Purpose: To investigate the impact of attention orientation in young myopic adults with astigmatism.
Methods: The effect of attention on foveal meridional performance and anisotropy was measured in corrected myopes with various levels of astigmatism (with-the-rule astigmatism ≤ -0.75D, Axis: 180 ± 20) using orientation-based attention. Attention was manipulated by instructing subjects to attend to either the horizontal or the vertical line of a central pre-stimulus (a pulsed cross) along separate blocks of trials. For each attention condition, meridional acuity and reaction times were measured via an annulus Gabor target situated remotely from the cross and presented at random horizontally and vertically in a two-alternative forced-choice employing two interleaved staircase procedures (one-up/one-down). Attention modulations were estimated by the difference in performance between horizontal and vertical attention.
Results: Foveal meridional performance and anisotropy were strongly affected by the orientation of attention, which appeared critical for the enhancement of reaction times and resolution. Under congruent orienting of attention, foveal meridional anisotropy was correlated with the amount of defocus for both reaction time and resolution, demonstrating greater vertical performance than horizontal performance as myopia increased. Compatible with an attentional compensation of blur through optimal orienting of attention, vertical attention enhanced reaction times compared to horizontal attention and was accompanied by an increase in overall acuity when myopia increased. Increased astigmatism was associated with smaller attention effects and asymmetry, suggesting potential deficits in the compensation of blur in astigmatic eyes.
Conclusion: Collectively, attention to orientation plays a significant role in horizontal-vertical foveal meridional anisotropy and can modulate the asymmetry of foveal perception imposed by the optics of the eye in episodes of uncorrected vision. Further work is necessary to understand how attention and refractive errors interact during visual development. These results may have practical implications for methods to enhance vision with attention training in myopic astigmats.
{"title":"Meridional Attentional Asymmetries in Astigmatic Eyes.","authors":"Elie de Lestrange-Anginieur","doi":"10.2147/EB.S407481","DOIUrl":"https://doi.org/10.2147/EB.S407481","url":null,"abstract":"<p><strong>Purpose: </strong>To investigate the impact of attention orientation in young myopic adults with astigmatism.</p><p><strong>Methods: </strong>The effect of attention on foveal meridional performance and anisotropy was measured in corrected myopes with various levels of astigmatism (with-the-rule astigmatism ≤ -0.75D, Axis: 180 ± 20) using orientation-based attention. Attention was manipulated by instructing subjects to attend to either the horizontal or the vertical line of a central pre-stimulus (a pulsed cross) along separate blocks of trials. For each attention condition, meridional acuity and reaction times were measured via an annulus Gabor target situated remotely from the cross and presented at random horizontally and vertically in a two-alternative forced-choice employing two interleaved staircase procedures (one-up/one-down). Attention modulations were estimated by the difference in performance between horizontal and vertical attention.</p><p><strong>Results: </strong>Foveal meridional performance and anisotropy were strongly affected by the orientation of attention, which appeared critical for the enhancement of reaction times and resolution. Under congruent orienting of attention, foveal meridional anisotropy was correlated with the amount of defocus for both reaction time and resolution, demonstrating greater vertical performance than horizontal performance as myopia increased. Compatible with an attentional compensation of blur through optimal orienting of attention, vertical attention enhanced reaction times compared to horizontal attention and was accompanied by an increase in overall acuity when myopia increased. Increased astigmatism was associated with smaller attention effects and asymmetry, suggesting potential deficits in the compensation of blur in astigmatic eyes.</p><p><strong>Conclusion: </strong>Collectively, attention to orientation plays a significant role in horizontal-vertical foveal meridional anisotropy and can modulate the asymmetry of foveal perception imposed by the optics of the eye in episodes of uncorrected vision. Further work is necessary to understand how attention and refractive errors interact during visual development. These results may have practical implications for methods to enhance vision with attention training in myopic astigmats.</p>","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/c9/21/eb-15-63.PMC10188198.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9483868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-25eCollection Date: 2022-01-01DOI: 10.2147/EB.S383231
Achim Fieß, Marilena Brandt, Eva Mildenberger, Michael Siegfried Urschitz, Felix Mathias Wagner, Stephanie Desiree Grabitz, Esther Maria Hoffmann, Norbert Pfeiffer, Alexander Konrad Schuster
Purpose: Prenatal growth restriction is associated with impaired neurodevelopment in childhood. This study investigated the effects of being born small for gestational age (SGA) on peripapillary retinal nerve fiber layer (pRNFL) thickness in adults born at term.
