Congenital levator synkinesis represents a complex spectrum of neurodevelopmental disorders characterized by involuntary coupling of eyelid movement with activation of extraocular or masticatory muscles. This review proposes a clinical classification of levator synkinesis into excitatory, inhibitory, and combined phenomena, based on whether synkinetic input results in eyelid elevation, depression, or a combination of both. The underlying pathophysiology is most consistent with a developmental dysinnervation process, likely involving aberrant neural connectivity "miswiring" or, supranuclear release of latent primitive pathways. Histopathologic evidence further supports a neurogenic etiology rather than primary myopathy. Surgical management, largely derived from experience with Marcus Gunn jaw-winking syndrome remains individualized and debated, ranging from levator-disabling procedures with frontalis suspension to more conservative levator-preserving approaches. Recognition of these entities is essential for accurate diagnosis, differentiation from simple congenital ptosis and acquired mimics, and appropriate surgical planning.

Accurate assessment of ocular toxicity, drug safety, and therapeutic efficacy remains a significant challenge due to the complex anatomy and physiology of the human cornea. Furthermore, conventional two-dimensional (2D) cell cultures and animal models have key limitations. Recent advances in alternative corneal models-three-dimensional (3D) tissue-engineered constructs, organ-on-chip platforms, corneal organoids, and bio-printed systems have transformed ophthalmic research by offering improved physiological relevance and translational value. These advanced models better recapitulate the multilayered architecture, biomechanical properties, fluid dynamics, and cellular microenvironment of the native cornea, enabling more accurate investigation of drug penetration, toxicity, wound healing, and disease mechanisms. In alignment with current National Institutes of Health (NIH) initiatives promoting the replacement, reduction, and refinement of animal research and the promotion of New Approach Methodologies (NAMs), this review examines emerging corneal models that collectively represent a paradigm shift in ophthalmic research. We first outline conventional in vivo and in vitro corneal models to provide historical context and their limitations, followed by a discussion of next-generation technologies. These include cornea-on-chip systems that integrate microfluidics to represent tear flow, blinking, and biomechanical forces; corneal organoids derived from pluripotent stem cells that offer self-organizing, human-specific platforms for disease modeling and safety assessment; and advances in 3D bioprinting enabling the fabrication of mechanically adjustable corneal constructs. The review also highlights the importance of bioinformatics/artificial intelligence in predicting ocular responses and complementing experimental platforms. Collectively, we emphasize that these alternative, emerging technologies support ethical science, improve translational accuracy, and meet federal regulations while reducing animal testing.

Meibomian gland (MG) dysfunction impairs the tear film lipid layer, which is critical for preventing aqueous evaporation and maintaining tear film stability. While a LipiView® II-reported mean lipid layer thickness (LLT) of ≥100 nm indicates a high- or ceiling-range device output rather than a calibrated absolute LLT, mean LLT alone may overlook clinically relevant information about the dynamic behavior of the tear film. This study aimed to evaluate whether qualitative variability in 20-s LipiView® II dynamic LLT traces is associated with MG morphology and ocular surface findings in eyes with device-reported high-range LLT values. In this retrospective, cross-sectional study, we analyzed 20-s dynamic LipiView® II recordings from eyes that were initially measured to have a mean LLT of ≥100 nm. Two masked observers classified LLT pattern variability as high or low based on predefined criteria. Clinical and demographic differences between the high- and low-variability groups were assessed statistically. Out of 85 eyes, 58 (68.2%) and 27 (31.8%) exhibited high- and low-variability, respectively. The high-variability group demonstrated markedly elevated meiboscores compared to the low-variability group, indicating a greater degree of MG dropouts (p = 0.042). Besides elevated meiboscores, patients in the high-variability group suffered from substantially worse dry eye disease (DED) symptoms, a trend toward higher corneal and conjunctival staining scores, and significantly increased blinking frequency (p < 0.05). Qualitative evaluation of LLT revealed increased meiboscores, greater severity of DED symptoms, and increased blinking frequency even in eyes with device-reported high-range mean LLT. LLT pattern analysis may warrant evaluation as an adjunctive approach for the early detection and targeted management of MG dysfunction-related evaporative DED.

