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1.
Malawi Med J ; 33(1): 15-20, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-34422229

RESUMO

Purpose: To evaluate the clinical and socio-demographic profile of patients living with glaucoma and receiving care in a tertiary eye center in Zimbabwe. Method: A hospital-based retrospective study of clinical records of glaucoma patients from January 2014 to December 2018. The study involved collating demographic information of patients, visual acuities, (VA) intraocular pressure, (IOP), cup-to-disc ratios, (CDRs), average retinal nerve fibers thickness, (RNFL), cup volume, cup-to-disc area, vertical cup-to-disc ratio, (VCDR), rim area, disc area, glaucoma hemifield test, visual field indices and the management of glaucoma. Results: Nine thousand one hundred and eighty-five (9,185) folders were retrieved. Out of these, 432 (4.7%) qualified for the study and were analyzed. There were 267 (61.8%) males and 165 (38.2%) females. The mean age (± Standard deviation, SD) of the patients was 62.66 ± 15.94 years, (range 10 - 110 years). The means visual acuity (VA): OD =1.30 ± 1.06 Logarithm of the Minimum Angle of Resolution, (logMAR), OS = 1.33 ± 1.06 logMAR; IOP: OD = 29.51 ± 12.89 mmHg, OS: 29.17 ± 12.59 mmHg; CDRs: OD = 0.91 ± 0.14 D, OS = 0.92 ± 0.14 D; and the average RNFL thickness was 72.76 ± 18.26 µm and 71.24 ± 23.17 µm in the right and left eye respectively. The mainstay of treatment was medication only. Conclusion: There were more males than females receiving glaucoma care at the tertiary level. Glaucoma cases included juveniles but the mean age was mostly the elderly. It was characterized by high IOPs, large CDRs, and thin RNFL suggestive of late presentation.


Assuntos
Glaucoma/diagnóstico , Glaucoma/epidemiologia , Encaminhamento e Consulta/estatística & dados numéricos , Adolescente , Adulto , Grupo com Ancestrais do Continente Africano , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Glaucoma/terapia , Glaucoma de Ângulo Aberto/epidemiologia , Humanos , Pressão Intraocular/fisiologia , Masculino , Pessoa de Meia-Idade , Fibras Nervosas/patologia , Retina/anatomia & histologia , Estudos Retrospectivos , Fatores Socioeconômicos , Campos Visuais/fisiologia , Adulto Jovem , Zimbábue/epidemiologia
2.
Nat Commun ; 12(1): 4745, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34362883

RESUMO

Spatial processing by receptive fields is a core property of the visual system. However, it is unknown how spatial processing in high-level regions contributes to recognition behavior. As face inversion is thought to disrupt typical holistic processing of information in faces, we mapped population receptive fields (pRFs) with upright and inverted faces in the human visual system. Here we show that in face-selective regions, but not primary visual cortex, pRFs and overall visual field coverage are smaller and shifted downward in response to face inversion. From these measurements, we successfully predict the relative behavioral detriment of face inversion at different positions in the visual field. This correspondence between neural measurements and behavior demonstrates how spatial processing in face-selective regions may enable holistic perception. These results not only show that spatial processing in high-level visual regions is dynamically used towards recognition, but also suggest a powerful approach for bridging neural computations by receptive fields to behavior.


Assuntos
Face/fisiologia , Reconhecimento Facial/fisiologia , Orientação/fisiologia , Processamento Espacial/fisiologia , Adulto , Comportamento , Encéfalo , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Reconhecimento Visual de Modelos/fisiologia , Reconhecimento Psicológico/fisiologia , Córtex Visual/fisiologia , Campos Visuais/fisiologia , Adulto Jovem
3.
J Neuroophthalmol ; 41(3): 351-355, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34415268

RESUMO

ABSTRACT: A 47-year-old man with a history of COVID-19 infection 2 months before presentation, presented with a scotoma of the paracentral visual field of the right eye. After thorough testing and evaluation, a diagnosis of paracentral acute middle maculopathy (PAMM) was established. Two months later, the patient developed temporal headache and jaw claudication. High-dose steroids were initiated, and workup for giant cell arteritis (GCA) was undertaken. The patient experienced resolution of the symptoms within 24 hours of steroid initiation. ESR, CRP, and temporal artery biopsy results were normal, although all were obtained more than 2 weeks after steroid initiation. To the best of our knowledge, our patient represents the first individual to date to potentially implicate COVID-19 in both small and large vessel vasculitis in the ophthalmic setting.