Methods: A retrospective cohort study was conducted with a prospective ophthalmologic examination of participants born at full-term (gestational age ≥37 weeks) between 1969 and 2002. All participants were examined with spectral-domain optical coherence tomography and grouped according to their birth weight in correlation to gestational age as former moderate (birth weight (BW) percentile 3rd to <10th) and severe SGA (<3rd percentile), normal (10th-90th percentile, AGA), and moderately (>90th to 97th percentile) and severely (>97th percentile) large for gestational age (LGA) adults (18 to 52 years).
Results: Overall, 547 eyes of 285 individuals (age 29.9±9.4 years, 151 females) born at term were included. Multivariable regression analyses revealed a strong association between a lower global pRNFL thickness in the severe SGA (B=-8.99 [95%-CI: -12.68; -5.30] µm; p<0.001) and in the moderate SGA groups (B=-6.40 [95%-CI: -10.29; -2.50] µm; p=0.001) compared to the reference AGA group.
Conclusion: Our results indicate that restricted fetal growth affects neurologic tissue development of the optic nerve head, particularly in individuals born severely SGA at term. This indicates that fetal growth restriction may exert disturbances in the development of neurologic tissue, which persists in adulthood.
{"title":"Adults Born Small for Gestational Age at Term Have Thinner Peripapillary Retinal Nerve Fiber Layers Than Controls.","authors":"Achim Fieß, Marilena Brandt, Eva Mildenberger, Michael Siegfried Urschitz, Felix Mathias Wagner, Stephanie Desiree Grabitz, Esther Maria Hoffmann, Norbert Pfeiffer, Alexander Konrad Schuster","doi":"10.2147/EB.S383231","DOIUrl":"https://doi.org/10.2147/EB.S383231","url":null,"abstract":"<p><strong>Purpose: </strong>Prenatal growth restriction is associated with impaired neurodevelopment in childhood. This study investigated the effects of being born small for gestational age (SGA) on peripapillary retinal nerve fiber layer (pRNFL) thickness in adults born at term.</p><p><strong>Methods: </strong>A retrospective cohort study was conducted with a prospective ophthalmologic examination of participants born at full-term (gestational age ≥37 weeks) between 1969 and 2002. All participants were examined with spectral-domain optical coherence tomography and grouped according to their birth weight in correlation to gestational age as former moderate (birth weight (BW) percentile 3rd to <10th) and severe SGA (<3rd percentile), normal (10th-90th percentile, AGA), and moderately (>90th to 97th percentile) and severely (>97th percentile) large for gestational age (LGA) adults (18 to 52 years).</p><p><strong>Results: </strong>Overall, 547 eyes of 285 individuals (age 29.9±9.4 years, 151 females) born at term were included. Multivariable regression analyses revealed a strong association between a lower global pRNFL thickness in the severe SGA (B=-8.99 [95%-CI: -12.68; -5.30] µm; p<0.001) and in the moderate SGA groups (B=-6.40 [95%-CI: -10.29; -2.50] µm; p=0.001) compared to the reference AGA group.</p><p><strong>Conclusion: </strong>Our results indicate that restricted fetal growth affects neurologic tissue development of the optic nerve head, particularly in individuals born severely SGA at term. This indicates that fetal growth restriction may exert disturbances in the development of neurologic tissue, which persists in adulthood.</p>","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2022-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/3c/df/eb-14-127.PMC9709856.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"35253933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Background: Ultrasonographic measurement of optic nerve sheath diameter is a simple, non-invasive, and reliable method of detecting elevated intracranial pressure (ICP) in critical patients. Optic nerve sheath communicates with the dura mater covering the brain and contains cerebrospinal fluid, allowing pressure transmission from the cranium. Therefore, changes in cerebrospinal fluid (CSF) pressure have been shown to produce changes in ONSD.
Objective: This study aimed to assess the accuracy of optic nerve sheath diameter (ONSD) in diagnosis and follow-up patients with disturbed conscious levels compared with CT brain and fundus examination.
Patients and methods: One hundred forty-one participants were included in the study, classified into 76 cases admitted with disturbed conscious levels due to elevated ICP and 65 controls. All patients were subjected to CT brain and optic nerve US and fundus examination at the time of admission and follow-up after 48 h after proper management.
Results: The current study showed that ONSD is significant in predicting elevated ICP at the cut-off point of average ONSD of 5.19 mm with 97% sensitivity and 98% specificity, and the area under the curve (AUC) was 0.996. The present study revealed a significant inverse correlation between ONSD and GCS in patients with increased ICP.
Conclusion: Ultrasonic measurement of ONSD is a promising technique in diagnosing and following patients with disturbed conscious levels.
