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BACKGROUND: Optic disc drusen (ODD) represent an important differential diagnosis of papilledema caused by intracranial hypertension, but their distinction may be difficult in clinical practice. The aim of this study was to train, validate, and test a dedicated deep learning system (DLS) for binary classification of ODD vs papilledema (including various subgroups within each category), on conventional mydriatic digital ocular fundus photographs collected in a large international multiethnic population. METHODS: This retrospective study included 4,508 color fundus images in 2,180 patients from 30 neuro-ophthalmology centers (19 countries) participating in the Brain and Optic Nerve Study with Artificial Intelligence (BONSAI) Group. For training and internal validation, we used 857 ODD images and 3,230 papilledema images, in 1,959 patients. External testing was performed on an independent data set (221 patients), including 207 images with ODD (96 visible and 111 buried), provided by 3 centers of the Optic Disc Drusen Studies Consortium, and 214 images of papilledema (92 mild-to-moderate and 122 severe) from a previously validated study. RESULTS: The DLS could accurately distinguish between all ODD and papilledema (all severities included): area under the receiver operating characteristic curve (AUC) 0.97 (95% confidence interval [CI], 0.96-0.98), accuracy 90.5% (95% CI, 88.0%-92.9%), sensitivity 86.0% (95% CI, 82.1%-90.1%), and specificity 94.9% (95% CI, 92.3%-97.6%). The performance of the DLS remained high for discrimination of buried ODD from mild-to-moderate papilledema: AUC 0.93 (95% CI, 0.90-0.96), accuracy 84.2% (95% CI, 80.2%-88.6%), sensitivity 78.4% (95% CI, 72.2%-84.7%), and specificity 91.3% (95% CI, 87.0%-96.4%). CONCLUSIONS: A dedicated DLS can accurately distinguish between ODD and papilledema caused by intracranial hypertension, even when considering buried ODD vs mild-to-moderate papilledema.
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PURPOSE: To study the associations between optic nerve head (ONH) strains under intraocular pressure (IOP) elevation with retinal sensitivity in patients with glaucoma. DESIGN: Clinic-based cross-sectional study. PARTICIPANTS: Two hundred twenty-nine patients with primary open-angle glaucoma (subdivided into 115 patients with high-tension glaucoma [HTG] and 114 patients with normal-tension glaucoma [NTG]). METHODS: For 1 eye of each patient, we imaged the ONH using spectral-domain OCT under the following conditions: (1) primary gaze and (2) primary gaze with acute IOP elevation (to approximately 35 mmHg) achieved through ophthalmodynamometry. A 3-dimensional strain-mapping algorithm was applied to quantify IOP-induced ONH tissue strain (i.e., deformation) in each ONH. Strains in the prelaminar tissue (PLT), the retina, the choroid, the sclera, and the lamina cribrosa (LC) were associated (using linear regression) with measures of retinal sensitivity from the 24-2 Humphrey visual field test (Carl Zeiss Meditec). This was performed globally, then locally according to a previously published regionalization scheme. MAIN OUTCOME MEASURES: Associations between ONH strains and values of retinal sensitivity from visual field testing. RESULTS: For patients with HTG, we found (1) significant negative linear associations between ONH strains and retinal sensitivity (P < 0.001; on average, a 1% increase in ONH strains corresponded to a decrease in retinal sensitivity of 1.1 decibels [dB]), (2) that high-strain regions colocalized with anatomically mapped regions of high visual field loss, and (3) that the strongest negative associations were observed in the superior region and in the PLT. In contrast, for patients with NTG, no significant associations between strains and retinal sensitivity were observed except in the superotemporal region of the LC. CONCLUSIONS: We found significant negative associations between IOP-induced ONH strains and retinal sensitivity in a relatively large glaucoma cohort. Specifically, patients with HTG who experienced higher ONH strains were more likely to exhibit lower retinal sensitivities. Interestingly, this trend in general was less pronounced in patients with NTG, which could suggest a distinct pathophysiologic relationship between the two glaucoma subtypes.
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Glaucoma de Ângulo Aberto , Glaucoma , Glaucoma de Baixa Tensão , Disco Óptico , Humanos , Testes de Campo Visual , Campos Visuais , Estudos Transversais , Tomografia de Coerência Óptica/métodos , Glaucoma de Baixa Tensão/diagnóstico , Pressão Intraocular , Transtornos da VisãoRESUMO
OBJECTIVES: To report the processes used to design and implement an assessment tool to inform funding decisions for competing health innovations in a tertiary hospital. METHODS: We designed an assessment tool for health innovation proposals with three components: "value to the institution," "novelty," and "potential for adoption and scaling." The "value to the institution" component consisted of twelve weighted value attributes identified from the host institution's annual report; weights were allocated based on a survey of the hospital's leaders. The second and third components consisted of open-ended questions on "novelty" and "barriers to implementation" to support further dialogue. Purposive literature review was performed independently by two researchers for each assessment. The assessment tool was piloted during an institutional health innovation funding cycle. RESULTS: We used 17 days to evaluate ten proposals. The completed assessments were shared with an independent group of panellists, who selected five projects for funding. Proposals with the lowest scores for "value to the institution" had less perceived impact on the patient-related value attributes of "access," "patient centeredness," "health outcomes," "prevention," and "safety." Similar innovations were reported in literature in seven proposals; potential barriers to implementation were identified in six proposals. We included a worked example to illustrate the assessment process. CONCLUSIONS: We developed an assessment tool that is aligned with local institutional priorities. Our tool can augment the decision-making process when funding health innovation projects. The tool can be adapted by others facing similar challenges of trying to choose the best health innovations to fund.
