencia Óptica/métodos , Humanos , Vasos Retinianos/fisiología , Vasos Retinianos/diagnóstico por imagen , Velocidad del Flujo Sanguíneo/fisiología , Flujo Sanguíneo Regional/fisiología , Disco Óptico/irrigación sanguínea , Disco Óptico/diagnóstico por imagen , Relación Señal-Ruido , Masculino , Femenino , Adulto , Persona de Mediana EdadRESUMEN
Purpose: To evaluate early detection of retinal hemangioblastomas (RHs) in von Hippel-Lindau disease (VHLD) with widefield optical coherence tomography angiography (wOCTA) compared to the standard of care in ophthalmologic VHLD screening in a routine clinical setting. Methods: We conducted prospective comparisons of three screening methods: wOCTA, standard ophthalmoscopy, and fluorescein angiography (FA), which was performed only in uncertain cases. The numbers of detected RHs were compared among the three screening methods. The underlying causes for the lack of detection were investigated. Results: In 91 eyes (48 patients), 67 RHs were observed (mean, 0.74 ± 1.59 RH per eye). FA was performed in eight eyes. Ophthalmoscopy overlooked 25 of the 35 RHs detected by wOCTA (71.4%) due to the background color of the choroid (n = 5), small tumor size (n = 13), masking by a bright fundus reflex (n = 2), and masking by surrounding retinal scars (n = 5). However, wOCTA missed 29 RHs due to peripheral location (43.3%). The overall detection rates were up to 37% on the basis of ophthalmoscopy alone, up to 52% for wOCTA, and 89% for FA. Within the retinal area covered by wOCTA, the detection rates were up to 46.7% for ophthalmoscopy alone, up to 92.1% for wOCTA, and 73.3% for FA. Conclusions: The overall low detection rate of RHs using wOCTA is almost exclusively caused by its inability to visualize the entire peripheral retina. Therefore, in unclear cases, FA is necessary after ophthalmoscopy. Translational Relevance: Within the imageable retinal area, wOCTA shows a high detection rate of RHs and therefore may be suitable to improve screening for RHs in VHLD.
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Hemangioblastoma , Neoplasias de la Retina , Enfermedad de von Hippel-Lindau , Humanos , Tomografía de Coherencia Óptica/métodos , Enfermedad de von Hippel-Lindau/diagnóstico por imagen , Hemangioblastoma/diagnóstico por imagen , Neoplasias de la Retina/diagnóstico por imagen , Angiografía con Fluoresceína/métodosRESUMEN
Optical coherence tomography angiography (OCTA) enables three-dimensional reconstruction of the functional blood vessels in the retina. Therefore, it enables the quantification of 3D retinal vessel parameters such as surface area and vessel volume. In spite of the widespread use of OCTA, no representative volume-rendered vessel volume (VV) data are published to date. In this study, OCTA 3 × 3 mm macular cubes were processed with volume-rendering techniques to measure VV in 203 eyes from 107 healthy volunteers. Generalized linear models (GLM) were constructed to assess the impact of age, gender, visual acuity (VA), spherical equivalent (SE), and axial length (AL) on VV. Overall mean VV was 0.23 ± 0.05mm3. Age and axial length showed a negative correlation with VV. However, GLM model analysis found that AL exerted the most pronounced influence on VV. No statistically significant associations were identified between gender or between left and right eyes. This is the first study to assess 3D OCTA VV and its naturally occurring variations in a large series of healthy subjects. It offers novel insights into the characterization of normal retinal vascular anatomy in healthy individuals, contributing to a valuable reference for future research in this field.
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Vasos Retinianos , Tomografía de Coherencia Óptica , Humanos , Angiografía con Fluoresceína/métodos , Tomografía de Coherencia Óptica/métodos , Vasos Retinianos/diagnóstico por imagen , Retina/diagnóstico por imagen , Agudeza VisualRESUMEN
Supervised deep learning (DL) algorithms are highly dependent on training data for which human graders are assigned, for example, for optical coherence tomography (OCT) image annotation. Despite the tremendous success of DL, due to human judgment, these ground truth labels can be inaccurate and/or ambiguous and cause a human selection bias. We therefore investigated the impact of the size of the ground truth and variable numbers of graders on the predictive performance of the same DL architecture and repeated each experiment three times. The largest training dataset delivered a prediction performance close to that of human experts. All DL systems utilized were highly consistent. Nevertheless, the DL under-performers could not achieve any further autonomous improvement even after repeated training. Furthermore, a quantifiable linear relationship between ground truth ambiguity and the beneficial effect of having a larger amount of ground truth data was detected and marked as the more-ground-truth effect.