{"title":"Value of Optic Nerve Sheath Diameter in Diagnosis and Follow Up of Patients with Disturbed Conscious Level.","authors":"Osama Mahmoud Momtaz, Omar M Said, Amany Mahmoud Mohamed, Tamer Sayed Abdel Mawla","doi":"10.2147/EB.S369813","DOIUrl":"https://doi.org/10.2147/EB.S369813","url":null,"abstract":"<p><strong>Background: </strong>Ultrasonographic measurement of optic nerve sheath diameter is a simple, non-invasive, and reliable method of detecting elevated intracranial pressure (ICP) in critical patients. Optic nerve sheath communicates with the dura mater covering the brain and contains cerebrospinal fluid, allowing pressure transmission from the cranium. Therefore, changes in cerebrospinal fluid (CSF) pressure have been shown to produce changes in ONSD.</p><p><strong>Objective: </strong>This study aimed to assess the accuracy of optic nerve sheath diameter (ONSD) in diagnosis and follow-up patients with disturbed conscious levels compared with CT brain and fundus examination.</p><p><strong>Patients and methods: </strong>One hundred forty-one participants were included in the study, classified into 76 cases admitted with disturbed conscious levels due to elevated ICP and 65 controls. All patients were subjected to CT brain and optic nerve US and fundus examination at the time of admission and follow-up after 48 h after proper management.</p><p><strong>Results: </strong>The current study showed that ONSD is significant in predicting elevated ICP at the cut-off point of average ONSD of 5.19 mm with 97% sensitivity and 98% specificity, and the area under the curve (AUC) was 0.996. The present study revealed a significant inverse correlation between ONSD and GCS in patients with increased ICP.</p><p><strong>Conclusion: </strong>Ultrasonic measurement of ONSD is a promising technique in diagnosing and following patients with disturbed conscious levels.</p>","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/5b/4a/eb-14-115.PMC9526430.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33487194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-08eCollection Date: 2022-01-01DOI: 10.2147/EB.S361946
Matthew A McDonald, Clark H Stevenson, Hannah M Kersten, Helen V Danesh-Meyer
Abstract Glaucoma is a common condition that relies on careful clinical assessment to diagnose and determine disease progression. There is growing evidence that glaucoma is associated not only with loss of retinal ganglion cells but also with degeneration of cortical and subcortical brain structures associated with vision and eye movements. The effect of glaucoma pathophysiology on eye movements is not well understood. In this review, we examine the evidence surrounding altered eye movements in glaucoma patients compared to healthy controls, with a focus on quantitative eye tracking studies measuring saccades, fixation, and optokinetic nystagmus in a range of visual tasks. The evidence suggests that glaucoma patients have alterations in several eye movement domains. Patients exhibit longer saccade latencies, which worsen with increasing glaucoma severity. Other saccadic abnormalities include lower saccade amplitude and velocity, and difficulty inhibiting reflexive saccades. Fixation is pathologically altered in glaucoma with reduced stability. Optokinetic nystagmus measures have also been shown to be abnormal. Complex visual tasks (eg reading, driving, and navigating obstacles), integrate these eye movements and result in behavioral adaptations. The review concludes with a summary of the evidence and recommendations for future research in this emerging field.
{"title":"Eye Movement Abnormalities in Glaucoma Patients: A Review.","authors":"Matthew A McDonald, Clark H Stevenson, Hannah M Kersten, Helen V Danesh-Meyer","doi":"10.2147/EB.S361946","DOIUrl":"https://doi.org/10.2147/EB.S361946","url":null,"abstract":"Abstract Glaucoma is a common condition that relies on careful clinical assessment to diagnose and determine disease progression. There is growing evidence that glaucoma is associated not only with loss of retinal ganglion cells but also with degeneration of cortical and subcortical brain structures associated with vision and eye movements. The effect of glaucoma pathophysiology on eye movements is not well understood. In this review, we examine the evidence surrounding altered eye movements in glaucoma patients compared to healthy controls, with a focus on quantitative eye tracking studies measuring saccades, fixation, and optokinetic nystagmus in a range of visual tasks. The evidence suggests that glaucoma patients have alterations in several eye movement domains. Patients exhibit longer saccade latencies, which worsen with increasing glaucoma severity. Other saccadic abnormalities include lower saccade amplitude and velocity, and difficulty inhibiting reflexive saccades. Fixation is pathologically altered in glaucoma with reduced stability. Optokinetic nystagmus measures have also been shown to be abnormal. Complex visual tasks (eg reading, driving, and navigating obstacles), integrate these eye movements and result in behavioral adaptations. The review concludes with a summary of the evidence and recommendations for future research in this emerging field.","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2022-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/89/f6/eb-14-83.PMC9467299.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40359286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-14eCollection Date: 2022-01-01DOI: 10.2147/EB.S358384
Chloé Chamard, Jerome J Maller, Nicolas Menjot, Eloi Debourdeau, Virginie Nael, Karen Ritchie, Isabelle Carriere, Vincent Daien
Purpose: Visual impairment is a major cause of disability and impairment of cognitive function in older people. Brain structural changes associated with visual function impairment are not well understood. The objective of this study was to assess the association between visual function and cortical thickness in older adults.