Assuntos
COVID-19/complicações , Arterite de Células Gigantes/etiologia , Degeneração Macular/etiologia , Campos Visuais/fisiologia , Doença Aguda , Biópsia , COVID-19/epidemiologia , Arterite de Células Gigantes/diagnóstico , Humanos , Degeneração Macular/diagnóstico , Masculino , Pessoa de Meia-Idade , SARS-CoV-2
4.
Neuron ; 109(16): 2616-2626.e6, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34228960

RESUMO

Vision develops rapidly during infancy, yet how visual cortex is organized during this period is unclear. In particular, it is unknown whether functional maps that organize the mature adult visual cortex are present in the infant striate and extrastriate cortex. Here, we test the functional maturity of infant visual cortex by performing retinotopic mapping with functional magnetic resonance imaging (fMRI). Infants aged 5-23 months had retinotopic maps, with alternating preferences for vertical and horizontal meridians indicating the boundaries of visual areas V1 to V4 and an orthogonal gradient of preferences from high to low spatial frequencies. The presence of multiple visual maps throughout visual cortex in infants indicates a greater maturity of extrastriate cortex than previously appreciated. The areas showed subtle age-related fine-tuning, suggesting that early maturation undergoes continued refinement. This early maturation of area boundaries and tuning may scaffold subsequent developmental changes.


Assuntos
Encéfalo/crescimento & desenvolvimento , Córtex Visual/crescimento & desenvolvimento , Campos Visuais/fisiologia , Vias Visuais/crescimento & desenvolvimento , Mapeamento Encefálico/métodos , Feminino , Humanos , Lactente , Imageamento por Ressonância Magnética/métodos , Masculino , Estimulação Luminosa/métodos
5.
Nat Commun ; 12(1): 4029, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34188047

RESUMO

The representation of space in mouse visual cortex was thought to be relatively uniform. Here we reveal, using population receptive-field (pRF) mapping techniques, that mouse visual cortex contains a region in which pRFs are considerably smaller. This region, the "focea," represents a location in space in front of, and slightly above, the mouse. Using two-photon imaging we show that the smaller pRFs are due to lower scatter of receptive-fields at the focea and an over-representation of binocular regions of space. We show that receptive-fields of single-neurons in areas LM and AL are smaller at the focea and that mice have improved visual resolution in this region of space. Furthermore, freely moving mice make compensatory eye-movements to hold this region in front of them. Our results indicate that mice have spatial biases in their visual processing, a finding that has important implications for the use of the mouse model of vision.


Assuntos
Movimentos Oculares/fisiologia , Córtex Visual/fisiologia , Campos Visuais/fisiologia , Percepção Visual/fisiologia , Animais , Feminino , Movimentos da Cabeça/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Estimulação Luminosa
6.
BMC Neurol ; 21(1): 211, 2021 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-34039302

RESUMO

BACKGROUND: To establish the effects of stimulating intrinsically-photosensitive retinal ganglion cells (ipRGCs) on migraine severity, and to determine if migraine produces objectively-measured visual field defects. METHODS: A randomized, open labelled, crossover study tested migraineurs and normal controls using multifocal pupillographic objective perimetry (mfPOP) with 44 test-regions/eye. A slow blue protocol (BP) stimulated ipRGCs, and a fast yellow protocol (YP) stimulated luminance channels. Migraine diaries assessed migraine severity. Per-region responses were analyzed according to response amplitude and time-to-peak. RESULTS: Thirty-eight migraineurs (42.0 ± 16.5 years, 23 females) and 24 normal controls (39.2 ± 15.2 years, 14 females) were tested. The proportion of subjects developing a migraine did not differ after either protocol, either during the 1st day (odds ratio 1.0; 95% confidence interval 0.2-4.4, p = 0.48) or during the first 3 days after testing (odds ratio 0.8; 95% confidence interval 0.3-2.1, p = 0.68). Migraine days/week did not increase following testing with either protocol in comparison to the baseline week (1.4 ± 1.6 pre-testing (mean ± SD), 1.3 ± 1.4 post-BP, and 1.3 ± 1.2 post-YP; p = 0.96), neither did other measures of severity. Migraine occurring up to 2 weeks before testing significantly lowered amplitudes, - 0.64 ± 0.14 dB (mean ± SE), while triptan use increased amplitudes by 0.45 ± 0.10 dB, both at p < 0.001. CONCLUSIONS: Stimulating ipRGCs did not affect migraine occurrence or severity. Pupillary response characteristics were influenced by the occurrence of a recent migraine attack and a history of triptan use.