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Aprendizaje Profundo , Humanos , Tomografía de Coherencia Óptica/métodos , Sesgo de Selección , AlgoritmosRESUMEN
INTRODUCTION: The aim of this study was to describe the design and the participants' baseline characteristics of a prospective natural history study of geographic atrophy (GA) secondary to age-related macular degeneration. METHODS: The optical coherence tomography (OCT) and microperimetry biomarker evaluation in patients with GA (OMEGA) study was conducted at a tertiary referral center (ClinicalTrials.gov identifier: NCT05963646). Participants were followed for 12 months during 4 visits (baseline and follow-up exams at weeks 12, 24, and 48) with best-corrected Early Treatment of Diabetic Retinopathy Study visual acuity, low-luminance visual acuity (LLVA), and quick contrast sensitivity function testing. Further, participants underwent spectral-domain OCT, OCT angiography, fundus autofluorescence imaging, and mesopic microperimetry testing. RESULTS: Thirty participants (median [IQR] age of 79 [77, 84] years) and 37 study eyes were included with a (median [IQR]) GA area of 1.40 mm2 (0.49, 5.24) at baseline. Out of 37 study eyes, six developed macular neovascularizations (16%). The study-eye best-corrected visual acuity was (median [IQR]) 0.18 logarithm of the minimum angle of resolution (logMAR) (0.06, 0.26), LLVA 0.66 logMAR (0.36, 0.88), and the microperimetry mean sensitivity 18.4 dB (9.21, 20.9). The highest correlation between square root GA area and a visual function test was evident for LLVA (R2 of 0.578), followed by area under the log contrast sensitivity function curve (0.519) and microperimetral retinal sensitivity (0.487). CONCLUSION: This report lays out the design and baseline characteristics of the OMEGA study, which aims to contribute to the understanding of the natural history of GA. The OMEGA study will provide estimates of the ability to detect change and retest reliability for a panel of structure and functional assessments.
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Atrofia Geográfica , Humanos , Angiografía con Fluoresceína , Estudios de Seguimiento , Atrofia Geográfica/diagnóstico , Estudios Prospectivos , Reproducibilidad de los Resultados , Tomografía de Coherencia Óptica/métodos , Trastornos de la Visión , Pruebas del Campo Visual/métodos , Campos VisualesRESUMEN
This case report describes a laser-induced chorioretinal anastomosis in a 38-year-old woman with neurofibromatosis type 1.
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Neurofibromatosis 1 , Oclusión de la Vena Retiniana , Vena Retiniana , Humanos , Neurofibromatosis 1/diagnóstico , Neurofibromatosis 1/cirugía , Rayos Láser , Anastomosis Quirúrgica , Coroides/cirugíaRESUMEN
Vessel tortuosity (VT) is a parameter used to assess retinal involvement in patients affected by systemic diseases such as Fabry disease (FD). In this study, we assessed a retinal VT index (VTI) using optical coherence tomography angiography (OCTA) in a group of patients with FD (FD cohort) compared to a healthy control group (HC cohort). This is a single-center, retrospective study analysis of all consecutive patients with genetically tested and confirmed FD who underwent regular ophthalmological visits from December 2017 to January 2020 at the Department of Ophthalmology at the University Hospital of Zurich, Switzerland. VTI was calculated for each OCTA image and the results were compared between FD and HC cohort. A total of 56 participants, 32 (male:female ratio 12:20) in the FD cohort and 24 (male:female ratio 13:11) in the HC cohort. Classic onset was determined in 18 patients. Overall, mean VTI (±SD) was 0.21 (±0.07). Male patients with classic-onset FD had a significantly higher mean VTI (0.33, SD ± 0.35) compared to all other subgroups (p-value < 0.05). Further investigations of retinal VTI in patients with FD could be helpful to use OCTA as a noninvasive screening and follow-up modality to assess disease progression in affected patients.
