Atypical Eye Research Articles

Spectrum of Visual Dysfunction Detected by a Novel Testing Protocol Within a Special School Eye Care Service.

Children with special educational needs are more likely to have vision problems than peers in mainstream education. Reports focus on visual acuity and refraction, overlooking visuoperceptual difficulties, including cerebral visual impairment. This article reports on the feasibility and outcomes of visual function testing performed during in-school visual assessments. A retrospective chart review was undertaken of children participating in a special school vision programme. The testing strategy included acuity, fields, contrast sensitivity, eye movements, accommodation, stereopsis, visual attention, refraction and a parent-completed questionnaire. The testing method was chosen based on the child's ability to engage with testing. 78 cases were identified (mean age 9.6 years). Low vision (worse than 6/19) was identified in 31%. All six tests of visual function were completed by 44% (mean 5.1; range 2-6). The mean number of atypical responses was 1 (range 0-4). Almost half (49%) showed at least one atypical response, most commonly visual attention (35%) and 25% had atypical eye movements. Overall, only 20% of children in the special school setting demonstrated a normal response to each test they were able to complete. Acuity testing alone does not demonstrate the atypical visual function of a child with special needs. Using techniques which require minimal cognitive, speech or motor function, a range of visual functions can be elicited during in-school testing. This testing strategy has the advantage of demonstrating areas of visual (dys)function impacting on the child's ability to access learning which can be immediately fed back to teaching staff and carers.

Update on intraocular lens formulas.

This review aims to discuss recent advances in intraocular lens (IOL) power calculation, including newly introduced formulas, classification updates, comparative analyses between formulas, and emerging trends in the field. A significant number of modern IOL power calculation formulas have become available, incorporating both established and novel concepts such as artificial intelligence and ray tracing. A revised classification system has been introduced, reflecting the underlying principles of each formula. Recent comparative studies demonstrate the excellent refractive outcomes achievable with modern formulas. Emerging trends, such as the use of sum-of-segments axial length and the incorporation of measured posterior corneal data, hold promise for refining predictions in cases of extreme axial lengths and nonphysiological corneas, respectively. Advances in optimization and analytical methods also have the potential to further enhance refractive results. The field of IOL power calculation is continually evolving through iterative improvements in formula design, driven by new technologies, advanced instrumentation, and innovative analytical approaches. These advancements enable excellent refractive outcomes, even in atypical eyes.

The NM_033380.2 transcript of the COL4A5 gene contains a variable splice site c.4822-10T>C, which has been identified as a causative factor for Alport syndrome.

Alport Syndrome (AS) is a genetic kidney disorder characterized by progressive hearing loss and atypical eye symptoms, resulting in a poor prognosis and lack of effective targeted therapy. The primary mode of inheritance is X-linked dominant (XLAS) due to variants in the COL4A5 gene. This study revealed a previously unidentified alternative form of the COL4A5 gene, namely, the c.4822-10T>C variant, which was confirmed through in vitro experiments. To investigate the impact of a splicing variant on COL4A5 mRNA production, an in vitro minigene splicing assay was utilized. Additionally, molecular dynamics was employed to predict the ability of α5(IV) to form a triple helix. Results from the experiment revealed that the wild-type (WT) plasmid produced two distinct mRNA products simultaneously. Sequence analysis using the BLAST database revealed a 173-bp deletion in the mRNA sequence of the first product, indicating a potential similarity to the XM_016942897.2 transcript of Pan troglodytes. The second mRNA product of the WT plasmid contained the full sequence of exons 51, 52, and 53, as anticipated. Conversely, the mutant (MT) plasmid generated a single mRNA product with a 173-bp deletion in exon 52, leading to the identification of the mature mRNA expression as NM_033380.2: COL4A5: c.4822_4994del. In the context of nonsense-mediated mRNA decay (NMD), the deletion c.4822_4994 results in the production of a truncated protein, p.His1608*, that terminates prematurely. This truncated protein may disrupt the secondary structure of α5(IV) and potentially cause an abnormal conformation of α345(IV). This study examines the relationship between the variable splicing pattern in the NM_033380.2 transcript of the COL4A5 gene in XLAS patients and the presence of the COL4A5 gene splice variant c.4822-10T>C. Our findings indicate that the c.4822-10T>C splice variant leads to activation of nonsense-mediated mRNA degradation (NMD) and reduced COL4A5 mRNA expression, resulting in inadequate synthesis of the corresponding proteins. This aligns with the patient's immunofluorescence results showing negative α5(IV) chain presence at the glomerular basement membrane, bursa, and tubular basement membrane, confirming the pathogenic nature of c.4822-10T>C.

