Quality assessment of polymer materials for human model eye development.

PURPOSE: We developed model eyes using six polymer materials to determine which materials were most appropriate in simulating real human sclera and extraocular muscle (EOM). METHODS: Five three-dimensional (3-D) printed polymers (FlexFill, PolyFlex, PCTPE, Soft PLA, and NinjaFlex) and one silicone material were systematically tested by board-certified ophthalmologists and senior ophthalmology residents. Material testing included scleral passes with 6-0 Vicryl sutures through each eye model. Participants completed a survey designed to collect demographic data, subjective assessment of each material's accuracy in simulating real human sclera and EOM, and a ranking for each polymer material to identify which would be most suitable for an ophthalmic surgery training tool. The Wilcoxon signed-rank test was conducted to determine if there was a statistically significant difference in the distribution of ranks between the polymer materials. RESULTS: The distribution of ranks for silicone material's "sclera" and "EOM" components were statistically significantly higher than that of all other polymer materials (all p < 0.05). Silicone material received the highest rank for both "sclera" and "EOM" components. Survey results indicated that the silicone material effectively simulated real human tissue. CONCLUSION: Silicone model eyes performed better than 3-D printed polymers as an educational tool for incorporation into a microsurgical training curriculum. Silicone models provide a low-cost teaching tool that allows for independent practice of microsurgical techniques without requiring a wet-laboratory facility.

Corneal Structural Changes in Congenital Glaucoma.

OBJECTIVE: To identify corneal structure differences on quantitative high-frequency ultrasound biomicroscopy (UBM) among subjects with congenital glaucoma compared with controls. METHODS: This prospective case-control study evaluated 180 UBM images from 44 eyes of 30 subjects (18 control and 12 glaucoma, mean age 5.2±8.0 years, range 0.2-25.8 years) enrolled in the Pediatric Anterior Segment Imaging and Innovation Study (PASIIS). ImageJ was used to quantify a comprehensive set of corneal structures according to 21 quantitative parameters. Statistical analysis compared corneal measurements in glaucoma subtypes and age-matched controls with significance testing and mixed effects models. RESULTS: Significant differences between congenital glaucoma cases and controls were identified in 16 of 21 measured parameters including angle-to-angle, central and peripheral corneal thicknesses, scleral integrated pixel density, anterior corneal radius of curvature, and posterior corneal radius of curvature. Eight parameters differed significantly between primary congenital glaucoma and glaucoma following congenital cataract surgery. CONCLUSION: Multiple measurable corneal structural differences exist between congenital glaucoma and control eyes, and between primary and secondary congenital glaucoma, including but not limited to corneal width and thickness. The structural differences can be quantified from UBM image analysis. Further studies are needed to determine whether corneal features associated with glaucoma can be used to diagnose or monitor progression of congenital glaucoma.

Thermocavitation: a mechanism to pulse fiber lasers.

In this paper, we present a novel mechanism for the generation of laser pulses based on the phenomenon of thermocavitation. Thermocavitation bubbles were generated within a glass cuvette filled with copper nitrate dissolved in water, where the tip of an optical fiber was placed very close to the bubble generation region. Once the bubble is generated, it expands rapidly and the incoming laser light transmitted through the optical fiber is reflected at the vapor-solution interface and reflected back into the fiber, which is coupled to an erbium-doped fiber ring laser. Laser pulses were extracted from the ring cavity and detected by a fast photodetector, which corresponds to a single thermocavitation event, obtaining a pulse repetition rate from 118 Hz to 2 kHz at 1560 nm, with a pulse width ranging from 64 to 57 µs. The repetition rate can be controlled by adjusting the laser power to induce thermocavitation. To our knowledge, this novel mechanism of laser pulses has not been reported in the literature.

Novel Homozygous Missense Variant in GJA3 Connexin Domain Causing Congenital Nuclear and Cortical Cataracts.

Congenital cataracts (CC) are responsible for approximately one-tenth of childhood blindness cases globally. Here, we report an African American family with a recessively inherited form of CC. The proband demonstrated decreased visual acuity and bilateral cataracts, with nuclear and cortical cataracts in the right and left eye, respectively. Exome sequencing revealed a novel homozygous variant (c.563A > G; p.(Asn188Ser)) in GJA3, which was predicted to be pathogenic by structural analysis. Dominantly inherited variants in GJA3 are known to cause numerous types of cataracts in various populations. Our study represents the second case of recessive GJA3 allele, and the first report in African Americans. These results validate GJA3 as a bona fide gene for recessively inherited CC in humans.

