Circadian Rhythm Disturbances in the Blind

The Role of Season, Sunlight, and Light Sensitivity in Self-Reported Depressive Symptoms by Adults With Visual Impairment

Purpose

Depression is common in people with visual impairment, and the onset may be influenced by aspects related to light. The aim was to explore the associations of season, sunlight, and light sensitivity with depressive symptoms in this population.

Methods

Data regarding self-reported depressive symptoms from seven cross-sectional studies conducted between 2009 and 2018 were combined with information concerning sensitivity to light, season on the date of self-report, and potential sunlight exposure in the 2 weeks prior to self-report. The latter was calculated by summing up the daily sunlight hours detected by the weather station nearest to the residence of each participant. Logistic regression analyses were performed to investigate the associations.

Results

Participants (N = 1925) experienced clinically significant depressive symptoms most often in winter (32.8%), followed by summer (27.4%), spring (26.2%), and fall (24.2%). The odds of experiencing depression in fall were significantly lower compared with winter (odds ratio [OR] = 0.67, P = 0.007). An increase in the hours of sunlight in the participant's environment was associated with lower odds to experience depressive symptoms (OR = 0.995, P = 0.011). People who were sensitive to bright light had higher odds of experiencing depressive symptoms (OR = 1.80, P < 0.001). Other differences found between subgroups were not consistent.

Conclusions

It seems likely that season, sunlight, and light sensitivity play a role in depression among people with visual impairment. Further research is needed, exploring the experiences in this population, the actual sunlight exposure using objective measures, and treatment options.

Translational Relevance

Clinicians should consider these factors when treating visually impaired patients with depressive symptoms.

Lighting the way: Exploring diurnal physical performance differences in school-aged visually impaired children and adolescents

Circadian rhythms play a pivotal role in governing various physiological processes, including physical performance. However, in individuals deprived of light perception, such as the blind, these circadian rhythms face disruption. This study aimed to explore the influence of disturbed circadian rhythms on short-term maximal physical performance in children and adolescents with visual impairment. Forty-five volunteers participated in this study, comprising 17 blind, 13 visually impaired, and 15 sighted participants. The participants underwent a series of tests assessing maximal isometric strength performance across two days. To mitigate the influence of morning session fatigue on the evening results, each participant group performed in two separate testing sessions (i.e. in the morning (7:00 h) and in the evening (17:00 h)) on non-consecutive days in a randomized and counterbalanced setting, with approximately 36 h of recovery time between sessions. To mitigate the impact of inter-individual differences on mean values and to account for the influence of age and sex on the studied variables, data were normalized. The outcomes revealed a significant diurnal variation in maximal isometric strength performance among sighted individuals, with peak performance observed in the evening. This pattern aligns with their well-entrained circadian rhythm. In contrast, blind and visually impaired individuals did not display significant diurnal variation, signaling disrupted circadian rhythms due to the absence of light perception. These findings emphasize the crucial consideration of circadian rhythms in assessments of physical performance, especially among participants with visual impairments.

Contribution of the eye and of opn4xa function to circadian photoentrainment in the diurnal zebrafish

The eye is instrumental for controlling circadian rhythms in mice and human. Here, we address the conservation of this function in the zebrafish, a diurnal vertebrate. Using lakritz (lak) mutant larvae, which lack retinal ganglion cells (RGCs), we show that while a functional eye contributes to masking, it is largely dispensable for the establishment of circadian rhythms of locomotor activity. Furthermore, the eye is dispensable for the induction of a phase delay following a pulse of white light at CT 16 but contributes to the induction of a phase advance upon a pulse of white light at CT21. Melanopsin photopigments are important mediators of photoentrainment, as shown in nocturnal mammals. One of the zebrafish melanopsin genes, opn4xa, is expressed in RGCs but also in photosensitive projection neurons in the pineal gland. Pineal opn4xa+ projection neurons function in a LIGHT ON manner in contrast to other projection neurons which function in a LIGHT OFF mode. We generated an opn4xa mutant in which the pineal LIGHT ON response is impaired. This mutation has no effect on masking and circadian rhythms of locomotor activity, or for the induction of phase shifts, but slightly modifies period length when larvae are subjected to constant light. Finally, analysis of opn4xa;lak double mutant larvae did not reveal redundancy between the function of the eye and opn4xa in the pineal for the control of phase shifts after light pulses. Our results support the idea that the eye is not the sole mediator of light influences on circadian rhythms of locomotor activity and highlight differences in the circadian system and photoentrainment of behaviour between different animal models.