Assuntos
Transtornos de Enxaqueca/diagnóstico , Testes de Campo Visual/métodos , Adulto , Estudos Cross-Over , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pupila/fisiologia , Campos Visuais/fisiologia
7.
Nat Med ; 27(5): 785-789, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33795869

RESUMO

Leber congenital amaurosis due to CEP290 ciliopathy is being explored by treatment with the antisense oligonucleotide (AON) sepofarsen. One patient who was part of a larger cohort (ClinicalTrials.gov NCT03140969 ) was studied for 15 months after a single intravitreal sepofarsen injection. Concordant measures of visual function and retinal structure reached a substantial efficacy peak near 3 months after injection. At 15 months, there was sustained efficacy, even though there was evidence of reduction from peak response. Efficacy kinetics can be explained by the balance of AON-driven new CEP290 protein synthesis and a slow natural rate of CEP290 protein degradation in human foveal cone photoreceptors.


Assuntos
Antígenos de Neoplasias/genética , Proteínas de Ciclo Celular/genética , Ciliopatias/terapia , Proteínas do Citoesqueleto/genética , Terapia Genética/métodos , Amaurose Congênita de Leber/terapia , Oligonucleotídeos Antissenso/uso terapêutico , Antígenos de Neoplasias/metabolismo , Proteínas de Ciclo Celular/metabolismo , Ciliopatias/genética , Proteínas do Citoesqueleto/metabolismo , Humanos , Amaurose Congênita de Leber/genética , Amaurose Congênita de Leber/fisiopatologia , Células Fotorreceptoras/metabolismo , Visão Ocular/fisiologia , Campos Visuais/fisiologia
8.
J Sports Sci ; 39(sup1): 150-158, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33861160

RESUMO

Classification within the sport of vision impairment (VI) shooting is based upon the athlete's visual function. This study aimed to determine whether more than one class of competition is needed within VI shooting on the basis of visual field loss. Qualification scores of 23 elite athletes were obtained at World Championship events in prone and standing shooting disciplines. Visual field data were obtained from classification data and from assessment at events. A standardized scoring protocol determined whether athletes had function (≥10 dB) or no function (<10 dB) at locations between 0-60 degrees eccentricity along 10 meridia. Visual field function was not associated with shooting performance in prone or standing disciplines (p > 0.05). Having measurable visual field function beyond 30 degrees made no difference to athletes' ability to shoot competitively in prone (p = 0.65) or standing disciplines (p = 0.47), although a potential impact on qualification was observed in the standing discipline. There was no evidence that loss of visual field function at any specific location adversely affected ability to shoot competitively. There is currently no evidence to consider visual fields in classification within prone or standing VI shooting, although further research is needed as the sport grows.


