Development and validation of methods to visualize conventional aqueous outflow pathways in canine primary angle closure glaucoma.

PURPOSE: Angle closure glaucoma (PACG) is highly prevalent in dogs and is often refractory to medical therapy. We hypothesized that pathology affecting the post-trabecular conventional aqueous outflow pathway contributes to persistent intraocular pressure (IOP) elevation in dogs with PACG. The goal of this study was to determine the potential for aqueous angiography (AA) and optical coherence tomography (OCT) to identify abnormalities in post-trabecular aqueous outflow pathways in canine PACG. METHODS: AA and anterior segment OCT (Spectralis HRA + OCT) were performed ex vivo in 19 enucleated canine eyes (10 normal eyes and 9 irreversibly blind eyes from canine patients enucleated for management of refractory PACG). Eyes were cannulated and maintained at physiologic IOP (10-20 mmHg) prior to intracameral infusion of fluorescent tracer. OCT scleral line scans were acquired in regions of high and low perilimbal AA signal. Eyes were then perfusion fixed and cryosections prepared from 10/10 normal and 7/9 PACG eyes and immunolabeled for a vascular endothelial marker. RESULTS: Normal canine eyes showed segmental, circumferential limbal AA signal, whereas PACG eyes showed minimal or no AA signal. AA signal correlated with scleral lumens on OCT in normal dogs, but lumens were generally absent or flattened in PACG eyes. Collapsed vascular profiles were identified in tissue sections from PACG eyes, including those in which no lumens were identified on AA and OCT. CONCLUSIONS: In canine eyes with PACG, distal aqueous outflow channels are not identifiable by AA, despite normalization of their IOP, and intra-scleral vascular profiles are collapsed on OCT and histopathology.

Leveraging the Value of CDISC SEND Data Sets for Cross-Study Analysis: Incidence of Microscopic Findings in Control Animals.

Implementation of the Clinical Data Interchange Standards Consortium (CDISC)'s Standard for Exchange of Nonclinical Data (SEND) by the United States Food and Drug Administration Center for Drug Evaluation and Research (US FDA CDER) has created large quantities of SEND data sets and a tremendous opportunity to apply large-scale data analytic approaches. To fully realize this opportunity, differences in SEND implementation that impair the ability to conduct cross-study analysis must be addressed. In this manuscript, a prototypical question regarding historical control data (see Table of Contents graphic) was used to identify areas for SEND harmonization and to develop algorithmic strategies for nonclinical cross-study analysis within a variety of databases. FDA CDER's repository of >1800 sponsor-submitted studies in SEND format was queried using the statistical programming language R to gain insight into how the CDISC SEND Implementation Guides are being applied across the industry. For each component needed to answer the question (defined as "query block"), the frequency of data population was determined and ranged from 6 to 99%. For fields populated <90% and/or that did not have Controlled Terminology, data extraction methods such as data transformation and script development were evaluated. Data extraction was successful for fields such as phase of study, negative controls, and histopathology using scripts. Calculations to assess accuracy of data extraction indicated a high confidence in most query block searches. Some fields such as vehicle name, animal supplier name, and test facility name are not amenable to accurate data extraction through script development alone and require additional harmonization to confidently extract data. Harmonization proposals are discussed in this manuscript. Implementation of these proposals will allow stakeholders to capitalize on the opportunity presented by SEND data sets to increase the efficiency and productivity of nonclinical drug development, allowing the most promising drug candidates to proceed through development.

SEND harmonization & cross-study analysis: A proposal to better harvest the value from SEND data.

The Standard for Exchange of Nonclinical Data (SEND) identifies an approach for representing nonclinical data in a structured format which has been widely adopted by the pharmaceutical industry as it is required for data submission to the United States Food & Drug Administration (US FDA). The SEND Implementation Guide (SENDIG) allows for considerable flexibility in how data is represented; interpretation of these guidelines has led to significant variability in the approach to SEND dataset creation. The purposes of this manuscript are to identify common variability in certain SEND domains and to describe how variability can be managed to enable valuable cross-study analysis use cases. The example of extracting a commonly used data point, animal age, is used to illustrate the complexity and variability of SEND datasets. Developing a solution framework to the variability problem that includes all stakeholders involved in the creation and use of SEND datasets may enable future, routine analysis of warehoused SEND data. Harmonizing the implementation and use of SEND is expected to benefit all involved stakeholders and to ultimately contribute to the goal of increased productivity in nonclinical research.