Pediatric Cluster Headache Case Series: Symptomatic Cases and the Migraine Relationship

BACKGROUND

Current criteria help differentiate cluster headache from migraine. However, children may have overlapping features making it difficult to distinguish the 2 conditions, which may delay diagnosis. Differentiating cluster headache from migraine is important regarding treatment as well as diagnostic workup of secondary headache etiologies.

METHODS

Cases at a single pediatric children's hospital from 2015 to 2023 diagnosed with cluster headache before the age of 18 years were reviewed.

RESULTS

Twenty-five cases were identified of which 22 cases met criteria for either chronic, episodic, or probable cluster headache. Three cases were diagnosed with cluster headache by their provider, but documentation was insufficient to meet criteria for cluster headache. There were 16 females and 9 males between ages 6 and 17 years. Five cases were identified as symptomatic, 2 cases as chronic, 7 cases as episodic, and 13 cases as probable cluster headache. Symptomatic etiologies include Graves disease, optic neuritis, prolactinoma, hypothalamic pilocytic astrocytoma with carotid stenosis, and congenital right eye blindness. Migrainous features were common, including 76% with nausea, 36% with vomiting, 68% with photophobia, and 56% with phonophobia. Patients with cluster headache also had an independent diagnosis of migraine in 64%.

CONCLUSION

Children with cluster headache have a high frequency of migrainous symptoms and co-occurrent diagnosis of migraine. A careful history may differentiate cluster headache from migraine and treated accordingly. Children with cluster headache features should undergo screening for secondary causes with appropriate imaging and other studies. Except for prolactinoma, the symptomatic associations noted in this case series have not been reported before.

Evaluation of Sleep Quality and Fatigue in Patients with Usher Syndrome Type 2a

Purpose

To study the prevalence, level, and nature of sleep problems and fatigue experienced by Usher syndrome type 2a (USH2a) patients.

Design

Cross-sectional study.

Participants

Fifty-six genetically confirmed Dutch patients with syndromic USH2a and 120 healthy controls.

Methods

Sleep quality, prevalence, and type of sleep disorders, chronotype, fatigue, and daytime sleepiness were assessed using 5 questionnaires: (1) Pittsburgh Sleep Quality Index, (2) Holland Sleep Disorders Questionnaire, (3) Morningness-Eveningness Questionnaire, (4) Checklist Individual Strength, and (5) Epworth Sleepiness Scale. For a subset of patients, recent data on visual function were used to study the potential correlation between the outcomes of the questionnaires and disease progression.

Main Outcome Measures

Results of all questionnaires were compared between USH2a and control cohorts, and the scores of the patients were compared with disease progression defined by age, visual field size, and visual acuity.

Results

Compared with the control population, patients with USH2a experienced a poorer quality of sleep, a higher incidence of sleep disorders, and higher levels of fatigue and daytime sleepiness. Intriguingly, the sleep disturbances and high levels of fatigue were not correlated with the level of visual impairment. These results are in accordance with the patients' experiences that their sleep problems already existed before the onset of vision loss.

Conclusions

This study demonstrates a high prevalence of fatigue and poor sleep quality experienced by patients with USH2a. Recognition of sleep problems as a comorbidity of Usher syndrome would be a first step toward improved patient care. The absence of a relationship between the level of visual impairment and the severity of reported sleep problems is suggestive of an extraretinal origin of the sleep disturbances.

Financial Disclosures

Proprietary or commercial disclosure may be found after the references.