Methods: Participants were selected from the French population-based ESPRIT cohort of 2259 community-dwelling adults ≥65 years old enrolled between 1999 and 2001. We considered visual function and brain MRI images at the 12-year follow-up in participants who were right-handed and free of dementia and/or stroke, randomly selected from the whole cohort. High-resolution structural T1-weighted brain scans acquired with a 3-Tesla scanner. Regional reconstruction and segmentation involved using the FreeSurfer image-analysis suite.
Results: A total of 215 participants were included (mean [SD] age 81.8 [3.7] years; 53.0% women): 30 (14.0%) had central vision loss and 185 (86.0%) normal central vision. Vision loss was associated with thinner cortical thickness in the right insula (within the lateral sulcus of the brain) as compared with the control group (mean thickness 2.38 [0.04] vs 2.50 [0.03] mm, 4.8% thinning, pcorrected= 0.04) after adjustment for age, sex, lifetime depression and cardiovascular disease.
Conclusion: The present study describes a significant thinning of the right insular cortex in older adults with vision loss. The insula subserves a wide variety of functions in humans ranging from sensory and affective processing to high-level cognitive processing. Reduced insula thickness associated with vision loss may increase cognitive burden in the ageing brain.
{"title":"Association Between Vision and Brain Cortical Thickness in a Community-Dwelling Elderly Cohort.","authors":"Chloé Chamard, Jerome J Maller, Nicolas Menjot, Eloi Debourdeau, Virginie Nael, Karen Ritchie, Isabelle Carriere, Vincent Daien","doi":"10.2147/EB.S358384","DOIUrl":"https://doi.org/10.2147/EB.S358384","url":null,"abstract":"<p><strong>Purpose: </strong>Visual impairment is a major cause of disability and impairment of cognitive function in older people. Brain structural changes associated with visual function impairment are not well understood. The objective of this study was to assess the association between visual function and cortical thickness in older adults.</p><p><strong>Methods: </strong>Participants were selected from the French population-based ESPRIT cohort of 2259 community-dwelling adults ≥65 years old enrolled between 1999 and 2001. We considered visual function and brain MRI images at the 12-year follow-up in participants who were right-handed and free of dementia and/or stroke, randomly selected from the whole cohort. High-resolution structural T1-weighted brain scans acquired with a 3-Tesla scanner. Regional reconstruction and segmentation involved using the FreeSurfer image-analysis suite.</p><p><strong>Results: </strong>A total of 215 participants were included (mean [SD] age 81.8 [3.7] years; 53.0% women): 30 (14.0%) had central vision loss and 185 (86.0%) normal central vision. Vision loss was associated with thinner cortical thickness in the right insula (within the lateral sulcus of the brain) as compared with the control group (mean thickness 2.38 [0.04] vs 2.50 [0.03] mm, 4.8% thinning, p<sub>corrected</sub>= 0.04) after adjustment for age, sex, lifetime depression and cardiovascular disease.</p><p><strong>Conclusion: </strong>The present study describes a significant thinning of the right insular cortex in older adults with vision loss. The insula subserves a wide variety of functions in humans ranging from sensory and affective processing to high-level cognitive processing. Reduced insula thickness associated with vision loss may increase cognitive burden in the ageing brain.</p>","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2022-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/fc/fd/eb-14-71.PMC9292457.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40540555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Spaceflight-associated neuro-ocular syndrome (SANS) has been well documented in astronauts both during and after long-duration spaceflight and is characterized by the development of optic disc edema, globe flattening, choroidal folds, and hyperopic refractive error shifts. The exact mechanisms underlying these ophthalmic abnormalities remain unclear. New findings regarding spaceflight-associated alterations in cerebrospinal fluid spaces, specifically perivascular spaces, may shed more light on the pathophysiology of SANS. The preliminary results of a recent brain magnetic resonance imaging study show that perivascular spaces enlarge under prolonged microgravity conditions, and that the amount of fluid in perivascular spaces is linked to SANS. The exact pathophysiological mechanisms underlying enlargement of perivascular spaces in space crews are currently unclear. Here, we speculate that the dilation of perivascular spaces observed in long-duration space travelers may result from impaired cerebral venous outflow and compromised cerebrospinal fluid resorption, leading to obstruction of glymphatic perivenous outflow and increased periarterial cerebrospinal fluid inflow, respectively. Further, we provide a possible explanation for how dilated perivascular spaces can be associated with SANS. Given that enlarged perivascular spaces in space crews may be a marker of altered venous hemodynamics and reduced cerebrospinal fluid outflow, at the level of the optic nerve and eye, these disturbances may contribute to SANS. If confirmed by further studies, brain glymphatic dysfunction in space crews could potentially be considered a risk factor for the development of neurodegenerative diseases, such as Alzheimer’s disease. Furthermore, long-duration exposure to microgravity might contribute to SANS through dysregulation of the ocular glymphatic system. If prolonged spaceflight exposure causes disruption of the glymphatic systems, this might affect the ability to conduct future exploration missions, for example, to Mars. The considerations outlined in the present paper further stress the crucial need to develop effective long-term countermeasures to mitigate SANS-related physiologic changes during long-duration spaceflight.