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Currently, most medical image data, such as optical coherence tomography (OCT) images, are displayed in two dimensions on a computer screen. Advances in computer information technology have contributed to the growing storage of these data in electronic form. However, the data are usually processed only locally on site. To overcome such hurdles, a cyberspace virtual reality (csVR) application was validated, in which interactive OCT data were presented simultaneously to geographically distant sites (Lucerne, London, and Barcelona) where three graders independently measured the ocular csVR OCT diameters. A total of 109 objects were measured, each three times, resulting in a total of 327 csVR measurements. A minor mean absolute difference of 5.3 µm was found among the 3 measurements of an object (standard deviation 4.2 µm, coefficient of variation 0.3% with respect to the mean object size). Despite the 5 h of online work, csVR was well tolerated and safe. Digital high-resolution OCT data can be remotely and collaboratively processed in csVR. With csVR, measurements and actions enhanced with spatial audio communication can be made consistently in near real time, even if the users are situated geographically far apart. The proposed visuo-auditory framework has the potential to further boost the convenience of digital medicine toward csVR precision and collaborative medicine.
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Ojo , Tomografía de Coherencia Óptica , Tomografía de Coherencia Óptica/métodos , Internet , LondresRESUMEN
PURPOSE: To report the prevalence of late postoperative opacification of a hydrophilic and hydrophobic acrylic intraocular lens (IOL) and to assess the risk factors in a subset of 212 eyes of patients referred to the University Eye Department in Basel, Switzerland. DESIGN: Retrospective case series. METHODS: A survey was performed at all large ophthalmological clinics in Switzerland regarding exchanged Lentis LS-502-1 lenses, and the number of affected eyes was counted. Moreover, consecutive patients who were referred to a tertiary clinic between September 2015 and November 2016 with Lentis LS-502-1 opacification were investigated. Peri- and postoperative charts, medical history, and topical and systemic medications were assessed. RESULTS: A total of 674 opacified Lentis LS-502-1 lenses have been reported in Switzerland, and 212 consecutive eyes of 182 patients were included in the study. All IOLs had a similar pattern of opacification with a yellowish, diffuse appearance, and most of them showed a small, paracentral, roundish area that was less affected or not at all. Arterial hypertension (73%), hypercholesterolemia (34%), and diabetes (21%) were the main associated systemic diseases, and statins (34%) and betablockers (34%) were the main treatments used. CONCLUSIONS: The prevalence of IOL opacification was 9.9%. No associated systemic eye disease or medications could be detected, which was implicated in the opacification process. The reason for opacification remains unclear, but it seems to be unrelated to the patient's state; therefore, it is attributed to primary calcification.
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Opacificación Capsular , Lentes Intraoculares , Facoemulsificación , Humanos , Implantación de Lentes Intraoculares/efectos adversos , Estudios Retrospectivos , Suiza/epidemiología , Lentes Intraoculares/efectos adversos , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Factores de Riesgo , Opacificación Capsular/etiologíaRESUMEN
Cynomolgus monkeys (Macaca fascicularis) are commonly used in pre-clinical ocular studies. However, studies that report the morphological features of the macaque retina are based only on minimal sample sizes; therefore, little is known about the normal distribution and background variation. This study was conducted using optical coherence tomography (OCT) imaging to investigate the variations in retinal volumes of healthy cynomolgus monkeys and the effects of sex, origin, and eye side on the retinal volumes to establish a comprehensive reference database. A machine-learning algorithm was employed to segment the retina within the OCT data (i.e., generated pixel-wise labels). Furthermore, a classical computer vision algorithm has identified the deepest point in a foveolar depression. The retinal volumes were determined and analyzed based on this reference point and segmented retinal compartments. Notably, the overall foveolar mean volume in zone 1, which is the region of the sharpest vision, was 0.205 mm3 (range 0.154-0.268 mm3), with a relatively low coefficient of variation of 7.9%. Generally, retinal volumes exhibit a relatively low degree of variation. However, significant differences in the retinal volumes due to the monkey's origin were identified. Additionally, sex had a significant impact on the paracentral retinal volume. Therefore, the origin and sex of cynomolgus monkeys should be considered when evaluating the macaque retinal volumes based on this dataset.