Structural analysis using X-rays and electron beams has long provided the average arrangement of atoms and molecules-that is, "structural information"-with high precision. By contrast, static measurements cannot directly yield dynamic information on how a material changes over time; instead, information on motion is convolved into a single numerical value such as the B-factor (atomic displacement parameter). Taking this limitation as its starting point, this review surveys the recent trend of introducing a time axis into measurements to observe material dynamics directly. First, we outline the technological foundations that have made the transition from static to time-resolved measurement possible. It rests on the dramatic shortening of exposure times, enabled by the increased brilliance of X-ray and electron sources and by advances in detection technology such as direct photon-counting detectors. Next, we survey dynamic measurement techniques, including time-resolved X-ray crystallography, coherent X-ray scattering, neutron scattering, and time-resolved electron microscopy. We also point out the essential limitation that most of them still return ensemble or volume averages. Building on this, we systematically describe diffracted X-ray tracking (DXT), diffracted X-ray blinking (DXB), small-angle X-ray blinking (SAXB), transmitted X-ray blinking (TXB), and electron-beam molecular dynamics (EBMD), which use gold nanocrystals and gold nanoparticles as motion probes. We distinguish throughout between methods that follow individual objects-DXT and EBMD, which yield trajectories of single labeled molecules or single particles-and methods that analyze intensity fluctuations arising from many contributors within one pixel or illuminated volume-DXB, SAXB and TXB. The latter are not single-molecule measurements; rather, they replace a global ensemble average by a spatially localized statistical one, retaining local heterogeneity that a bulk measurement would average away. Finally, we discuss the implementation and prospects of the large-volume data analysis-principal component analysis, Bayesian inference, machine learning, and autonomous measurement-needed to handle the explosively increasing amount of information that the time axis introduces. We close with the outlook that time-resolved measurement incorporating AI and big-data analysis will become established as a new measurement platform that complements and extends conventional static structural analysis.

Nanoscale protein dynamics are closely associated with molecular function and pathological structure formation, yet their measurement within animal tissues remains technically challenging. In this study, we developed a diffracted X-ray blinking (DXB) method to evaluate amyloid-β (Aβ)-associated nanoscale fluctuations in fixed and permeabilized whole-mount Caenorhabditis elegans. Intracellular Aβ expressed in neurons (nAβ) or body-wall muscle cells (mAβ) was labelled with gold nanoparticles using an antibody-mediated strategy, without dissection or sectioning. The labelled worms produced detectable Au(111) diffraction signals, and the resulting time-resolved diffraction intensity fluctuations were analysed by autocorrelation function (ACF) analysis. A comparison of the ACF decay constants obtained from nAβ and mAβ worms revealed that compared with nAβ, mAβ contained a greater fraction of fast relaxation components. Furthermore, in-vitro DXB measurements of Aβ revealed local fast relaxation components that changed over time in association with changes in Aβ assemblies, partly resembling the Aβ-associated motional features observed in worms. These findings suggest that the detected relaxation components may reflect structurally diverse Aβ states arising during aggregation. These results demonstrate the feasibility of applying DXB to detect Aβ-associated nanoscale fluctuation signatures in fixed whole-mount C. elegans and provide a methodological framework for analysing protein-associated dynamic states in animal tissue samples.

This chapter reviews the development of looming motion perception in infancy, tracing the progression from early behavioral defensive behaviors, such as blinking, to contemporary EEG-based brain-computer interface approaches. Grounded in ecological optics, it examines how infants learn to detect approaching objects that signal impending collision and how this skill becomes increasingly refined with age and locomotor experience. Behavioral studies show that younger infants tend to rely on simpler cues, such as the visual angle of the approaching object, whereas older infants and crawlers increasingly use time-to-collision information for more accurate responses. High-density EEG studies extend these findings by revealing developmental changes in parieto-occipital brain activity, theta and alpha synchronization, and more efficient neural timing strategies. The chapter also highlights differences between full-term and preterm children, with preterm children showing poorer prospective control and delayed visual motion processing, resulting in sustained vulnerabilities in dorsal-stream function. Recent work further demonstrates that EEG-based BCI methods can detect infant perceptual responses to looming stimuli with promising classification accuracy, pointing toward future applications in early cognitive monitoring and intervention. Overall, the chapter presents looming perception as a powerful window into the developing perception-action system and a potential tool for identifying atypical developmental trajectories early.

