Ocular Components Research Articles

Ocular Manifestations in Seborrheic Dermatitis Epidemiology, Clinical Features, and Management: A Comprehensive Review.

Seborrheic dermatitis (SD) often leads to ocular manifestations (OM) that are frequently overlooked. This study comprehensively explains the genesis of these ocular issues, which involves a combination of Malassezia overgrowth, changes in sebum production, and inflammatory responses in the body. The periocular region is rich in sebaceous glands, allowing Malassezia to thrive, which can lead to an inflammatory reaction that spreads to the eye surface, causing disorders such as blepharitis, conjunctivitis, keratitis, and ocular surface diseases. Although epidemiological data are limited, it is well established that ocular involvement occurs in approximately 10%-40% of individuals with SD. Early detection and treatment are crucial to prevent potential vision-threatening complications. A comprehensive diagnostic approach is necessary, including clinical examination, slit-lamp biomicroscopy, tear film analysis, and corneal imaging. Managing these conditions requires a multidisciplinary strategy involving collaboration between dermatologists and ophthalmologists. The treatment should involve topical and systemic medications to address the skin and ocular components. Patient education is critical for improving adherence to therapy, self-management, and the early identification of problems. In the future, it will be essential to investigate the intricate interactions between Malassezia species and host immunological processes. This collective effort will involve creating new biomarkers and diagnostic tools, investigating targeted immunomodulatory drugs and novel lipid-based medicines as potential treatments, and conducting large-scale longitudinal studies to understand the epidemiological patterns and prognostic variables better. By raising awareness, encouraging collaboration across disciplines, and advancing research, healthcare practitioners can significantly improve patients' quality of life with SD and OM.

Prediction of low-addition segmented refractive intraocular lens position and deviation using anterior-segment optical coherence tomography.

This study aimed to develop and analyze the accuracy of predictive formulae for postoperative anterior chamber depth, tilt, and decentration of low-added-segment refractive intraocular lenses. This single-center, retrospective, observational study included the right eyes of 96 patients (mean age: 72.43 ± 6.58 years), who underwent a cataract surgery with implantation of a low-added segmented refractive intraocular lens at the Medical University Hospital between July 2019 and January 2021, and were followed up for more than 1 month postoperatively. The participants were divided into an estimation group to create a prediction formula and a validation group to verify the accuracy of the formula. Anterior segment optical coherence tomography (CASIA 2, Tomey Corporation, Japan) and swept-source optical coherence tomography biometry (IOL Master 700, Carl Zeiss Meditec AG) were used to measure the anterior ocular components. A predictive formula was devised for postoperative anterior chamber depth, intraocular lens tilt, and intraocular lens decentration (p <0.01) in the estimation group. A significant positive correlation was observed between the estimated values calculated using the prediction formula and the measured values for postoperative anterior chamber depth (r = 0.792), amount of intraocular lens tilt (r = 0.610), direction of intraocular lens tilt (r = 0.668), and amount of intraocular lens decentration (r = 0.431) (p < 0.01) in the validation group. In conclusion, our findings reveal that predicting the position of the low-added segmented refractive intraocular lens enables the prognosis of postoperative refractive values with a greater accuracy in determining the intraocular lens adaptation.

Ocular Biometric Components in Hyperopic Children and a Machine Learning-Based Model to Predict Axial Length.

The purpose of this study was to investigate the development of optical biometric components in children with hyperopia, and apply a machine-learning model to predict axial length. Children with hyperopia (+1 diopters [D] to +10 D) in 3 age groups: 3 to 5years (n=74), 6 to 8years (n=102), and 9 to 11years (n=36) were included. Axial length, anterior chamber depth, lens thickness, central corneal thickness, and corneal power were measured; all participants had cycloplegic refraction within 6 months. Spherical equivalent (SEQ) was calculated. A mixed-effects model was used to compare sex and age groups and adjust for interocular correlation. A classification and regression tree (CART) analysis was used to predict axial length and compared with the linear regression. Mean SEQ for all 3 age groups were similar but the 9 to 11year old group had 0.49D less hyperopia than the 3 to 5year old group (P < 0.001). With the exception of corneal thickness, all other ocular components had a significant sex difference (P < 0.05). The 3 to 5year group had significantly shorter axial length and anterior chamber depth and higher corneal power than older groups (P < 0.001). Using SEQ, age, and sex, axial length can be predicted with a CART model, resulting in lower mean absolute error of 0.60 than the linear regression model (0.76). Despite similar values of refractive errors, ocular biometric parameters changed with age in hyperopic children, whereby axial length growth is offset by reductions in corneal power. We provide references for optical components in children with hyperopia, and a machine-learning model for convenient axial length estimation based on SEQ, age, and sex.