Assuntos
Desempenho Atlético/fisiologia , Paratletas , Esportes para Pessoas com Deficiência/fisiologia , Transtornos da Visão/fisiopatologia , Campos Visuais/fisiologia , Pessoas com Deficiência Visual , Adulto , Idoso , Desempenho Atlético/classificação , Sensibilidades de Contraste , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Paratletas/classificação , Decúbito Ventral , Esportes para Pessoas com Deficiência/classificação , Posição Ortostática , Acuidade Visual
9.
Optom Vis Sci ; 98(4): 394-403, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33828037

RESUMO

SIGNIFICANCE: Contrast sensitivity changes across the visual field with age and is often measured clinically with various forms of perimetry on plain backgrounds. In daily life, the visual scene is more complicated, and therefore, the standard clinical measures of contrast sensitivity may not predict a patient's visual experience in more natural environments. PURPOSE: This study aims to determine whether contrast thresholds in older adults are different from younger adults when measured on a 1/f noise background (a nonuniform background whose spatial frequency content is similar to those present in the natural vision environments). METHODS: Twenty younger (age range, 20 to 35 years) and 20 older adults (age range, 61 to 79 years) with normal ocular health were recruited. Contrast thresholds were measured for a Gabor patch of 6 cycles per degree (sine wave grating masked by a Gaussian envelope of standard deviation 0.17°) presented on 1/f noise background (root-mean-square contrast, 0.05 and 0.20) that subtended 15° diameter of the central visual field. The stimulus was presented at four eccentricities (0°, 2°, 4°, and 6°) along the 45° meridian in the noise background, and nine contrast levels were tested at each eccentricity. The proportion of correct responses for detecting the target at each eccentricity was obtained, and psychometric functions were fit to estimate the contrast threshold. RESULTS: Older adults demonstrate increased contrast thresholds compared with younger adults. There was an eccentricity-dependent interaction with age, with the difference between groups being highest in the fovea compared with other eccentricities. Performance was similar for the two noise backgrounds tested. CONCLUSIONS: Our results revealed a strong eccentricity dependence in performance between older and younger adults, highlighting age-related differences in the contrast detection mechanisms between fovea and parafovea for stimuli presented on nonuniform backgrounds.


Assuntos
Envelhecimento/fisiologia , Sensibilidades de Contraste/fisiologia , Fóvea Central/fisiologia , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Psicometria , Limiar Sensorial/fisiologia , Testes de Campo Visual/métodos , Campos Visuais/fisiologia , Adulto Jovem
10.
Optom Vis Sci ; 98(4): 310-325, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33828038

RESUMO

SIGNIFICANCE: This article summarizes the evidence for a higher prevalence of binocular vision dysfunctions in individuals with vision impairment. Assessment for and identification of binocular vision dysfunctions can detect individuals experiencing difficulties in activities including reading, object placement tasks, and mobility.Comprehensive vision assessment in low vision populations is necessary to identify the extent of remaining vision and to enable directed rehabilitation efforts. In patients with vision impairment, little attention is typically paid to assessments of binocular vision, including ocular vergence, stereopsis, and binocular summation characteristics. In addition, binocular measurements of threshold automated visual fields are not routinely performed in clinical practice, leading to an incomplete understanding of individuals' binocular visual field and may affect rehabilitation outcomes.First, this review summarizes the prevalence of dysfunctions in ocular vergence, stereopsis, and binocular summation characteristics across a variety of ocular pathologies causing vision impairment. Second, this review examines the links between clinical measurements of binocular visual functions and outcome measures including quality of life and performance in functional tasks. There is an increased prevalence of dysfunctions in ocular alignment, stereopsis, and binocular summation across low vision cohorts compared with those with normal vision. The identification of binocular vision dysfunctions during routine low vision assessments is especially important in patients experiencing difficulties in activities of daily living, including but not limited to reading, object placement tasks, and mobility. However, further research is required to determine whether addressing the identified deficits in binocular vision in low vision rehabilitative efforts directly impacts patient outcomes.


Assuntos
Visão Binocular/fisiologia , Baixa Visão/fisiopatologia , Atividades Cotidianas/psicologia , Percepção de Profundidade/fisiologia , Humanos , Qualidade de Vida/psicologia , Leitura , Baixa Visão/psicologia , Campos Visuais/fisiologia , Percepção Visual/fisiologia , Pessoas com Deficiência Visual
11.
Optom Vis Sci ; 98(4): 374-383, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33828040

