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1.
Brain Inj ; 35(10): 1218-1228, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34383619

RESUMO

PURPOSE: To examine the association between Post-Concussion Symptom Scale (PCSS) scores, Convergence Insufficiency Symptom Survey (CISS) scores, and oculomotor deficits post-concussion. METHODS: Records of adolescent patients examined in a multidisciplinary concussion clinic between July 2014 and May 2019 were reviewed. PCSS and CISS scores, results of eye examination and oculomotor assessment, concussion history, and demographics were abstracted. RESULTS: One hundred and forty patient records (median age, 15.3 years; 52 males, presented 109 days (median) from their most recent concussion) met inclusion criteria. Mean total scores on PCSS and CISS were 46.67 ± 25.89 and 27.13 ± 13.22, respectively, and were moderately correlated with each other (r = 0.53, p < .001). Oculomotor deficits were observed in 123 (88%) patients. Step-wise linear regression identified increased PCSS total score to be significantly associated with decreased amplitude of accommodation (p < .001). Increased CISS total score was significantly associated with receded near point of convergence, developmental eye movement test error scores, and cause of concussion. CONCLUSION: High PCSS scores may indicate an accommodation deficit and thus prompt an oculomotor assessment in patients following a concussion. Using the CISS and a detailed oculomotor assessment may reveal underlying oculomotor deficits, which may benefit from treatment.


Assuntos
Traumatismos em Atletas , Concussão Encefálica , Síndrome Pós-Concussão , Adolescente , Concussão Encefálica/complicações , Movimentos Oculares , Humanos , Masculino , Testes Neuropsicológicos , Síndrome Pós-Concussão/diagnóstico , Síndrome Pós-Concussão/epidemiologia
2.
Am J Ophthalmol ; 206: 235-244, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31004592

RESUMO

PURPOSE: To determine the frequency of occurrence of receded near point of convergence (NPC) in patients with chronic concussion-related symptoms and in those with receded NPC to enumerate the frequency of convergence insufficiency and other oculomotor disorders. DESIGN: Retrospective cross-sectional study. METHODS: Clinic charts were retrospectively reviewed for the prior 3.5 years to identify all patients < 21 years old who were > 28 days postconcussion, had chronic concussion-related symptoms, had normal visual acuity, and had received a comprehensive sensorimotor examination. The frequency of receded NPC and oculomotor diagnoses were determined. RESULTS: Of the 83 eligible patients, 74 (89%) had receded NPC. Of these, 70 (95%) had oculomotor disorders; 30 (41%) had disorders of accommodation only; 21 (28%) had convergence insufficiency and accommodation deficits; and 6 (8%) had convergence insufficiency only. Six (8%) had a convergence deficit other than convergence insufficiency (all with concurrent accommodative disorders); 4 (5%) had both a nonspecific vergence dysfunction and accommodation deficits; 2 (3%) had convergence excess only; and 1 (1%) had both convergence excess and accommodative deficits. CONCLUSION: A receded NPC was present in the majority of young patients with chronic postconcussion symptoms. Associated with numerous underlying oculomotor dysfunctions, the clinical finding of a receded NPC is not synonymous with the diagnosis of convergence insufficiency. Because treatment options for the various oculomotor dysfunctions differ, it is prudent that these patients undergo a thorough examination of their vergence and accommodative systems so that an accurate diagnosis can be made and appropriate treatment prescribed.


Assuntos
Acomodação Ocular/fisiologia , Concussão Encefálica/complicações , Convergência Ocular/fisiologia , Transtornos da Motilidade Ocular/etiologia , Transtornos da Motilidade Ocular/fisiopatologia , Músculos Oculomotores/fisiopatologia , Visão Binocular/fisiologia , Adolescente , Concussão Encefálica/fisiopatologia , Estudos Transversais , Feminino , Humanos , Masculino , Estudos Retrospectivos
3.
Ophthalmology ; 126(6): 783-791, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30664893