{"title":"Does Long-Duration Exposure to Microgravity Lead to Dysregulation of the Brain and Ocular Glymphatic Systems?","authors":"P. Wostyn, T. Mader, C. Gibson, M. Nedergaard","doi":"10.2147/EB.S354710","DOIUrl":"https://doi.org/10.2147/EB.S354710","url":null,"abstract":"Abstract Spaceflight-associated neuro-ocular syndrome (SANS) has been well documented in astronauts both during and after long-duration spaceflight and is characterized by the development of optic disc edema, globe flattening, choroidal folds, and hyperopic refractive error shifts. The exact mechanisms underlying these ophthalmic abnormalities remain unclear. New findings regarding spaceflight-associated alterations in cerebrospinal fluid spaces, specifically perivascular spaces, may shed more light on the pathophysiology of SANS. The preliminary results of a recent brain magnetic resonance imaging study show that perivascular spaces enlarge under prolonged microgravity conditions, and that the amount of fluid in perivascular spaces is linked to SANS. The exact pathophysiological mechanisms underlying enlargement of perivascular spaces in space crews are currently unclear. Here, we speculate that the dilation of perivascular spaces observed in long-duration space travelers may result from impaired cerebral venous outflow and compromised cerebrospinal fluid resorption, leading to obstruction of glymphatic perivenous outflow and increased periarterial cerebrospinal fluid inflow, respectively. Further, we provide a possible explanation for how dilated perivascular spaces can be associated with SANS. Given that enlarged perivascular spaces in space crews may be a marker of altered venous hemodynamics and reduced cerebrospinal fluid outflow, at the level of the optic nerve and eye, these disturbances may contribute to SANS. If confirmed by further studies, brain glymphatic dysfunction in space crews could potentially be considered a risk factor for the development of neurodegenerative diseases, such as Alzheimer’s disease. Furthermore, long-duration exposure to microgravity might contribute to SANS through dysregulation of the ocular glymphatic system. If prolonged spaceflight exposure causes disruption of the glymphatic systems, this might affect the ability to conduct future exploration missions, for example, to Mars. The considerations outlined in the present paper further stress the crucial need to develop effective long-term countermeasures to mitigate SANS-related physiologic changes during long-duration spaceflight.","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2022-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43062695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Santorini, T. Ferreira de Moura, S. Barraud, C. Litré, C. Brugniart, A. Denoyer, Z. Djerada, C. Arndt
Purpose To evaluate the relationship between different macular thickness parameters analyzed by SD-OCT and the central visual field (VF) evaluated with automated kinetic perimetry in a cohort of patients with pituitary tumors. Methods Data from patients with pituitary adenoma treated at Reims University Hospital between October 1st, 2017, and May 31st, 2018 were collected. All patients underwent an automated kinetic perimetry and a SD-OCT to map the ganglion cell complex (GCC), the ganglion cell layer (GCL) thickness and the retinal nerve fiber layer (RNFL) using devices from two different manufacturers. Univariate and multivariate analysis were used to evaluate the correlation between the area of central VF in square degrees (deg2) and the SD-OCT parameters (μm). Results Eighty-eight eyes were included in the analysis. All the thickness parameters measured in SD-OCT decreased with the visual field alteration. The best correlation was observed between superior thickness parameters (GCC, GCL) and the inferior central visual field. The most pertinent predictive factors for visual field loss were the inferior central GCL and the nasal RNFL (both AUC=0.775) with a sensitivity respectively of 86% and 70%. Conclusion This study suggests that both GCC, GCL thickness parameters could be reliable predictors of central visual field impairment in patients with pituitary tumors. There was no significative difference between both devices.