Wound leakage rates of ex vivo uniplanar versus biplanar phacoemulsification clear corneal incisions in dogs.

OBJECTIVE: The purpose of this study was to compare the leakage rates of perilimbal uniplanar and biplanar clear corneal incisions in dogs when subjected to increased intraocular pressure (IOP) both from within the eye and via external pressure. PROCEDURE: Uniplanar clear corneal incisions were created in eight freshly enucleated canine eyes using a 3.2 mm straight slit knife while 8 fellow eyes received a biplanar clear corneal incision consisting of an approximately 300 µm deep groove followed by a 3.2 mm straight slit knife entry into the anterior chamber. Both wounds were reapposed using three simple interrupted 8-0 polyglactin 910 sutures. Eyes were cannulated with two 25 g needles: One connected to a pressure transducer, and the other connected to a reservoir of isotonic saline. The IOP at which the wound leaked was recorded when the intraocular pressure was increased internally by raising the height of the fluid bag, and again when the cornea was externally compressed. Kaplan-Meier survival curves compared incision types for each method of increasing IOP and were evaluated using Mantel-Cox log-rank analysis. RESULTS: Both wound types resisted leakage at IOP in the physiologically achievable range and no significant differences were observed between clear corneal incisions when pressure was applied externally (P = .353) or was increased from within the globe (P = .615). CONCLUSION: Ex vivo uniplanar and biplanar clear corneal incisions in dogs are equally strong, with no significant differences in leakage rates when IOP is increased internally or externally.

Tonometer validation and intraocular pressure reference values in the normal chinchilla (Chinchilla lanigera).

OBJECTIVES: To determine accuracy and precision of three commonly used tonometers (TonoVet® and TonoLab® (ICare Oy, Finland)-rebound tonometers, and Tono-Pen VET™ (Reichert, NY)-applanation tonometer) in normal chinchillas, and to establish a normal intraocular pressure (IOP) reference range in this species. METHODS: The anterior chambers of three chinchilla eyes were cannulated ex vivo and readings obtained at manometric IOPs from 5 to 80 mmHg, using each of the three tonometers in random order. Data were analyzed by linear regression, ANOVA, and Bland-Altman plots. Tonometry was performed in both eyes of 60 chinchillas (age 8 weeks-16.2 years) using the TonoVet® and relationship between age and IOP analyzed using linear regression. For all statistical tests, P < 0.05 was significant. RESULTS: Intraocular pressure values obtained using the Tono-Pen VET™ and TonoVet® (in dog calibration mode;'d') showed strong linear correlation with manometry within the physiologic and clinically relevant range of IOP (0-50 mmHg). The TonoVet® 'd' setting displayed significantly greater precision over the full range of IOP evaluated than the Tono-Pen VET™, and both TonoVet and Tono-Pen VET™ were significantly more accurate than the TonoLab® tonometer. Mean ± SD IOP (TonoVet® 'd') in chinchillas was 9.7 ± 2.5 mmHg, and the 95% reference interval was 4.7-14.7 mmHg. CONCLUSIONS: Both the Tono-Pen VET™ and TonoVet® provided clinically acceptable estimates of IOP in chinchillas. The TonoVet® provides accurate and precise IOP values, while Tono-Pen VET™ derived measurements showed greater variability. Values obtained either with the TonoLab® or TonoVet® used in the 'unspecified' calibration setting were inaccurate in this species.

Diastereoselective Synthesis of and Mechanistic Understanding for the Formation of 2-Piperidinones from Imines and Cyano-Substituted Anhydrides.

2-Piperidinones are synthesized in a single step from imines and 2-cyano glutaric anhydrides. The reaction provides the products in good diastereoselectivity and generates a quaternary stereogenic center. Substitutions on the anhydride skeleton are well tolerated to provide 2-piperidinones with three stereogenic centers from a single transformation. The pertinent transition structures have also been computed using quantum mechanics and reveal the key interactions controlling the stereochemical outcome of the reaction.

Construction of Stereogenic α,α-Disubstituted Cycloalkanones via 1° Amine Thiourea Dual Catalysis: Experimental Scope and Computational Analyses.