Direct stochastic optical reconstruction microscopy (dSTORM) relies on controlled fluorophore blinking to achieve nanometer-scale resolution, yet the field's benchmark dye, Alexa Fluor 647, underperforms when conjugated to nanobodies, limiting the practical use of minimal-linkage labeling strategies. Here, we show that the self-blinking dye JF635b overcomes this limitation by maintaining robust, photostable blinking upon conjugation to nanobodies under buffer-independent conditions. This enables reliable single-molecule localization microscopy (SMLM) without the need for complex switching buffers. Using JF635b-labeled nanobodies, we demonstrate consistent performance across multiple imaging modalities, including wide-field dSTORM, fluorescence-lifetime SMLM, and MINFLUX nanoscopy, achieving localization precisions from ∼15 nm down to the subnanometer regime. In addition, JF635b supports long-term sample preservation and efficient blinking even in pure water, enabling minimally perturbative imaging conditions. Together, these results establish self-blinking dSTORM as a robust and accessible platform for quantitative nanoscopy across experimental contexts.

Dry eye disease (DED) is a common, multifactorial disorder of the ocular surface, and rising digital device use is increasingly recognised as a modifiable contributor. Digital eye strain (DES), a related but distinct symptom construct that also encompasses uncorrected refractive error and binocular vision anomalies, is reported in 50-90% of regular device users, compared with 5-50% for DED itself depending on diagnostic criteria; these figures should not be conflated. Reduced blink rate during screen viewing appears driven substantially by cognitive task demand rather than the screen itself, since a controlled comparison of matched digital and hard-copy reading found no difference in blink rate between formats. Incomplete blinking, however, was higher with the digital device and is independently associated with dry eye signs and symptoms in cross-sectional data, though that data did not measure device exposure and cannot establish that screen use causes the incomplete blinking seen in habitual users. No additional effect of contact lens wear on screen-related dryness was detected in one experimental study using 20-minute exposures; this is not evidence of no effect. Behavioural interventions, including the 20-20-20 rule, and oral omega-3 carry only low-certainty evidence, and a large randomised trial found omega-3 ineffective for dry eye more broadly. The 2023 Tear Film and Ocular Surface Society (TFOS) Lifestyle report comprehensively reviewed this literature and identified an unanswered question: no study has systematically tracked how ocular surface measurements change over time after digital device exposure ends. This review takes that gap as its focus. It argues that recent, unstandardised device exposure before ocular surface testing is a source of measurement error that has not been controlled for across the dry eye literature, examines the evidence for this effect, and proposes a research design and, informed by imaging tools that have become available since 2022, a feasible way to close the gap.