Effect of isoflurane anaesthetic time on ocular a-scan ultrasonography measures and their relationship to age and OCT measures in the Guinea pig

A-scan ultrasonography enables precise measurement of internal ocular structures. Historically, its use has underpinned fundamental studies of eye development and aberrant eye growth in animal models of myopia; however, the procedure typically requires anaesthesia. Since anaesthesia affects intra-ocular pressure (IOP), we investigated changes in internal ocular structures with isoflurane exposure and compared measurements with those taken in awake animals using optical coherence tomography (OCT). Continuous A-scan ultrasonography was undertaken in tri-coloured guinea pigs aged 21 (n = 5), 90 (n = 5) or 160 (n = 5) days while anaesthetised (up to 36 min) with isoflurane (5% in 1.5L/min O2). Peaks were selected from ultrasound traces corresponding to the boundaries of the cornea, crystalline lens, retina, choroid and sclera. OCT scans (Zeiss Cirrus Photo 800) of the posterior eye layers were taken in 28-day-old animals (n = 19) and compared with ultrasound traces, with choroid and scleral thickness adjusted for the duration of anaesthesia based on the changes modelled in 21-day-old animals. Ultrasound traces recorded sequentially in left and right eyes in 14-day-old animals (n = 30) were compared, with each adjusted for anaesthesia duration. The thickness of the cornea was measured in enucleated eyes (n = 5) using OCT following the application of ultrasound gel (up to 20 min). Retinal thickness was the only ultrasound internal measure unaffected by anaesthesia. All other internal distances rapidly changed and were well fitted by exponential functions (either rise-to-max or decay). After 10 and 20 min of anaesthesia, the thickness of the cornea, crystalline lens and sclera increased by 17.1% and 23.3%, 0.4% and 0.6%, and 5.2% and 6.5% respectively, whilst the anterior chamber, vitreous chamber and choroid decreased by 4.4% and 6.1%, 0.7% and 1.1%, and 10.7% and 11.8% respectively. In enucleated eyes, prolonged contact of the cornea with ultrasound gel resulted in an increase in thickness of 9.3% after 10 min, accounting for approximately half of the expansion observed in live animals. At the back of the eye, ultrasound measurements of the thickness of the retina, choroid and sclera were highly correlated with those from posterior segment OCT images (R2 = 0.92, p = 1.2 × 10−13, R2 = 0.55, p = 4.0 × 10−4, R2 = 0.72, p = 5.0 × 10−6 respectively). Furthermore, ultrasound measures for all ocular components were highly correlated in left and right eyes measured sequentially, when each was adjusted for anaesthetic depth. This study shows that the depth of ocular components can change dramatically with anaesthesia. Researchers should therefore be wary of these concomitant effects and should employ adjustments to better render ‘true’ values.

Neonatal Orthoptic Screening Battery (NOSB): Four-decade Experience of Orthoptic Best Practice

The present study describes the neonatal orthoptic screening battery (NOSB), a comprehensive orthoptic screening, based on four decades of application, aimed at early identification of signs and symptoms of ocular pathology or functional disorders. The NOSB allows for verifying the integrity of ocular components and early detection of functional alterations in ocular movements that could lead to the development of amblyopia or strabismus. The NOSB is the result of 45 years of screening activity in a primary health center assured by the National Health System in the city of Ragusa – Italy. It aims to examine and assess the neonate within the first 3 days of extrauterine life to identify visual system issues as early as possible. The NOSB may be conducted by Orthoptists, healthcare professionals specializing in neonatal and pediatric visual prevention. The Neonatal Orthoptic Screening battery (NOSB) here reported is proposed as a standard suitable for widespread adoption to be considered a "Best Practice".

