Pupil Response (pupil + response)

Distribution by Scientific Domains


Selected Abstracts


ApoE allelic variability influences pupil response to cholinergic challenge and cognitive impairment

GENES, BRAIN AND BEHAVIOR, Issue 3 2007
L.F.M. Scinto
Exaggerated pupil response to dilute tropicamide has been suggested as an early biological marker for Alzheimer's disease. The current study links apolipoprotein E (ApoE) allelic variability to the magnitude of pupil response in a sample of community-dwelling elderly without a diagnosis of Alzheimer's disease or dementia. Possession of an ,4 allele influences both the likelihood of exhibiting an exaggerated pupil response above a predetermined cut-off (13% above baseline diameter) and the absolute overall magnitude of the response. Allelic variability was also shown to correlate with cognitive impairments in memory and attention. The data in this study further elucidate the nature of the biological bond between an exaggerated pupil response and the pathology of Alzheimer's disease. ApoE allelic variability is probably linked to pupil response through its influence on tau hyperphosphorylation. The early Alzheimer's pathology seen in the Edinger,Westphal area of cranial nerve III, a major centre for pupil control, is primarily tau-based with significant cell loss in this nucleus leading to central denervation hypersensitivity even in elderly who are clinically silent but who have early pathology. [source]


Clinical utility of an automated pupillometer for assessing and monitoring recipients of liver transplantation

LIVER TRANSPLANTATION, Issue 12 2009
Sheng Yan
Pupil examination has been used as a basic measure in critically ill patients and has great importance for the prognosis and management of disease. An automated pupillometer is a computer-based infrared digital video system by which the accuracy and precision of the pupil examination are markedly improved. We conducted an observational study of pupil assessment with automated pupillometry in clinical liver transplantation settings, including pretransplant evaluations and posttransplant surveillance. Our results showed that unconscious patients (grade 4 hepatic encephalopathy) had a prolonged latency phase (left side: 283 ± 80 milliseconds; right side: 295 ± 96 milliseconds) and a reduced pupillary constrictive ratio (left direct response: 0.23 ± 0.10; left indirect response: 0.21 ± 0.07; right direct response: 0.20 ± 0.08; right indirect response: 0.21 ± 0.08) in comparison with normal and conscious patients. After liver transplantation, the recovery of pupillography in these patients was slower than that in conscious patients. However, the surviving recipients without major complications all had a gradual recovery of pupillary responses, which occurred on the first or second posttransplant day. We also reported 4 cases of futile LT in the absence of pretransplant pupillary responses and other pupillary abnormalities revealed by automated pupillometry in our study. In conclusion, patients with grade 4 hepatic encephalopathy had a sluggish pupil response and a delayed recovery pattern after LT. An automated pupillometer is potentially a supplementary device for pretransplant screening and posttransplant monitoring in patients undergoing LT, but further prospective studies are required. Liver Transpl 15: 1718,1727, 2009. © 2009 AASLD. [source]


Continuous recording of accommodation and pupil size using the Shin-Nippon SRW-5000 autorefractor

OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 2 2001
J. S. Wolffsohn
Summary A newly released commercial autorefractor, the Shin-Nippon SRW-5000 (Japan), has been found to be valid compared to subjective refraction and repeatable over a wide prescription range. Its binocular open field-of-view allows the accommodative state to be monitored while a natural environment is viewed. In conventional static mode, the device can take up to 45 readings in 1 min using digital image analysis of the reflected retinal image of a measurement ring. Continuous on-line analysis of the ring provides high (up to 60 Hz) temporal resolution of the refractive state to an accuracy of <0.001 D. Pupil size can also be analysed to a resolution of <0.001 mm. The measurement of accommodation and pupil size was relatively unaffected by eccentricity of viewing up to ±10° and instrument focusing inaccuracies of ±5 mm. The resolution properties of the analysis are shown to be ideal for measurement of dynamic accommodation and pupil responses. [source]


Accommodation microfluctuations and pupil size during sustained viewing of visual display terminals

OPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 1 2000
L.S. Gray
Summary Accommodation microfluctuations comprise two dominant frequencies; a low frequency component (LFC0.6 Hz) and a high frequency component (1.0 Hzpupil responses during sustained viewing of visual display terminals (VDTs). Steady-state accommodation and pupil responses were measured continuously and simultaneously using a modified Canon Autoref R-1 infra-red objective optometer and an Hamamatsu C3160 Perceptscope Video Area Analyser. Measurements were obtained at three time intervals (0, 10 and 20 min) during a 20 min reading task presented on five different displays. With the displays placed at 50 cm, the task was to locate and identify typographical errors in one of five sets of standard text. Five young visually-normal emmetropic subjects with a mean age of 22.5±3.0 years participated in the study. Two-way ANOVA revealed no significant variation in the magnitude of the accommodation microfluctuations with either display or task duration, nor was there any significant interaction between these two factors. There was no significant variation in mean pupil diameter with either display or task duration. These measures may have the potential to provide objective information about visual display quality. [source]


The effect of school resources on pupil attainment: a multilevel simultaneous equation modelling approach

JOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 3 2007
Fiona Steele
Summary., Improving educational achievement in UK schools is a priority, and of particular concern is the low achievement of specific groups, such as those from lower socio-economic backgrounds. An obvious question is whether we should be improving the outcomes of these pupils by spending more on their education. The literature on the effect of educational spending on the achievement of pupils has some methodological difficulties, in particular the endogeneity of school resource levels, and the intraschool correlations in pupils' responses. We adopt a multi-level simultaneous equation modelling approach to assess the effect of school resources on pupil attainment at age 14 years. The paper is the first to apply a simultaneous equation model to estimate the effect of school resources on pupils' achievement, using the newly available national pupil database and pupil level annual school census. [source]