PURPOSE OF REVIEW: Artificial intelligence has already provided multiple clinically relevant applications in ophthalmology. Yet, the explosion of nonstandardized reporting of high-performing algorithms are rendered useless without robust and streamlined implementation guidelines. The development of protocols and checklists will accelerate the translation of research publications to impact on patient care. RECENT FINDINGS: Beyond technological scepticism, we lack uniformity in analysing algorithmic performance generalizability, and benchmarking impacts across clinical settings. No regulatory guardrails have been set to minimize bias or optimize interpretability; no consensus clinical acceptability thresholds or systematized postdeployment monitoring has been set. Moreover, stakeholders with misaligned incentives deepen the landscape complexity especially when it comes to the requisite data integration and harmonization to advance the field. Therefore, despite increasing algorithmic accuracy and commoditization, the infamous 'implementation gap' persists. Open clinical data repositories have been shown to rapidly accelerate research, minimize redundancies and disseminate the expertise and knowledge required to overcome existing barriers. Drawing upon the longstanding success of existing governance frameworks and robust data use and sharing agreements, the ophthalmic community has tremendous opportunity in ushering artificial intelligence into medicine. By collaboratively building a powerful resource of open, anonymized multimodal ophthalmic data, the next generation of clinicians can advance data-driven eye care in unprecedented ways. SUMMARY: This piece demonstrates that with readily accessible data, immense progress can be achieved clinically and methodologically to realize artificial intelligence's impact on clinical care. Exponentially progressive network effects can be seen by consolidating, curating and distributing data amongst both clinicians and data scientists.
PURPOSE: Optical coherence tomography angiography (OCT-A) is a novel imaging modality for the diagnosis of chorioretinal diseases. A number of FDA-approved OCT-A devices are currently commercially available, each with unique algorithms and scanning protocols. Although several published studies have compared different combinations of OCT-A machines, there is a lack of agreement on the consistency of measurements across OCT-A devices. Therefore, we conducted a prospective quantitative comparison of four available OCT-A platforms. METHODS: Subjects were scanned on four devices: Optovue RTVue-XR, Heidelberg Spectralis OCT2 module, Zeiss Plex Elite 9000 Swept-Source OCT, and Topcon DRI-OCT Triton Swept-Source OCT. 3 mm × 3 mm images were utilized for analysis. Foveal avascular zone (FAZ) area was separately and independently measured by two investigators. Fractal dimension (FD), superficial capillary plexus (SCP), and deep capillary plexus (DCP) vessel densities (VD) were calculated from binarized images using the Fiji image processing software. SCP and DCP VD were further calculated after images were skeletonized. Repeated measures ANOVA, post hoc tests, and interclass correlation coefficient (ICC) were performed for statistical analysis. RESULTS: Sixteen healthy eyes from sixteen patients were scanned on the four devices. Images of five eyes from the Triton device were excluded due to poor image quality; thus, the authors performed two sets comparisons, one with and one without the Triton machine. FAZ area showed no significant difference across devices with an ICC of > 95%. However, there were statistically significant differences for SCP and DCP VD both before and after skeletonization (p < 0.05). Fractal analysis revealed no significant difference of FD at the SCP; however, a statistically significant difference was found for FD at the DCP layer (p < 0.05). CONCLUSIONS: The results showed that FAZ measurements were consistent across all four devices, while significant differences in VD and FD measurements existed. Therefore, we suggest that for both clinical follow-up and research studies, FAZ area is a useful parameter for OCT-A image analysis when measurements are made on different machines, while VD and FD show significant variability when measured across devices.