RESUMO

SIGNIFICANCE: Identifying glaucomatous damage to the macula has become important for diagnosing and managing patients with glaucoma. In this study, we presented an approach that provides better perimetric sampling for the macular region, by testing four locations, with a good structure-function agreement. PURPOSE: We previously presented a basis for customizing perimetric locations within the macula. In this study, we aimed to improve perimetric sampling within the macula by presenting a stimulus at four locations, with maintaining a good structure-function agreement. METHODS: We tested one eye each of 30 patients (aged 50 to 88 years). Patients were selected based on observed structural damage to the macula, whereas perimetric defect (using 24-2) did not reflect the locations and extent of this damage. We used en face images to visualize retinal nerve fiber bundle defects. To measure perimetric sensitivities, we used a blob stimulus (standard deviation of 0.25°) at the 10-2 locations. A perimetric defect for a location was defined as any value equal to or deeper than -4, -5, and -6 dB below the mean sensitivity for 37 age-similar controls (aged 47 to 78 years). We also presented an elongated sinusoidal stimulus for 20 patients at four locations within the macula, in which we defined a perimetric defect as any value below the 2.5th percentile from controls. RESULTS: The -4, -5, and -6 dB criteria identified perimetric defects in 14, 13, and 11 patients, respectively. When testing with the elongated stimulus, 18 patients were identified with perimetric defect. The perimetric defects were consistent with the structural damage. CONCLUSIONS: The elongated stimulus showed a good structure-function agreement with only four testing locations as compared with 68 locations used with the blob stimulus. This demonstrates a clinical potential for this new stimulus in the next generation of perimetry.


Assuntos
Glaucoma de Ângulo Aberto/diagnóstico , Macula Lutea/patologia , Doenças Retinianas/diagnóstico , Campos Visuais/fisiologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Glaucoma de Ângulo Aberto/fisiopatologia , Humanos , Macula Lutea/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Doenças Retinianas/fisiopatologia , Tomografia de Coerência Óptica , Testes de Campo Visual/métodos
12.
Optom Vis Sci ; 98(4): 367-373, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33828042

RESUMO

SIGNIFICANCE: Although corneal biomechanical parameters are well linked with glaucoma, their clinical utility has not yet been fully elucidated. This study was designed to provide unique evidence about the dynamic nature of corneal biomechanical parameters and their potential prognostic ability for glaucoma. PURPOSE: This study aimed to evaluate the effect of acute intraocular pressure (IOP) elevation on corneal hysteresis (CH) and corneal resistance factor (CRF) and the associations of these biomechanical parameters with glaucomatous disease. METHODS: Subjects participating in a prospective, longitudinal glaucoma research study had CH and CRF measured before and during ophthalmodynamometry during visits in the years 2011 to 2012. All participants were diagnosed with primary open-angle glaucoma, ocular hypertension, glaucoma suspect, or normal eyes and had a minimum of 3 years of study participation with at least five reliable visual field (VF) tests. Changes in CH, CRF, and IOP induced by ophthalmodynamometry were compared between diagnostic groups and evaluated for relationships with existing and future glaucomatous VF loss. RESULTS: In 248 eyes of 248 subjects followed up for 7.7 ± 2.3 years, ophthalmodynamometry induced a mean IOP increase from 15.1 to 29.9 mmHg, causing a mean 34 ± 28% increase in CRF and 21 ± 25% decrease in CH. Magnitude of CH change did not differ between diagnostic groups or between eyes that did (n = 20) and did not (n = 95) develop new VF loss during the study period, nor was it related to rate of future VF progression. CONCLUSIONS: Ophthalmodynamometry-induced IOP elevation resulted in significant acute changes in CH and CRF in this study; this suggests accounting for IOP may be important in clinical interpretation of these parameters. However, because the degree of CH change was not related to glaucoma or its progression, acute changes in CH and CRF do not seem to have a prognostic value for glaucoma.