Association Between Vision-Related Functional Burden and Sleep Disorders in Adults Aged 20 and Over in the United States

Purpose

The impact of functional vision, rather than visual acuity, on sleep disorders is not well understood. This study estimated the relationship between vision-related functional burden and sleep disorders among a nationally representative sample in the United States.

Methods

Data from the National Health and Nutrition Examination Survey (NHANES) 2005-2008 were analyzed, which included a total of 10,914 US adults 20 years and older. Sleep disorders and vision-related functional burden were measured by the NHANES questionnaire sleep disorders section and vision section, respectively. Logistic regression was used to explore the association between vision-related functional burden and sleep disorders.

Results

A total of 9384 NHANES participants had complete functional vision and sleep disorders data. The mean age at baseline was 47.8 years, and the weighted prevalence of sleep disorders among adults with vision-related functional burden was 20.3%. After controlling for age, gender, race, smoking status, drinking frequency, general health condition, hypertension, diabetes, coronary heart disease, and depression, vision-related functional burden remained significantly associated with sleep disorders (adjusted odds ratio, 1.502; 95% confidence interval, 1.210-1.864; P < 0.001), whereas the association between presenting visual acuity and sleep disorders was not statistically significant.

Conclusions

Vision-related functional burden rather than impairment of visual acuity was related to the increased prevalence of sleep disorders in adults 20 years and older in the United States.

Translational Relevance

Our study provides insight into the relationship between functional vision and sleep disorders. It should be noted that individuals who report vision-related functional burden might be at risk of sleep disorders.

The Roles of Stress, Sleep, and Fatigue on Depression in People with Visual Impairments

The study aimed to investigate the mediating effect of fatigue and the moderating effect of sleep quality on stress and depressive symptoms among people with visual impairments. A total of 155 participants completed the online survey. The Perceived Stress Scale, the Fatigue Symptom Inventory, the Centre for Epidemiological Studies-Depression Inventory (CES-D), and the Pittsburgh Sleep Quality Index (PSQI) were used. Descriptive analysis, correlations, and moderated mediation modelling were conducted using R software. From the mediator variable (FSI) model (F = 22.427, R2 = 56.5, p < .001) and the dependent variable (CES-D) model (F = 35.912, R2 = 70.5, p < .001), after controlling for age, sex, employment, and education, sleep quality positively predicted fatigue levels (β = 2.422, p = .009), and fatigue positively predicted depressive symptoms (β = .152, p < .001). Sleep quality is an essential component of psychological well-being in people with visual impairments.

Congenital blindness does not protect against a schizophrenia-related phenotype in rodents

BACKGROUND

In 1950, Drs. Chevigny and Braverman authored a book about people's attitudes and prejudices toward the blind, noting that out of the thousands of schizophrenia patients they and others had treated, not one was blind. This led some to the intriguing hypothesis that congenital blindness may provide protection against schizophrenia. In this study, we directly examined whether congenital blindness protects against a schizophrenia-related phenotype in the methylazoxymethanol acetate (MAM) rodent model.

DESIGN

Enucleation surgeries were performed on pups of MAM- or saline-treated rats on post-natal day 10. Once pups reached adulthood, male and female rats were evaluated for schizophrenia-like phenotypes using behavioral and electrophysiological measures. Consistent with previous work, MAM-treated rats display elevated dopamine neuron population activity, deficits in pre-pulse inhibition of startle, and hypersensitivity to psychomotor stimulants.

RESULTS

Blindness did not protect against any of the MAM-induced phenotypes. Surprisingly, blindness in saline-treated rats caused changes in behavior and dopamine neuron activity. To examine the circadian rhythms of enucleated rats, we performed non-invasive measurements of corticosterone, a steroid hormone known to vary across the light/dark period, revealing blind rats display aberrant (non-cycling) corticosterone levels.

CONCLUSIONS

Alterations in dopamine neuron activity and associated behaviors observed in blind rats are likely secondary to aberrant circadian regulation. This is the first preclinical study examining whether congenital blindness protects against a schizophrenia-like phenotype. While support of this hypothesis would have led to novel avenues of research and potential novel therapies, the results of current study suggest that blindness does not protect against schizophrenia.