The mechanistic exploration and an expanded experimental discussion of the organocatalyzed, asymmetric Pfau-d'Angelo reaction by exploiting a bifunctional 1° amine thiourea catalyst system is disclosed. Notable breadth in substrate scope has been demonstrated on both the cyclic ketone moiety and the α,ß-unsaturated electrophile. Exploration into the matched and mismatched selectivity of this process with a ketone containing pre-existing stereocenters has been demonstrated. Computational analyses of the reaction mechanism are reported. In concert with kinetic isotope effect (KIE) experiments, these computational results provide a detailed understanding of the likely mechanism, including the aspects of the organocatalyst scaffold that are critical for stereoselectivity.

Towards theory driven structure elucidation of complex natural products: mandelalides and coibamide A.

The effectiveness of computational tools in determining relative configurations of complex molecules is investigated, using natural products mandelalides A-D and coibamide A, towards a generalized recipe for the scientific community at large. Ultimately, continuing efforts in this vein will accelerate and strengthen relative structure elucidation of complex molecules, such as natural products. Molecular mechanics conformational search, quantum mechanical NMR chemical shift predictions, and DP4 analyses led to confirmation of the revised structures of mandelalides A-D and coibamide A. All chiral centers in the northern hemisphere of mandelalides A-D are inverted with respect to the originally proposed structures, in agreement with recent total syntheses of mandelalide A by Ye, Fürstner & Carter. In the case of coibamide A, it was found that Fang & Su's revision, in which both the macrocycle [MeAla(11)] and the side chain [HIV(2)] residues are inverted from l to d, was consistent with the authentic natural product and computations.

Xenbase: expansion and updates of the Xenopus model organism database.

Xenbase (http://www.xenbase.org) is a model organism database that provides genomic, molecular, cellular and developmental biology content to biomedical researchers working with the frog, Xenopus and Xenopus data to workers using other model organisms. As an amphibian Xenopus serves as a useful evolutionary bridge between invertebrates and more complex vertebrates such as birds and mammals. Xenbase content is collated from a variety of external sources using automated and semi-automated pipelines then processed via a combination of automated and manual annotation. A link-matching system allows for the wide variety of synonyms used to describe biological data on unique features, such as a gene or an anatomical entity, to be used by the database in an equivalent manner. Recent updates to the database include the Xenopus laevis genome, a new Xenopus tropicalis genome build, epigenomic data, collections of RNA and protein sequences associated with genes, more powerful gene expression searches, a community and curated wiki, an extensive set of manually annotated gene expression patterns and a new database module that contains data on over 700 antibodies that are useful for exploring Xenopus cell and developmental biology.

Cross study analyses of SEND data: toxicity profile classification.

A SEND toxicology data transformation, harmonization, and analysis platform were created to improve the identification of unique findings related to the intended target, species, and duration of dosing using data from multiple studies. The lack of a standardized digital format for data analysis had impeded large-scale analysis of in vivo toxicology studies. The CDISC SEND standard enables the analysis of data from multiple studies performed by different laboratories. This work describes methods to analyze data and automate cross-study analysis of toxicology studies. Cross-study analysis can be used to understand a single compound's toxicity profile across all studies performed and/or to evaluate on-target versus off-target toxicity for multiple compounds intended for the same pharmacological target. This work involved development of data harmonization/transformation strategies to enable cross-study analysis of both numerical and categorical SEND data. Four de-identified SEND datasets from the BioCelerate database were used for the analyses. Toxicity profiles for key organ systems were developed for liver, kidney, male reproductive tract, endocrine system, and hematopoietic system using SEND domains. A cross-study analysis dashboard with a built-in user-defined scoring system was created for custom analyses, including visualizations to evaluate data at the organ system level and drill down into individual animal data. This data analysis provides the tools for scientists to compare toxicity profiles across multiple studies using SEND. A cross-study analysis of 2 different compounds intended for the same pharmacological target is described and the analyses indicate potential on-target effects to liver, kidney, and hematopoietic systems.

Toward implementing virtual control groups in nonclinical safety studies.