Assuntos
Córnea/fisiopatologia , Glaucoma de Ângulo Aberto/fisiopatologia , Pressão Intraocular/fisiologia , Idoso , Anti-Hipertensivos/uso terapêutico , Fenômenos Biomecânicos/fisiologia , Elasticidade/fisiologia , Feminino , Seguimentos , Glaucoma de Ângulo Aberto/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , Hipertensão Ocular/tratamento farmacológico , Hipertensão Ocular/fisiopatologia , Soluções Oftálmicas , Oftalmodinamometria , Estudos Prospectivos , Tonometria Ocular , Testes de Campo Visual , Campos Visuais/fisiologia
13.
Optom Vis Sci ; 98(4): 409-417, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33852556

RESUMO

SIGNIFICANCE: Idiopathic sclerosing orbital inflammation (ISOI) is characterized by insidious, chronic, progressive inflammation and fibrosis that damage ocular structures and produce a mass effect. This case highlights the challenges in diagnosis and management of ISOI, as well as the associated ocular morbidities, including potential vision loss. PURPOSE: The purpose of this study was to provide education regarding a rare condition that exhibits variable presentation and has an unpredictable success rate with regard to treatment paradigm. Improved therapeutic options are promising. Ultimately, early detection and management are key and may allow for better visual outcome. CASE REPORT: A 46-year-old woman presented with complaints of chronic right-sided facial headaches and eye pain and gradual right globe prominence over the previous 6 months. Worsening vision and decreased right peripheral visual field were also noted. Upon examination, an afferent pupillary defect and florid disc edema were evident. Imaging studies revealed an orbital and extraorbital infiltrative mass involving the right orbital apex, inferior orbital fissure, pterygopalatine fossa, and cavernous sinus. Right anterior orbitotomy with biopsy revealed fragments of fibroconnective and adipose tissue with sclerosis and chronic focal inflammation, consistent with ISOI. Treatment included intravenous methylprednisone, followed by oral prednisone, beginning at 60 mg/d with a slow taper thereafter. Signs and symptoms improved dramatically and eventually resolved. Vision significantly improved, and the afferent pupillary defect resolved. The patient remained asymptomatic at 3-month follow-up. CONCLUSIONS: Idiopathic sclerosing orbital inflammation is difficult to diagnose and manage. No large studies exist because of the rare nature of the disease. Slowly progressive, nonspecific signs and symptoms may delay recognition and treatment. Orbital imaging and histopathologic analysis are critical for definitive diagnosis. Conventional treatment with corticosteroids is not uniformly successful, but newer combined therapy options can improve outcomes. Early identification and treatment are key to management and ultimate preservation of function and vision.


Assuntos
Pseudotumor Orbitário/diagnóstico , Esclerose/diagnóstico , Administração Oral , Feminino , Glucocorticoides/uso terapêutico , Humanos , Infusões Intravenosas , Metilprednisolona/uso terapêutico , Pessoa de Meia-Idade , Órbita/diagnóstico por imagem , Pseudotumor Orbitário/tratamento farmacológico , Pseudotumor Orbitário/fisiopatologia , Prednisona/uso terapêutico , Esclerose/tratamento farmacológico , Esclerose/fisiopatologia , Tomografia de Coerência Óptica , Acuidade Visual/fisiologia , Testes de Campo Visual , Campos Visuais/fisiologia
14.
Am J Ophthalmol ; 227: 222-230, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33831342

RESUMO

PURPOSE: The purpose of this study was to determine if a mobile application, the Checkup Vision Assessment System, could reliably monitor visual acuity (VA) and metamorphopsia remotely versus standard VA reference tests in the clinic. With the current COVID-19 pandemic, an even greater need for remote monitoring exists. Mobile tools enhance the ability to monitor patients virtually by enabling remote monitoring of VA and Amsler grid findings. DESIGN: Prospective, multicenter reliability analysis. METHODS: Participants: Patients (N = 108) with near corrected VA better than 20/200 and a diagnosis of age-related macular degeneration, diabetic retinopathy, or healthy patients without retinal disease (best-corrected visual acuity [BCVA] of 20/32 or better). INTERVENTION: participants were tested using the Checkup, reference VA, and Amsler tests, with the order of testing (Checkup or reference) randomized. Patients monitored their vision using Checkup at least twice a week at home between office visits. Main outcome measurements were near corrected VA and Amsler grid test results. RESULTS: Agreement was strong between Checkup and reference tests for VA (r = 0.86) and Amsler grid (sensitivity: 93%; specificity: 92%). Home versus clinic testing showed excellent agreement (r = 0.96). Patients reported successful home use. There were no serious adverse events or discontinuations. Patients rated the usability of Checkup to be excellent. CONCLUSIONS: There was good agreement between Checkup and in-clinic test results for VA and Amsler grid. The low variance of Checkup testing, agreement between in-clinic and home results, and excellent usability support Checkup as a reliable method for monitoring retinal pathology in clinic and home settings.