Association between sleep duration and myopia among Chinese children during the COVID-19 pandemic: A cross-sectional study

Background

The studies on the association between sleep duration and myopia are limited, and the evidence is inconsistent. This study aimed to evaluate the association between sleep duration and myopia, cycloplegic spherical equivalent (SE) and axial length (AL) among Chinese children during the Corona Virus Disease 2019 (COVID-19) pandemic.

Methods

The study was a cross-sectional study on Chinese children aged 6-18 years. The comprehensive ophthalmic examinations for children included cycloplegic SE, AL, and standardized questionnaires. The questionnaire included sleep duration, parental myopia, outdoor time, and continuous near work duration without breaks. Myopia was defined as SE ≤-0.50 diopters (D).

Results

A total of 1,140 children were included in the analyses, with 84.7% of myopic children and 74.4% of children's daily sleep duration being more than 8 h/d. In univariate regression analysis, compared with sleep duration < 8 h/d, children with sleep duration of 8-9 and >9 h/d were less myopia (p < 0.01 for all), and had less myopic SE (p < 0.01 for all), and shorter AL (p < 0.01 for all). After adjusting for age, gender, parental myopia, outdoor time, and continuous near work duration without breaks, sleep duration was not associated with myopia, cycloplegic SE, and AL (p > 0.05 for all).

Conclusions

This study showed sleep duration was related to myopia, cycloplegic SE, and AL among Chinese children during the COVID-19 pandemic-related lifestyles, but no independent association.

The impact of COVID-19 on the everyday life of blind and sighted individuals

The COVID-19 pandemic caused unexpected and unavoidable changes in daily life worldwide. Governments and communities found ways to mitigate the impact of these changes, but many solutions were inaccessible to people with visual impairments. This work aimed to investigate how blind individuals subjectively experienced the restrictions and isolation caused by the COVID-19 pandemic. To this end, a group of twenty-seven blind and seventeen sighted people took part in a survey addressing how COVID-19 impacted life practically and psychologically, how it affected their daily habits, and how it changed their experiences of themselves and others. Results demonstrated that both sighted and blind individuals had a hard time adapting to the new situation. However, while sighted people struggled more with personal and social aspects, the frustration of the blind population derived mostly from more practical and logistical issues. Likely as consequences, results showed that blind people engaged more in their inner life and experienced fear and anger as main emotions. This study suggests that changes in life associated with COVID-19 have been subjectively experienced differently based on the presence or not of blindness, and that tailored future interventions should be considered to take care of the different needs of blind individuals.

Chronotype, circadian rhythm, and psychiatric disorders: Recent evidence and potential mechanisms

The circadian rhythm is crucial for physiological and behavioral functions. Chronotype, which represents individual preferences for activity and performance, is associated with human health issues, particularly psychiatric disorders. This narrative review, which focuses on the relationship between chronotype and mental disorders, provides an insight into the potential mechanism. Recent evidence indicates that (1) the evening chronotype is a risk factor for depressive disorders and substance use disorders, whereas the morning chronotype is a protective factor. (2) Evening chronotype individuals with bipolar disorder tend to have more severe symptoms and comorbidities. (3) The evening chronotype is only related to anxiety symptoms. (4) The relationship between chronotype and schizophrenia remains unclear, despite increasing evidence on their link. (5) The evening chronotype is significantly associated with eating disorders, with the majority of studies have focused on binge eating disorders. Furthermore, the underlying mechanisms or influence factors are described in detail, including clock genes, brain characteristics, neuroendocrinology, the light/dark cycle, social factors, psychological factors, and sleep disorders. These findings provide the latest evidence on chronotypes and psychiatric disorders and serve as a valuable reference for researchers.