RESUMO

PURPOSE: With the current wide adoption of electronic health records (EHRs) by ophthalmologists, there are widespread concerns about the amount of time spent using the EHR. The goal of this study was to examine how the amount of time spent using EHRs as well as related documentation behaviors changed 1 decade after EHR adoption. DESIGN: Single-center cohort study. PARTICIPANTS: Six hundred eighty-five thousand three hundred sixty-one office visits with 70 ophthalmology providers. METHODS: We calculated time spent using the EHR associated with each individual office visit using EHR audit logs and determined chart closure times and progress note length from secondary EHR data. We tracked and modeled how these metrics changed from 2006 to 2016 with linear mixed models. MAIN OUTCOME MEASURES: Minutes spent using the EHR associated with an office visit, chart closure time in hours from the office visit check-in time, and progress note length in characters. RESULTS: Median EHR time per office visit in 2006 was 4.2 minutes (interquartile range [IQR], 3.5 minutes), and increased to 6.4 minutes (IQR, 4.5 minutes) in 2016. Median chart closure time was 2.8 hours (IQR, 21.3 hours) in 2006 and decreased to 2.3 hours (IQR, 18.5 hours) in 2016. In 2006, median note length was 1530 characters (IQR, 1435 characters) and increased to 3838 characters (IQR, 2668.3 characters) in 2016. Linear mixed models found EHR time per office visit was 31.9±0.2% (P < 0.001) greater from 2014 through 2016 than from 2006 through 2010, chart closure time was 6.7±0.3 hours (P < 0.001) shorter from 2014 through 2016 versus 2006 through 2010, and note length was 1807.4±6.5 characters (P < 0.001) longer from 2014 through 2016 versus 2006 through 2010. CONCLUSIONS: After 1 decade of use, providers spend more time using the EHR for an office visit, generate longer notes, and close the chart faster. These changes are likely to represent increased time and documentation pressure for providers. Electronic health record redesign and new documentation regulations may help to address these issues.


Assuntos
Documentação/tendências , Registros Eletrônicos de Saúde/tendências , Oftalmologia/tendências , Optometria/tendências , Centros Médicos Acadêmicos , Estudos de Coortes , Documentação/estatística & dados numéricos , Registros Eletrônicos de Saúde/estatística & dados numéricos , Feminino , Pessoal de Saúde , Humanos , Masculino , Visita a Consultório Médico/estatística & dados numéricos , Oftalmologistas , Oftalmologia/estatística & dados numéricos , Optometristas , Optometria/estatística & dados numéricos , Fatores de Tempo
4.
Vision Res ; 155: 11-16, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30528188

RESUMO

Although there are many anecdotal reports of children with developmental dyslexia complaining of vision symptoms when reading, empirical studies are lacking. The primary aim of the present study was to document self-reported vision-related symptoms in children with developmental dyslexia and typically reading peers. We also explored whether vision symptoms were correlated with sensorimotor measures of vergence, accommodation and ocular motor tracking skills. Using a prospective group comparison observational design, we assessed 28 children with developmental dyslexia (DD) and 33 typically reading children (TR) 7-11 years of age. Participants completed psychoeducational testing, a comprehensive sensorimotor eye examination, and the Convergence Insufficiency Symptom Survey (CISS), which includes 9 items pertaining to vision-related symptoms (CISS-V) and 6 that could have cognitive influence (CISS-C). CISS-V were significantly greater in DD than TR children. Ocular motor tracking, assessed by an infra-red limbal eye tracker while reading text, was most clearly associated with the visual symptoms, but only within the DD group. Vision-related symptom surveys followed by a comprehensive eye examination with detailed evaluation of sensorimotor functioning for those who report a high prevalence of symptoms may be clinically relevant for children with DD.