THE RELATION BETWEEN SMARTPHONE USAGE IN CHANGES OF OCULAR BIOMETRY COMPONENTS AND REFRACTION AMONG ELEMENTARY SCHOOL CHILDREN

Abstract&#x0D; Introduction &amp; Objectives : Digital media is currently being increasingly used in recent years. The development of the visual system begins as soon as a child is born through visual stimulation and interaction with the environment that develops comprehensively with the general development of children. Smartphone usage affects eye developmental process. Explain the effect of ocular biometry components and refraction change in elementary school children due to duration of smartphone usage&#x0D; Methods : A one-year cohort prospective study was taken on 6-8-year-old children in the selected elementary school in South Sulawesi, Indonesia divided into two groups focused on the duration of smartphone usage and its relationship to changes in ocular biometric components and refraction.&#x0D; Results : The ocular biometry will develop in 6 and 12 months. The axial length, corneal diameter, keratometry, central corneal thickness, anterior chamber depth increased, spherical equivalent experienced a myopic shift, while the lens thickness decreased. Smartphone usage of more 3 hours had a significant difference compared to smartphone usage less than 3 hours in changes in the axial length of the eyeballs at 6 and 12 months, spherical equivalent on examination 12 (p&lt;0.05), while other tests were not significant (p&gt;0.05).&#x0D; Conclusion : Smartphone usage more than three hours per day will cause a significant change in ocular biometry and refraction

Quantitative analysis of crystalline lens and vitreous opacities

Intraocular light scattering affects the contrast of the image created on the retina thus reducing the vision quality. Although one can consider the ocular components transparent, the microstructural changes (that are associated with aging or other factors) lead to the increase in intraocular light scattering. Therefore, the opacification of ocular structures is associated with vision‐affecting diseases such as corneal dystrophies, crystalline lens cataracts, vitreous floaters etc.Optical coherence tomography (OCT) is a non‐invasive imaging modality enabling generation of micrometre resolution, two‐dimensional (2‐D) cross‐sectional images and three‐dimensional (3‐D) volumetric data presenting internal structure of optically scattering tissues. OCT detects light that is back‐scattered/back‐reflected at the optical in homogeneities within the ocular structures. Due to its high sensitivity, OCT enables detection of ultralow scattered light levels obtained from weakly scattering tissues such as the vitreous body.In this talk, we will demonstrate in vivo enhanced three‐dimensional visualization of vitreous and lens opacities in normal subjects and cataract patients of different ages using a swept source OCT (SS‐OCT) system deployed to the Laboratory of Optics at the University of Murcia, Spain. The instrument operated at the central wavelength of 1050 nm and was optimized to image the anterior segment of the eye. Volumetric images were used to effectively map the opacities and to generate en‐face projection images of opacities.The results revealed the changes in the transparency of the crystalline lens showing lens micro‐ and macro‐scale features related to cataract such as cortical spokes, water clefts and enhanced scattering in the lens nucleus. On the other hand, vitreous imaging with SS‐OCT allowed for visualization of gel vitreous, liquefied lacunae, Berger's space, retrolental laminae and fibrous opacifications.Volumetric OCT data of the lens and retrolental vitreous were used to perform quantitative analysis of light scattering (transparency). We introduced indices describing transparency and optical homogeneity of ocular structures. Later on, we showed that those biomarkers correlate with age. Finally, statistical association between transparency of crystalline lens / vitreous and degradation of visual function was performed.The proposed imaging platform can be a new‐generation ophthalmic diagnostic tool in the fundamental studies as well as for objective clinical evaluation and management of eye diseases.

