RESUMO
PURPOSE: We quantified the main sequence of spontaneous blinks in normal subjects and Graves' disease patients with upper eyelid retraction using a nonlinear and two linear models, and examined the variability of the main sequence estimated with standard linear regression for 10-minute periods of time. METHODS: A total of 20 normal subjects and 12 patients had their spontaneous blinking measured with the magnetic search coil technique when watching a video during one hour. The main sequence was estimated with a power-law function, and with standard and trough the origin linear regressions. Repeated measurements ANOVA was used to test the mean sequence stability of 10-minute bins measured with standard linear regression. RESULTS: In 95% of the sample the correlation coefficients of the main sequence ranged from 0.60 to 0.94. Homoscedasticity of the peak velocity was not verified in 20% of the subjects and 25% of the patients. The power-law function provided the best main sequence fitting for subjects and patients. The mean sequence of 10-minute bins measured with standard linear regression did not differ from the one-hour period value. For the entire period of observation and the slope obtained by standard linear regression, the main sequence of the patients was reduced significantly compared to the normal subjects. CONCLUSIONS: Standard linear regression is a valid and stable approximation for estimating the main sequence of spontaneous blinking. However, the basic assumptions of the linear regression model should be examined on an individual basis. The maximum velocity of large blinks is slower in Graves' disease patients than in normal subjects.
Assuntos
Piscadela/fisiologia , Pálpebras/fisiopatologia , Oftalmopatia de Graves/fisiopatologia , Adulto , Análise de Variância , Pálpebras/patologia , Feminino , Oftalmopatia de Graves/patologia , Humanos , Masculino , Gravação em VídeoRESUMO
Graves upper eyelid retraction (GUER) is the most common and characteristic sign of Graves orbitopathy. Despite being well recognized since the 19th century, GUER is still a subject of controversy. We review GUER, including historical aspects, diagnosis, methods of measurements, ocular surface abnormalities, etiology, and medical and surgical treatments. There is no consensus about the mechanisms of its etiology or the best surgical correction. There is a need for quantitative studies on the effects of GUER on lid movements.
Assuntos
Doenças Palpebrais , Oftalmopatia de Graves , Doenças Palpebrais/diagnóstico , Doenças Palpebrais/etiologia , Doenças Palpebrais/terapia , Oftalmopatia de Graves/diagnóstico , Oftalmopatia de Graves/etiologia , Oftalmopatia de Graves/terapia , HumanosRESUMO
Spontaneous blinking is essential for maintaining a healthy ocular surface and clarity of vision. The spontaneous blink rate (SBR) is believed to reflect a complex interaction between peripheral influences mediated by the eye surface and the central dopaminergic activity. The SBR is thus extremely variable and dependent on a variety of psychological and medical conditions. Many different methods have been employed to measure the SBR and the upper eyelid kinematics during a blink movement. Each has its own merits and drawbacks, and the choice of a specific method should be tailored to the specific needs of the investigation. Although the sequence of muscle events that leads to a blink has been fully described, knowledge about the neural control of spontaneous blinking activity is not complete. The tear film is dynamically modified between blinks, and abnormalities of the blink rate have an obvious influence on the ocular surface.
Assuntos
Piscadela/fisiologia , Pálpebras/fisiologia , Lágrimas/fisiologia , HumanosRESUMO
Patient that make use of chloroquine or hydroxychloroquine, drugs which are frequently administered for treatment of rheumatoid arthritis, lupus erithromatosus or malaria, may suffer alterations in color vision and in contrast sensitivity. The present work evaluates the visual functions of these patients in a joint study of the University of São Paulo (USP), in São Paulo, and of the Federal University of Pará (UFPA), in belém. Thirty two chloroquine user patients without alterations in the eye fundus exam were evaluated in São Paulo (n=10; aged 38 to 71 years; mean=55,8 years) and in Belém (n=22; aged 20 to 67; mean=40 years). The described accumulated chloroquine dose was 45 to 430g (mean=213g; as=152g) for the São Paulo group, and 36 to 540g (mean=174g; sd=183g) for the Belém group. Tests were performed monocularly corrected eye refractive state. Color discrimination was evaluated using the Cambridge Colour Test (CCT): the color discrimination threshold was measured first in the protan, deutan and tritan axes and , in succession, three MacAdamÆs ellipses were determined. The patientÆs color vision was also evaluated with color arrangement tests: the Farnsworth-Munsell 100 Hue (FM100), the Farnsworth-Munsell D15, and the Lanthony Desaturated (D15d) tests. We also measured the contrast sensitivity for black-and-white sine wave grating of twenty two patients. The results were compared with control without ophthalmologic or neuro-ophthalmologic pathologies. Twenty four patients presented acquired dyschromatopsia. There were cases of selective loss (11 patients) and of diffuse loss (13 patients). Although losses were present in the FM100 there was no correlation between the FM100 error score and the ellipse area measured by the CCT. Moreover, three patients that scored normal in the FM100, failed to reach normal threshold in the CCT. The Lanthony test was less sensitive than the other two tests, since it failed to indicate loss in about half the patients, and the D15 was the least sensitive test, having failed to indicate loss in 9 out of 10 patients. Contrast sensitivity was within normal values for patients submitted to this test. The extent of losses in color discrimination was positively correlated with the accumulated dose. The CCT is recommended for follow up since it provides quantitative data that can be directly interpreted in CIE (Commission Internationalle dÆÉclairage) color space.