Assuntos
Convergência Ocular/fisiologia , Dislexia/complicações , Transtornos da Motilidade Ocular/etiologia , Transtornos da Motilidade Ocular/fisiopatologia , Transtornos da Visão/etiologia , Criança , Autoavaliação Diagnóstica , Feminino , Humanos , Masculino , Estudos Prospectivos , Autorrelato , Transtornos da Visão/fisiopatologia
5.
JAMA Ophthalmol ; 136(10): 1089-1095, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30027208

RESUMO

Importance: Developmental dyslexia (DD) is a specific learning disability of neurobiological origin whose core cognitive deficit is widely believed to involve language (phonological) processing. Although reading is also a visual task, the potential role of vision in DD has been controversial, and little is known about the integrity of visual function in individuals with DD. Objective: To assess the frequency of visual deficits (specifically vergence, accommodation, and ocular motor tracking) in children with DD compared with a control group of typically developing readers. Design, Setting, and Participants: A prospective, uncontrolled observational study was conducted from May 28 to October 17, 2016, in an outpatient ophthalmology ambulatory clinic among 29 children with DD and 33 typically developing (TD) children. Main Outcomes and Measures: Primary outcomes were frequencies of deficits in vergence (amplitude, fusional ranges, and facility), accommodation (amplitude, facility, and accuracy), and ocular motor tracking (Developmental Eye Movement test and Visagraph eye tracker). Results: Among the children with DD (10 girls and 19 boys; mean [SD] age, 10.3 [1.2] years) and the TD group (21 girls and 12 boys; mean [SD] age, 9.4 [1.4] years), accommodation deficits were more frequent in the DD group than the TD group (16 [55%] vs 3 [9%]; difference = 46%; 95% CI, 25%-67%; P < .001). For ocular motor tracking, 18 children in the DD group (62%) had scores in the impaired range (in the Developmental Eye Movement test, Visagraph, or both) vs 5 children in the TD group (15%) (difference, 47%; 95% CI, 25%-69%; P < .001). Vergence deficits occurred in 10 children in the DD group (34%) and 5 children in the TD group (15%) (difference, 19%; 95% CI, -2.2% to 41%; P = .08). In all, 23 children in the DD group (79%) and 11 children in the TD group (33%) had deficits in 1 or more domain of visual function (difference, 46%; 95% CI, 23%-69%; P < .001). Conclusions and Relevance: These findings suggest that deficits in visual function are far more prevalent in school-aged children with DD than in TD readers, but the possible cause and clinical relevance of these deficits are uncertain. Further study is needed to determine the extent to which treating these deficits can improve visual symptoms and/or reading parameters.


Assuntos
Dislexia/epidemiologia , Leitura , Transtornos da Visão/epidemiologia , Acomodação Ocular/fisiologia , Criança , Convergência Ocular/fisiologia , Feminino , Humanos , Masculino , Transtornos da Motilidade Ocular/epidemiologia , Estudos Prospectivos , Testes Visuais
6.
Doc Ophthalmol ; 134(2): 111-128, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28243926

RESUMO

PURPOSE: To compare diagnostic performance and structure-function correlations of multifocal electroretinogram (mfERG), full-field flash ERG (ff-ERG) photopic negative response (PhNR) and transient pattern-reversal ERG (PERG) in a non-human primate (NHP) model of experimental glaucoma (EG). METHODS: At baseline and after induction of chronic unilateral IOP elevation, 43 NHP had alternating weekly recordings of retinal nerve fiber layer thickness (RNFLT) by spectral domain OCT (Spectralis) and retinal function by mfERG (7F slow-sequence stimulus, VERIS), ff-ERG (red 0.42 log cd-s/m2 flashes on blue 30 scotopic cd/m2 background, LKC UTAS-E3000), and PERG (0.8° checks, 99% contrast, 100 cd/m2 mean, 5 reversals/s, VERIS). All NHP were followed at least until HRT-confirmed optic nerve head posterior deformation, most to later stages. mfERG responses were filtered into low- and high-frequency components (LFC, HFC, >75 Hz). Peak-to-trough amplitudes of LFC features (N1, P1, N2) and HFC RMS amplitudes were measured and ratios calculated for HFC:P1 and N2:P1. ff-ERG parameters included A-wave (at 10 ms), B-wave (trough-to-peak) and PhNR (baseline-to-trough) amplitudes as well as PhNR:B-wave ratio. PERG parameters included P50 and N95 amplitudes as well as N95:P50 ratio and N95 slope. Diagnostic performance of retinal function parameters was compared using the area under the receiver operating characteristic curve (A-ROC) to discriminate between EG and control eyes. Correlations to RNFLT were compared using Steiger's test. RESULTS: Study duration was 15 ± 8 months. At final follow-up, structural damage in EG eyes measured by RNFLT ranged from 9% above baseline (BL) to 58% below BL; 29/43 EG eyes (67%) and 0/43 of the fellow control eyes exhibited significant (>7%) loss of RNFLT from BL. Using raw parameter values, the largest A-ROC findings for mfERG were: HFC (0.82) and HFC:P1 (0.90); for ff-ERG: PhNR (0.90) and PhNR:B-wave (0.88) and for PERG: P50 (0.64) and N95 (0.61). A-ROC increased when data were expressed as % change from BL, but the pattern of results persisted. At 95% specificity, the diagnostic sensitivity of mfERG HFC:P1 ratio was best, followed by PhNR and PERG. The correlation to RNFLT was stronger for mfERG HFC (R = 0.65) than for PhNR (R = 0.59) or PERG N95 (R = 0.36), (p = 0.20, p = 0.0006, respectively). The PhNR flagged a few EG eyes at the final time point that had not been flagged by mfERG HFC or PERG. CONCLUSIONS: Diagnostic performance and structure-function correlation were strongest for mfERG HFC as compared with ff-ERG PhNR or PERG in NHP EG.