Relationship between smartphone usage in changes of ocular biometry components and refraction among elementary school children

Relationship between smartphone usage in changes of ocular biometry components and refraction among elementary school children

The association between ocular biometric components and corneal aberrations

ABSTRACT Clinical relevance Evaluating factors affecting corneal higher-order aberration component has a very important role in interpreting the characteristics of the formed image on the retina. Background To determine the relationship between ocular biometric components and corneal higher-order aberrations in an elderly population. Methods This report is related to a subsample of the Tehran Geriatric Eye study (TGES), a population-based cross-sectional study that was conducted on individuals aged 60 years and above in Tehran city, Iran using multistage stratified random cluster sampling. All study participants underwent ocular examinations including visual acuity measurement, refraction and slit-lamp biomicroscopy. Anterior segment imaging and corneal aberrometry were performed using Pentacam AXL. Results In the present study, 644 eyes of 415 individuals (56.9% female) with mean age of 66.36 ± 4.70 years were evaluated. According to a multiple generalised estimating equation model, the root mean square of total higher-order aberrations was related to age (β = 0.081, p = 0.002), crystalline lens thickness (β = 0.08, p < 0.001), and corneal diameter (β = -0.04, p = 0.014). The root mean square of total coma aberration was directly related to the female sex (β = 0.02, p = 0.05), and crystalline lens thickness (β = 0.06, p < 0.001). There was a direct relationship between the root mean square of third- and fourth-order higher-order aberrations and crystalline lens thickness (p < 0.001). Spherical aberration was directly related to the male sex (β = -0.02, p = 0.004), axial length (β = 0.05, p < 0.001) and central corneal thickness (β = 0.001, p = 0.025), and was inversely related to anterior chamber depth (β = -0.07, p = 0.031) and crystalline lens thickness (β = -0.25, p < 0.001). Conclusion Ocular biometric components are related to corneal aberrations in the elderly. These factors need to be considered in respect of medical and surgical procedures required for the elderly.

Evaluation of orbital soft tissue biomechanical parameters in patients with thyroid eye disease using the non-contact Corvis ST.

In thyroid eye disease (TED), all ocular components and adnexa such as extraocular muscles, orbital adipose tissues, eyelids, and tear glands could be affected. This study aimed to study the orbital biomechanical parameters in patients with TED, in terms of differences with healthy individuals and correlation with clinical findings, using Corvis ST (CST, Oculus Wetzlar). In this study, 26 consecutive patients with TED were recruited. Demographic data were collected, and patients with TED were assessed for exophthalmos, intraocular pressure, and clinical activity score. Biomechanical response parameters of one randomly-chosen eye of each patient, including whole eye movement length (WEMl) and time (WEMt), were evaluated by the CST, and data were compared between patients and age- and gender-matched healthy controls. The mean age was 39.88 ± 11.61years old for patients with TED and 34.38 ± 8.57years old for the healthy subjects. Nine out of 26 patients with TED and nine of 26 healthy individuals were male. The median duration of thyroid disease was 36 (IQR 54) months and the median duration of thyroid ophthalmopathy was 27 (IQR 27) months. Four out of 26 patients (7.7%) had active disease. The mean WEMl was 206.15 ± 61.58µm in the TED group and 254.23 ± 64.01μm in the healthy group, the difference of which was statistically significant (p = 0.008). The median of WEMt was 20.90 (1.15) msec in the TED group and 21.45 (0.93) msec in the healthy group (p < 0.001). Also, the mean of WEMl and WEMt were lower in patients with active disease compared to patients with quiescent disease. The CST-derived WEMl was significantly smaller in patients with thyroid eye disease compared to normal subjects. The WEMl and WEMt were relatively shorter in the patients with active TED compared to the patients with quiescent TED, although small numbers of patients with active TED limits took a statistically significant conclusion. WEMl and WEMt might be useful in evaluating the compliance of the orbit in patients with TED.

Tracking gaze position from EEG: Exploring the possibility of an EEG-based virtual eye-tracker.