Theoretical and experimental study of acoustic waves generated by thermocavitation and its application in the generation of liquid jets.

Numerical simulations using the Finite-Difference Time-Domain method were used to study the propagation of an acoustic wave within a truncated ellipsoidal cavity. Based in our simulations, a fluidic device was designed and fabricated using a 3D printer in order to focus an acoustic wave more efficiently and expel a liquid jet. The device consists of an ellipsoidal shaped chamber filled with a highly absorbent solution at the operating wavelength (1064 nm) in order to create a vapor bubble using a continuous wavelength laser. The bubble rapidly expands and collapses emitting an acoustic wave that propagates inside the cavity, which was measured by using a needle hydrophone. The bubble collapse, and source of the acoustic wave, occurs in one focus of the cavity and the acoustic wave is focused on the other one, expelling a liquid jet to the exterior. The physical mechanism of the liquid jet generation is momentum transfer from the acoustic wave, which is strongly focused due to the geometry of the cavity. This mechanism is different to the methods that uses pulsed lasers for the same purpose. The maximum speed of the generated liquid microjets was approximately 20 m/s. One potential application of this fluidic device can be found for inkjet printing, coating and, maybe the most attractive, for drug delivery.

Indexing sensory plasticity: Evidence for distinct Predictive Coding and Hebbian learning mechanisms in the cerebral cortex.

The Roving Mismatch Negativity (MMN), and Visual LTP paradigms are widely used as independent measures of sensory plasticity. However, the paradigms are built upon fundamentally different (and seemingly opposing) models of perceptual learning; namely, Predictive Coding (MMN) and Hebbian plasticity (LTP). The aim of the current study was to compare the generative mechanisms of the MMN and visual LTP, therefore assessing whether Predictive Coding and Hebbian mechanisms co-occur in the brain. Forty participants were presented with both paradigms during EEG recording. Consistent with Predictive Coding and Hebbian predictions, Dynamic Causal Modelling revealed that the generation of the MMN modulates forward and backward connections in the underlying network, while visual LTP only modulates forward connections. These results suggest that both Predictive Coding and Hebbian mechanisms are utilized by the brain under different task demands. This therefore indicates that both tasks provide unique insight into plasticity mechanisms, which has important implications for future studies of aberrant plasticity in clinical populations.

Propofol-induced unresponsiveness is associated with impaired feedforward connectivity in cortical hierarchy.

BACKGROUND: Impaired consciousness has been associated with impaired cortical signal propagation after transcranial magnetic stimulation (TMS). We hypothesised that the reduced current propagation under propofol-induced unresponsiveness is associated with changes in both feedforward and feedback connectivity across the cortical hierarchy. METHODS: Eight subjects underwent left occipital TMS coupled with high-density EEG recordings during wakefulness and propofol-induced unconsciousness. Spectral analysis was applied to responses recorded from sensors overlying six hierarchical cortical sources involved in visual processing. Dynamic causal modelling (DCM) of induced time-frequency responses and evoked response potentials were used to investigate propofol's effects on connectivity between regions. RESULTS: Sensor space analysis demonstrated that propofol reduced both induced and evoked power after TMS in occipital, parietal, and frontal electrodes. Bayesian model selection supported a DCM with hierarchical feedforward and feedback connections. DCM of induced EEG responses revealed that the primary effect of propofol was impaired feedforward responses in cross-frequency theta/alpha-gamma coupling and within frequency theta coupling (F contrast, family-wise error corrected P<0.05). An exploratory analysis (thresholded at uncorrected P<0.001) also suggested that propofol impaired feedforward and feedback beta band coupling. Post hoc analyses showed impairments in all feedforward connections and one feedback connection from parietal to occipital cortex. DCM of the evoked response potential showed impaired feedforward connectivity between left-sided occipital and parietal cortex (T contrast P=0.004, Bonferroni corrected). CONCLUSIONS: Propofol-induced loss of consciousness is associated with impaired hierarchical feedforward connectivity assessed by EEG after occipital TMS.