{"title":"Comparative Evaluation of Two SD-OCT Macular Parameters (GCC, GCL) and RNFL in Chiasmal Compression","authors":"M. Santorini, T. Ferreira de Moura, S. Barraud, C. Litré, C. Brugniart, A. Denoyer, Z. Djerada, C. Arndt","doi":"10.2147/EB.S337333","DOIUrl":"https://doi.org/10.2147/EB.S337333","url":null,"abstract":"Purpose To evaluate the relationship between different macular thickness parameters analyzed by SD-OCT and the central visual field (VF) evaluated with automated kinetic perimetry in a cohort of patients with pituitary tumors. Methods Data from patients with pituitary adenoma treated at Reims University Hospital between October 1st, 2017, and May 31st, 2018 were collected. All patients underwent an automated kinetic perimetry and a SD-OCT to map the ganglion cell complex (GCC), the ganglion cell layer (GCL) thickness and the retinal nerve fiber layer (RNFL) using devices from two different manufacturers. Univariate and multivariate analysis were used to evaluate the correlation between the area of central VF in square degrees (deg2) and the SD-OCT parameters (μm). Results Eighty-eight eyes were included in the analysis. All the thickness parameters measured in SD-OCT decreased with the visual field alteration. The best correlation was observed between superior thickness parameters (GCC, GCL) and the inferior central visual field. The most pertinent predictive factors for visual field loss were the inferior central GCL and the nasal RNFL (both AUC=0.775) with a sensitivity respectively of 86% and 70%. Conclusion This study suggests that both GCC, GCL thickness parameters could be reliable predictors of central visual field impairment in patients with pituitary tumors. There was no significative difference between both devices.","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68359890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-25eCollection Date: 2022-01-01DOI: 10.2147/EB.S313090
Christianne E Strang, Franklin R Amthor
Purpose: Transcranial alternating current stimulation (tACS) is used as a brain stimulation mechanism to enhance learning, ameliorate some psychiatric disorders, and modify behavior. This study assessed the effects of near threshold tACS-like currents on Off-center and On-Off retinal ganglion cell responsiveness in the rabbit retina eyecup preparation as a model for central nervous system effects.
Materials and methods: We made extracellular recordings in the isolated rabbit eyecup preparation using single electrodes and microelectrode arrays to measure light-evoked spike responses in different classes of Off-center and On-Off retinal ganglion cells before, during, and after brief applications of alternating currents of 1-2 microamperes, at frequencies of 10, 20, 30, and 40 Hz.
Results: tACS application sculpted the light-evoked response profiles without directly driving spiking activity of the 20 Off-center and On-Off ganglion cells we recorded from. During tACS application, Off responses were significantly enhanced for 6 cells and significantly suppressed for 14 cells, but after tACS application, Off responses were significantly enhanced for 7 cells and suppressed for 12 cells. The Off responses of the remaining two cells returned to baseline. On responses were less affected during and after tACS.
Conclusion: tACS sculpts Off-center and On-Off retinal ganglion cell responsiveness. The dissimilarity of effects in different cells within the same class and the differential effects on the On and Off components of the light response within the same cell are consistent with the hypothesis that tACS acts at threshold on amacrine cells in the inner plexiform layer.
{"title":"Effects of tACS-Like Electrical Stimulation on Off- and On-Off Center Retinal Ganglion Cells: Part II.","authors":"Christianne E Strang, Franklin R Amthor","doi":"10.2147/EB.S313090","DOIUrl":"10.2147/EB.S313090","url":null,"abstract":"<p><strong>Purpose: </strong>Transcranial alternating current stimulation (tACS) is used as a brain stimulation mechanism to enhance learning, ameliorate some psychiatric disorders, and modify behavior. This study assessed the effects of near threshold tACS-like currents on Off-center and On-Off retinal ganglion cell responsiveness in the rabbit retina eyecup preparation as a model for central nervous system effects.</p><p><strong>Materials and methods: </strong>We made extracellular recordings in the isolated rabbit eyecup preparation using single electrodes and microelectrode arrays to measure light-evoked spike responses in different classes of Off-center and On-Off retinal ganglion cells before, during, and after brief applications of alternating currents of 1-2 microamperes, at frequencies of 10, 20, 30, and 40 Hz.</p><p><strong>Results: </strong>tACS application sculpted the light-evoked response profiles without directly driving spiking activity of the 20 Off-center and On-Off ganglion cells we recorded from. During tACS application, Off responses were significantly enhanced for 6 cells and significantly suppressed for 14 cells, but after tACS application, Off responses were significantly enhanced for 7 cells and suppressed for 12 cells. The Off responses of the remaining two cells returned to baseline. On responses were less affected during and after tACS.</p><p><strong>Conclusion: </strong>tACS sculpts Off-center and On-Off retinal ganglion cell responsiveness. The dissimilarity of effects in different cells within the same class and the differential effects on the On and Off components of the light response within the same cell are consistent with the hypothesis that tACS acts at threshold on amacrine cells in the inner plexiform layer.</p>","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2022-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/4c/32/eb-14-17.PMC8800591.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39885813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-12eCollection Date: 2022-01-01DOI: 10.2147/EB.S313161
Franklin R Amthor, Christianne E Strang
Purpose: Transcranial alternating current stimulation (tACS) is a stimulation protocol used for learning enhancement and mitigation of cognitive dysfunction. Correlated firing has been postulated to be a meta-code that links neuronal spike responses associated with a single entity and may be an important component of high-level cognitive functions. Thus, changes in the covariance firing structure of CNS neurons such as retinal ganglion cells are one potential mechanism by which tACS can exert its effects.