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Centros Médicos Acadêmicos , Humanos , Inquéritos e QuestionáriosRESUMO
PURPOSE: To compare regional variations in lamina cribrosa (LC) curvature and depth between healthy eyes (group 1) and naïve eyes with primary open-angle glaucoma (POAG) having superior (group 2), inferior (group 3), and both (group 4) hemifield retinal nerve fiber layer (RNFL) defects. DESIGN: Cross-sectional study. PARTICIPANTS: Each group consisted of 39 eyes of 39 Korean patients who were matched for age, sex, and axial length. METHODS: The LC curvature index (LCCI) and LC depth (LCD) were measured in B-scan images obtained using enhanced depth imaging OCT at 7 locations spaced equidistantly across the vertical optic disc diameter. Superior and inferior LCCI and LCD were compared by calculating the superior-to-inferior (Sup/Inf) ratios. MAIN OUTCOME MEASURES: Comparisons of LCCI, LCD, and Sup/Inf ratio among the 4 groups. RESULTS: Compared with healthy eyes (group 1), LCCIs were larger at the superior and middle planes in group 2, at the inferior and middle planes in group 3, and at all planes in group 4 (P ≤ 0.003). The LCD showed similar results, but there was no difference in superior planes between groups 1 and 2. The Sup/Inf ratio of LCCI differed significantly between groups 1 (1.03) and 2 (1.20), groups 1 and 3 (0.79), groups 2 and 3, groups 2 and 4 (0.96), and groups 3 and 4 (all P < 0.001), but not between groups 1 and 4 (P = 0.273). The Sup/Inf ratio of LCD differed only between groups 2 and 3 (P = 0.002). CONCLUSIONS: Eyes with POAG showed regional differences in LC morphology, corresponding with the location of RNFL defects. The regional variations in LCCI suggest that LC morphology in POAG would be better assessed on a regional basis than by a global index.
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Glaucoma de Ângulo Aberto/diagnóstico , Pressão Intraocular/fisiologia , Disco Óptico/patologia , Doenças do Nervo Óptico/diagnóstico , Tomografia de Coerência Óptica/métodos , Campos Visuais/fisiologia , Estudos Transversais , Progressão da Doença , Feminino , Seguimentos , Glaucoma de Ângulo Aberto/complicações , Glaucoma de Ângulo Aberto/epidemiologia , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Fibras Nervosas/patologia , Doenças do Nervo Óptico/epidemiologia , Doenças do Nervo Óptico/etiologia , Estudos Prospectivos , República da Coreia/epidemiologia , Microscopia com Lâmpada de Fenda , UltrassonografiaRESUMO
Current literature has not considered or provided any data on the permeability of the iris stroma. In this study, we aimed to determine the hydraulic permeability of porcine irides from the isolated stroma. Fifteen enucleated porcine eyes were acquired from the local abattoir. The iris pigment epithelium was scraped off using a pair of forceps and the dilator muscles were pinched off using a pair of colibri toothed forceps. We designed an experimental setup, based on Darcy's law, and consisting of a custom 3D-printed pressure column using acrylonitrile butadiene styrene (ABS) plastic. PBS solution was passed through the iris stroma in a 180° arc shape, with a column height of approximately 204â¯mm (2000â¯Pa). Measurements of iris stromal thickness were conducted using optical coherence tomography (OCT). To measure flow rate, we measured the mass (volume) of PBS solution using a mass balance in approximately 1â¯min. Histology was performed using hematoxylin and eosin (H&E) and anti-smooth muscle antibody (anti-α-SMA) for validation. The permeability experiments demonstrated that the iris stroma is a biphasic tissue that allows fluid flow. Our image processing results determined the area of flow to be 7.55â¯mm2 and the tissue thickness to be between 180 and 430⯵m. The hydraulic permeability of the porcine stroma, calculated using Darcy's law, was 5.13⯱â¯2.39â¯×â¯10-5â¯mm2/Paâ¢s. Histological and immunochemical studies confirmed that the tissues used for this permeability study were solely iris stroma. Additionally, anti-α-SMA staining revealed staining specific for stromal blood vessels, with the notable absence of dilator and sphincter muscle staining. Our study combined experimental microscopic data with the theory of biphasic materials to investigate the hydraulic permeability of the iris stroma. This work will serve as a basis on which to validate future biomechanical studies of human irides with which may ultimately aid disease diagnosis and inform the design of novel treatments.