Egg viability decreases rapidly with time since ovulation in the rainbow darter Etheostoma caeruleum: implications for the costs of choosiness.

Egg viability in the rainbow darter Etheostoma caeruleum, a fish apparently lacking female mate choice, was found to decline rapidly after ovulation. It was observed that the majority of a female's clutch may fail to hatch if she is prevented from mating for as little as 6 h. These data suggest that exercising female mate preferences may be selectively disfavoured in E. caeruleum due to the high cost of delaying mating.

Neurophysiologically-informed markers of individual variability and pharmacological manipulation of human cortical gamma.

The ability to quantify synaptic function at the level of cortical microcircuits from non-invasive data would be enormously useful in the study of neuronal processing in humans and the pathophysiology that attends many neuropsychiatric disorders. Here, we provide proof of principle that one can estimate inter-and intra-laminar interactions among specific neuronal populations using induced gamma responses in the visual cortex of human subjects - using dynamic causal modelling based upon the canonical microcircuit (CMC; a simplistic model of a cortical column). Using variability in induced (spectral) responses over a large cohort of normal subjects, we find that the predominant determinants of gamma responses rest on recurrent and intrinsic connections between superficial pyramidal cells and inhibitory interneurons. Furthermore, variations in beta responses were mediated by inter-subject differences in the intrinsic connections between deep pyramidal cells and inhibitory interneurons. Interestingly, we also show that increasing the self-inhibition of superficial pyramidal cells suppresses the amplitude of gamma activity, while increasing its peak frequency. This systematic and nonlinear relationship was only disclosed by modelling the causes of induced responses. Crucially, we were able to validate this form of neurophysiological phenotyping by showing a selective effect of the GABA re-uptake inhibitor tiagabine on the rate constants of inhibitory interneurons. Remarkably, we were able to recover the pharmacodynamics of this effect over the course of several hours on a per subject basis. These findings speak to the possibility of measuring population specific synaptic function - and its response to pharmacological intervention - to provide subject-specific biomarkers of mesoscopic neuronal processes using non-invasive data. Finally, our results demonstrate that, using the CMC as a proxy, the synaptic mechanisms that underlie the gain control of neuronal message passing within and between different levels of cortical hierarchies may now be amenable to quantitative study using non-invasive (MEG) procedures.

Computational neuroimaging strategies for single patient predictions.

Neuroimaging increasingly exploits machine learning techniques in an attempt to achieve clinically relevant single-subject predictions. An alternative to machine learning, which tries to establish predictive links between features of the observed data and clinical variables, is the deployment of computational models for inferring on the (patho)physiological and cognitive mechanisms that generate behavioural and neuroimaging responses. This paper discusses the rationale behind a computational approach to neuroimaging-based single-subject inference, focusing on its potential for characterising disease mechanisms in individual subjects and mapping these characterisations to clinical predictions. Following an overview of two main approaches - Bayesian model selection and generative embedding - which can link computational models to individual predictions, we review how these methods accommodate heterogeneity in psychiatric and neurological spectrum disorders, help avoid erroneous interpretations of neuroimaging data, and establish a link between a mechanistic, model-based approach and the statistical perspectives afforded by machine learning.

First detection and characterization of Salmonella spp. in poultry and swine raised in backyard production systems in central Chile.