Assuntos
Eletrorretinografia/métodos , Glaucoma/diagnóstico , Glaucoma/fisiopatologia , Animais , Modelos Animais de Doenças , Eletrorretinografia/normas , Feminino , Glaucoma/patologia , Macaca mulatta , Masculino , Fibras Nervosas/patologia , Fibras Nervosas/fisiologia , Disco Óptico/fisiopatologia , Células Ganglionares da Retina/patologia , Células Ganglionares da Retina/fisiologia , Tomografia de Coerência Óptica
7.
Work ; 52(2): 303-14, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26519133

RESUMO

BACKGROUND: Computer vision syndrome (CVS) is a collection of symptoms related to prolonged work at a computer display. OBJECTIVE: This article reviews the current knowledge about the symptoms, related factors and treatment modalities for CVS. METHODS: Relevant literature on CVS published during the past 65 years was analyzed. RESULTS: Symptoms reported by computer users are classified into internal ocular symptoms (strain and ache), external ocular symptoms (dryness, irritation, burning), visual symptoms (blur, double vision) and musculoskeletal symptoms (neck and shoulder pain). The major factors associated with CVS are either environmental (improper lighting, display position and viewing distance) and/or dependent on the user's visual abilities (uncorrected refractive error, oculomotor disorders and tear film abnormalities). CONCLUSION: Although the factors associated with CVS have been identified the physiological mechanisms that underlie CVS are not completely understood. Additionally, advances in technology have led to the increased use of hand-held devices, which might impose somewhat different visual challenges compared to desktop displays. Further research is required to better understand the physiological mechanisms underlying CVS and symptoms associated with the use of hand-held and stereoscopic displays.


Assuntos
Terminais de Computador , Oftalmopatias/etiologia , Cervicalgia/etiologia , Doenças Profissionais/etiologia , Dor de Ombro/etiologia , Computadores de Mão , Ergonomia , Humanos , Iluminação/efeitos adversos , Postura , Fatores de Risco , Síndrome
8.
Vis Neurosci ; 30(4): 147-52, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24016531

RESUMO

At certain temporal frequencies, the human cone flicker electroretinogram (ERG) contains multiple additional responses following the termination of a flicker train. The purpose of this study was to determine whether these poststimulus responses are a continuing response to the terminated flicker train or represent the oscillation of a resonant system. ERGs were recorded from 10 visually normal adults in response to full-field sinusoidally modulated flicker trains presented against a short-wavelength rod-saturating adapting field. The amplitude and timing properties of the poststimulus responses were evaluated within the context of a model of a second-order resonant system. At stimulus frequencies between 41.7 and 71.4 Hz, the majority of subjects showed at least three additional ERG responses following the termination of the flicker train. The interval between the poststimulus responses was approximately constant across stimulus frequency, with a mean of 14.4 ms, corresponding to a frequency of 69.4 Hz. The amplitude and timing characteristics of the poststimulus ERG responses were well described by an underdamped second-order system with a resonance frequency of 70.3 Hz. The observed poststimulus ERG responses may represent resonant oscillations of retinal ON bipolar cells, as has been proposed for electrophysiological recordings of poststimulus responses from retinal ganglion cells. However, further investigation is required to determine the types of retinal neurons involved in the generation of the poststimulus responses of the human flicker ERG.