Assuntos
COVID-19/epidemiologia , Retinopatia Diabética/fisiopatologia , Degeneração Macular/fisiopatologia , Aplicativos Móveis , Monitorização Fisiológica/métodos , Acuidade Visual , Campos Visuais/fisiologia , Idoso , Comorbidade , Retinopatia Diabética/diagnóstico , Retinopatia Diabética/epidemiologia , Feminino , Humanos , Degeneração Macular/diagnóstico , Degeneração Macular/epidemiologia , Masculino , Pessoa de Meia-Idade , Pandemias , Estudos Prospectivos , Reprodutibilidade dos Testes , SARS-CoV-2
15.
Nat Commun ; 12(1): 1900, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33772000

RESUMO

The computations performed by a neural circuit depend on how it integrates its input signals into an output of its own. In the retina, ganglion cells integrate visual information over time, space, and chromatic channels. Unlike the former two, chromatic integration is largely unexplored. Analogous to classical studies of spatial integration, we here study chromatic integration in mouse retina by identifying chromatic stimuli for which activation from the green or UV color channel is maximally balanced by deactivation through the other color channel. This reveals nonlinear chromatic integration in subsets of On, Off, and On-Off ganglion cells. Unlike the latter two, nonlinear On cells display response suppression rather than activation under balanced chromatic stimulation. Furthermore, nonlinear chromatic integration occurs independently of nonlinear spatial integration, depends on contributions from the rod pathway and on surround inhibition, and may provide information about chromatic boundaries, such as the skyline in natural scenes.


Assuntos
Potenciais de Ação/fisiologia , Retina/fisiologia , Células Ganglionares da Retina/fisiologia , Campos Visuais/fisiologia , Vias Visuais/fisiologia , Potenciais de Ação/efeitos dos fármacos , Algoritmos , Animais , Cor , Feminino , HEPES/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Dinâmica não Linear , Estimulação Luminosa/métodos , Piridazinas/farmacologia , Retina/citologia , Estricnina/farmacologia
16.
Nature ; 592(7854): 409-413, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33692544

RESUMO

The output of the retina is organized into many detector grids, called 'mosaics', that signal different features of visual scenes to the brain1-4. Each mosaic comprises a single type of retinal ganglion cell (RGC), whose receptive fields tile visual space. Many mosaics arise as pairs, signalling increments (ON) and decrements (OFF), respectively, of a particular visual feature5. Here we use a model of efficient coding6 to determine how such mosaic pairs should be arranged to optimize the encoding of natural scenes. We find that information is maximized when these mosaic pairs are anti-aligned, meaning that the distances between the receptive field centres across mosaics are greater than expected by chance. We tested this prediction across multiple receptive field mosaics acquired using large-scale measurements of the light responses of rat and primate RGCs. ON and OFF RGC pairs with similar feature selectivity had anti-aligned receptive field mosaics, consistent with this prediction. ON and OFF RGC types that encode distinct features have independent mosaics. These results extend efficient coding theory beyond individual cells to predict how populations of diverse types of RGC are spatially arranged.