Little is known about Salmonella serovars circulating in backyard poultry and swine populations worldwide. Backyard production systems (BPS) that raise swine and/or poultry are distributed across Chile, but are more heavily concentrated in central Chile, where industrialized systems are in close contact with BPS. This study aims to detect and identify circulating Salmonella serovars in poultry and swine raised in BPS. Bacteriological Salmonella isolation was carried out for 1744 samples collected from 329 BPS in central Chile. Faecal samples were taken from swine, poultry, geese, ducks, turkeys and peacocks, as well as environmental faecal samples. Confirmation of Salmonella spp. was performed using invA-polymerase chain reaction (PCR). Identification of serovars was carried out using a molecular serotyping approach, where serogroups were confirmed by a multiplex PCR of Salmonella serogroup genes for five Salmonella O antigens (i.e., D, B, C1, C2-C3, and E1), along with two PCR amplifications, followed by sequencing of fliC and fljB genes. A total of 25 samples (1·4% of total samples) from 15 BPS (4·6 % of total sampled BPS) were found positive for Salmonella. Positive samples were found in poultry (chickens and ducks), swine and environmental sources. Molecular prediction of serovars on Salmonella isolated showed 52·0% of S. Typhimurium, 16·0% of S. Infantis, 16·0% S. Enteritidis, 8·0% S. Hadar, 4·0% S. Tennessee and 4·0% S. Kentucky. Poor biosecurity measures were found on sampled BPS, where a high percentage of mixed confinement systems (72·8%); and almost half of the sampled BPS with improper management of infected mortalities (e.g. selling the carcasses of infected animals for consumption). Number of birds other than chickens (P = 0·014; OR = 1·04; IC (95%) = 1·01-1·07), mixed productive objective (P = 0·030; OR = 5·35; IC (95%) = 1·24-27·59) and mixed animal replacement origin (P = 0017; OR = 5·19; IC (95%) = 1·35-20·47) were detected as risk factors for BPS positivity to Salmonella spp. This is the first evidence of serovars of Salmonella spp. circulating in BPS from central Chile. Detected serovars have been linked to human and animal clinical outbreaks worldwide and in Chile, highlighting the importance of BPS on the control and dissemination of Salmonella serovars potentially hazardous to public health.

Serous cystic neoplasm of the pancreas: a multinational study of 2622 patients under the auspices of the International Association of Pancreatology and European Pancreatic Club (European Study Group on Cystic Tumors of the Pancreas).

OBJECTIVES: Serous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, including the specific mortality. DESIGN: Retrospective multinational study including SCN diagnosed between 1990 and 2014. RESULTS: 2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58 years (16-99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40 mm (2-200)), 9% had resection beyond 1 year of follow-up (3 years (1-20), size at diagnosis: 25 mm (4-140)) and 39% had no surgery (3.6 years (1-23), 25.5 mm (1-200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1 year (n=1271), size increased in 37% (growth rate: 4 mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1). CONCLUSIONS: After a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN. TRIAL REGISTRATION NUMBER: IRB 00006477.

Reliability and Determinants of Self-Evaluation of Breathing Questionnaire (SEBQ) Score: A Symptoms-Based Measure of Dysfunctional Breathing.

Dysfunctional breathing is characterised by an abnormal breathing pattern leading to respiratory symptoms. The 25-item Self Evaluation of Breathing Questionnaire (SEBQ) has been developed to measure breathing-related symptoms and their severity but lacks thorough evaluation. To determine reproducibility, internal consistency and predictors of SEBQ score, 180 participants completed an online SEBQ with additional demographic and lifestyle questions. Two weeks later, 155 of those repeated SEBQ. Test-retest correlation of the SEBQ was high [intraclass correlation coefficient (3, 1) = 0.89; 95 % CI 0.85-0.92]. There was no difference in SEBQ score between test and retest (15.1 (11.6) [mean (SD)] versus 14.7 (12.4); P = 0.4) and the score showed a typical error (standard error of measurement) of 4.0. Internal consistency was high (Cronbach's α = 0.93), and a single factor structure for items was shown. Smoking status, reported respiratory disease, recent respiratory illness and female gender were positively-associated predictors of SEBQ score, and together explained 25.6 % of score variance (P ≤ 0.001). The SEBQ has high test-retest reproducibility and its score may be predicted by current smoking, chronic respiratory disease, recent respiratory illness and female gender, thus may be a useful clinical screening tool for dysfunctional breathing.

A DCM study of spectral asymmetries in feedforward and feedback connections between visual areas V1 and V4 in the monkey.