Ocular artifact has long been viewed as an impediment to the interpretation of electroencephalogram (EEG) signals in basic and applied research. Today, the use of blind source separation (BSS) methods, including independent component analysis (ICA) and second-order blind identification (SOBI), is considered an essential step in improving the quality of neural signals. Recently, we introduced a method consisting of SOBI and a discriminant and similarity (DANS)-based identification method, capable of identifying and extracting eye movement-related components. These recovered components can be localized within ocular structures with a high goodness of fit (>95%). This raised the possibility that such EEG-derived SOBI components may be used to build predictive models for tracking gaze position. As proof of this new concept, we designed an EEG-based virtual eye-tracker (EEG-VET) for tracking eye movement from EEG alone. The EEG-VET is composed of a SOBI algorithm for separating EEG signals into different components, a DANS algorithm for automatically identifying ocular components, and a linear model to transfer ocular components into gaze positions. The prototype of EEG-VET achieved an accuracy of 0.920° and precision of 1.510° of a visual angle in the best participant, whereas an average accuracy of 1.008°±0.357° and a precision of 2.348°±0.580° of a visual angle across all participants (N=18). This work offers a novel approach that readily co-registers eye movement and neural signals from a single-EEG recording, thus increasing the ease of studying neural mechanisms underlying natural cognition in the context of free eye movement.

Study on relationship between intraocular pressure and hyperthyroidism

Thyroid-associated ophthalmopathy (TAO) represents a persistent autoimmune inflammatory condition impacting various ocular components, including orbital fat (OF), extraocular muscles (EOMs), the eyeball, and associated eye structures. This disorder is closely associated with autoimmune thyroid pathology. A body of research has indicated an elevated susceptibility to heightened intraocular pressure (IOP) and glaucoma among individuals with thyroid-related ailments. Nonetheless, certain studies have expressed reservations about affirming these conclusions. Furthermore, there exists a diversity of viewpoints regarding the optimal approaches for managing elevated IOP in TAO patients afflicted with ocular hypertensionA prospective research investigation was undertaken within the Department of Ophthalmology at a Tertiary Care Teaching Hospital, spanning a duration of 12 months. The techniques employed for the diagnosis of open-angle glaucoma (OAG) have been comprehensively outlined. Goldmann applanation tonometry was utilized to determine intraocular pressure (IOP). Employing a Zeiss FF3 fundus camera, a series of dilated stereoscopic 300-color retinal and optic disc images were captured. The evaluation of optic disc photographs was conducted by one of two evaluators, both of whom remained masked to the study's particulars, employing a customized protocol. In order to ascertain optic disc dimensions, adjustments for camera magnification were performed, accounting for the spherical equivalent refraction of each individual eye.A total of 90 patients were examined. Of the 90 cases, male preponderance was noted. Among 90 patients, 20 (22.2%) were hyperthyroid, 61 (67.8%) were hypothyroid, and 9 (10%) patients were euthyroid. In our study shows the frequency of different symptoms among the study group. Most of the patients came with complaint itching of (27.8%). The second most common symptom was foreign body sensation (21.1%). In this study shows the different types of signs among these two groups. In hyperthyroid lid, retraction was more common (12%). In hypothyroid lid, edema was more common (18.5%). Frequency of dry eye syndrome in patients with TD was present; 29 (26.4%) patients had dry eye disease. Among 90 patients, proptosis was present in 4 patients had proptosis. Most of the patients were myopic.Our results imply the potential link between intraocular pressure (IOP) and thyroid-related disorders, particularly in individuals undergoing thyroxine treatment. Conducting further comprehensive investigations to explore and substantiate this prospective association is advisable.

Multifocal acoustic radiation force-based reverberant optical coherence elastography for evaluation of ocular globe biomechanical properties.