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Permeabilidade da Membrana Celular/fisiologia , Iris/metabolismo , Células Estromais/metabolismo , Animais , Iris/citologia , Modelos Animais , Células Estromais/citologia , Suínos , Tomografia de Coerência ÓpticaRESUMO
BACKGROUND: Attenuation-compensated (AC) technique was recently introduced to improve the plaque characterization of optical coherence tomography (OCT). Histological validation demonstrated promising results but the efficacy and reproducibility of this technique for assessing in-vivo tissue composition remains unclear.MethodsâandâResults:OCT images portraying native (n=200) and stented (n=200) segments and 31 histological cross-sections were analyzed. AC-OCT appeared superior to conventional (C)-OCT in detecting the external elastic lamina (EEM) borders (76% vs. 65.5%); AC-OCT enabled larger EEM arc detection compared with C-OCT (174.2±58.7° vs. 137.5±57.9°; P<0.001). There was poor agreement between the 2 techniques for detection of lipid in native and lipid and calcific tissue in stented segments (κ range: 0.164-0.466) but the agreement of C-OCT and AC-OCT was high for calcific tissue in native segments (κ=0.825). Intra and interobserver agreement of the 2 analysts was moderate to excellent with C-OCT (κ range: 0.681-0.979) and AC-OCT (κ range: 0.733-0.892) for all tissue types in both native and stented segments. Ex-vivoanalysis demonstrated that C-OCT was superior to AC-OCT (κ=0.545 vs. κ=0.296) for the detection of the lipid component in native segments. CONCLUSIONS: The AC technique allows better delineation of the EEM but it remains inferior for lipid pool detection and neointima characterization. Combined AC- and C-OCT imaging may provide additional value for complete assessment of plaque and neointima characteristics.
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Doença da Artéria Coronariana , Vasos Coronários , Placa Aterosclerótica , Tomografia de Coerência Óptica , Idoso , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/metabolismo , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/metabolismoRESUMO
Purpose: We aimed to characterize any bulk changes in posterior scleral collagen fibril bundle architecture in human eyes with high myopia. Methods: Wide-angle X-ray scattering (WAXS) was employed to map collagen orientation at 0.5 mm × 0.5 mm spatial intervals across the posterior sclera of seven non-myopic human eyes and three eyes with high myopia (>6D of refractive error). At each sampled point, WAXS provided thickness-averaged measures of the angular distribution of preferentially aligned collagen fibrils within the tissue plane and the anisotropic proportion (the ratio of preferentially aligned to total collagen scatter). Results: Non-myopic specimens featured well-conserved microstructural features, including strong uniaxial collagen alignment along the extraocular muscle insertion sites of the mid-posterior sclera and a highly anisotropic annulus of collagen circumscribing the nerve head in the peripapillary sclera. All three myopic specimens exhibited notable alterations in the peripapillary sclera, including a partial loss of circumferential collagen alignment and a redistribution of the normally observed regional pattern of collagen anisotropic proportion. Linear mixed-model analysis indicated that the mean fiber angle deviation from the circumferential orientation in the peripapillary sclera of highly myopic eyes (23.9° ± 18.2) was statistically significantly higher than that of controls (17.9° ± 12.0; p<0.05). Conclusions: Bulk alterations in the normal posterior scleral collagen microstructure occur in human eyes with high myopia. These changes could reflect remodeling of the posterior sclera during axial lengthening and/or a mechanical adaption to tissue stresses induced by fluid pressure or eye movements that may be exacerbated in enlarged eyes.
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Colágeno/ultraestrutura , Miopia/patologia , Esclera/ultraestrutura , Anisotropia , Autopsia , Estudos de Casos e Controles , Colágeno/química , Humanos , Miopia/diagnóstico por imagem , Espalhamento de Radiação , Esclera/diagnóstico por imagem , Esclera/patologia , Raios XRESUMO
PURPOSE: To evaluate changes in lamina cribrosa (LC) shape, curvature, and depth after trabeculectomy. DESIGN: Prospective, observational case series. PARTICIPANTS: A total of 112 patients (118 eyes) with open- or closed-angle glaucoma undergoing trabeculectomy. METHODS: The optic nerve head was imaged using enhanced depth imaging spectral-domain OCT before trabeculectomy and at 6 follow-up visits throughout the first postoperative year. The anterior LC surface and Bruch's membrane opening were marked in the serial horizontal B scans for the analysis of LC parameters using Morphology 1.0 software. Postoperative morphologic LC changes were assessed. MAIN OUTCOME MEASURES: The postoperative LC global shape index (GSI), nasal-temporal (N-T) and superior-inferior (S-I) curvatures, and mean and sectoral LC depth (LCD). RESULTS: The mean LC GSI increased only during the early postoperative period (P = 0.02), resulting in a change toward the saddle-rut shape. There was a flattening of the LC curvature in N-T (P < 0.001) and S-I (P = 0.003) meridians 12 months after trabeculectomy. A shallowing of the mean and sectoral LCD from baseline was significant throughout the entire follow-up period (P < 0.001) and progressed up to postoperative month 6. Twenty-eight patients showed a deepening of the LC from baseline in at least 1 visit. Eyes with shallower LCD compared with baseline responded to intraocular pressure (IOP) reduction with greater movement anteriorly than eyes with deeper LCD (P = 0.002). Greater IOP reduction (P = 0.007), less retinal nerve fiber layer thinning over the year (P = 0.003), and more superiorly-inferiorly curved baseline LC (P = 0.001) were associated with an increase in GSI. Younger age and IOP reduction were related to LC shallowing (P < 0.001, P = 0.002) and N-T flattening (P < 0.001). CONCLUSIONS: In most eyes, trabeculectomy resulted in long-term flattening and shallowing of the LC. However, in some eyes, LC deepened from baseline. Change in LC global shape appeared to be temporal. Reduction in IOP plays an important role in the early phase of LC change; however, in the later phase, LC remodeling may play a crucial role in view of stable IOP.