PURPOSE: Von Hippel-Lindau (VHL) disease is a hereditary disorder that can lead to ophthalmic manifestations, including retinal capillary hemangioma (RCH). The diagnosis of RCH is often guided by wide-field fluorescein angiography. In some cases, optical coherence tomography angiography (OCT-A) serves as a non-invasive alternative to FA. Herein, we used OCT-A to examine the macular microvasculature in patients with VHL disease. SUBJECTS: Subjects were selected from patients with a diagnosis of VHL. The control group included eyes without retinal diagnosis from patients with an episode of unilateral retinal detachment or trauma and age ≤ 50 years old. METHODS: Subjects were scanned on the Optovue RTVue-XR device to acquire 3mm x 3mm OCT-A images of the superficial (SCP) and deep capillary plexus (DCP). SCP and DCP vessel density (VD) were calculated after the images were binarized. Furthermore, for subjects with RCH, each OCT-A image was divided equally into four quadrants. SCP and DCP VD of quadrants with RCH were compared to those without RCH. T-tests were performed for statistical analysis. RESULTS: 67 eyes with a history of VHL disease were included as study subjects, while 16 eyes were included as controls. Significant increases in VD were found in patients with VHL disease for both the SCP (p = 0.0441) and DCP (p = 0.0344). When comparing quadrants with associated RCH development to those without, we found no significant difference in SCP VD (p = 0.160) or DCP VD (p = 0.484). CONCLUSIONS: OCT-A can detect changes in the retinal microvasculature in the macula of patients with VHL disease. OCT-A imaging may be an additional tool for screening and early detection of patients at risk of developing ocular complications of VHL disease. Future studies should explore subtle progression on OCT-A associated with the pathogenesis and development of RCH, particularly with larger scan patterns.
Topic : Ultra-widefield (UWF) imaging of the myopic eye. Clinical Relevance : Myopes, and particularly high and pathologic myopes, present a unique challenge in fundoscopic imaging. Critical pathology is often located in the anteriormost portion of the retina, variations in posterior segment contour are difficult to capture in two-dimensional images, and extremes in axial length make simply focusing imaging devices difficult. Methods: We review the evolution of modalities for ophthalmic imaging (color fundus photography [CFP], optical coherence topography [OCT], angiography, artificial intelligence [AI]) to present day UWF technology and its impact on our understanding of myopia. Results: Advances in UWF technology address many of the challenges in fundoscopic imaging of myopes, providing new insights into the structure and function of the myopic eye. UWF CFP improves our ability to detect and document anterior peripheral pathology prevalent in approximately half of all high myopes. UWF OCT better captures the staphylomatous contour of the myopic eye, providing enhanced visualization of the vitreoretinal interface and progressive development of myopic traction maculopathy. UWF angiography highlights the posterior vortex veins, thin choriocapillaris, far peripheral avascularity, and peripheral retinal capillary microaneurysms more prevalent in the myopic eye. Researchers have demonstrated the ability of AI algorithms to predict refractive error, and great potential remains in the use of AI technology for the screening and prevention of myopic disease. Conclusion: We note significant progress in our ability to capture anterior pathology and improved image quality of the posterior segment of high and pathologic myopes. The next jump forward for UWF imaging will be the ability to capture a high quality ora to ora multimodal fundoscopic image in a single scan that will allow for sensitive AI-assisted screening of myopic disease.
PURPOSE: To describe 7 patients with paraproteinemic keratopathy and to highlight the clinical and pathologic diversity of this rare entity and the importance of timely, systemic evaluation. DESIGN: Retrospective, multicenter collaborative case series. PARTICIPANTS: Seven patients with paraproteinemic keratopathy. METHODS: Clinical and pathologic records were reviewed to identify patients with well-documented corneal immunoglobulin deposits. Detailed ophthalmologic and medical histories were assembled. In 6 patients, corneal tissue was evaluated histochemically and immunohistochemically; in selected cases, corneal tissue was evaluated by in situ hybridization and ultrastructurally. MAIN OUTCOME MEASURES: Visual acuity and anterior segment examination at presentation and follow-up; local therapy; systemic diagnosis and management; and histopathologic, immunohistochemical, in situ hybridization, and ultrastructural findings. RESULTS: Seven patients were identified with corneal immunoglobulin deposition. In addition to previously reported crystalline, nummular, patch-like, and lattice-like corneal opacities, prominent corneal vascularization was present in 2 patients mimicking interstitial keratitis and limbal stem cell deficiency. All patients had evidence of paraproteinemia in a setting of monoclonal gammopathy of undetermined significance, smoldering plasma cell myeloma, or Waldenström macroglobulinemia. Corneal findings were the first manifestation of systemic disease in 4 patients, and the diagnosis was not suspected in 3 of these patients. Pathologic evaluation of biopsied corneal and conjunctival tissues demonstrated immunoglobulin deposits. Previously unreported ultrastructural patterns in the cornea were noted: large scroll-like immunotactoid deposits, immune complex-like deposits, and randomly arranged fibrils morphologically intermediate between amyloid and immunotactoid deposits. Surgical intervention to improve vision was performed in 4 patients, with recurrence of deposits in 3 patients. Three patients underwent systemic therapy with diminution of the deposits and improvement in vision in 1 patient. CONCLUSIONS: The clinical and pathologic expressions of corneal immunoglobulin deposits are protean and present a diagnostic challenge. Early recognition of this rare entity is important to address the potentially serious associated systemic disease.