Quantifying the biomechanical properties of the whole eye globe can provide a comprehensive understanding of the interactions among interconnected ocular components during dynamic physiological processes. By doing so, clinicians and researchers can gain valuable insights into the mechanisms underlying ocular diseases, such as glaucoma, and design interventions tailored to each patient's unique needs. The aim of this study was to evaluate the feasibility and effectiveness of a multifocal acoustic radiation force (ARF) based reverberant optical coherence elastography (RevOCE) technique for quantifying shear wave speeds in different ocular components simultaneously. We implemented a multifocal ARF technique to generate reverberant shear wave fields, which were then detected using phase-sensitive optical coherence tomography. A 3D-printed acoustic lens array was employed to manipulate a collimated ARF beam generated by an ultrasound transducer, producing multiple focused ARF beams on mouse eye globes ex vivo. RevOCE measurements were conducted using an excitation pulse train consisting of 10 cycles at 3kHz, followed by data processing to produce a volumetric map of the shear wave speed. The results show that the system can successfully generate reverberant shear wave fields in the eye globe, allowing for simultaneous estimation of shear wave speeds in various ocular components, including cornea, iris, lens, sclera, and retina. A comparative analysis revealed notable differences in wave speeds between different parts of the eye, for example, between the apical region of the cornea and the pupillary zone of the iris (). Moreover, the study also revealed regional variations in the biomechanical properties of ocular components as evidenced by greater wave speeds near the apex of the cornea compared to its periphery. The study demonstrated the effectiveness of RevOCE based on a non-invasive multifocal ARF for assessing the biomechanical properties of the whole eyeball. The findings indicate the potential to provide a comprehensive understanding of the mechanical behavior of the whole eye, which could lead to improved diagnosis and treatment of ocular diseases.

Digital Health Technologies in Vision Care: Transforming Diagnostics and Management

A significant change in the diagnosis and treatment of ocular disorders has resulted from the integration of digital health technology in the field of ophthalmology. This thorough analysis looks at the broad influence and uses of digital solutions in vision care, including wearable technology, teleophthalmology, diagnostic tools, and artificial intelligence (AI) algorithms.&#x0D; With the use of digital imaging methods like fundus photography and optical coherence tomography (OCT), physicians may now see ocular components with previously unheard-of accuracy. These imaging modalities provide early illness identification and customised treatment plans when combined with AI-driven diagnostic tools.&#x0D; Platforms for teleophthalmology provide remote screenings, consultations, and monitoring, greatly enhancing access to specialised eye care. Artificial intelligence (AI)-powered telemonitoring systems and mobile applications provide real-time data transfer for effective illness management and prompt treatments.

High-resolution imaging of the whole eye with photoacoustic microscopy.

Observation and characterization of any changes in anatomical structures of ocular components remain as a conventional technique for diagnosis, staging, therapeutic treatments, and post-treatment monitoring of any ophthalmic disorders. The existing technologies fail to provide imaging of all of the various components of the eye simultaneously at one scanning time, i.e., one can recover vital patho-physiological information (structure and bio-molecular content) of the different ocular tissue sections only one after another. This article addresses the longstanding technological challenge by use of an emerging imaging modality [photoacoustic imaging (PAI)] in which we integrated a synthetic aperture reconstruction technique (SAFT). Experimental results-with experiments being conducted in excised tissues (goat eye)-demonstrated that we can simultaneously image the entire structure of the eye (∼2.5 cm) depicting clearly the distinctive ocular structures (cornea, aqueous humor, iris, pupil, eye lens, vitreous humor, and retina). This study uniquely opens an avenue for promising ophthalmic (clinical) applications of high clinical impact.

A-41 The Use of Virtual Reality for the Diagnosis of Pediatric Sports-Related Concussion: A Feasibility Study

Abstract Purpose Virtual Reality (VR) based concussion software has shown potential in diagnosing sports-related concussion (SRC). The purpose of this study was to explore potential symptom provocation when using a VR based diagnostic concussion software among SRC patients. Methods Pediatric SRC patients aged 12-18 and within 72 hours from injury to initial visit were recruited. While wearing the VR device, patients were instructed to fixate gaze on various targets to track eye movements in a gamified manner. The Post-Concussive Symptom Scale (PCSS) and Virtual Reality Sickness Questionnaire (VRSQ) were administered on a scale of 0 (none) to 3 (severe). Results A total of 21 patients were eligible (Age=14.9±1.7; Female 57.1%; White 61.9%). Patients noted minimal to no symptoms in terms of discomfort (.48±.60), fatigue (.48±.68), headache (1.48±.60), eye strain (.90±.77), inattention (.38±.59), blurred vision (.29±.64), and dizziness (.71±.56) while completing the VR task. Conclusions Compared to other studies using VRSQ among healthy subjects, our sample of acutely injured children with SRC reported minimally provoked symptoms that were below empirically established limits. Specifically, both components of the VRSQ (ocular component MOcu=3.24, SD=1.89; disorientation component MDis=2.59, SD=2.27) ranked below the average limit compared to other studies using VRSQ (MOcu=6.7; MDis=5.8). Future research should gather validity and reliability data to establish the clinical environment in which to diagnose pediatric SRC.