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Glaucoma de Ângulo Fechado/cirurgia , Glaucoma de Ângulo Aberto/cirurgia , Disco Óptico/patologia , Doenças do Nervo Óptico/diagnóstico , Trabeculectomia/métodos , Idoso , Feminino , Seguimentos , Glaucoma de Ângulo Fechado/diagnóstico por imagem , Glaucoma de Ângulo Aberto/diagnóstico por imagem , Humanos , Pressão Intraocular/fisiologia , Masculino , Pessoa de Meia-Idade , Fibras Nervosas/patologia , Disco Óptico/diagnóstico por imagem , Doenças do Nervo Óptico/fisiopatologia , Período Pós-Operatório , Estudos Prospectivos , Células Ganglionares da Retina/patologia , Tonometria Ocular , Acuidade Visual/fisiologia , Testes de Campo Visual , Campos Visuais/fisiologiaRESUMO
PURPOSE: To investigate the relationship between the degree of posterior bowing of the lamina cribrosa (LC) at baseline and the rate of subsequent visual field (VF) progression in eyes with primary open-angle glaucoma (POAG). DESIGN: Prospective, observational study. PARTICIPANTS: One hundred one early-stage (VF mean deviation [MD], -5.0 to -0.01 dB) POAG eyes that met the following conditions: (1) follow-up longer than 3.5 years, (2) more than 5 reliable standard automated perimetry tests, and (3) medically well-controlled intraocular pressure during follow-up. METHODS: All participants underwent swept-source OCT scanning of the LC at baseline. The area enclosed by a vertical line at the anterior laminar insertion, anterior LC plane, and reference plane of Bruch's membrane opening (BMO) was divided by D (distance between the 2 cross-points made by vertical lines drawn from the anterior laminar insertion to the reference plane of BMO) to approximate the LC depth (LCD). The difference between the LCD and mean anterior laminar insertion depth was defined as the LC curvature index (LCCI). To consider the steepness of the LC curve, the adjusted LCCI (aLCCI) was calculated as LCCI divided by D and multiplied by 100. The mean LCD (mLCD), mean LCCI (mLCCI), and mean aLCCI (maLCCI) were computed by averaging the measurements on 12 radial scans. The subsequent MD slope and associated factors were analyzed. MAIN OUTCOME MEASURES: Lamina cribrosa parameters and subsequent MD slope. RESULTS: The participants' mean baseline MD was -3.8 ± 3.4 dB. The mean baseline mLCD, mLCCI, and maLCCI were 419.0 ± 111.2 µm, 76.4 ± 29.0 µm, and 4.8 ± 1.9, respectively. A greater MD slope was associated with a greater baseline maLCCI (P < 0.001). We found a statistically significant breakpoint for the maLCCI (4.12) above which a larger maLCCI showed a steeper MD slope (P < 0.001). Analysis by age revealed that significantly more VF progression with maLCCI changes occurred in the relatively younger group (≤69 years; P = 0.043). CONCLUSIONS: The baseline maLCCI showed a significant correlation with the rate of subsequent VF deterioration. This suggests that, in POAG eyes with greater posterior bowing of the LC, the axons of retinal ganglion cells may be more vulnerable to further glaucomatous injury.
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Glaucoma de Ângulo Aberto/diagnóstico , Disco Óptico/patologia , Transtornos da Visão/diagnóstico , Campos Visuais/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Axônios/patologia , Progressão da Doença , Feminino , Humanos , Pressão Intraocular/fisiologia , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Células Ganglionares da Retina/patologia , Tonometria Ocular , Transtornos da Visão/fisiopatologia , Testes de Campo VisualRESUMO
Due to the embedded nature of the lamina cribrosa (LC) microcapillary network, conventional imaging techniques have failed to obtain the high-resolution images needed to assess the perfusion state of the LC. In this study, both optical resolution (OR) and acoustic resolution (AR) photoacoustic microscopy (PAM) techniques were used to obtain static and dynamic information about LC perfusion in ex vivo porcine eyes. The OR-PAM system could resolve a perfused LC microcapillary network with a lateral resolution of 4.2 µm and also provided good depth information (33 µm axial resolution) to visualize through-thickness vascular variations. The AR-PAM system was capable of detecting time-dependent perfusion variations. This study represents the first step towards using an emerging imaging modality (PAM) to study the LC's perfusion, which could be a basis for further investigation of the hemodynamic aspects of glaucomatous optic neuropathy.