The vision of dreams: from ontogeny to dream engineering in blindness

The mechanisms involved in the origin of dreams remain one of the great unknowns in science. In the 21st century, studies in the field have focused on 3 main topics: functional networks that underlie dreaming, neural correlates of dream contents, and signal propagation. We review neuroscientific studies about dreaming processes, focusing on their cortical correlations. The involvement of frontoparietal regions in the dream-retrieval process allows us to discuss it in light of the Global Workspace theory of consciousness. However, dreaming in distinct sleep stages maintains relevant differences, suggesting that multiple generators are implicated. Then, given the strong influence of light perception on sleep regulation and the mostly visual content of dreams, we investigate the effect of blindness on the organization of dreams. Blind individuals represent a worthwhile population to clarify the role of perceptual systems in dream generation, and to make inferences about their top-down and/or bottom-up origin. Indeed, congenitally blind people maintain the ability to produce visual dreams, suggesting that bottom-up mechanisms could be associated with innate body schemes or multisensory integration processes. Finally, we propose the new dream-engineering technique as a tool to clarify the mechanisms of multisensory integration during sleep and related mental activity, presenting possible implications for rehabilitation in sensory-impaired individuals. The Theory of Proto-consciousness suggests that the interaction of brain states underlying waking and dreaming ensures the optimal functioning of both. Therefore, understanding the origin of dreams and capabilities of our brain during a dreamlike state, we could introduce it as a rehabilitative tool.

CITATION

Vitali H, Campus C, De Giorgis V, Signorini S, Gori M. The vision of dreams: from ontogeny to dream engineering in blindness. J Clin Sleep Med. 2022;18(8):2051-2062.

Dry-Lensectomy Assisted Lensectomy in the Management for End-Stage Familial Exudative Vitreoretinopathy Complicated With Anterior Segment Abnormalities

Purpose

To report a modified technique of dry-lensectomy assisted lensectomy in the management of end-stage familial exudative vitreoretinopathy (FEVR) complicated with capsule-endothelial, iris-endothelial adhesion and secondary glaucoma.

Methods

24 eyes of 16 patients with severe complications of advanced pediatric total retinal detachment caused by FEVR who received limbus-based dry-lensectomy were studied retrospectively. Preoperative and postoperative clinical information was collected and reviewed.

Results

Among the 24 eyes, three eyes (12.50%) underwent lensectomy combined with vitrectomy and membrane peeling simultaneously. 21 (87.50%) eyes underwent lensectomy without membrane peeling due to severe corneal opacity or retinal vascular activity, of which eight underwent another vitrectomy combined with membrane peeling. At the last visit (mean:13.86 ± 5.24 months of follow-up), all eyes had a reconstructed anterior chamber with normal depth. Among 21 eyes having preoperative corneal opacity, 15 (71.43%) had a clearer cornea with reduced opacity, 5 (23.81%) showed similar corneal opacification without deterioration. Among 11 eyes undergone retrolental fibroplasia peeling, seven (63.64%) eyes showed partial retinal reattachment in open-funnel type.

Conclusion

Dry-lensectomy offered a simple way to lower the intraocular pressure and simplified the surgery, which helped to solve the severe anterior segment complications and offer a chance for following retrolental fibroplasia peeling and potential visual gain for selected end-stage FEVR patients.

The Impact of COVID-19 on Sleep Quality in People Living With Disabilities

Background: Research exploring the impact of the COVID-19 pandemic on sleep in people with disabilities has been scarce. This study provides a preliminary assessment of sleep in people with disabilities, across two timepoints during the pandemic, with a focus on those with visual impairment (VI).

Methods: Two online surveys were conducted between April 2020 and March 2021 to explore sleep quality using the Pittsburgh Sleep Quality Index (PSQI). A convenience sample of 602 participants completed the first survey and 160 completed the follow-up survey.

Results: Across both timepoints, participants with disabilities reported significantly poorer global sleep quality and higher levels of sleep disturbance, use of sleep medication and daytime dysfunction than those with no disabilities. Participants with VI reported significantly higher levels of sleep disturbance and use of sleep medication at both timepoints, poorer global sleep quality, sleep duration and latency at time 1, and daytime dysfunction at time 2, than those with no disabilities. Global sleep quality, sleep duration, sleep efficiency, and self-rated sleep quality deteriorated significantly in participants with no disabilities, but daytime dysfunction increased in all three groups. Disability and state anxiety were significant predictors of sleep quality across both surveys.