Immune Fingerprint in Diabetes: Ocular Surface and Retinal Inflammation.

Diabetes is a prevalent global health issue associated with significant morbidity and mortality. Diabetic retinopathy (DR) is a well-known inflammatory, neurovascular complication of diabetes and a leading cause of preventable blindness in developed countries among working-age adults. However, the ocular surface components of diabetic eyes are also at risk of damage due to uncontrolled diabetes, which is often overlooked. Inflammatory changes in the corneas of diabetic patients indicate that inflammation plays a significant role in diabetic complications, much like in DR. The eye's immune privilege restricts immune and inflammatory responses, and the cornea and retina have a complex network of innate immune cells that maintain immune homeostasis. Nevertheless, low-grade inflammation in diabetes contributes to immune dysregulation. This article aims to provide an overview and discussion of how diabetes affects the ocular immune system's main components, immune-competent cells, and inflammatory mediators. By understanding these effects, potential interventions and treatments may be developed to improve the ocular health of diabetic patients.

Parasympathetic and sympathetic control of emmetropization in chick

Emmetropization can be altered by temporal visual stimulation and the spectral properties of the visual environment. The goal of the current experiment is to test the hypothesis that there is an interaction between these properties and autonomic innervation. For that purpose, selective lesions of the autonomic nervous system were performed in chickens followed by temporal stimulation. Parasympathetic lesioning involved transection of both the ciliary ganglion and the pterygopalatine ganglion (PPG_CGX; n = 38), while sympathetic lesioning involved transection of the superior cervical ganglion (SCGX; n = 49). After one week of recovery, chicks were then exposed to temporally modulated light (3 days, 2 Hz, Mean: 680 lux) that was either achromatic (with blue [RGB], or without blue [RG]), or chromatic (with blue [B/Y] or without blue [R/G]). Control birds with lesions, or unlesioned, were exposed to white [RGB] or yellow [RG] light. Ocular biometry and refraction (Lenstar and a Hartinger refractometer) was measured before and after exposure to light stimulation. Measurements were statistically analyzed for the effects of a lack of autonomic input and the type of temporal stimulation.In PPG_CGX lesioned eyes, there was no effect of the lesions one-week post-surgery. However, after exposure to achromatic modulation, the lens thickened (with blue) and the choroid thickened (without blue) but there was no effect on axial growth. Chromatic modulation thinned the choroid with R/G.In the SGX lesioned eye, there was no effect of the lesion 1-week post-surgery. However, after exposure to achromatic modulation (without blue), the lens thickened and there was a reduction in vitreous chamber depth and axial length. Chromatic modulation caused a small increase in vitreous chamber depth with R/G.Both autonomic lesion and visual stimulation were necessary to affect the growth of ocular components. The bidirectional responses observed in axial growth and in choroidal changes suggest that autonomic innervation combined with spectral cues from longitudinal chromatic aberration may provide a mechanism for homeostatic control of emmetropization.

Analysis of dietary nitrate incorporation in porcine ocular tissues after supplementing 15N-labeled sodium nitrate