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Aprendizaje Profundo , Tomografía de Coherencia Óptica , Animales , Macaca fascicularis , Tomografía de Coherencia Óptica/métodos , Retina/diagnóstico por imagen , AlgoritmosRESUMEN
Ophthalmology faces many challenges in providing effective and meaningful eye care to an ever-increasing group of people. Even health systems that have so far been able to cope with the quantitative patient increase, due to their funding and the availability of highly qualified professionals, and improvements in practice routine efficiency, will be pushed to their limits. Further pressure on care will also be caused by new active substances for the largest group of patients with AMD, the so-called dry form. Treatment availability for this so far untreated group will increase the volume of patients 2-3 times. Without the adaptation of the care structures, this quantitative and qualitative expansion in therapy will inevitably lead to an undersupply.There is increasing scientific evidence that significant efficiency gains in the care of chronic diseases can be achieved through better networking of stakeholders in the healthcare system and greater patient involvement. Digitalization can make an important contribution here. Many technological solutions have been developed in recent years and the time is now ready to exploit this potential. The exceptional setting during the SARS-CoV-2 pandemic has shown many that new technology is available safely, quickly, and effectively. The emergency has catalyzed innovation processes and shown for post-pandemic time after that we are equipped to tackle the challenges in ophthalmic healthcare - ultimately for the benefit of patients and society.
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COVID-19 , Oftalmología , Humanos , SARS-CoV-2 , Atención a la Salud , PacientesRESUMEN
Purpose: To analyze natural variability in pupillary contractility with dynamic volume-rendered optical coherence tomography (OCT) pupillometry regarding iris color, age, and sex in healthy Caucasian participants. Methods: The intrapupillary spaces (IPSs) derived from anterior segment swept-source OCT of 71 healthy eyes were retrospectively analyzed. Baseline scotopic and photopic volumes and the functional parameters of pupillary ejection fraction (PEF), three-dimensional (3D) contractility, and relative light response (RLR) were measured on the swept-source OCT volumes. The effect on these parameters of iris color (brown, green, and blue), age, and sex was assessed. Results: More pigmented irises were more contractile than less pigmented irises. Iris color significantly affected scotopic baseline IPSs (brown, 10.39 ± 4.86 mm3; green, 9.68 ± 3.31 mm3; blue, 6.75 ± 4.27 mm3; P = 0.018), PEF (brown, 90.8% ± 2.7%; green, 89.1% ± 2.5%; blue, 85.0% ± 9.3%; P = 0.010), 3D contractility (brown, 9.52 ± 4.59 mm3; green, 8.66 ± 3.07 mm3; blue, 6.44 ± 4.87 mm3; P = 0.016), and RLR (brown, 11.90 ± 4.03; green, 9.75 ± 2.73; blue, 8.52 ± 3.88; P = 0.026). Absolute scotopic volume (P = 0.022) and 3D contractility (P = 0.024) decreased with age. Sex showed no correlations. Conclusions: The natural variability of pupillary contractility can be analyzed with dynamic OCT pupillometry. Iris color and age can impact pupillary response with this method. Translational Relevance: Iris contractility parameters can be measured using a commercially available OCT system, allowing for quantification of the aqueous humor volume inside the pupil.
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Visión de Colores , Tomografía de Coherencia Óptica , Humanos , Tomografía de Coherencia Óptica/métodos , Estudios Retrospectivos , Iris/diagnóstico por imagen , Pupila/fisiologíaRESUMEN
Deep optic disc drusen (ODD) are located below Bruch's membrane opening (BMO) and may go undetected due to the challenges in imaging them. The purpose of this study is a head-to-head comparison of currently widely used imaging technologies: swept-source optical coherence tomography (SS-OCT; DRI OCT-1 Triton, Topcon) and enhanced depth imaging spectral-domain optical coherence tomography (EDI SD-OCT; Spectralis OCT, Heidelberg Engineering) for the detection of deep ODD and associated imaging features. The eyes included in this study had undergone high-resolution imaging via both EDI SD-OCT and SS-OCT volume scans, which showed at least one deep ODD or a hyperreflective line (HL). Grading was performed by three graders in a masked fashion. The study findings are based on 46 B-scan stacks of 23 eyes including a total of 7981 scans. For scan images with ODD located above or below the level of BMO, no significant difference was found between the two modalities compared in this study. However, for HLs and other features, EDI SD-OCT scan images had better visualization and less artifacts. Although SS-OCT offers deep tissue visualization, it did not appear to offer any advantage in ODD detection over a dense volume scan via EDI SD-OCT with B-scan averaging.