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Capilares/diagnóstico por imagem , Disco Óptico/irrigação sanguínea , Animais , Artérias Ciliares/fisiologia , Imageamento Tridimensional , Técnicas Fotoacústicas/métodos , SuínosRESUMO
PURPOSE: To map the 3-dimensional (3D) strain of the optic nerve head (ONH) in vivo after intraocular pressure (IOP) lowering by trabeculectomy (TE) and to establish associations between ONH strain and retinal sensitivity. DESIGN: Observational case series. PARTICIPANTS: Nine patients with primary open-angle glaucoma (POAG) and 3 normal controls. METHODS: The ONHs of 9 subjects with POAG (pre-TE IOP: 25.3±13.9 mmHg; post-TE IOP: 11.8±8.6 mmHg) were imaged (1 eye per subject) using optical coherence tomography (OCT) (Heidelberg Spectralis, Heidelberg Engineering GmbH, Heidelberg, Germany) before (<21 days) and after (<50 days) TE. The imaging protocol was repeated for 3 controls in whom IOP was not altered. In each post-TE OCT volume, 4 tissues were manually segmented (prelamina, choroid, sclera, and lamina cribrosa [LC]). For each ONH, a 3D tracking algorithm was applied to both post- and pre-TE OCT volumes to extract IOP-induced 3D displacements at segmented nodes. Displacements were filtered, smoothed, and processed to extract 3D strain relief (the amount of tissue deformation relieved after TE). Strain relief was compared with measures of retinal sensitivity from visual field testing. MAIN OUTCOME MEASURES: Three-dimensional ONH displacements and strain relief. RESULTS: On average, strain relief (averaged or effective component) in the glaucoma ONHs (8.6%) due to TE was higher than that measured in the normal controls (1.07%). We found no associations between the magnitude of IOP decrease and the LC strain relief (P > 0.05), suggesting biomechanical variability across subjects. The LC displaced posteriorly, anteriorly, or not at all. Furthermore, we found linear associations between retinal sensitivity and LC effective strain relief (P < 0.001; high strain relief associated with low retinal sensitivity). CONCLUSIONS: We demonstrate that ONH displacements and strains can be measured in vivo and that TE can relieve ONH strains. Our data suggest a wide variability in ONH biomechanics in the subjects examined in this study. We further demonstrate associations between LC effective strain relief and retinal sensitivity.
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Glaucoma de Ângulo Aberto/fisiopatologia , Imageamento Tridimensional , Pressão Intraocular/fisiologia , Disco Óptico/fisiopatologia , Doenças do Nervo Óptico/fisiopatologia , Trabeculectomia , Adulto , Idoso , Algoritmos , Fenômenos Biomecânicos , Feminino , Glaucoma de Ângulo Aberto/diagnóstico por imagem , Glaucoma de Ângulo Aberto/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Disco Óptico/diagnóstico por imagem , Doenças do Nervo Óptico/diagnóstico por imagem , Retina/fisiopatologia , Tomografia de Coerência Óptica , Tonometria Ocular , Transtornos da Visão/diagnóstico , Campos Visuais/fisiologiaRESUMO
PURPOSE: To determine the association of iris surface features with iris volume change after physiologic pupil dilation in adults. DESIGN: Cross-sectional observational study. PARTICIPANTS: Chinese adults aged ≥ 50 years without ocular diseases. METHODS: Digital iris photographs were taken from eyes of each participant and graded for crypts (by number and size) and furrows (by number and circumferential extent) following a standardized grading scheme. Iris color was measured objectively, using the Commission Internationale de l'Eclairage (CIE) L* color parameter (higher value denoting lighter iris). The anterior segment was imaged by swept-source optical coherence tomography (SS-OCT) (Casia; Tomey, Nagoya, Japan) under bright light and dark room conditions. Iris volumes in light and dark conditions were measured with custom semiautomated software, and the change in iris volume was quantified. Associations of the change in iris volume after pupil dilation with underlying iris surface features in right eyes were assessed using linear regression analysis. MAIN OUTCOME MEASURES: Iris volume change after physiologic pupil dilation from light to dark condition. RESULTS: A total of 65 Chinese participants (mean age, 59.8±5.7 years) had gradable data for iris surface features. In light condition, higher iris crypt grade was associated independently with smaller iris volume (ß [change in iris volume in millimeters per crypt grade increment] = -1.43, 95% confidence interval [CI], -2.26 to -0.59; P = 0.001) and greater reduction of iris volume on pupil dilation (ß [change in iris volume in millimeters per crypt grade increment] = 0.23, 95% CI, 0.06-0.40; P = 0.010), adjusting for age, gender, presence of corneal arcus, and change in pupil size. Iris furrows and iris color were not associated with iris volume in light condition or change in iris volume (all P > 0.05). CONCLUSIONS: Although few Chinese persons have multiple crypts on their irides, irides with more crypts were significantly thinner and lost more volume on pupil dilation. In view that the latter feature is known to be protective for acute angle-closure attack, it is likely that the macroscopic and microscopic composition of the iris is a contributing feature to angle-closure disease.