Deliberate and Self-Conscious Adaptation of Eye-Contact by Autistic Adults.

Eye gaze is widely recognised as an important element in managing social interactions, receiving information from others and communicating information about ourselves. Atypical eye gaze is one of the characteristic hallmarks of autism. Experimental research has contributed significantly to our knowledge of eye-gaze in autism, however, there is a lack of research exploring how autistic individuals describe and understand the phenomenological experience of eye-gaze and eye-contact. The current study explores the subjective experience of deliberate and self-conscious adaptation of eye-contact by autistic adults. Nine autistic adults were interviewed individually about their experiences of eye-contact. Audio recordings were transcribed, and analysed using Interpretative Phenomenological Analysis (IPA). Themes included gaining awareness of eye contact differences through feedback from others, the interaction of motivation to make eye-contact with a sense of autistic identity, difficulties listening when making eye contact, the importance of familiarity of conversational partners, and strategies to make eye-contact. This study makes an important and novel contribution to understanding the experience of eye-contact differences from the perspective of autistic adults themselves, highlighting the phenomenology of eye-contact as potentially aversive and the social pressure to engage in it, and exploring factors influencing effective eye-contact, with implications for psychological intervention.

Seeing through a robot's eyes: A cross-sectional exploratory study in developing a robotic screening technology for autism.

The present exploratory cross-sectional case-control study sought to develop a reliable and scalable screening tool for autism using a social robot. The robot HUMANE, installed with computer vision and linked with recognition technology, detected the direction of eye gaze of children. Children aged 3-8 (M = 5.52; N = 199) participated, 87 of whom had been confirmed with autism, 55 of whom were suspected to have autism, and 57 of whom were not considered to cause any concern for having autism. Before a session, a human experimenter instructed HUMANE to narrate a story to a child. HUMANE prompted the child to return his/her eye gaze to the robot if the child looked away, and praised the child when it re-established its eye gaze quickly after a prompt. The reliability of eye gaze detection was checked across all pairs of human raters and HUMANE and reached 0.90, indicating excellent interrater agreement. Using the pre-specified reference standard (Autism Spectrum Quotient), the sensitivity and specificity of the index tests (i.e., the number of robot prompts and duration of inattentiveness) reached 0.88 or above and the Diagnostic Odds Ratios were beyond 190. These results show that social robots may detect atypical eye patterns, suggesting a potential future for screening autism using social robots.

Infant responses to direct gaze and associations to autism: A live eye-tracking study.

When other people look directly towards us, we often respond by looking back at them, and such direct-gaze responses are important for establishing eye contact. Atypical eye contact is common in autism, but how and when this aspect of autism develops is not well understood. Here, we studied whether how much and how quickly infants respond to others' direct gaze is associated with autism in toddlerhood. We did this by measuring direct-gaze responses in a playful social interaction using live eye tracking. The study included 169 infants, of whom 129 had an elevated likelihood of developing autism due to having a first-degree family member with the condition, and 40 with typical likelihood of autism. In the elevated likelihood group, 35 were diagnosed with autism spectrum disorder at 3 years of age, and 94 were not. The results showed that infants in all three groups tended to increase their looking towards the adult's face after the adult looked directly at them. However, neither how much nor how quickly the infants responded to direct gaze by looking back at the adult reliably differentiated the infants with or without subsequent autism. While infants in the elevated likelihood of autism and subsequent diagnosis group tended to look away quicker from faces with direct gaze than infants in the typical likelihood group, this measure did not differentiate between the two elevated likelihood groups. We interpret the results as supporting the view that atypical direct-gaze responses are not early markers of autism.