BACKGROUND/AIMS: Pathological myopia (PM) is a leading cause of blindness worldwide. We aimed to evaluate microvascular and chorioretinal changes in different stages of myopia with wide-field (WF) swept-source (SS) optical coherence tomography angiography (OCTA). METHODS: This prospective cross-sectional observational study included 186 eyes of 122 patients who had undergone imaging between November 2018 and October 2020. Vessel density (VD) and vessel skeletonised density (VSD) of superficial capillary plexus, deep capillary plexus and whole retina, as well as foveal avascular zone parameters, retinal thickness (RT) and choroidal thickness (CT), were calculated. RESULTS: This study evaluated 75 eyes of 48 patients with high myopia (HM), 43 eyes of 31 patients with mild to moderate myopia and 68 eyes of 53 age-matched controls. Controlling for age and the presence of systemic hypertension, we found that HM was associated with decrease in VD and VSD in all layers on 12×12 mm² scans. Furthermore, HM was associated with a VD and VSD decrease in every Early Treatment Diabetic Retinopathy Study grid, with a larger decrease temporally (βVD=-0.39, βVSD=-10.25, p<0.01). HM was associated with decreased RT and CT. Reduction in RT was outside the macular region, while reduction in CT was in the macular region. CONCLUSION: Using WF SS-OCTA, we identified reduction in microvasculature and structural changes associated with myopia. Decrease in VD and VSD was greater in the temporal quadrant, and reductions in RT and CT were uneven across the retina. Further work may help identify risk factors for the progression of PM and associated vision-threatening complications.
Purpose: To compare the rates of clinically significant artifacts for two-dimensional peripapillary retinal nerve fiber layer (RNFL) thickness versus three-dimensional (3D) neuroretinal rim thickness using spectral-domain optical coherence tomography (SD-OCT). Methods: Only one eye per patient was used for analysis of 120 glaucoma patients and 114 normal patients. For RNFL scans and optic nerve scans, 15 artifact types were calculated per B-scan and per eye. Neuroretinal rim tissue was quantified by the minimum distance band (MDB). Global MDB neuroretinal rim thicknesses were calculated before and after manual deletion of B-scans with artifacts and subsequent automated interpolation. A clinically significant artifact was defined as one requiring manual correction or repeat scanning. Results: Among glaucomatous eyes, artifact rates per B-scan were significantly more common in RNFL scans (61.7%, 74 of 120) compared to B-scans in neuroretinal rim volume scans (20.9%, 1423 of 6820) (95% confidence interval [CI], 31.6-50.0; < 0.0001). For clinically significant artifact rates per eye, optic nerve scans had significantly fewer artifacts (15.8% of glaucomatous eyes, 13.2% of normal eyes) compared to RNFL scans (61.7% of glaucomatous eyes, 25.4% of normal eyes) (glaucoma group: 95% CI, 34.1-57.5, < 0.0001; normal group: 95% CI, 1.3-23.3, = 0.03). Conclusions: Compared to the most commonly used RNFL thickness scans, optic nerve volume scans less frequently require manual correction or repeat scanning to obtain accurate measurements. Translational Relevance: This paper illustrates the potential for 3D OCT algorithms to improve in vivo imaging in glaucoma.