Materials and methods: We used microelectrode arrays to record light-evoked spike responses of 24 retinal ganglion cells in 7 rabbit eyecup preparations and analyzed the covariance between 30 pairs of neighboring retinal ganglion cells before, during, and after 10-minute application of alternating currents of 1 microampere at 10 or 20 Hz.
Results: tACS stimulation significantly changed the covariance structure of correlated firing in 60% of simultaneously recorded retinal ganglion cells. Application of tACS in the retinal preparation increased cross-covariance in 26% of cell pairs, an effect usually associated with increased light-evoked ganglion cell firing. tACS associated decreases in cross-covariance occurred in 37% of cell pairs. Increased covariance was more common in response to the first, 10-minute application of tACS in isolated retina preparation. Changes in covariance were rare after repeated stimulation, and more likely to result in decreased covariance.
Conclusion: Retinal ganglion cell correlated firing is modulated by 1 microampere tACS currents showing that electrical stimulation can significantly and persistently change the structure of the correlated firing of simultaneously recorded rabbit retinal ganglion cells.
{"title":"Effects of tACS-Like Electrical Stimulation on Correlated Firing of Retinal Ganglion Cells: Part III.","authors":"Franklin R Amthor, Christianne E Strang","doi":"10.2147/EB.S313161","DOIUrl":"https://doi.org/10.2147/EB.S313161","url":null,"abstract":"<p><strong>Purpose: </strong>Transcranial alternating current stimulation (tACS) is a stimulation protocol used for learning enhancement and mitigation of cognitive dysfunction. Correlated firing has been postulated to be a meta-code that links neuronal spike responses associated with a single entity and may be an important component of high-level cognitive functions. Thus, changes in the covariance firing structure of CNS neurons such as retinal ganglion cells are one potential mechanism by which tACS can exert its effects.</p><p><strong>Materials and methods: </strong>We used microelectrode arrays to record light-evoked spike responses of 24 retinal ganglion cells in 7 rabbit eyecup preparations and analyzed the covariance between 30 pairs of neighboring retinal ganglion cells before, during, and after 10-minute application of alternating currents of 1 microampere at 10 or 20 Hz.</p><p><strong>Results: </strong>tACS stimulation significantly changed the covariance structure of correlated firing in 60% of simultaneously recorded retinal ganglion cells. Application of tACS in the retinal preparation increased cross-covariance in 26% of cell pairs, an effect usually associated with increased light-evoked ganglion cell firing. tACS associated decreases in cross-covariance occurred in 37% of cell pairs. Increased covariance was more common in response to the first, 10-minute application of tACS in isolated retina preparation. Changes in covariance were rare after repeated stimulation, and more likely to result in decreased covariance.</p><p><strong>Conclusion: </strong>Retinal ganglion cell correlated firing is modulated by 1 microampere tACS currents showing that electrical stimulation can significantly and persistently change the structure of the correlated firing of simultaneously recorded rabbit retinal ganglion cells.</p>","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2022-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/7f/d2/eb-14-1.PMC8763268.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39947324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Manzar Ashtari, Mikhail Lipin, Michelle Duong, Gui-Shuang Ying, Yinxi Yu, Albert Maguire, Jean Bennett
Introduction: Previous works on experience-dependent brain plasticity have been limited to the cortical structures, overlooking subcortical visual structures such as the lateral geniculate nucleus (LGN). Animal studies have shown substantial experience dependent plasticity and using fMRI, human studies have demonstrated similar properties in patients with cataract surgery. However, in neither animal nor human studies LGN has not been directly assessed, mainly due to its small size, tissue heterogeneity, low contrast/noise ratio, and low spatial resolution.
Methods: Utilizing a new algorithm that markedly improves the LGN visibility, LGN was evaluated in a group of low vision patients before and after retinal intervention to reinstate vision and normal sighted matched controls.