The Current Burden and Future Solutions for Preoperative Cataract-Refractive Evaluation Diagnostic Devices: A Modified Delphi Study.

To obtain consensus on the key areas of burden associated with existing devices and to understand the requirements for a comprehensive next-generation diagnostic device to be able to solve current challenges and provide more accurate prediction of intraocular lens (IOL) power and presbyopia correction IOL success. Thirteen expert refractive cataract surgeons including three steering committee (SC) members constituted the voting panel. Three rounds of voting included a Round 1 structured electronic questionnaire, Round 2 virtual face-to-face meeting, and Round 3 electronic questionnaire to obtain consensus on topics related to current limitations and future solutions for preoperative cataract-refractive diagnostic devices. Forty statements reached consensus including current limitations (n = 17) and potential solutions (n = 23) associated with preoperative diagnostic devices. Consistent with existing evidence, the panel reported unmet needs in measurement accuracy and validation, IOL power prediction, workflow, training, and surgical planning. A device that facilitates more accurate corneal measurement, effective IOL power prediction formulas for atypical eyes, simplified staff training, and improved decision-making process for surgeons regarding IOL selection is expected to help alleviate current burdens. Using a modified Delphi process, consensus was achieved on key unmet needs of existing preoperative diagnostic devices and requirements for a comprehensive next-generation device to provide better objective and subjective outcomes for surgeons, technicians, and patients.

More Than Meets the Eye: IgG4-related Disease presentation as fluctuating ocular symptoms

A 13-year-old boy with seasonal allergies and purported mild asthma originally presented with a month-long history of bilateral upper eyelid swelling and pruritis to the emergency department. He had intermittent relief of symptoms on antihistamines. He was diagnosed with dacryocystitis and discharged on Bactrim and prednisone. Over the next month his eye swelling worsened, localizing to his right eye and developing pain despite extending antibiotics. He was then evaluated in hospital with a presumptive diagnosis of pre-septal cellulitis and admitted for IV antibiotics. He was discharged on Clindamycin and a referral to allergy/immunology was made. He continued to have poor response to outpatient treatment by Ophthalmology for presumed infectious dacryocystitis. Eventually, he was admitted for an excisional biopsy of his right lower lid and probing of his lacrimal system. Fibrotic tissue with some pus drainage was found at the time, cultures being eventually negative.The patient was evaluated by Allergy & Immunology where his symptoms did not fit a classic angioedema. Labs were obtained to rule out nephrotic syndrome and IgG4-related disease. Interestingly, patient’s IgG4 subclass was significantly elevated, and IHC staining was added on to the biopsy done with ophthalmology previous which supported the diagnosis of IgG4-related disease.IgG4- related disease is an immune-mediated fibroinflammatory disease with varied clinical presentation. Our case adds to the literature of IgG4-related disease with a curious case of a pediatric male patient with bilateral eye lid swelling which was wrongly treated as dacrocystitis. In conclusion, IgG4-related disease should be in the differential diagnosis of pediatric patients presenting with atypical eye swelling not fitting into angioedema.

Comparison of the accuracy of nine intraocular lens power calculation formulas using partial coherence interferometry.

Cataract surgery is the most performed procedure in the world. To achieve the target refraction, several intraocular lens (IOL) power calculation formulas have been developed to improve the accuracy of IOL power predictions. We compared the accuracy of 9 IOL power calculation formulas (SRK/T, Hoffer Q, Holladay 1, Haigis, Barrett Universal II, Kane, EVO 2.0, Ladas Super formula and Hill-RBF 3.0) using partial coherence interferometry (PCI). We collected data from patients who underwent uncomplicated cataract surgery with implantation of 1 of 3 IOL types currently used in our center. All preoperative biometric measurements were performed using PCI. Prediction errors (PE) were deduced from refractive outcomes evaluated 3 months after surgery. The mean prediction error (ME), mean absolute prediction error (MAE), median absolute prediction error (MedAE), and standard deviation of prediction error (SD) were calculated, as well as the percentage of eyes with a PE within ±0.25, ±0.50, ±0.75 and ±1.00D for each formula. We included 126 eyes of 126 patients. Kane achieved the lowest MAE and SD across the entire sample as well as the highest percentage of PE within ±0.50D and was shown to be more accurate than Haigis and Hoffer Q (P<001). For an axial length of more than 26.0mm, EVO 2.0 and Barrett obtained the lowest MAEs, with EVO 2.0 and Kane showing a higher percentage of prediction at ±0.50D compared to old generation formulas except for SRK/T (P=04). All investigated formulas achieved good results; there was a tendency toward better outcomes with new generation formulas, especially in atypical eyes.