Assuntos
Eletrorretinografia , Células Fotorreceptoras Retinianas Cones/fisiologia , Adulto , Algoritmos , Eletrodos Implantados , Potenciais Evocados Visuais/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Estimulação Luminosa , Células Ganglionares da Retina/fisiologia , Adulto Jovem
9.
Doc Ophthalmol ; 126(1): 9-19, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23054159

RESUMO

BACKGROUND: This study aimed to determine whether the properties of the late negative responses (LNRs) of the electroretinogram (ERG) elicited by sawtooth flicker are consistent with the characteristics of the photopic negative response generated by a light pulse (PhNRpulse). METHODS: ERG recordings were obtained from 10 visually normal individuals and from 6 patients with optic atrophy (OA) in response to 8-Hz rapid-on and rapid-off sawtooth flicker and to brief (4 ms) light pulses. All stimuli were either long wavelength (R), middle wavelength (G), or a combination of equal luminances of long and middle wavelengths (Y) presented on a short-wavelength, rod-saturating adapting field. Amplitudes of LNRs were obtained in response to rapid-on (LNRon) and rapid-off (LNRoff) sawtooth flicker and were also derived from the sum of the ERG waveforms to the two sawtooth phases (LNRadd). RESULTS: For the control subjects, PhNRpulse amplitude varied with stimulus wavelength, being largest in response to a long-wavelength pulse, as expected. However, the amplitudes of LNRon, LNRoff, and LNRadd were not significantly different for R, Y, and G sawtooth flicker. Despite the absence of a chromatic effect, LNRoff and LNRadd amplitudes were significantly smaller in the OA patients than in the controls, similar to the results for the PhNRpulse, implying an inner retinal origin for the LNRoff and LNRadd. However, LNRon amplitudes did not differ significantly between the OA patients and controls, although there was a significant correlation between the LNRon and PhNRpulse for R stimuli. CONCLUSION: We conclude that LNRoff and LNRadd but not LNRon can be useful measures to assess the integrity of the inner retina that can complement the PhNRpulse.


Assuntos
Adaptação Ocular , Visão de Cores/fisiologia , Eletrorretinografia/métodos , Atrofia Óptica/fisiopatologia , Células Fotorreceptoras Retinianas Cones/fisiologia , Adulto , Feminino , Humanos , Interneurônios/fisiologia , Luz , Masculino , Pessoa de Meia-Idade , Atrofia Óptica/diagnóstico , Estimulação Luminosa , Adulto Jovem
10.
Doc Ophthalmol ; 125(1): 21-9, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22581377

RESUMO

Period doubling in the full-field cone flicker electroretinogram (ERG) refers to an alternation in waveform amplitude and/or shape from cycle to cycle, presumably owing to the operation of a nonlinear gain control mechanism. This study examined the influence of stimulus chromatic properties on the characteristics of period doubling in order to better understand the underlying mechanism. ERGs were acquired from 5 visually normal subjects in response to sinusoidally modulated flicker presented at frequencies from 25 to 100 Hz. The test stimuli and the pre-stimulus adaptation were either long wavelength (R), middle wavelength (G), or an equal combination of long and middle wavelengths (Y), all equated for photopic luminance. Fourier analysis was used to obtain the response amplitude at the stimulus frequency F and at a harmonic frequency of 3F/2, which was used as the index of period doubling. The frequency-response function for 3F/2 typically showed two peaks, occurring at approximately 33.3 and 50 Hz. However, the magnitude of period doubling within these frequency regions was dependent on the chromatic properties of both the test stimulus and the pre-stimulus adaptation. Period doubling was generally smallest when an R test was used, even though the stimuli were luminance-equated and the amplitude of F did not differ between the various conditions. The pattern of results indicates that the mechanism that generates period doubling is influenced by chromatic signals from both the test stimulus and the pre-stimulus adaptation, even though the high stimulus frequencies presumably favor the achromatic luminance system.