BACKGROUND/AIMS: Although being a more objective tool for assessment and follow-up of angle closure, reliability studies have reported a moderate diagnostic performance for anterior segment optical coherence tomography (OCT) technologies when comparing with gonioscopy as the reference standard. We aim to determine factors associated with diagnostic disagreement in angle closure when assessed by anterior segment swept source OCT (SS-OCT, CASIA SS-1000; Tomey, Nagoya, Japan) and gonioscopy. METHODS: Cross-sectional study. A total of 2027 phakic subjects aged ≥50 years, with no relevant previous ophthalmic history, were consecutively recruited from a community polyclinic in Singapore. Gonioscopy and SS-OCT (128 radial scans) for the entire circumference of the angle were performed for each subject. A two-quadrant closed gonioscopic definition was used. On SS-OCT images, angle closure was defined as iridotrabecular contact (ITC) to the extent of ≥35%, ≥50% and ≥75% of the circumferential angle. Diagnostic disagreements between both methods, that is, false positives or overcalls and false negatives or undercalls were defined, respectively, as gonioscopic open/closed angles inversely assessed as closed/open by SS-OCT. RESULTS: Two hundred and seventy-two (14.7%) resulted in overcall results (false positives) when ≥50% of the angle circumference was closed using SS-OCT. These eyes had significantly wider (anterior chamber width, 11.7 vs 11.6 mm, p<0.001) and deeper (anterior chamber depth (ACD), 2.4 vs 2.2 mm, p<0.001) anterior chambers than eyes assessed by both methods as closed (true positives). Deeper ACD (OR 9.31) and lower lens vault (LV) (OR 0.04) were significantly associated with a false positive diagnosis in the multivariate analysis. Most of these cases had short (52.6%) or irregular (39%) ITC in SS-OCT images. CONCLUSIONS: We found that anterior chamber dimensions, determined by ACD and LV, were factors significantly associated with diagnostic disagreement between anterior segment SS-OCT and gonioscopy in angle closure assessment.
IMPORTANCE: Brain imaging and fluid biomarkers are characterized in children at risk for autosomal dominant Alzheimer disease (ADAD). OBJECTIVE: To characterize and compare structural magnetic resonance imaging (MRI), resting-state and task-dependent functional MRI, and plasma amyloid-β (Aβ) measurements in presenilin 1 (PSEN1) E280A mutation-carrying and noncarrying children with ADAD. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional measures of structural and functional MRI and plasma Aβ assays were assessed in 18 PSEN1 E280A carriers and 19 noncarriers aged 9 to 17 years from a Colombian kindred with ADAD. Recruitment and data collection for this study were conducted at the University of Antioquia and the Hospital Pablo Tobon Uribe in Medellín, Colombia, between August 2011 and June 2012. MAIN OUTCOMES AND MEASURES: All participants had blood sampling, structural MRI, and functional MRI during associative memory encoding and resting-state and cognitive assessments. Outcome measures included plasma Aβ1-42 concentrations and Aβ1-42:Aβ1-40 ratios, memory encoding-dependent activation changes, resting-state connectivity, and regional gray matter volumes. Structural and functional MRI data were compared using automated brain mapping algorithms and search regions related to AD. RESULTS: Similar to findings in adult mutation carriers, in the later preclinical and clinical stages of ADAD, mutation-carrying children were distinguished from control individuals by significantly higher plasma Aβ1-42 levels (mean [SD]: carriers, 18.8 [5.1] pg/mL and noncarriers, 13.1 [3.2] pg/mL; P < .001) and Aβ1-42:Aβ1-40 ratios (mean [SD]: carriers, 0.32 [0.06] and noncarriers, 0.21 [0.03]; P < .001), as well as less memory encoding task-related deactivation in parietal regions (eg, mean [SD] parameter estimates for the right precuneus were -0.590 [0.50] for noncarriers and -0.087 [0.38] for carriers; P < .005 uncorrected). Unlike carriers in the later stages, mutation-carrying children demonstrated increased functional connectivity of the posterior cingulate cortex with medial temporal lobe regions (mean [SD] parameter estimates were 0.038 [0.070] for noncarriers and 0.190 [0.057] for carriers), as well as greater gray matter volumes in temporal regions (eg, left parahippocampus; P < . 049, corrected for multiple comparisons). CONCLUSIONS AND RELEVANCE: Children at genetic risk for ADAD have functional and structural brain changes and abnormal levels of plasma Aβ1-42. The extent to which the underlying brain changes are either neurodegenerative or developmental remains to be determined. This study provides additional information about the earliest known biomarker changes associated with ADAD.