Prediction of dyslexia severity levels from fixation and saccadic eye movement using machine learning

BackgroundDyslexia is a neurological disorder that causes poor reading and comprehension skills. Dyslexics experience problems in understanding phonemes of languages hence they show less ability to relate letters to form words and sentences. Dyslexia is not directly related to vision but it has been observed that most dyslexics have a magnocellular deficit which causes abnormal eye movements. From the literature, it has been observed that atypical eye movement could be a strong indicator of dyslexia. MethodsThis research work identifies the severity levels of dyslexia from fixations and saccade eye movement events based on eye gaze points. Fixations and saccades are computed using a velocity threshold algorithm. Features related to fixations and saccades are used to divide dyslexics into high and low based on their severity levels. Unsupervised learning approach K-Means clustering is adopted to group the dyslexics into high and low groups. Cluster evaluation measures such as Silhouette analysis, Elbow Method, and Davies Bouldin Index are used to find the optimal value of K. The quality of the clusters is further reinforced by Multivariate analysis of variance (MANOVA) analysis. Data in the clusters are visualized to understand the data distribution and range of different features. ResultsK-means clustering gave two clusters – high and low dyslexics. The Silhouette score was high and the Davies Bouldin Index was low showing that the clusters are of good quality. MANOVA analysis has given a p-value less than 0.01 which further reinforces the quality of clusters to be good. The data in clusters are visualized, analyzed, and compared to existing eye movement findings on dyslexia in literature. ConclusionIt has been observed that features such as fixation duration, number of fixations, saccade duration, and number of saccades act as key indicators to identify the severity levels of dyslexia. The characteristics of data in the clusters generated using these features match with the characteristics of existing eye movement findings, hence the data value ranges can be used to identify the severity levels of dyslexia.

Emotion recognition and eye tracking of static and dynamic facial affect: Acomparison of individuals with and without traumatic brain injury

ABSTRACT Diminished social functioning is often seen after traumatic brain injury (TBI). Mechanisms contributing to these deficits are poorly understood but thought to relate to impaired ability to recognize facial expressions. Static stimuli are often used to investigate ability post-TBI, and there is less evidence using more real-life dynamic stimuli. In addition, most studies rely on behavioral responses alone. The present study investigated the performance of a TBI group and matched non-TBI group on static and dynamic tasks using eye-tracking technology alongside behavioral measures. This is the first study to use eye tracking methodology alongside behavioral measures in emotion recognition tasks in people with brain injury. Eighteen individuals with heterogeneous TBI and 18 matched non-TBI participants were recruited. Stimuli representing six core emotions (Anger, Disgust, Fear, Happy, Sad, and Surprise faces) were selected from the Amsterdam Dynamic Facial Expression Set (ADFES). Participants were instructed to identify the emotion displayed correctly whilst eye movement metrics were recorded. Results Results of analyses showed that TBI patients had First Fixation to nose for all emotion stimuli, shorter Fixation Duration and lower Fixation Count to eyes, were generally slower to classify stimuli, and less accurate than non-TBI group for the static task. Those with TBI were also less accurate at identifying Angry, Disgust, and Fear stimulus faces compared to the non-TBI group during the dynamic unfolding of an emotion. Conclusion In the present study, those with TBI had atypical eye scan patterns during emotion identification in the static emotion recognition task compared to the non-TBI group and were associated with lower identification accuracy on behavioral measures in both static and dynamic tasks. Findings suggest potential disruption to oculomotor systems vital for first stage perceptual processing. Arguably, these impairments may contribute to diminished social functioning.