Congenital nasolacrimal duct obstruction (CNLDO) is defined as the failure of tear drainage through the nasolacrimal system during the neonatal period. Tear overflow resulting from this obstruction is termed epiphora. The prevalence of CNLDO ranges from 5% to 20%. A comprehensive study of 4792 infants in Great Britain showed that the prevalence of epiphora during the first year of life was 20%, with symptoms observed in 95% of affected infants by 1 month of age. A higher prevalence of CNLDO has been reported among premature infants. Bilateral involvement is observed in 14% to 34% of cases. Anisometropic amblyopia has also been reported in 10% to 12% of children with CNLDO. Therefore, all cases undergo a thorough ophthalmic examination and cycloplegic refraction, followed by careful follow-up for 3 to 4 years. In 1952, obstruction of the nasolacrimal duct was noted by Cassidy in 13 of 15 stillborn infants. His postulation that patency of the nasolacrimal duct is achieved within the first few days to weeks after birth is considered reasonable. Children most often present within a few months of birth with epiphora and, sometimes, mucoid discharge from one or both sides. However, even when symptoms have been present since birth, presentation may be delayed until several years of age. Other causes of epiphora in children must be excluded, including epiblepharon, congenital glaucoma, foreign bodies, corneal infections, and corneal dystrophies. Although the Jones 1 test, in which fluorescein dye is instilled into the eye and its presence in the nose is observed after 5 minutes, can be performed, it is now rarely used because the diagnosis can generally be confirmed by the clinical history and the presence of tearing and mucoid discharge. Similarly, the dye disappearance test may be performed over 5 minutes; however, significant false-positive and false-negative results may occur in infants. CNLDO is the most common cause of persistent epiphora in infants and young children and is among the most frequently encountered conditions in pediatric ophthalmology. Impaired drainage of tears through the lacrimal outflow system leads to tear overflow, intermittent mucous reflux, and recurrent periocular discharge despite normal tear production. Although the condition is generally benign and self-limiting, ocular surface health may be adversely affected by persistent obstruction, recurrent infections, increased caregiver anxiety, and occasional need for surgical intervention. Consequently, a thorough understanding of the embryology, anatomy, natural history, clinical spectrum, and management principles of CNLDO is essential for ophthalmologists, pediatricians, neonatologists, family physicians, and primary healthcare providers who care for infants. Considerable variability is observed in the clinical presentation of CNLDO. Some infants exhibit only mild, intermittent tearing under conditions of increased tear production. In contrast, others experience persistent epiphora with significant mucopurulent discharge, eyelash crusting, recurrent conjunctivitis, or lacrimal sac reflux that is elicited by digital pressure. Symptoms are often exacerbated during upper respiratory tract infections, allergic rhinitis, or exposure to cold and windy environments because mucosal edema may further compromise tear drainage. Symptom severity does not necessarily correlate with the degree of anatomical obstruction, and clinical manifestations may fluctuate over time. Although most cases are isolated developmental abnormalities, CNLDO is associated with craniofacial syndromes, chromosomal disorders, and congenital anomalies affecting the orbit or midface. Children with craniofacial dysostoses, cleft facial syndromes, trisomy 21, ectodermal dysplasias, and other congenital malformations may demonstrate abnormalities of the lacrimal drainage system, which may increase both the incidence and complexity of obstruction. Recognizing these associations is important because affected patients may require individualized evaluation, management, and modified surgical approaches. The natural history of CNLDO is favorable, with a high rate of spontaneous resolution during infancy. Progressive maturation of the lacrimal drainage pathway, combined with increased hydrostatic pressure generated by blinking and crying, frequently results in spontaneous canalization of residual membranous obstruction. Consequently, conservative management remains the initial treatment strategy for most infants during the early months of life. However, persistent obstruction beyond the period of expected spontaneous resolution may warrant procedural intervention to restore tear drainage and reduce the risk of recurrent infection and chronic symptoms. The timing of intervention should be individualized based on patient age, symptom severity, infection frequency, bilateral involvement, parental concerns, and response to conservative measures. The diagnosis of CNLDO is primarily clinical and requires careful differentiation from other causes of epiphora during infancy. Conditions such as congenital glaucoma, ocular surface disease, punctal abnormalities, canalicular obstruction, eyelid malposition, conjunctival inflammation, corneal pathology, and lacrimal drainage anomalies may produce similar symptoms but have substantially different prognosis and management approaches. A systematic ophthalmic examination is therefore essential to exclude vision-threatening disorders and to identify associated ocular abnormalities requiring additional investigation or treatment. In selected patients with atypical presentations, recurrent infections, failed primary interventions, or suspected complex lacrimal anomalies, further diagnostic evaluation using imaging or endoscopic techniques may be appropriate. Management strategies for CNLDO have evolved considerably over recent decades with advances in pediatric anesthesia, lacrimal endoscopy, minimally invasive instrumentation, and image-guided surgical techniques. A stepwise approach is currently used in the treatment of CNLDO, with conservative management emphasized during infancy and age-appropriate procedural interventions performed when spontaneous resolution fails. Options such as nasolacrimal duct probing, balloon catheter dilation, silicone tube intubation, and dacryocystorhinostomy have demonstrated excellent outcomes when appropriately selected based on patient age, anatomical findings, and prior treatment history. Emerging technologies, including nasal endoscopy and lacrimal endoscopy, have further improved visualization of the lacrimal drainage system and enhanced success rates in complex or recurrent cases. Beyond its direct clinical implications, CNLDO is associated with important psychosocial and healthcare considerations. Persistent tearing and discharge often cause significant parental concern because these symptoms may be mistaken for recurrent ocular infection or inadequate hygiene. Caregiver anxiety may be increased by repeated healthcare visits, prolonged use of topical medications, and uncertainty regarding the optimal timing of intervention. Effective counseling regarding the benign natural history of the condition, expected rates of spontaneous resolution, appropriate eyelid hygiene, and indications for referral or surgery is therefore an integral component of comprehensive patient care. Shared decision-making between clinicians and caregivers can promote realistic expectations and improve adherence to conservative management strategies. Recent research has focused on identifying predictors of spontaneous resolution, optimizing the timing of surgical intervention, improving minimally invasive lacrimal procedures, and evaluating long-term visual and refractive outcomes in affected children. Evidence-based management algorithms in pediatric ophthalmology continue to evolve, with individualized care guided by patient age, anatomical features, symptom burden, and associated ocular or systemic conditions.See Image. Management Algorithm for CNLDO. A comprehensive understanding of CNLDO, including its developmental basis, clinical manifestations, differential diagnosis, and evolving therapeutic options, remains fundamental to timely diagnosis, prevention of avoidable complications, and achievement of excellent functional and anatomical outcomes in infants and children. See Image. Differential Diagnosis of Epiphora in Infants.