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Imageamento Tridimensional , Pressão Intraocular/fisiologia , Iris/anatomia & histologia , Pupila/fisiologia , Tomografia de Coerência Óptica/métodos , Estudos Transversais , Feminino , Seguimentos , Gonioscopia , Humanos , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Projetos Piloto , Valores de Referência , Estudos RetrospectivosRESUMO
We have developed an extended source optical coherence tomography (SEES-OCT) technique in an attempt to improve signal strength for ophthalmic imaging. A line illumination with a visual angle of 7.9 mrad is produced by introducing a dispersive element in the infinity space of the sample arm. The maximum permissible exposure (MPE) of such an extended source is 3.1 times larger than that of a "standard" point source OCT, which corresponds to sensitivity improvement of 5 dB. The advantage of SEES-OCT in providing superior penetration depth over a point source system is demonstrated using swine eye tissues ex vivo.
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Tomografia de Coerência Óptica/métodos , Animais , Imageamento Tridimensional , Disco Óptico/citologia , SuínosRESUMO
Purpose: The purpose of this study was to investigate the effect of globe and optic nerve (ON) morphologies and tissue stiffnesses on gaze-induced optic nerve head deformations using parametric finite element modeling and a design of experiment (DOE) approach. Methods: A custom software was developed to generate finite element models of the eye using 10 morphological parameters: dural radius, scleral, choroidal, retinal, pial and peripapillary border tissue thicknesses, prelaminar tissue depth, lamina cribrosa (LC) depth, ON radius, and ON tortuosity. A central composite face-centered design (1045 models) was used to predict the effects of each morphological factor and their interactions on LC strains induced by 13 degrees of adduction. Subsequently, a further DOE analysis (1045 models) was conducted to study the effects and potential interactions between the top five morphological parameters identified from the initial DOE study and five critical tissue stiffnesses. Results: In the DOE analysis of 10 morphological parameters, the 5 most significant factors were ON tortuosity, dural radius, ON radius, scleral thickness, and LC depth. Further DOE analysis incorporating biomechanical parameters highlighted the importance of dural and LC stiffness. A larger dural radius and stiffer dura increased LC strains but the other main factors had the opposite effects. Notably, the significant interactions were found between dural radius with dural stiffness, ON radius, and ON tortuosity. Conclusions: This study highlights the significant impact of morphological factors on LC deformations during eye movements, with key morphological effects being more pronounced than tissue stiffnesses.
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Análise de Elementos Finitos , Disco Óptico , Humanos , Disco Óptico/patologia , Fenômenos Biomecânicos , Doenças do Nervo Óptico/fisiopatologia , Doenças do Nervo Óptico/etiologia , Fixação Ocular/fisiologia , Esclera/patologia , Olho , Modelos BiológicosRESUMO
BACKGROUND/AIMS: To use artificial intelligence (AI) to: (1) exploit biomechanical knowledge of the optic nerve head (ONH) from a relatively large population; (2) assess ONH robustness (ie, sensitivity of the ONH to changes in intraocular pressure (IOP)) from a single optical coherence tomography (OCT) volume scan of the ONH without the need for biomechanical testing and (3) identify what critical three-dimensional (3D) structural features dictate ONH robustness. METHODS: 316 subjects had their ONHs imaged with OCT before and after acute IOP elevation through ophthalmo-dynamometry. IOP-induced lamina cribrosa (LC) deformations were then mapped in 3D and used to classify ONHs. Those with an average effective LC strain superior to 4% were considered fragile, while those with a strain inferior to 4% robust. Learning from these data, we compared three AI algorithms to predict ONH robustness strictly from a baseline (undeformed) OCT volume: (1) a random forest classifier; (2) an autoencoder and (3) a dynamic graph convolutional neural network (DGCNN). The latter algorithm also allowed us to identify what critical 3D structural features make a given ONH robust. RESULTS: All three methods were able to predict ONH robustness from a single OCT volume scan alone and without the need to perform biomechanical testing. The DGCNN (area under the curve (AUC): 0.76±0.08) outperformed the autoencoder (AUC: 0.72±0.09) and the random forest classifier (AUC: 0.69±0.05). Interestingly, to assess ONH robustness, the DGCNN mainly used information from the scleral canal and the LC insertion sites. CONCLUSIONS: We propose an AI-driven approach that can assess the robustness of a given ONH solely from a single OCT volume scan of the ONH, and without the need to perform biomechanical testing. Longitudinal studies should establish whether ONH robustness could help us identify fast visual field loss progressors. PRECIS: Using geometric deep learning, we can assess optic nerve head robustness (ie, sensitivity to a change in IOP) from a standard OCT scan that might help to identify fast visual field loss progressors.