Assuntos
Visão de Cores/fisiologia , Eletrorretinografia , Luz , Células Fotorreceptoras Retinianas Cones/fisiologia , Adaptação Ocular/fisiologia , Adulto , Feminino , Análise de Fourier , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa , Adulto Jovem
11.
Optom Vis Sci ; 89(1): 97-104, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22051780

RESUMO

PURPOSE: Asthenopia has been associated with reading under visually stressful conditions. However, it is not known whether increased cognitive load contributes to asthenopic symptoms. The purpose of this study was to evaluate the contribution of increased cognitive load (with or without visual stress inducing conditions) to asthenopic symptoms associated with prolonged near work. METHODS: Thirty-three visually normal subjects, aged 18 to 30 years, participated in the study. Subjects read texts or watched videos under different visual stress and cognitive loads. Visual stress conditions were good visual quality, low contrast, and induced refractive error. The cognitive load levels were watching video, reading fairy tales, and reading technical articles. As an additional task, subjects also listened to technical articles. At the end of each condition, subjects rated the magnitude of any asthenopic symptoms, visual discomfort, and cognitive discomfort they experienced during the task. Electromyography potentials recorded from the lower orbicularis oculi muscle were used to obtain blink rate. RESULTS: Subjects reported greater internal symptoms for the refractive error condition coupled with higher cognitive load compared to good visual and low contrast conditions (p < 0.01). For the low contrast condition coupled with higher cognitive load, greater external symptoms were reported compared to good visual and refractive error conditions (p < 0.05). However, asthenopic symptoms were not reported for cognitively demanding tasks when the visual condition was good. Blink rates were not significantly different between the good visual and low contrast conditions within each cognitive load level. For the cognitively difficult reading conditions, blink rate was significantly decreased for the low contrast and good visual conditions compared to the refractive error condition. CONCLUSIONS: An interaction between cognitive and visual demands was observed. Greater cognitive loads accentuate the same differentiated symptoms normally caused by visual stressors.


Assuntos
Astenopia/fisiopatologia , Piscadela/fisiologia , Cognição/fisiologia , Pálpebras/fisiopatologia , Estresse Psicológico/complicações , Acomodação Ocular/fisiologia , Adolescente , Adulto , Astenopia/diagnóstico , Astenopia/etiologia , Eletromiografia , Seguimentos , Humanos , Estimulação Luminosa/efeitos adversos , Leitura , Valores de Referência , Estresse Psicológico/fisiopatologia , Adulto Jovem
12.
Optometry ; 82(11): 689-96, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21885351

RESUMO

BACKGROUND: The objective of this research is to assess the ocular and muscular response to long-duration reading under different visual and cognitive difficulty levels. METHODS: Thirty-five subjects, with 20/20 vision and without history of ocular pathology or cognitive deficits, participated in the study. Subjects read under different visual and cognitive difficulty levels for 6 (30-minute) conditions. Upper and lower orbicularis oculi, frontalis, and trapezius muscle activities were recorded using surface electromyography (EMG). Aperture size, pupil diameter, and pulse rate of the subjects were recorded with a video camera, pulse meter, and ISCAN eye tracker (ISCAN Inc.), respectively. RESULTS: The results show that the texts read with a refractive error caused increased orbicularis oculi EMG power and reduced aperture size (P < 0.001). There was no statistically significant difference between the conditions for pulse rate, pupil diameter, or EMG activity of the frontalis and trapezius muscles with either visual or cognitive stress presented in this experiment. CONCLUSION: Visual stress experienced due to reading under an induced refractive error is potentially mediated by a local mechanism, different from the mechanism underlying reading under low contrast or high cognitive demand.