Conclusion: While sleep was consistently poorer in people with disabilities such as VI, it appears that the COVID-19 pandemic has had a greater impact on sleep in people with no disabilities. State anxiety and, to a lesser extent, disability, were significant predictors of sleep across both surveys, suggesting the need to address anxiety in interventions targeted toward improving sleep.

Melatonin: From Neurobiology to Treatment

Melatonin, the major regulator of the sleep/wake cycle, also plays important physiological and pharmacological roles in the control of neuronal plasticity and neuroprotection. Accordingly, the secretion of this hormone reaches the maximal extent during brain development (childhood-adolescence) while it is greatly reduced during aging, a condition associated to altered sleep pattern and reduced neuronal plasticity. Altogether, these properties of melatonin have allowed us to demonstrate in both experimental models and clinical studies the great chronobiotic efficacy and sleep promoting effects of exogenous melatonin. Thus, the prolonged release formulation of melatonin, present as a drug in the pharmaceutical market, has been recently recommended for the treatment of insomnia in over 55 years old subjects.

International Expert Opinions and Recommendations on the Use of Melatonin in the Treatment of Insomnia and Circadian Sleep Disturbances in Adult Neuropsychiatric Disorders

Introduction: Insomnia and circadian rhythm disorders, such as the delayed sleep phase syndrome, are frequent in psychiatric disorders and their evaluation and management in early stages should be a priority. The aim of this paper was to express recommendations on the use of exogenous melatonin, which exhibits both chronobiotic and sleep-promoting actions, for the treatment of these sleep disturbances in psychiatric disorders. Methods: To this aim, we conducted a systematic review according to PRISMA on the use of melatonin for the treatment of insomnia and circadian sleep disorders in neuropsychiatry. We expressed recommendations for the use of melatonin in psychiatric clinical practice for each disorder using the RAND/UCLA appropriateness method. Results: We selected 41 studies, which included mood disorders, schizophrenia, substance use disorders, attention deficit hyperactivity disorders, autism spectrum disorders, neurocognitive disorders, and delirium; no studies were found for both anxiety and eating disorders. Conclusion: The administration of prolonged release melatonin at 2-10 mg, 1-2 h before bedtime, might be used in the treatment of insomnia symptoms or comorbid insomnia in mood disorders, schizophrenia, in adults with autism spectrum disorders, neurocognitive disorders and during sedative-hypnotics discontinuation. Immediate release melatonin at <1 mg might be useful in the treatment of circadian sleep disturbances of neuropsychiatric disorders.

Melatonin-Measurement Methods and the Factors Modifying the Results. A Systematic Review of the Literature

Melatonin plays an important role in regulating the sleep-wake cycle and adaptation to environmental changes. Concentration measurements in bioliquids such as serum/plasma, saliva and urine are widely used to assess peripheral rhythm. The aim of the study was to compare methods and conditions of determinations carried out with the identification of factors potentially affecting the measurements obtained. We have identified a group of modifiable and unmodifiable factors that facilitate data interpretation. Knowledge of modifiers allows you to carefully plan the test protocol and then compare the results. There is no one universal sampling standard, because the choice of method and biofluid depends on the purpose of the study and the research group.

Current concepts and techniques of vitrectomy for retinopathy of prematurity

Retinopathy of prematurity (ROP) is a leading cause of childhood blindness worldwide. ROP screening and interventions (e.g., laser ablation and anti-vascular endothelial growth factor [VEGF] therapy) at the right time can reduce disease activity and prevent retinal detachment. However, sometimes, ROP is refractory to treatment, leading to tractional retinal detachment (TRD), requiring surgical intervention, such as vitrectomy. Vitrectomy for Stage 5 ROP (total retinal detachment) is beneficial in preventing total blindness in some patients. However, it has poor anatomical and functional results. Vitrectomy (lens-sparing vitrectomy, if possible) should be performed at Stage 4A ROP (partial TRD not involving the macula) because the anatomical and functional results are much better.