The mechanisms for the generation of nitric oxide (NO) include reduction of nitrate (NO 3 - ) and nitrite (NO 2 - ) as well as the classic nitric oxide synthase (NOS) pathways. In the reductive pathways, ingested nitrate is reduced to nitrite, mainly by oral bacteria and to some extent by tissue enzymes, then these nitrite ions can be reduced to NO by several endogenous proteins or, in stomach, by acid disproportionation. Dietary nitrate, rich in green leafy vegetables and beets, has beneficial effects in lowering blood pressure and improving vascular health by enhancing NO bioavailability. Previously, we showed that porcine eye components contain substantial amounts of nitrate and nitrite ions that are similar to those in blood. More importantly, cornea and sclera exhibited a nitrate reduction capability. To extend our knowledge on nitrate metabolism in the eye, in the present study, we fed pigs (Yorkshire domestic cross swine weighing 35-40kg, housed in an AAALAC (Association for Assessment and Accreditation of Laboratory Animal Care)-accredited facility with environmental enrichment) with either NaCl or Na 15 NO 3 and assessed the amount of 15 NO 3 - and 15 NO 2 - in various parts of the eye by LC-MS/MS at 3 or 24h after supplementation. We also measured the total concentrations of nitrate and nitrite ions using a standard chemiluminescence nitric oxide analyzer. At 3h, there was a marked increase in both 15 NO 3 - and 15 NO 2 - in all parts of the eye; in particular, aqueous and vitreous humor showed very high 15 NO 3 - contents (77.5 and 74.5% respectively), similar to plasma (77.1%) and even higher 15 NO 2 - contents (39.9% and 35.3% respectively) than plasma (19.8%). Cornea (64.4%) and sclera (63.4%) also showed notable increases in 15 NO 3 - content at 3h, then retina (48.8%) and lens (44.8%) followed. In 15 NO 2 - percent analysis at 3h, except aqueous and vitreous humor, other eye parts showed similar levels to plasma. At 24h, 15 NO 3 - contents decreased significantly compared to the 3h point, but it was still higher than the baseline in all ocular components. The 15 NO 2 - contents at 24h were almost back to the baseline. Absolute values of nitrate and nitrite ions in these tissues show similar patterns as shown in 15 N analysis. These results indicate that dietary nitrate supplementation has a vast impact on the levels of nitrate and nitrite and likely NO as well in the eye. NO generation via the nitrate-nitrite reductive pathway may contribute to various physiological and pathophysiological processes in the eye and may be useful therapeutically. This work was supported by intramural NIDDK/NIH grant ZIA DK 025104-15 to Alan N. Schechter. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A scalable corneal xenograft platform: simultaneous opportunities for tissue engineering and circular economic sustainability by repurposing slaughterhouse waste.

Introduction: Corneal disease is a leading cause of blindness globally that stems from various etiologies. High-throughput platforms that can generate substantial quantities of corneal grafts will be invaluable in addressing the existing global demand for keratoplasty. Slaughterhouses generate substantial quantities of underutilized biological waste that can be repurposed to reduce current environmentally unfriendly practices. Such efforts to support sustainability can simultaneously drive the development of bioartificial keratoprostheses. Methods: Scores of discarded eyes from the prominent Arabian sheep breeds in our surrounding region of the United Arab Emirates (UAE) were repurposed to generate native and acellular corneal keratoprostheses. Acellular corneal scaffolds were created using a whole-eye immersion/agitation-based decellularization technique with a widely available, eco-friendly, and inexpensive 4% zwitterionic biosurfactant solution (Ecover, Malle, Belgium). Conventional approaches like DNA quantification, ECM fibril organization, scaffold dimensions, ocular transparency and transmittance, surface tension measurements, and Fourier-transform infrared (FTIR) spectroscopy were used to examine corneal scaffold composition. Results: Using this high-throughput system, we effectively removed over 95% of the native DNA from native corneas while retaining the innate microarchitecture that supported substantial light transmission (over 70%) after reversing opacity, a well-established hallmark of decellularization and long-term native corneal storage, with glycerol. FTIR data revealed the absence of spectral peaks in the frequency range 2849cm-1 to 3075cm-1, indicating the effective removal of the residual biosurfactant post-decellularization. Surface tension studies confirmed the FTIR data by capturing the surfactant's progressive and effectual removal through tension measurements ranging from approximately 35mN/m for the 4% decellularizing agent to 70mN/m for elutes highlighting the effective removal of the detergent. Discussion: To our knowledge, this is the first dataset to be generated outlining a platform that can produce dozens of ovine acellular corneal scaffolds that effectively preserve ocular transparency, transmittance, and ECM components using an eco-friendly surfactant. Analogously, decellularization technologies can support corneal regeneration with attributes comparable to native xenografts. Thus, this study presents a simplified, inexpensive, and scalable high-throughput corneal xenograft platform to support tissue engineering, regenerative medicine, and circular economic sustainability.