Historical data from control groups in animal toxicity studies is currently mainly used for comparative purposes to assess validity and robustness of study results. Due to the highly controlled environment in which the studies are performed and the homogeneity of the animal collectives it has been proposed to use the historical data for building so-called virtual control groups, which could replace partly or entirely the concurrent control. This would constitute a substantial contribution to the reduction of animal use in safety studies. Before the concept can be implemented, the prerequisites regarding data collection, curation and statistical evaluation together with a validation strategy need to be identified to avoid any impairment of the study outcome and subsequent consequences for human risk assessment. To further assess and develop the concept of virtual control groups the transatlantic think tank for toxicology (t4) sponsored a workshop with stakeholders from the pharmaceutical and chemical industry, academia, FDA, pharmaceutical, contract research organizations (CROs), and non-governmental organizations in Washington, which took place in March 2023. This report summarizes the current efforts of a European initiative to share, collect and curate animal control data in a centralized database and the first approaches to identify optimal matching criteria between virtual controls and the treatment arms of a study as well as first reflections about strategies for a qualification procedure and potential pitfalls of the concept.

Animal safety studies are usually performed with three groups of animals where increasing amounts of the test chemical are given to the animals and one control group where the animals do not receive the test chemical. The design of such studies, the characteristics of the animals, and the measured parameters are often very similar from study to study. Therefore, it has been suggested that measurement data from the control groups could be reused from study to study to lower the total number of animals per study. This could reduce animal use by up to 25% for such standardized studies. A workshop was held to discuss the pros and cons of such a concept and what would have to be done to implement it without threatening the reliability of the study outcome or the resulting human risk assessment.

Xenbase: gene expression and improved integration.

Xenbase (www.xenbase.org), the model organism database for Xenopus laevis and X. (Silurana) tropicalis, is the principal centralized resource of genomic, development data and community information for Xenopus research. Recent improvements include the addition of the literature and interaction tabs to gene catalog pages. New content has been added including a section on gene expression patterns that incorporates image data from the literature, large scale screens and community submissions. Gene expression data are integrated into the gene catalog via an expression tab and is also searchable by multiple criteria using an expression search interface. The gene catalog has grown to contain over 15,000 genes. Collaboration with the European Xenopus Research Center (EXRC) has resulted in a stock center section with data on frog lines supplied by the EXRC. Numerous improvements have also been made to search and navigation. Xenbase is also the source of the Xenopus Anatomical Ontology and the clearinghouse for Xenopus gene nomenclature.

A robust biostatistical method leverages informative but uncertainly determined qPCR data for biomarker detection, early diagnosis, and treatment.

As a common medium-throughput technique, qPCR (quantitative real-time polymerase chain reaction) is widely used to measure levels of nucleic acids. In addition to accurate and complete data, experimenters have unavoidably observed some incomplete and uncertainly determined qPCR data because of intrinsically low overall amounts of biological materials, such as nucleic acids present in biofluids. When there are samples with uncertainly determined qPCR data, some investigators apply the statistical complete-case method by excluding the subset of samples with uncertainly determined data from analysis (CO), while others simply choose not to analyze (CNA) these datasets altogether. To include as many observations as possible in analysis for interesting differential changes between groups, some investigators set incomplete observations equal to the maximum quality qPCR cycle (MC), such as 32 and 40. Although straightforward, these methods may decrease the sample size, skew the data distribution, and compromise statistical power and research reproducibility across replicate qPCR studies. To overcome the shortcomings of the existing, commonly-used qPCR data analysis methods and to join the efforts in advancing statistical analysis in rigorous preclinical research, we propose a robust nonparametric statistical cycle-to-threshold method (CTOT) to analyze incomplete qPCR data for two-group comparisons. CTOT incorporates important characteristics of qPCR data and time-to-event statistical methodology, resulting in a novel analytical method for qPCR data that is built around good quality data from all subjects, certainly determined or not. Considering the benchmark full data (BFD), we compared the abilities of CTOT, CO, MC, and CNA statistical methods to detect interesting differential changes between groups with informative but uncertainly determined qPCR data. Our simulations and applications show that CTOT improves the power of detecting and confirming differential changes in many situations over the three commonly used methods without excess type I errors. The robust nonparametric statistical method of CTOT helps leverage qPCR technology and increase the power to detect differential changes that may assist decision making with respect to biomarker detection and early diagnosis, with the goal of improving the management of patient healthcare.

Analysis of secondary pharmacology assays received by the US Food and Drug Administration.