BACKGROUND: The severity and extent of microaneurysms (MAs) have been used to determine diabetic retinopathy (DR) severity and estimate the risk of DR progression over time. The recent introduction of ultrawide field (UWF) imaging has allowed ophthalmologists to readily image nearly the entire retina. Manual counting of MAs, especially on UWF images, is laborious and time-consuming, limiting its potential use in clinical settings. Automated MA counting techniques are potentially more accurate and reproducible compared to manual methods. METHOD: Review of available literature on current techniques of automated MA counting techniques on both ultrawide field (UWF) color images (CI) and fluorescein angiography (FA) images. RESULTS: Automated MA counting techniques on UWF images are still in the early phases of development with UWF-FA counts being further along. Early studies have demonstrated that these techniques are accurate and reproducible. CONCLUSION: Automated techniques may be an appropriate option for detecting and quantifying MAs on UWF images, especially in eyes with earlier DR severity. Larger studies are needed to appropriately validate these techniques and determine if they add substantially to clinical practice compared to standard DR grading.
The Tolosa-Hunt syndrome is a rare clinical condition characterized by painful opthalmoparesis associated with idiopathic granulomatous inflammation of the orbital apex and cavernous sinus. Historically, this condition was thought to result from arteritic changes in the internal carotid artery and cavernous sinus. Modern digital angiographic techniques were unavailable when THS was initially described, and few reports exist on its high-resolution angiographic findings. Painful ophthalmoparesis, especially of the oculomotor nerve, warrants vascular imaging because of the concern for an underlying aneurysm. Here, we describe angiographic findings of THS which may be useful for clinicians when encountering patients presenting with painful ophthalmoplegia.
: To determine the imaging approach for evaluating intraocular foreign bodies (IOFBs) by comparing the ability of different modalities [plain film x-ray, computed tomography (CT), magnetic resonsance imaging (MRI), convetional ultrasound, and ultrasound biomicroscopy] to detect and characterize IOFBs. : Systematic review of the literature. : CT is the most practical first step for evaluating patients with suspected IOFBs because it can detect a wide range of IOFB types at small limitis of detection. MRI and ultrasound are best reserved as adjunctive tests in most cases although these tests may provide important insights especially with wood, plastic, and glass IOFBs. Imaging characteristics of metal, wood, glass, plastic, stone, concrete, and graphite IOFBs are reviewed. : Understanding the limits of detection for each IOFB type and imaging modality as well as the characteristic features of different IOFBs is of paramount importance to optimizing the management of ocular trauma patients.
Tree shrews are small mammals with excellent vision and are closely related to primates. They have been used extensively as a model for studying refractive development, myopia, and central visual processing and are becoming an important model for vision research. Their cone dominant retina (∼95% cones) provides a potential avenue to create new damage/disease models of human macular pathology and to monitor progression or treatment response. To continue the development of the tree shrew as an animal model, we provide here the first measurements of higher order aberrations along with adaptive optics scanning light ophthalmoscopy (AOSLO) images of the photoreceptor mosaic in the tree shrew retina. To compare intra-animal in vivo and ex vivo cone density measurements, the AOSLO images were matched to whole-mount immunofluorescence microscopy. Analysis of the tree shrew wavefront indicated that the optics are well-matched to the sampling of the cone mosaic and is consistent with the suggestion that juvenile tree shrews are nearly emmetropic (slightly hyperopic). Compared with in vivo measurements, consistently higher cone density was measured ex vivo, likely due to tissue shrinkage during histological processing. Tree shrews also possess massive mitochondria ("megamitochondria") in their cone inner segments, providing a natural model to assess how mitochondrial size affects in vivo retinal imagery. Intra-animal in vivo and ex vivo axial distance measurements were made in the outer retina with optical coherence tomography (OCT) and transmission electron microscopy (TEM), respectively, to determine the origin of sub-cellular cone reflectivity seen on OCT. These results demonstrate that these megamitochondria create an additional hyper-reflective outer retinal reflective band in OCT images. The ability to use noninvasive retinal imaging in tree shrews supports development of this species as a model of cone disorders.