Results: Between and within groups comparisons showed that patients had significantly smaller left (p< 0.0001) and right (p < 0.00002) LGN volumes at baseline as compared to the one-year follow-up volumes. The same baseline and one year comparison in controls was not significant. Significant positive correlations were observed between the incremental volume increase after gene therapy of the left LGN and the incremental increase in the right (r = 0.71, p < 0.02) and left (r = 0.72, p = 0.018) visual fields. Incremental volume increase of the right LGN also showed a similar positive slope but did not reach significance.
Discussion: These results show that despite significantly less volume at baseline, retinal gene therapy promotes robust expansion and increase in LGN volume. Reinstating vision may have facilitated the establishment of new connections between the retina and the LGN and/or unmasking of the dormant connections. The exact trajectory of the structural changes taking place in LGN is unclear but our data shows that even after years of low vision, the LGN in RPE65 patients has the potential for plasticity and expansion to a nearly normal volume one year after gene therapy administration.
以往关于经验依赖大脑可塑性的研究仅限于皮层结构,忽视了皮层下的视觉结构,如外侧膝状核(LGN)。动物研究已经显示了大量的经验依赖可塑性,使用功能磁共振成像,人类研究已经在白内障手术患者中证明了类似的特性。然而,在动物和人类研究中,LGN都没有被直接评估,主要是由于其体积小、组织异质性、低对比度/噪声比和低空间分辨率。方法:采用一种明显提高LGN可见度的新算法,对一组低视力患者进行视网膜干预恢复视力前后的LGN进行评估,并与正常视力对照进行比较。结果:组间和组内比较显示,基线时患者左侧LGN体积(p< 0.0001)和右侧LGN体积(p< 0.00002)明显小于1年随访时的体积。相同的基线和对照组的一年比较无显著性。左侧LGN基因治疗后体积增量与右侧视野(r = 0.71, p < 0.02)、左侧视野(r = 0.72, p = 0.018)体积增量呈显著正相关。右侧LGN的增量体积增加也呈现类似的正斜率,但没有达到显著性。讨论:这些结果表明,尽管在基线时体积明显减少,视网膜基因治疗促进了LGN的强劲扩张和体积的增加。恢复视力可能有助于在视网膜和LGN之间建立新的连接和/或揭开休眠连接的面纱。LGN发生结构变化的确切轨迹尚不清楚,但我们的数据显示,即使经过多年的低视力,RPE65患者的LGN在接受基因治疗一年后仍具有可塑性和扩大到接近正常体积的潜力。
{"title":"Neuroplasticity of the Lateral Geniculate Nucleus in Response to Retinal Gene Therapy in a Group of Patients with <i>RPE65</i> Mutations.","authors":"Manzar Ashtari, Mikhail Lipin, Michelle Duong, Gui-Shuang Ying, Yinxi Yu, Albert Maguire, Jean Bennett","doi":"10.2147/EB.S377275","DOIUrl":"https://doi.org/10.2147/EB.S377275","url":null,"abstract":"<p><strong>Introduction: </strong>Previous works on experience-dependent brain plasticity have been limited to the cortical structures, overlooking subcortical visual structures such as the lateral geniculate nucleus (LGN). Animal studies have shown substantial experience dependent plasticity and using fMRI, human studies have demonstrated similar properties in patients with cataract surgery. However, in neither animal nor human studies LGN has not been directly assessed, mainly due to its small size, tissue heterogeneity, low contrast/noise ratio, and low spatial resolution.</p><p><strong>Methods: </strong>Utilizing a new algorithm that markedly improves the LGN visibility, LGN was evaluated in a group of low vision patients before and after retinal intervention to reinstate vision and normal sighted matched controls.</p><p><strong>Results: </strong>Between and within groups comparisons showed that patients had significantly smaller left (p< 0.0001) and right (p < 0.00002) LGN volumes at baseline as compared to the one-year follow-up volumes. The same baseline and one year comparison in controls was not significant. Significant positive correlations were observed between the incremental volume increase after gene therapy of the left LGN and the incremental increase in the right (r = 0.71, p < 0.02) and left (r = 0.72, p = 0.018) visual fields. Incremental volume increase of the right LGN also showed a similar positive slope but did not reach significance.</p><p><strong>Discussion: </strong>These results show that despite significantly less volume at baseline, retinal gene therapy promotes robust expansion and increase in LGN volume. Reinstating vision may have facilitated the establishment of new connections between the retina and the LGN and/or unmasking of the dormant connections. The exact trajectory of the structural changes taking place in LGN is unclear but our data shows that even after years of low vision, the LGN in RPE65 patients has the potential for plasticity and expansion to a nearly normal volume one year after gene therapy administration.</p>","PeriodicalId":51844,"journal":{"name":"Eye and Brain","volume":null,"pages":null},"PeriodicalIF":4.4,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/39/70/eb-14-137.PMC9749418.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9489794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}