Assuntos
Disco Óptico , Humanos , Disco Óptico/diagnóstico por imagem , Inteligência Artificial , Pressão Intraocular , Tonometria Ocular , Testes de Campo Visual , Tomografia de Coerência ÓpticaRESUMO
PURPOSE: To assess intraocular pressure (IOP)-induced and gaze-induced optic nerve head (ONH) strains in subjects with high-tension glaucoma (HTG) and normal-tension glaucoma (NTG). DESIGN: Clinic-based cross-sectional study. METHODS: The ONH from one eye of 228 subjects (114 subjects with HTG (pre-treatment IOP≥21 mm Hg) and 114 with NTG (pre-treatment IOP<21 mm Hg)) was imaged with optical coherence tomography (OCT) under the following conditions: (1) OCT primary gaze, (2) 20° adduction from OCT primary gaze, (3) 20° abduction from OCT primary gaze and (4) OCT primary gaze with acute IOP elevation (to approximately 33 mm Hg). We then performed digital volume correlation analysis to quantify IOP-induced and gaze-induced ONH tissue deformations and strains. RESULTS: Across all subjects, adduction generated high effective strain (4.4%±2.3%) in the LC tissue with no significant difference (p>0.05) with those induced by IOP elevation (4.5%±2.4%); while abduction generated significantly lower (p=0.01) effective strain (3.1%±1.9%). The lamina cribrosa (LC) of HTG subjects exhibited significantly higher effective strain than those of NTG subjects under IOP elevation (HTG: 4.6%±1.7% vs NTG: 4.1%±1.5%, p<0.05). Conversely, the LC of NTG subjects exhibited significantly higher effective strain than those of HTG subjects under adduction (NTG: 4.9%±1.9% vs HTG: 4.0%±1.4%, p<0.05). CONCLUSION: We found that NTG subjects experienced higher strains due to adduction than HTG subjects, while HTG subjects experienced higher strain due to IOP elevation than NTG subjects-and that these differences were most pronounced in the LC tissue.
Assuntos
Glaucoma de Ângulo Aberto , Glaucoma , Glaucoma de Baixa Tensão , Disco Óptico , Humanos , Glaucoma de Ângulo Aberto/diagnóstico , Estudos Transversais , Glaucoma de Baixa Tensão/diagnóstico , Pressão Intraocular , Tomografia de Coerência ÓpticaRESUMO
Purpose: We wanted to develop a deep-learning algorithm to automatically segment optic nerve head (ONH) and macula structures in three-dimensional (3D) wide-field optical coherence tomography (OCT) scans and to assess whether 3D ONH or macula structures (or a combination of both) provide the best diagnostic power for glaucoma. Methods: A cross-sectional comparative study was performed using 319 OCT scans of glaucoma eyes and 298 scans of nonglaucoma eyes. Scans were compensated to improve deep-tissue visibility. We developed a deep-learning algorithm to automatically label major tissue structures, trained with 270 manually annotated B-scans. The performance was assessed using the Dice coefficient (DC). A glaucoma classification algorithm (3D-CNN) was then designed using 500 OCT volumes and corresponding automatically segmented labels. This algorithm was trained and tested on three datasets: cropped scans of macular tissues, those of ONH tissues, and wide-field scans. The classification performance for each dataset was reported using the area under the curve (AUC). Results: Our segmentation algorithm achieved a DC of 0.94 ± 0.003. The classification algorithm was best able to diagnose glaucoma using wide-field scans, followed by ONH scans, and finally macula scans, with AUCs of 0.99 ± 0.01, 0.93 ± 0.06 and 0.91 ± 0.11, respectively. Conclusions: This study showed that wide-field OCT may allow for significantly improved glaucoma diagnosis over typical OCTs of the ONH or macula. Translational Relevance: This could lead to mainstream clinical adoption of 3D wide-field OCT scan technology.