Galectins have emerged as potent immunoregulatory agents that control chronic inflammation through distinct mechanisms. Here, we report that treatment with Galectin-8 (Gal-8), a tandem-repeat member of the galectin family, reduces retinal pathology and prevents photoreceptor cell damage in a murine model of experimental autoimmune uveitis. Gal-8 treatment increased the number of regulatory T cells (Treg) in both the draining lymph node (dLN) and the inflamed retina. Moreover, a greater percentage of Treg cells in the dLN and retina of Gal-8 treated animals expressed the inhibitory coreceptor cytotoxic T lymphocyte antigen (CTLA)-4, the immunosuppressive cytokine IL-10, and the tissue-homing integrin CD103. Treg cells in the retina of Gal-8-treated mice were primarily inducible Treg cells that lack the expression of neuropilin-1. In addition, Gal-8 treatment blunted production of inflammatory cytokines by retinal T helper type (TH) 1 and TH17 cells. The effect of Gal-8 on T cell differentiation and/or function was specific for tissues undergoing an active immune response, as Gal-8 treatment had no effect on T cell populations in the spleen. Given the need for rational therapies for managing human uveitis, Gal-8 emerges as an attractive therapeutic candidate not only for treating retinal autoimmune diseases, but also for other TH1- and TH17-mediated inflammatory disorders.
Memories are encoded in a manner that depends on our knowledge and expectations ("schemas"). Consistent with this, expertise tends to improve memory: Experts have elaborated schemas in their domains of expertise, allowing them to efficiently represent information in this domain (e.g., chess experts have enhanced memory for realistic chess layouts). On the other hand, in most situations, people tend to remember abnormal or surprising items best-those that are also rare or out-of-the-ordinary occurrences (e.g., surprising-but not random-chess board configurations). This occurs, in part, because such images are distinctive relative to other images. In the current work, we ask how these factors interact in a particularly interesting case-the domain of radiology, where experts actively search for abnormalities. Abnormality in mammograms is typically focal but can be perceived in the global "gist" of the image. We ask whether, relative to novices, expert radiologists show improved memory for mammograms. We also test for any additional advantage for abnormal mammograms that can be thought of as unexpected or rare stimuli in screening. We find that experts have enhanced memory for focally abnormal images relative to normal images. However, radiologists showed no memory benefit for images of the breast that were not focally abnormal, but were only abnormal in their gist. Our results speak to the role of schemas and abnormality in expertise; the necessity for spatially localized abnormalities versus abnormalities in the gist in enhancing memory; and the nature of memory and decision-making in radiologists.
: To review the current literature regarding optical coherence tomography angiography (OCT-A) applications in the anterior segment. : A literature search was performed for terms including OCT-Angiography, anterior segment, cornea, conjunctiva, iris, applications and use in ophthalmology. : Fifteen studies were identified, 14 in human subjects. Studies with OCT-A of the conjunctiva, episclera, cornea, and iris were identified, some with normal eyes imaged and others with various pathologies. Most of these studies imaged corneal neovascularization. Three studies described protocols used for image acquisition, one of which was referenced by two later papers. : OCT-A is a noninvasive technology with recent applications in the anterior segment. Several pilot studies have been performed on various anterior segment structures and disease states however standardization of image acquisition techniques is still needed. Future imaging could allow noninvasive and serial monitoring of pathology as well as recurrence after therapeutic intervention.
PURPOSE: To evaluate the capacity of spectral domain optical coherence tomography macular findings to predict best-corrected visual acuity (BCVA) outcomes after treatment for symptomatic vitreomacular traction. METHODS: This consecutive, retrospective study included 24 patients (29 eyes) who experienced vitreomacular traction release with pneumatic vitreolysis (n = 9), intravitreal ocriplasmin (n = 6), or pars plana vitrectomy (n = 14). Preoperative and postoperative spectral domain optical coherence tomography images were used to determine the cone outer segment tips (COST) line, inner segment/outer segment line, and other frequently used features. Correlations between optical coherence tomography findings and BCVA were determined using regression analyses. RESULTS: Postoperative BCVA was correlated with length of the COST line and inner segment/outer segment line defects at 1, 3, 6, and 12 months postoperatively (P < 0.05) by simple linear regression analysis. However, multivariable regression analysis showed that only length of the COST line defect was significantly correlated with BCVA preoperatively and postoperatively (P < 0.05). Postoperative BCVA improvement at 12 months was significantly correlated with preoperative length of the COST line defect (P < 0.01). CONCLUSION: Recovery of the COST line and inner segment/outer segment line defects as observed by spectral domain optical coherence tomography is positively correlated with visual acuity improvement after successful vitreomacular traction treatment. Best-corrected visual acuity improvement may be predicted using the length of the preoperative COST line defect.