Secondary pharmacology studies are a time-efficient and cost-effective method for determining the safety profile of a potential new drug before it enters human trials. The results of these multi-target screens are commonly submitted with Investigational New Drug (IND) applications, but there currently is little guidance on how such information is presented and which targets are chosen for testing. In this study, we expand on our previous analysis of secondary pharmacology reports by manually curating and analyzing all secondary pharmacology results received by the FDA received as part of an IND submission. A total of 1120 INDs submitted by 480 sponsors between 1999 and October 2020 were included in this study. The overall results were largely consistent with previous internal and external studies, showing that the most tested target in our set was the histamine 1 receptor (tested 938 times), the most hit target was sodium channel site 2 (hit 141 times), and the target with the highest hit percentage was the vesicular monoamine transporter 2 (hit 42.2% of the time). Additionally, this study demonstrated that improvements in the secondary pharmacology submission process, such as changes in formatting and nomenclature, could enhance the utility of these assays for regulatory review, including assisting with identifying the safety liabilities of a drug candidate early in development. This updated data set will allow FDA-industry collaborative working groups to continue developing the best methods for regulatory submission of secondary pharmacology data and evaluate the need for a standard target panel.

Aggregation and analysis of secondary pharmacology data from investigational new drug submissions at the US Food and Drug Administration.

Secondary pharmacology studies are utilized by the pharmaceutical industry as a cost-efficient tool to identify potential safety liabilities of drugs before entering Phase 1 clinical trials. These studies are recommended by the Food and Drug Administration (FDA) as a part of the Investigational New Drug (IND) application. However, despite the utility of these assays, there is little guidance on which targets should be screened and which format should be used. Here, we evaluated 226 secondary pharmacology profiles obtained from close to 90 unique sponsors. The results indicated that the most tested target in our set was the GABA benzodiazepine receptor (tested 168 times), the most hit target was adenosine 3 (hit 24 times), and the target with the highest hit percentage was the quinone reductase 2 (NQO2) receptor (hit 29% of the time). The overall results were largely consistent with those observed in previous publications. However, this study also identified the need for improvement in the submission process of secondary pharmacology studies by industry, which could enhance their utility for regulatory purpose. FDA-industry collaborative working groups will utilize this data to determine the best methods for regulatory submission of these studies and evaluate the need for a standard target panel.

Xenbase: a Xenopus biology and genomics resource.

Xenbase (www.xenbase.org) is a model organism database integrating a diverse array of biological and genomic data on the frogs, Xenopus laevis and Xenopus (Silurana) tropicalis. Data is collected from other databases, high-throughput screens and the scientific literature and integrated into a number of database modules covering subjects such as community, literature, gene and genomic analysis. Gene pages are automatically assembled from data piped from the Entrez Gene, Gurdon Institute, JGI, Metazome, MGI, OMIM, PubMed, Unigene, Zfin, commercial suppliers and others. These data are then supplemented with in-house annotation. Xenbase has implemented the Gbrowse genome browser and also provides a BLAST service that allows users to specifically search either laevis or tropicalis DNA or protein targets. A table of Xenopus gene synonyms has been implemented and allows the genome, genes, publications and high-throughput gene expression data to be seamlessly integrated with other Xenopus data and to external database resources, making the wealth of developmental and functional data from the frog available to the broader research community.

Sub-region-Specific Optic Nerve Head Glial Activation in Glaucoma.

Glaucoma, a multifactorial neurodegenerative disease characterized by progressive loss of retinal ganglion cells and their axons in the optic nerve, is a leading cause of irreversible vision loss. Intraocular pressure (IOP) is a risk factor for axonal damage, which initially occurs at the optic nerve head (ONH). Complex cellular and molecular mechanisms involved in the pathogenesis of glaucomatous optic neuropathy remain unclear. Here we define early molecular events in the ONH in an inherited large animal glaucoma model in which ONH structure resembles that of humans. Gene expression profiling of ONH tissues from rigorously phenotyped feline subjects with early-stage glaucoma and precisely age-matched controls was performed by RNA-sequencing (RNA-seq) analysis and complementary bioinformatic approaches applied to identify molecular processes and pathways of interest. Immunolabeling supported RNA-seq findings while providing cell-, region-, and disease stage-specific context in the ONH in situ. Transcriptomic evidence for cell proliferation and immune/inflammatory responses is identifiable in early glaucoma, soon after IOP elevation and prior to morphologically detectable axon loss, in this large animal model. In particular, proliferation of microglia and oligodendrocyte precursor cells is a prominent feature of early-stage, but not chronic, glaucoma. ONH microgliosis is a consistent hallmark in both early and chronic stages of glaucoma. Molecular pathways and cell type-specific responses strongly implicate toll-like receptor and NF-κB signaling in early glaucoma pathophysiology. The current study provides critical insights into molecular pathways, highly dependent on cell type and sub-region in the ONH even prior to irreversible axon degeneration in glaucoma.