Assuntos
Glaucoma , Disco Óptico , Humanos , Disco Óptico/diagnóstico por imagem , Inteligência Artificial , Tomografia de Coerência Óptica , Estudos Transversais , Glaucoma/diagnóstico por imagemRESUMO
PURPOSE: To compare the prevalence, location and magnitude of optic nerve head (ONH) OCT-detected, exposed neural canal (ENC), externally oblique choroidal border tissue (EOCBT) and exposed scleral flange (ESF) regions in 122 highly myopic (Hi-Myo) versus 362 nonhighly myopic healthy (Non-Hi-Myo-Healthy) eyes. DESIGN: Cross-sectional study. METHODS: After OCT radial B-scan, ONH imaging, Bruch's membrane opening (BMO), the anterior scleral canal opening (ASCO), and the scleral flange opening (SFO) were manually segmented in each B-scan and projected to BMO reference plane. The direction and magnitude of BMO/ASCO offset and BMO/SFO offset as well as the location and magnitude of ENC, EOCBT and ESF regions, perineural canal (pNC) retinal nerve fiber layer thickness (RNFLT) and pNC choroidal thickness (CT) were calculated within 30° sectors relative to the Foveal-BMO (FoBMO) axis. Hi-ESF eyes were defined to be those with an ESF region ≥100 µms in at least 1 sector. RESULTS: Hi-Myo eyes more frequently demonstrated Hi-ESF regions (87/122) than Non-Hi-myo-Healthy eyes (73/362) and contained significantly larger ENC, EOCBT, and ESF regions (P < .001) which were greatest in magnitude and prevalence within the inferior-temporal FoBMO sectors where Hi-Myo pNC-RNFLT and pNCCT were thinnest. BMO/ASCO offset and the BMO/SFO offset were both significantly increased (P < .001) in the Hi-Myo eyes, with the latter demonstrating a greater increase. CONCLUSIONS: ENC region tissue remodeling that includes the scleral flange is enhanced in Hi-Myo compared to Non-Hi-Myo-Healthy eyes. Longitudinal studies are necessary to determine whether the presence of an ENC region influences ONH susceptibility to aging and/or glaucoma.
Assuntos
Miopia , Disco Óptico , Humanos , Disco Óptico/anatomia & histologia , Tomografia de Coerência Óptica/métodos , Tubo Neural , Estudos Transversais , Miopia/diagnóstico , Lâmina Basilar da Corioide/anatomia & histologia , Pressão IntraocularRESUMO
Purpose: (1) To assess the performance of geometric deep learning in diagnosing glaucoma from a single optical coherence tomography (OCT) scan of the optic nerve head and (2) to compare its performance to that obtained with a three-dimensional (3D) convolutional neural network (CNN), and with a gold-standard parameter, namely, the retinal nerve fiber layer (RNFL) thickness. Methods: Scans of the optic nerve head were acquired with OCT for 477 glaucoma and 2296 nonglaucoma subjects. All volumes were automatically segmented using deep learning to identify seven major neural and connective tissues. Each optic nerve head was then represented as a 3D point cloud with approximately 1000 points. Geometric deep learning (PointNet) was then used to provide a glaucoma diagnosis from a single 3D point cloud. The performance of our approach (reported using the area under the curve [AUC]) was compared with that obtained with a 3D CNN, and with the RNFL thickness. Results: PointNet was able to provide a robust glaucoma diagnosis solely from a 3D point cloud (AUC = 0.95 ± 0.01).The performance of PointNet was superior to that obtained with a 3D CNN (AUC = 0.87 ± 0.02 [raw OCT images] and 0.91 ± 0.02 [segmented OCT images]) and with that obtained from RNFL thickness alone (AUC = 0.80 ± 0.03). Conclusions: We provide a proof of principle for the application of geometric deep learning in glaucoma. Our technique requires significantly less information as input to perform better than a 3D CNN, and with an AUC superior to that obtained from RNFL thickness. Translational Relevance: Geometric deep learning may help us to improve and simplify diagnosis and prognosis applications in glaucoma.
Assuntos
Aprendizado Profundo , Glaucoma , Disco Óptico , Humanos , Células Ganglionares da Retina , Campos Visuais , Glaucoma/diagnóstico , Tomografia de Coerência Óptica/métodosRESUMO
PURPOSE: To compare the performance of 2 relatively recent geometric deep learning techniques in diagnosing glaucoma from a single optical coherence tomographic (OCT) scan of the optic nerve head (ONH); and to identify the 3-dimensional (3D) structural features of the ONH that are critical for the diagnosis of glaucoma. DESIGN: Comparison and evaluation of deep learning diagnostic algorithms. METHODS: In this study, we included a total of 2247 nonglaucoma and 2259 glaucoma scans from 1725 participants. All participants had their ONHs imaged in 3D with Spectralis OCT. All OCT scans were automatically segmented using deep learning to identify major neural and connective tissues. Each ONH was then represented as a 3D point cloud. We used PointNet and dynamic graph convolutional neural network (DGCNN) to diagnose glaucoma from such 3D ONH point clouds and to identify the critical 3D structural features of the ONH for glaucoma diagnosis. RESULTS: Both the DGCNN (area under the curve [AUC]: 0.97±0.01) and PointNet (AUC: 0.95±0.02) were able to accurately detect glaucoma from 3D ONH point clouds. The critical points (ie, critical structural features of the ONH) formed an hourglass pattern, with most of them located within the neuroretinal rim in the inferior and superior quadrant of the ONH. CONCLUSIONS: The diagnostic accuracy of both geometric deep learning approaches was excellent. Moreover, we were able to identify the critical 3D structural features of the ONH for glaucoma diagnosis that tremendously improved the transparency and interpretability of our method. Consequently, our approach may have strong potential to be used in clinical applications for the diagnosis and prognosis of a wide range of ophthalmic disorders.