Assuntos
Astenopia/fisiopatologia , Cognição/fisiologia , Movimentos Oculares/fisiologia , Músculos Oculomotores/fisiopatologia , Estresse Fisiológico/fisiologia , Estresse Psicológico/fisiopatologia , Acuidade Visual/fisiologia , Adolescente , Astenopia/etiologia , Progressão da Doença , Eletromiografia , Músculos Faciais/fisiopatologia , Seguimentos , Humanos , Leitura , Estresse Psicológico/complicações , Gravação em Vídeo , Adulto Jovem
13.
Ophthalmic Genet ; 32(3): 188-92, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21707411

RESUMO

PURPOSE: To report measures of inner retinal integrity following improvement in visual acuity and visual fields in a patient with hereditary motor and sensory neuropathy type VI (HMSN VI). CASE REPORT: The patient is a Caucasian male with HMSN VI (type 2A Charcot-Marie-Tooth disease and associated optic atrophy) and a c.1090C→T (p.R364W) mutation in the mitofusin 2 (MFN2) gene. The patient's best-corrected visual acuity improved from 20/200 (OD) and 20/400 (OS) at the initial visit to 20/25 in each eye when tested 7 years later. The visual field defects in both eyes that were present at the initial visit were absent at the follow-up visit. The structural integrity of the inner retina was assessed by an evaluation of retinal nerve fiber layer thickness (RNFLT) using optical coherence tomography (OCT), and the functional integrity was assessed by the amplitude of the photopic negative response (PhNR) of the electroretinogram (ERG). At the follow-up visit, the patient's RNFLT was less than the 5th percentile for control subjects in the superior and inferior quadrants OD and in one sector of the temporal quadrant OS, but was within normal limits elsewhere. The PhNR amplitude of each eye was below the lower limit of the normal range. CONCLUSION: The abnormally low PhNR amplitudes and abnormally thin RNFL in certain quadrants of the retina following improvement of visual acuity and visual fields to near-normal values illustrates the potential usefulness of assessing the structure and function of the inner retina in HMSN VI patients.


Assuntos
Doença de Charcot-Marie-Tooth/fisiopatologia , Fibras Nervosas/patologia , Doenças Retinianas/fisiopatologia , Células Ganglionares da Retina/patologia , Acuidade Visual/fisiologia , Adulto , Doença de Charcot-Marie-Tooth/genética , Eletrorretinografia , GTP Fosfo-Hidrolases , Humanos , Masculino , Proteínas de Membrana/genética , Proteínas Mitocondriais/genética , Mutação Puntual , Doenças Retinianas/genética , Tomografia de Coerência Óptica , Transtornos da Visão/fisiopatologia , Campos Visuais/fisiologia
14.
Vision Res ; 49(14): 1795-804, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19389417

RESUMO

The objectives of this experiment were to measure the effect of sustained convergence on the open-loop vergence peak velocity and open-loop vergence amplitude, and to assess the correlation between changes in the phoria and changes in open-loop vergence peak velocity induced by sustained convergence. Subjects sustained convergence on a target that required 12 degrees of convergence for 5 minutes. Convergence and divergence movements of 4 degrees from the 12 degrees convergent position were measured before and after sustained convergence. Following sustained convergence, the open-loop vergence peak velocity and vergence amplitude both increased for convergence (regression slope=3.68, r=0.47). Vergence velocity and vergence amplitude both decreased for divergence (regression slope=1.76, r=0.36). After sustained convergence, a convergent shift in the phoria was noted in most cases. This shift correlated with changes in open-loop peak vergence velocity more for convergence (regression slope=1.1, r=0.33) than for divergence (regression slope=0.71, r=0.22). The results might be due to shifts in disparity detection brought about by the period of sustained convergence.


Assuntos
Adaptação Ocular/fisiologia , Convergência Ocular/fisiologia , Acomodação Ocular/fisiologia , Adulto , Movimentos Oculares , Feminino , Fixação Ocular , Análise de Fourier , Humanos , Masculino , Estimulação Luminosa , Tempo de Reação , Erros de Refração , Adulto Jovem
15.
Optom Vis Sci ; 84(7): 611-9, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17632310