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Purpose: To evaluate the feasibility of automated segmentation of pigmented choroidal lesions (PCLs) in optical coherence tomography (OCT) data and compare the performance of different deep neural networks. Methods: Swept-source OCT image volumes were annotated pixel-wise for PCLs and background. Three deep neural network architectures were applied to the data: the multi-dimensional gated recurrent units (MD-GRU), the V-Net, and the nnU-Net. The nnU-Net was used to compare the performance of two-dimensional (2D) versus three-dimensional (3D) predictions. Results: A total of 121 OCT volumes were analyzed (100 normal and 21 PCLs). Automated PCL segmentations were successful with all neural networks. The 3D nnU-Net predictions showed the highest recall with a mean of 0.77 ± 0.22 (MD-GRU, 0.60 ± 0.31; V-Net, 0.61 ± 0.25). The 3D nnU-Net predicted PCLs with a Dice coefficient of 0.78 ± 0.13, outperforming MD-GRU (0.62 ± 0.23) and V-Net (0.59 ± 0.24). The smallest distance to the manual annotation was found using 3D nnU-Net with a mean maximum Hausdorff distance of 315 ± 172 µm (MD-GRU, 1542 ± 1169 µm; V-Net, 2408 ± 1060 µm). The 3D nnU-Net showed a superior performance compared with stacked 2D predictions. Conclusions: The feasibility of automated deep learning segmentation of PCLs was demonstrated in OCT data. The neural network architecture had a relevant impact on PCL predictions. Translational Relevance: This work serves as proof of concept for segmentations of choroidal pathologies in volumetric OCT data; improvements are conceivable to meet clinical demands for the diagnosis, monitoring, and treatment evaluation of PCLs.
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Aprendizaje Profundo , Tomografía de Coherencia Óptica , Coroides/diagnóstico por imagen , Estudios de Factibilidad , Redes Neurales de la Computación , Tomografía de Coherencia Óptica/métodosRESUMEN
We aimed to test for feasibility of volume-rendered optical coherence tomography angiography (OCTA) as a novel method for assessing/quantifying retinal vasculature during ocular procedures and to explore the potential for intraoperative use. Thirty patients undergoing periocular anaesthesia were enrolled, since published evidence suggests a reduction in ocular blood flow. Retinal perfusion was monitored based on planar OCTA image-derived data provided by a standard quantification algorithm and postprocessed/volume-rendered OCTA data using a custom software script. Overall, imaging procedures were successful, yet imaging artifacts occurred frequently. In interventional eyes, perfusion parameters decreased during anaesthesia. Planar image-derived and volume rendering-derived parameters were correlated. No correlation was found between perfusion parameters and a motion artifact score developed for this study, yet all perfusion parameters correlated with signal strength as displayed by the device. Concluding, volume-rendered OCTA allows for noninvasive three-dimensional retinal vasculature assessment/quantification in challenging surgical settings and appears generally feasible for intraoperative use.
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Retina , Tomografía de Coherencia Óptica , Humanos , Angiografía con Fluoresceína/métodos , Tomografía de Coherencia Óptica/métodos , Retina/diagnóstico por imagen , Retina/cirugía , Vasos Retinianos/diagnóstico por imagen , PerfusiónRESUMEN
This study aimed to provide volumetric choroidal readings regarding sex, origin, and eye side from healthy cynomolgus monkey eyes as a reference database using optical coherence tomography (OCT) imaging. A machine learning (ML) algorithm was used to extract the choroid from the volumetric OCT data. Classical computer vision methods were then applied to automatically identify the deepest location in the foveolar depression. The choroidal thickness was determined from this reference point. A total of 374 eyes of 203 cynomolgus macaques from Asian and Mauritius origin were included in the analysis. The overall subfoveolar mean choroidal volume in zone 1, in the region of the central bouquet, was 0.156 mm3 (range, 0.131-0.193 mm3). For the central choroid volume, the coefficient of variation (CV) was found of 6.3%, indicating relatively little variation. Our results show, based on analyses of variance, that monkey origin (Asian or Mauritius) does not influence choroid volumes. Sex had a significant influence on choroidal volumes in the superior-inferior axis (p ≤ 0.01), but not in the fovea centralis. A homogeneous foveolar choroidal architecture was also observed.