This paper reports a dynamic causal modeling study of electrocorticographic (ECoG) data that addresses functional asymmetries between forward and backward connections in the visual cortical hierarchy. Specifically, we ask whether forward connections employ gamma-band frequencies, while backward connections preferentially use lower (beta-band) frequencies. We addressed this question by modeling empirical cross spectra using a neural mass model equipped with superficial and deep pyramidal cell populations-that model the source of forward and backward connections, respectively. This enabled us to reconstruct the transfer functions and associated spectra of specific subpopulations within cortical sources. We first established that Bayesian model comparison was able to discriminate between forward and backward connections, defined in terms of their cells of origin. We then confirmed that model selection was able to identify extrastriate (V4) sources as being hierarchically higher than early visual (V1) sources. Finally, an examination of the auto spectra and transfer functions associated with superficial and deep pyramidal cells confirmed that forward connections employed predominantly higher (gamma) frequencies, while backward connections were mediated by lower (alpha/beta) frequencies. We discuss these findings in relation to current views about alpha, beta, and gamma oscillations and predictive coding in the brain.

Reading front to back: MEG evidence for early feedback effects during word recognition.

Magnetoencephalography studies in humans have shown word-selective activity in the left inferior frontal gyrus (IFG) approximately 130 ms after word presentation ( Pammer et al. 2004; Cornelissen et al. 2009; Wheat et al. 2010). The role of this early frontal response is currently not known. We tested the hypothesis that the IFG provides top-down constraints on word recognition using dynamic causal modeling of magnetoencephalography data collected, while subjects viewed written words and false font stimuli. Subject-specific dipoles in left and right occipital, ventral occipitotemporal and frontal cortices were identified using Variational Bayesian Equivalent Current Dipole source reconstruction. A connectivity analysis tested how words and false font stimuli differentially modulated activity between these regions within the first 300 ms after stimulus presentation. We found that left inferior frontal activity showed stronger sensitivity to words than false font and a stronger feedback connection onto the left ventral occipitotemporal cortex (vOT) in the first 200 ms. Subsequently, the effect of words relative to false font was observed on feedforward connections from left occipital to ventral occipitotemporal and frontal regions. These findings demonstrate that left inferior frontal activity modulates vOT in the early stages of word processing and provides a mechanistic account of top-down effects during word recognition.

Polybrominated diphenyl ether (PBDE) concentrations and resulting exposure in homes in California: relationships among passive air, surface wipe and dust concentrations, and temporal variability.

Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in furniture foam, electronics, and other home furnishings. A field study was conducted that enrolled 139 households from California, which has had more stringent flame retardant requirements than other countries and areas. The study collected passive air, floor and indoor window surface wipes, and dust samples (investigator collected using an HVS3 and vacuum cleaner) in each home. PentaBDE and BDE209 were detected in the majority of the dust samples and many floor wipe samples, but the detection in air and window wipe samples was relatively low. Concentrations of each PBDE congener in different indoor environmental media were moderately correlated, with correlation coefficients ranging between 0.42 and 0.68. Correlation coefficients with blood levels were up to 0.65 and varied between environmental media and age group. Both investigator-collected dust and floor wipes were correlated with serum levels for a wide range of congeners. These two sample types also had a relatively high fraction of samples with adequate mass for reliable quantification. In 42 homes, PBDE levels measured in the same environmental media in the same home 1 year apart were statistically correlated (correlation coefficients: 0.57-0.90), with the exception of BDE209 which was not well correlated longitudinally.

Seasonal colour and antipredator behaviour in Etheostoma (Percidae).

This study examined how colour varies across season and sex in the fantail darter Etheostoma flabellare and the banded darter Etheostoma zonale. Etheostoma flabellare has male-only parental care and exhibited slight sexual dimorphism in overall colour, with no discernible effect of season on colour; whereas E. zonale does not have parental care and exhibited substantial sexual dimorphism in colour, but only in the breeding season. Additionally, antipredator behaviour of E. zonale was compared between males that were fully coloured during the breeding season and males that were partially coloured at that time, but the effects of colour and season were not consistent across males.

Anterior Chamber Depth and Lens Thickness Measurements in Pediatric Eyes: Ultrasound Biomicroscopy Versus Immersion A-Scan Ultrasonography.