The Impaired Subcortical Pathway From Superior Colliculus to the Amygdala in Boys With Autism Spectrum Disorder.

ObjectiveIncreasing evidence suggests that a subcortical pathway from the superior colliculus (SC) through the pulvinar to the amygdala plays a crucial role in mediating non-conscious processing in response to emotional visual stimuli. Given the atypical eye gaze and response patterns to visual affective stimuli in autism, we examined the functional and white matter structural difference of the pathway in boys with autism spectrum disorder (ASD) and typically developing (TD) boys.MethodsA total of 38 boys with ASD and 38 TD boys were included. We reconstructed the SC-pulvinar-amygdala pathway in boys with ASD and TD using tractography and analyzed tract-specific measurements to compare the white matter difference between the two groups. A region of interest-based functional analysis was also applied among the key nodes of the pathway to explore the functional connectivity network.ResultsDiffusion tensor imaging analysis showed decreased fractional anisotropy (FA) in pathways for boys with ASD compared to TD. The FA change was significantly associated with the atypical communication pattern in boys with ASD. In addition, compared to TD, we found that the ASD group was associated with increased functional connectivity between the right pulvinar and the left SC.ConclusionOur results indicated that the functional and white matter microstructure of the subcortical route to the amygdala might be altered in individuals with autism. This atypical structural change of the SC-pulvinar-amygdala pathway may be related to the abnormal communication patterns in boys with ASD.

Damage to the human dentate gyrus impairs the perceptual discrimination of complex, novel objects

The hippocampus (HPC), and the dentate gyrus (DG) subregion in particular, is purported to be a pattern separator, orthogonally representing similar information so that distinct memories may be formed. The HPC may also be involved in complex perceptual discrimination. It is unclear if this role is limited to spatial/scene stimuli or extends to the discrimination of objects. Also unclear is whether the DG itself contributes to pattern separation beyond memory. BL, an individual with bilateral DG lesions, was previously shown to have poor discrimination of similar, everyday objects in memory. Here, we demonstrate that BL's deficit extends to complex perceptual discrimination of novel objects. Specifically, BL was presented with closely matched possible and impossible objects, which give rise to fundamentally different 3D perceptual representations despite being visually similar. BL performed significantly worse than controls when asked to select an odd object (e.g., impossible) amongst three identical counterpart objects (e.g., possible) presented at different rotations. His deficit was also evident in an atypical eye fixation pattern during this task. In contrast, BL's performance was indistinguishable from that of controls on other tasks involving the same objects, indicating that he could visually differentiate the object pairs, that he perceived the objects holistically in 3D, and that he has only a mild weakness in categorizing object possibility. Furthermore, his performance on standardized neuropsychological measures indicated intact mental rotation, visual-spatial attention, and working memory (visual and auditory). Collectively, these results provide evidence that the DG is necessary for complex perceptual discrimination of novel objects, indicating that the DG might function as a generic pattern separator of a wide range of stimuli within high-level perception, and that its role is not limited to memory.

Hidradenitis suppurativa and bilateral interstitial keratitis: A case report

Hidradenitis Suppurativa (HS) is a chronic inflammatory disease that cause painful abscess and nodules in skin that contain apocrine glands. While HS has known associations with several inflammatory disorders, a rare association is interstitial keratitis. We present a case of bilateral interstitial keratitis attributed to a severe flare of HS disease resulting in systemic inflammation. Other case reports have established that bilateral interstitial keratitis can be attributed to HS, as well as other eye symptoms and diseases. Despite the rarity of keratitis in patients with HS, clinicians should be aware that this association does exist when their HS patient presents with severe or atypical eye symptoms.

Clinical applications of personalising the neural components of visual image quality metrics for individual eyes.