Correction: The effect of uncertainty in patient classification on diagnostic performance estimations.

[This corrects the article DOI: 10.1371/journal.pone.0217146.].

The effect of uncertainty in patient classification on diagnostic performance estimations.

BACKGROUND: The performance of a new diagnostic test is typically evaluated against a comparator which is assumed to correspond closely to some true state of interest. Judgments about the new test's performance are based on the differences between the outputs of the test and comparator. It is commonly assumed that a small amount of uncertainty in the comparator's classifications will negligibly affect the measured performance of a diagnostic test. METHODS: Simulated datasets were generated to represent typical diagnostic scenarios. Comparator noise was introduced in the form of random misclassifications, and the effect on the apparent performance of the diagnostic test was determined. An actual dataset from a clinical trial on a new diagnostic test for sepsis was also analyzed. RESULTS: We demonstrate that as little as 5% misclassification of patients by the comparator can be enough to statistically invalidate performance estimates such as sensitivity, specificity and area under the receiver operating characteristic curve, if this uncertainty is not measured and taken into account. This distortion effect is found to increase non-linearly with comparator uncertainty, under some common diagnostic scenarios. For clinical populations exhibiting high degrees of classification uncertainty, failure to measure and account for this effect will introduce significant risks of drawing false conclusions. The effect of classification uncertainty is magnified further for high performing tests that would otherwise reach near-perfection in diagnostic evaluation trials. A requirement of very high diagnostic performance for clinical adoption, such as a 99% sensitivity, can be rendered nearly unachievable even for a perfect test, if the comparator diagnosis contains even small amounts of uncertainty. This paper and an accompanying online simulation tool demonstrate the effect of classification uncertainty on the apparent performance of tests across a range of typical diagnostic scenarios. Both simulated and real datasets are used to show the degradation of apparent test performance as comparator uncertainty increases. CONCLUSIONS: Overall, a 5% or greater misclassification rate by the comparator can lead to significant underestimation of true test performance. An online simulation tool allows researchers to explore this effect using their own trial parameters (https://imperfect-gold-standard.shinyapps.io/classification-noise/) and the source code is freely available (https://github.com/ksny/Imperfect-Gold-Standard).

Imaging Distal Aqueous Outflow Pathways in a Spontaneous Model of Congenital Glaucoma.

PURPOSE: To validate the use of aqueous angiography (AA) in characterizing distal aqueous outflow pathways in normal and glaucomatous cats. METHODS: Ex vivo AA and optical coherence tomography (OCT) were performed in nine adult cat eyes (5 feline congenital glaucoma [FCG] and 4 normal), following intracameral infusion of 2.5% fluorescein and/or 0.4% indocyanine green (ICG) at physiologic intraocular pressure (IOP). Scleral OCT line scans were acquired in areas of high- and low-angiographic signal. Tissues dissected in regions of high- and low-AA signal, were sectioned and hematoxylin and eosin (H&E)-stained or immunolabeled (IF) for vascular endothelial and perivascular cell markers. Outflow vessel numbers and locations were compared between groups by Student's t-test. RESULTS: AA yielded circumferential, high-quality images of distal aqueous outflow pathways in normal and FCG eyes. No AA signal or scleral lumens were appreciated in one buphthalmic FCG eye, though collapsed vascular profiles were identified on IF. The remaining eight of nine eyes all showed segmental AA signal, distinguished by differences in time of signal onset. AA signal always corresponded with lumens seen on OCT. Numbers of intrascleral vessels were not significantly different between groups, but scleral vessels were significantly more posteriorly located relative to the limbus in FCG. CONCLUSIONS: A capacity for distal aqueous humor outflow was confirmed by AA in FCG eyes ex vivo but with significant posterior displacement of intrascleral vessels relative to the limbus in FCG compared with normal eyes. TRANSLATIONAL RELEVANCE: This report provides histopathologic correlates of advanced diagnostic imaging findings in a spontaneous model of congenital glaucoma.