Assuntos
Retina/citologia , Retina/fisiologia , Campos Visuais/fisiologia , Animais , Feminino , Macaca , Masculino , Modelos Neurológicos , Ratos , Ratos Long-Evans , Células Ganglionares da Retina/fisiologia
17.
Gait Posture ; 86: 233-239, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33774584

RESUMO

BACKGROUND: Integration of visual, vestibular, and proprioceptive sensations contributes to postural control. People with peripheral visual field loss have serious postural instability. However, the directional specificity of postural stability and sensory reweighting caused by gradual peripheral visual field loss remain unclear. RESEARCH QUESTION: What are the effects of peripheral visual field loss on static postural control? METHODS: Fifteen healthy young adults participated in this study. The participants were asked to stand quietly on a foam surface. Three conditions of virtual visual field loss (90°, 45°, and 15°) were provided by a head-mounted display, and ground reaction forces were collected using a force plate to calculate the displacements of the center of pressure (COP). RESULTS: The root mean square (RMS), mean velocity, and 95% ellipse area of COP displacements in the horizontal plane increased, and RMS in the anteroposterior (AP) direction was unchanged under the smallest visual field condition compared to the largest one. The power spectrum density of COP displacements in the low-frequency band was decreased and that in the medium-frequency band was increased in the AP direction. SIGNIFICANCE: During quiet standing of young healthy adults with peripheral visual field loss, increased peripheral visual field loss resulted in lower postural stability. Postural stability in the AP direction was maintained contrary to the functional sensitivity hypothesis. Peripheral visual field loss reduced the weighting of the visual input and increased that of the vestibular input in the AP direction to maintain equilibrium.


Assuntos
Equilíbrio Postural/fisiologia , Transtornos da Visão/fisiopatologia , Campos Visuais/fisiologia , Feminino , Humanos , Masculino , Propriocepção , Vestíbulo do Labirinto , Adulto Jovem
19.
J Vis ; 21(3): 14, 2021 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-33688921

RESUMO

Shape perception varies depending on many factors. For example, presenting a stimulus in the periphery often yields a different appearance compared with its foveal presentation. However, how exactly shape appearance is altered under different conditions remains elusive. One reason for this is that studies typically measure identification performance, leaving details about target appearance unknown. The lack of appearance-based methods and general challenges to quantify appearance complicate the investigation of shape appearance. Here, we introduce Geometrically Restricted Image Descriptors (GRIDs), a method to investigate the appearance of shapes. Stimuli in the GRID paradigm are shapes consisting of distinct line elements placed on a grid by connecting grid nodes. Each line is treated as a discrete target. Observers are asked to capture target appearance by placing lines on a freely viewed response grid. We used GRIDs to investigate the appearance of letters and letter-like shapes. Targets were presented at 10° eccentricity in the right visual field. Gaze-contingent stimulus presentation was used to prevent eye movements to the target. The data were analyzed by quantifying the differences between targets and response in regard to overall accuracy, element discriminability, and several distinct error types. Our results show how shape appearance can be captured by GRIDs, and how a fine-grained analysis of stimulus parts provides quantifications of appearance typically not available in standard measures of performance. We propose that GRIDs are an effective tool to investigate the appearance of shapes.


Assuntos
Percepção de Forma/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Biologia Computacional , Discriminação Psicológica , Movimentos Oculares/fisiologia , Feminino , Humanos , Masculino , Mascaramento Perceptivo , Campos Visuais/fisiologia , Adulto Jovem
20.
Nat Commun ; 12(1): 1757, 2021 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-33741947

RESUMO

Voluntary allocation of visual attention is controlled by top-down signals generated within the Frontal Eye Fields (FEFs) that can change the excitability of lower-level visual areas. However, the mechanism through which this control is achieved remains elusive. Here, we emulated the generation of an attentional signal using single-pulse transcranial magnetic stimulation to activate the FEFs and tracked its consequences over the visual cortex. First, we documented changes to brain oscillations using electroencephalography and found evidence for a phase reset over occipital sites at beta frequency. We then probed for perceptual consequences of this top-down triggered phase reset and assessed its anatomical specificity. We show that FEF activation leads to cyclic modulation of visual perception and extrastriate but not primary visual cortex excitability, again at beta frequency. We conclude that top-down signals originating in FEF causally shape visual cortex activity and perception through mechanisms of oscillatory realignment.


Assuntos
Lobo Frontal/fisiologia , Estimulação Magnética Transcraniana/métodos , Córtex Visual/fisiologia , Campos Visuais/fisiologia , Percepção Visual/fisiologia , Adulto , Algoritmos , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Modelos Neurológicos , Lobo Occipital/fisiologia , Estimulação Luminosa
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