Objective: To analyze the differences in blink patterns among patients with mild thyroid-associated ophthalmopathy (TAO, with eyelid retraction<2 mm), patients with primary dry eye disease (DED), and non-dry-eye controls, and to explore the association between these patterns and tear film stability. Methods: The data of patients who were admitted to the Department of Ophthalmology at Ningbo Medical Center Lihuili Hospital between July and September 2025 were retrospectively collected. Based on clinical features, patients were classified into three groups: mild TAO group, primary DED group, and non-dry-eye control group. All subjects underwent standardized ocular surface assessments. Dry eye-related parameters were measured, and spontaneous blink frequency and incomplete blink ratio were quantified. Intergroup differences were compared, correlations between blink patterns and dry eye parameters were analyzed, and multiple linear regression was performed to identify factors associated with incomplete blink ratio. Results: A total of 140 patients (140 eyes) were included. The mild TAO group comprised 45 patients (45 eyes; 19 males and 26 females), with a median age of 45 (31, 50) years. The primary DED group comprised 45 patients (45 eyes; 18 males and 27 females), with a median age of 40 (32, 54) years. The non-dry-eye control group comprised 50 subjects (50 eyes; 19 males and 31 females), with a median age of 40 (30, 50) years. No significant differences were observed in age or sex among the three groups (all P>0.05). Between the mild TAO group and the primary DED group, no significant differences were found in Schirmer test results, tear meniscus height, ocular redness score, meibomian margin morphology score, lipid layer saturation, or lipid spread speed (all P>0.05). However, non-invasive tear film breakup time (NIBUT) was significantly shorter in the mild TAO group than in the primary DED group [2.0 (2.0, 2.5) s vs 4.2 (2.4, 6.0) s, P<0.001]. The meibomian gland area ratio was higher in the mild TAO group than that in the primary DED group (P<0.001), but was comparable to that in the non-dry-eye control group (P=0.051). Blink frequency was lower in the mild TAO group than those in both the primary DED group (P=0.026) and the non-dry-eye control group (P<0.001). The incomplete blink ratio in the mild TAO group [50.0% (31.7%, 70.7%)] was significantly higher than that in the primary DED group [16.7% (7.7%, 26.7%)] and the non-dry-eye control group [5.6% (0, 11.1%)] (both P<0.001). In the mild TAO group, the incomplete blink ratio was strongly negatively correlated with NIBUT (rₛ=-0.826, P<0.001) and positively correlated with ocular surface disease index (OSDI) score (rₛ=0.320, P=0.032). Multiple linear regression showed that shortened NIBUT (β=-0.061, 95%CI:-0.093--0.029, P<0.001) and reduced blink frequency (β=-0.042, 95%CI:-0.053--0.030, P<0.001) were independently associated with an increased incomplete blink ratio. Conclusion: In patients with mild TAO who have minimized mechanical exposure (eyelid retraction<2 mm), an abnormal blink pattern characterized by increased incomplete blink ratio and decreased blink frequency is observed, and this pattern is significantly correlated with reduced tear film stability.