Eyecare is evolving increasingly personalised corrections and increasingly personalised evaluations of corrections on-eye. This report describes individualising optical and neural components of the VSX (visual Strehl) metric and evaluates personalisation using two clinical applications. (1) Better understanding visual experience: While VSX tracks visual performance in typical eyes, non-individualised metrics underestimated visual performance in highly aberrated eyes - could this be understood by personalising metrics? (2) Metric-optimised objective spherocylindrical refractions in typical and atypical eyes have used neural weighting functions of typical eyes - will personalisation affect the outcome in clinical 0.25D steps? Orientation-specific neural contrast sensitivity was measured in four typical myopic and astigmatic eyes and six eyes with keratoconus. Wavefront error was measured in all eyes while uncorrected and when the keratoconic eyes wore wavefront-guided scleral lenses. Total experiment duration was 24-28h per subject. Two versions of VSX were calculated for each application: one weighted ocular optics with measured neural contrast sensitivity data from that eye, another weighted optics with a representative neural function of typical eyes. Wavefront-guided corrections were evaluated using the two metric values. Spherocylindrical corrections that optimised each metric were identified. Metric values for keratoconic eyes improved by a mean factor of 1.99 (~0.3log units) when personalised. Applying this factor to a larger sample of eyes from a previous keratoconus study reconciled dissonances between the percentage of eyes reaching normative best-corrected metric levels and the percentages of eyes reaching normative levels of visual acuity and contrast sensitivity. Spherocylindrical corrections that optimised both versions of VSX were clinically equivalent (mean±SD Euclidean dioptric difference 0.13±0.18 D). Personalising visual image quality metrics is beneficial when actual metric values are used (evaluating ophthalmic corrections on-eye against norms) and when fine increments in visual quality are imparted (wavefront-guided corrections). However, partially individualised metrics appear adequate when metrics relatively rank spherocylindrical corrections in 0.25 D steps.

Atypical Christmas Eye Disease: A Case Report and Literature Review

Background: Christmas Eye Disease (CED), also known as the “Albury-Wodonga syndrome” or “Harvester's Keratitis”, is a seasonal acute corneal ulceration syndrome, which is geographically limited to Australia, specifically in the south-west region of New South Wales (NSW) and north-east region of Victoria. The mechanism of injury is unknown, but the secretions from native beetles of the genus Orthoperus have been implicated. There remains a dearth of literature on CED, particularly with atypical disease presentations. We present the first reported case of CED in the upper Blue Mountains Region, presenting atypically with mild pain and foreign body sensation. We also aim to explore the possible entomological precipitants of the disease. Case Presentation: A 77-year-old man with a 1-day history of a mildly painful red eye was found to have acute corneal ulceration. He experienced mild discomfort in his right eye while asleep and woke the following morning with persistent blur, foreign body sensation, and photophobia. He had no history of ocular trauma or chemical exposure. He reported going for daily bushwalks in the upper Blue Mountains region but did not recall any exposure to environmental or entomological precipitants. Clinical Findings and Outcomes: Slit-lamp examination revealed a substantial corneal epithelial loss in the right eye with fluorescein staining, revealing a characteristic ‘green splash’ over 90% of the cornea. Other clinical findings included marked corneal edema, moderate conjunctival injection, mild palpebral swelling, and mild papillae. No anterior uveitis was observed, and the posterior segment examination was normal. There was a considerable reduction in his right visual acuity from baseline. He was empirically treated with 1% tropicamide ocular drops, 1% chloramphenicol ointment, and lubricant ocular drops. The bacterial and viral conjunctival swabs were unremarkable. Clinical progression was self-limiting, and complete resolution of the ulcer was achieved after one month. Conclusion: CED is a clinical diagnosis, and medical practitioners should be aware of atypical features, such as the absence of debilitating pain. Additionally, our case demonstrates that the geographic distribution of CED appears to be far more extensive than previously thought, thereby raising the possibility of disease manifestation in regions not commonly associated with it. Entomological precipitants of this condition remain circumstantial and warrant further validation.

Towards Autism Screening through Emotion-guided Eye Gaze Response.