OBJECTIVE: To compare anterior chamber depth (ACD) and lens thickness (LT) measurements by ultrasound biomicroscopy (UBM), A-scan cross vector (CV) overlay with UBM, and immersion A-scan technique in pediatric eyes. METHODS: This prospective comparative cohort study comprised 43 eyes of 25 pediatric participants (mean age: 2.3±2.2 y). UBM and immersion A-scan biometry were performed prior to dilation and intraocular surgery. ACD and LT were measured by UBM image analysis, A-scan CV UBM overlay, and immersion A-scan technique. RESULTS: ACD and LT measurements obtained using immersion A-scan were significantly greater than with UBM image analysis with mean differences of 0.52 mm and 0.62 mm, respectively (p < 0.001). Immersion A-scan and UBM measurements were moderately correlated (r = 0.70 and 0.64, p < 0.001). ACD and LT measurements obtained using CV overlay were not significantly different than UBM measurements and the values were strongly positively correlated (r = 0.95 and 0.93, p < 0.001). CONCLUSION: Immersion A-scan may overestimate ACD and LT compared to UBM in pediatric patients due to oblique placement of the A-scan probe relative to the optical axis. Supplemental use of UBM and/or CV overlay is indicated to improve measurement accuracy in pediatric patients who cannot reliably fixate due to the ability to confirm proper alignment of the probe with the pupil by visualizing the anterior segment.

Comparison of angle-to-angle distance and corneal diameter in pediatric eyes using ultrasound biomicroscopy.

OBJECTIVE: To investigate the relationship between corneal diameter and internal corneal span determined from angle-to-angle distance using ultrasound biomicroscopy (UBM) in an observational cross-sectional patient population comprised of 54 eyes (28 healthy control eyes, ages 0.1 to 11.3 years; 26 eyes with primary congenital glaucoma, ages 0.1 to 3.5 years) from 41 pediatric participants ages 0.1 to 11.3 years (mean age: 3±3 years, median age: 2 years). METHODS: Forty cornea photographs with reference ruler and 110 UBM images were obtained. Three observers measured horizontal and vertical corneal diameter and angle-to-angle distance in each cornea photo and UBM image using ImageJ and the average values were used. Main outcome measures were Pearson correlation coefficient, linear regression, mean difference between corneal diameter and angle-to-angle distance, and intra-class correlation coefficients among measurements from all three observers for each parameter. RESULTS: Corneal diameter and angle-to-angle distance had a strong positive correlation horizontally (Pearson r = 0.89, p<0.001) and vertically (r = 0.93, p<0.001). Correlation was consistent regardless of presence of primary congenital glaucoma and participant age. Regression analysis demonstrated a linear relationship between the parameters for horizontal (CD = 0.99*AA+0.28, R2 = 0.81, p<0.001) and vertical (CD = 0.91 *AA+1.32, R2 = 0.85, p<0.001) dimensions. Overall, reliability was good-excellent, ranging from an ICC of 0.76 for vertical corneal diameter to 0.90 for horizontal angle-to-angle distance. CONCLUSIONS: Based on the strong positive correlation found between corneal diameter and angle-to-angle distance in our study population, UBM image analysis can be used to accurately estimate corneal diameter from angle-to-angle distance in children with healthy eyes and primary congenital glaucoma. UBM may provide a useful intraocular alternative for estimating corneal diameter and monitoring diseases that affect the cornea in infants and children, such as congenital glaucoma.

Characterization of the anterior segment in Trisomy 21-associated cataract using ultrasound biomicroscopy.

Backgroundobjectives: To compare the structural anatomy of the anterior segment in pediatric Trisomy 21 (T21) subjects with and without cataracts to age-matched controls. Design: Prospective case-control study. Participants: 40 subjects (57 eyes) age 0-25 years old (9.1 ± 10.6 years). Methods: This prospective case-control study evaluated anterior segment measurements from ultrasound biomicroscopy (UBM) imaging on 342 images. Results: Among persons with T21 cataract, the iris was significantly thinner than T21 individuals without cataract (0.28 vs 0.32 mm, p = 0.0181). T21/cataract subjects also had significantly thinner lenses than subjects without cataract, regardless of whether they have T21 or are controls (3.1 mm vs 3.5 mm, p = 0.0074).Thinner lens (<3.5 mm) was insignificantly associated with increased odds of cataract (OR = 9.5 [0.872,104], p = 0.065). Thinner iris (<0.32 mm) was associated with increased odds of cataract (OR = 8.4 [1.188, 59.273], p = 0.033). Conclusions: These findings support the hypothesis that subtle quantitative anatomic variants are present in the anterior eye of individuals with T21. Specific anatomic variants are unique to the presence of cataract among subjects with T21.