RESUMO

PURPOSE: To study the orbicularis oculi muscle response to asthenopia-inducing conditions. METHODS: Twenty subjects (18-36 years) screened for 20/20 vision in each eye participated in the study. Subjects read passages under different asthenopia-inducing conditions. The inducing conditions were glare, low contrast, small font size, refractive error, up gaze, accommodative stress and convergence stress. Surface electromyography (EMG) was used to study the orbicularis oculi response from the right eye. Palpebral fissure height was measured from recorded video images of the right eye. At the end of each condition subjects were asked to rate the severity and type of visual discomfort experienced. RESULTS: Outcome measures for the asthenopia-inducing conditions were compared with their respective nonstress controls. Repeated measures analysis of variance was used to analyze the data. Refractive error (p = 0.0001), glare (p = 0.0001), low contrast (p = 0.007), small font (p = 0.034), and up gaze (p = 0.001) resulted in a significant increase in EMG power. Refractive error (p = 0.0001) and glare (p = 0.0001) also caused significant reduction in aperture size. Reading a low contrast text caused a reduction in blink rate (p = 0.035), whereas refractive error (p = 0.005) and glare (p = 0.01) caused an increase in blink rate. All conditions induced significant visual discomfort (p < 0.001). CONCLUSION: Refractive error and glare, which reduce image quality and benefit from eyelid squint, caused increased EMG power, eyelid squint response and increased blink rate. Low contrast and small font, which reduce image quality but do not benefit from eyelid squint, resulted in increased EMG power without changes in aperture size and reduced blink rate (for low contrast). Accommodative and convergence stress (in subjects with normal accommodative and vergence abilities) did not cause changes in EMG power, aperture size or blink rate. These results suggest that contraction of the orbicularis oculi is a part of the asthenopia mechanism related to compromised image quality.


Assuntos
Astenopia/fisiopatologia , Piscadela/fisiologia , Pálpebras/fisiopatologia , Músculos Oculomotores/fisiopatologia , Erros de Refração/complicações , Acomodação Ocular/fisiologia , Adolescente , Adulto , Astenopia/etiologia , Progressão da Doença , Eletromiografia , Feminino , Humanos , Masculino , Prognóstico , Refração Ocular , Erros de Refração/fisiopatologia , Índice de Gravidade de Doença
16.
Optom Vis Sci ; 82(10): 905-11, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16276323

RESUMO

PURPOSE: We hypothesize that eyelid squint inhibits blink rate. This is part of a larger hypothesis that, because eyelid squint improves vision under conditions of optical defocus and/or glare, and reduced blink rate is assumed to contribute to dry eye symptoms, eyelid squint is part of the mechanism resulting in asthenopia. This study investigates the effect of voluntary eyelid squint on blink activity and on electromyography (EMG) measures from the orbicularis oculi. METHODS: Ten subjects (18 to 38 years of age) performed 3 1-minute trials each (Latin Square order) of voluntary target squint levels of 5%, 20%, 35%, and 50% with respect to previously demonstrated 0% (relaxed) and 100% (maximum) squint levels. EMG recordings using surface electrodes were obtained from the orbicularis muscle. Vertical dimension of the palpebral fissure and eye lid blinks were measured with an ISCAN eye tracker and video recorder. RESULTS: Each target squint level produced significant changes (p<0.0001) in ocular aperture size, EMG power, and EMG amplitude. For target voluntary squint levels of 5%, 20%, 35%, and 50%, the mean squint responses were 24%, 35%, 42%, and 53%, respectively. Blink rate was inversely related to both target squint level and squint response (p<0.0001), decreasing from 15 blinks per minute at 0% squint to 7.5 blinks per minute at 5% target voluntary squint and to 4 blinks per minute at 50% target voluntary squint. CONCLUSIONS: Voluntary eyelid squint significantly reduces blink rate by an average of 50% or more dependent on attempted level. Further study is required to determine if involuntary squint causes the same. All tested levels of voluntary squint resulted in an EMG signal from the orbicularis muscle that is measurably different from resting state. This indicates that EMG can be used as a reliable indicator of eyelid squint.


Assuntos
Piscadela , Pálpebras/fisiologia , Contração Muscular , Músculo Esquelético/fisiologia , Adulto , Eletromiografia , Humanos , Valores de Referência , Estrabismo/fisiopatologia , Gravação de Videoteipe
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