Individuals with Autism Spectrum Disorder (ASD) are known to have significantly limited social interaction abilities, which are often manifested in different non-verbal cues of communication such as facial expression, atypical eye gaze response. While prior works leveraged the role of pupil response for screening ASD, limited works have been carried out to find the influence of emotion stimuli on pupil response for ASD screening. We, in this paper, design, develop, and evaluate a light-weight LSTM (Long-short Term Memory) model that captures pupil responses (pupil diameter, fixation duration, and fixation location) based on the social interaction with a virtual agent and detects ASD sessions based on short interactions. Our findings demonstrate that all the pupil responses vary significantly in the ASD sessions in response to the different emotion (angry, happy, neutral) stimuli applied. These findings reinforce the ASD screening with an average accuracy of 77%, while the accuracy improves further (>80%) with respect to angry and happy emotion stimuli.

A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites

Trilobites, extinct arthropods that dominated the faunas of the Palaeozoic, since their appearance c 523 million years ago, were equipped with elaborate compound eyes. While most of them possessed apposition compound eyes (in trilobites called holochroal eyes), comparable to the compound eyes of many diurnal crustaceans and insects living today, trilobites of the suborder Phacopina developed atypical large eyes with wide lenses and wide interspaces in between (schizochroal eyes). Here, we show that these compound eyes are highly sophisticated systems—hyper-compound eyes hiding an individual compound eye below each of the big lenses. Thus, each of the phacopid compound eyes comprises several tens, in cases even hundreds of small compound eye systems composing a single visual surface. We discuss their development, phylogenetic position of this hyper-compound eye, and its neuronal infrastructure. A hyper-compound eye in this form is unique in the animal realm.

A biomarker and endophenotype for anorexia nervosa?

Recent research has suggested that a type of atypical eye movement, called square wave jerks, together with anxiety, may distinguish individuals with anorexia nervosa from those without anorexia nervosa and may represent a biomarker and endophenotype for the illness. The aim of this study was to identify the presence of this proposed marker in individuals currently with anorexia nervosa relative to healthy controls, and to identify the state independence and heritability of this putative marker by exploring whether it also exists in individuals who are weight-restored from anorexia nervosa and first-degree relatives (i.e. sisters of people with anorexia nervosa). Data from 80 female participants (20/group: current anorexia nervosa, weight-restored from anorexia nervosa, sisters of people with anorexia nervosa and healthy controls) were analysed. Square wave jerk rate was acquired during a fixation task, and anxiety was measured with the State Trait Anxiety Inventory. Current anorexia nervosa, weight-restored from anorexia nervosa and sisters of people with anorexia nervosa groups made significantly more square wave jerks than healthy controls, but did not differ from one another. Square wave jerk rate and anxiety were found to discriminate groups with exceptionally high accuracy (current anorexia nervosa vs healthy control = 92.5%; weight-restored from anorexia nervosa vs healthy control = 77.5%; sisters of people with anorexia nervosa vs healthy control = 77.5%; p < .001). The combination of square wave jerk rate and anxiety was found to be a promising two-element marker for anorexia nervosa, and has the potential to be used as a biomarker or endophenotype to identify people at risk of anorexia nervosa and inform future treatments.

Estimation of the degree of autism spectrum disorder by the slow phase of optokinetic nystagmus in typical adults

Atypical eye movement patterns demonstrated by individuals with autism spectrum disorder (ASD) have the potential to serve as biomarkers for ASD diagnosis. However, instead of estimating individual differences in the degree of ASD from those patterns, many researchers have compared ASD groups with typical development groups. This study investigates the relationship between the Autism-spectrum Quotient (AQ) scores in typical adults, which can evaluate the degree of the traits associated with ASD, as well as the properties of optokinetic nystagmus (OKN), including the gain of the slow phase, the peak velocity and duration of the fast phase, the frequency, and the mean eye position of OKN. A random dot pattern that moved in one direction was presented on the display, and the participants' eye movements were measured. The results showed a negative correlation between subjects' AQ scores and the gain of slow-phase OKN. In addition, the correlations between subjects' AQ scores and the properties of OKN fast phase were not significant. These results indicate that the gain of slow-phase OKN could be a biomarker that estimates individual differences in the degree of ASD, reflected in our findings which considered AQ scores in typical adults.