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Coroides , Tomografía de Coherencia Óptica , Algoritmos , Animales , Coroides/diagnóstico por imagen , Macaca fascicularis , Aprendizaje Automático , Tomografía de Coherencia Óptica/métodosRESUMEN
Cynomolgus monkeys exhibit human-like features, such as a fovea, so they are often used in non-clinical research. Nevertheless, little is known about the natural variation of the choroidal thickness in relation to origin and sex. A combination of deep learning and a deterministic computer vision algorithm was applied for automatic segmentation of foveolar optical coherence tomography images in cynomolgus monkeys. The main evaluation parameters were choroidal thickness and surface area directed from the deepest point on OCT images within the fovea, marked as the nulla with regard to sex and origin. Reference choroid landmarks were set underneath the nulla and at 500 µm intervals laterally up to a distance of 2000 µm nasally and temporally, complemented by a sub-analysis of the central bouquet of cones. 203 animals contributed 374 eyes for a reference choroid database. The overall average central choroidal thickness was 193 µm with a coefficient of variation of 7.8%, and the overall mean surface area of the central bouquet temporally was 19,335 µm2 and nasally was 19,283 µm2. The choroidal thickness of the fovea appears relatively homogeneous between the sexes and the studied origins. However, considerable natural variation has been observed, which needs to be appreciated.
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Aprendizaje Profundo , Tomografía de Coherencia Óptica , Animales , Coroides/diagnóstico por imagen , Fóvea Central/diagnóstico por imagen , Humanos , Macaca fascicularis , Tomografía de Coherencia Óptica/métodosRESUMEN
PURPOSE: To evaluate the anatomic changes in the vitreous associated with evolving posterior vitreous detachment over the macula. METHODS: A novel scanning method by which four A-scans at each position were averaged before the Fourier transform that boosted the image quality sufficiently such that frame averaging could occur. B-scans and volume rendered images of eyes with evidence of any partial separation of the vitreous in the macular regions were evaluated. RESULTS: There were 43 eyes of 23 subjects with particular attention paid to the findings of seven eyes with various stages of posterior vitreous detachment occurring over the macula. In eyes from young subjects with no vitreous degeneration, the outer vitreous showed a diffuse, poorly defined increase in reflectivity in the region where the vitreous cortex was expected to be. In eyes with vitreous degeneration, there was a hyperreflective zone, called the cortical vitreous condensation, that coursed parallel to the curvature of the retina. The posterior vitreous face elevated from the retina with either a well-defined, smooth outer surface, consistent with the posterior vitreous membrane, or a poorly defined flocculent outer border. The cortical vitreous near the fovea was thin and in eyes in the process of posterior vitreous detachment had visible tears. In more advanced eyes, a circular dehiscence of the cortical vitreous in the central macula occurred with herniation of the vitreous gel through the hole. CONCLUSION: The methodology produced images of unprecedented clarity that highlighted several newly described details concerning the vitreous changes associated with posterior vitreous detachment over the macula.
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Mácula Lútea , Desprendimiento del Vítreo , Fóvea Central , Humanos , Tomografía de Coherencia Óptica/métodos , Trastornos de la Visión , Cuerpo Vítreo/diagnóstico por imagen , Desprendimiento del Vítreo/complicaciones , Desprendimiento del Vítreo/diagnóstico por imagenRESUMEN
PURPOSE: To evaluate the degenerative findings including cistern formation in the premacular vitreous using optical coherence tomography. METHODS: A novel enhanced vitreous imaging method by which four A-scans at each position were averaged before the Fourier transform increased the image quality per frame so that subsequent image registration for averaging could occur. Analysis of B-scans and volume-rendered images of eyes in subjects of various ages was performed. RESULTS: There were 43 eyes of 23 subjects ranging in age from 23 to 68 years. The texture in the vitreous images suggests specific orientations of the vitreous fibers in the macular region; there were fibers circumferential to the retina immediately anterior to the premacular bursa. The pattern of the vitreous fibers seemed less well-defined internal to the zone of circumferential fibers. In younger eyes, there were striations oriented in a roughly inferior to superior direction in this zone. In older eyes, there were striations in the same orientation but actually were alternating zones of vitreous synchysis and syneresis. In these same eyes, numerous cisterns appeared at various levels in the vitreous gel. With extensive vitreous condensation and synchysis, definition of the premacular bursa was lost. CONCLUSION: With this novel method of enhanced vitreous imaging, the vitreous seemed to have stereotypic patterns of degeneration. The formation of vitreous syneresis and synchysis may be related to organization architecture of the vitreous, including the pattern of vitreous collagen deposition, and the effects of eye motion through decades of time.