Evaluation of Pupillary Diameter in Preschool Children

Few quantitative data exist on pupil diameter, particularly in children. In this article we describe an analysis of pupil diameter and pupil area in normal preschool children during attentive gaze (AG) and spontaneous gaze (SG) using digital imaging. The pupil diameter and pupil area of 200 preschool children aged 4 to 6 years were evaluated. The images were recorded with a digital camera, transferred to a computer, processed by movie software and submitted to the Invert filter of Adobe Photoshop (R) software. Three consecutive measures of pupil diameter and pupil area were taken for both eyes during AG and SG. Arithmetic means of each parameter were calculated and data were expressed in millimeters. Mean pupil diameter was similar for both eyes, presenting values of 4.9 mm during AG and 4.1 mm during SG. Mean pupil area was also similar for both eyes, presenting values of 15.6 mm(2) and 9.1 mm(2) during AG and SG, respectively. There were no differences between boys and girls. However, 6-year-old children showed lower pupil diameter and area under both evaluation conditions.

Grading of corneal transparency

Aim: To examine the academic literature on the grading of corneal transparency and to assess the potential use of objective image analysis. Method: Reference databases of academic literature were searched and relevant manuscripts reviewed. Annunziato, Efron (Millennium Edition) and Vistakon-Synoptik corneal oedema grading scale images were analysed objectively for relative intensity, edges detected, variation in intensity and maximum intensity. In addition, corneal oedema was induced in one subject using a low oxygen transmissibility (Dk/t) hydrogel contact lens worn for 3 hours under a light eye patch. Recovery from oedema was monitored over time using ultrasound pachymetry, high and low contrast visual acuity measures, bulbar hyperaemia grading and transparency image analysis of the test and control eyes. Results: Several methods for assessing corneal transparency are described in the academic literature, but none have gained widespread in clinical practice. The change in objective image analysis with printed scale grade was best described by quadratic parametric or sigmoid 3-parameter functions. ‘Pupil image scales’ (Annunziato and Vistakon-Synoptik) were best correlated to average intensity; however, the corneal section scale (Efron) was strongly correlated to variations in intensity. As expected, patching an eye wearing a low Dk/t hydrogel contact lens caused a significant (F=119.2, P<0.001) 14.3% increase in corneal thickness, which gradually recovered under open eye conditions. Corneal section image analysis was the most affected parameter and intensity variation across the slit width, in isolation, was the strongest correlate, accounting for 85.8% of the variance with time following patching, and 88.7% of the variance with corneal thickness. Conclusion: Corneal oedema is best determined objectively by the intensity variation across the width of a corneal section. This can be easily measured using a slit-lamp camera connected to a computer. Oedema due to soft contact lens wear is not easily determined over the pupil area by sclerotic scatter illumination techniques.

Accommodative response to electrical stimulation of the sclera of peripheral cornea in cats and porcines

Purpose: We have reported that the changes in the accommodative response to electrical stimulation of the branches of the ciliary nerves in cats. (Miyagawa et al, PLoS One, 2014). We have also reported that no robust accommodative responses to the electrical stimulations of the sclera of peripheral cornea (SSPC) were observed in enucleated porcine eyes (Mihashi et al, VPOptics, 2014). In this study, accommodative responses to SSPC stimulation in cats and porcines were investigated. Methods: Two eyes of two cats under anesthesia and after they were sacrificed were studied. Three enucleated porcine eyes obtained from a local slaughterhouse were also studied. Trains of biphasic pulses (current, 3 mA; duration, 2 ms/phase; frequency, 40 Hz) were applied using a tungsten electrode (0.3mm diameter) from several orientations. Wavefront sensing with a compact wavefront aberrometer (Uday et al J Cataract Refract Surg, 2013) were performed before and 4 s (cat) and 10 s (pig) after the stimulations and wavefront aberrations including spherical errors were analyzed over a 4-mm pupil area. Results: In the first cat under anesthesia, at three out of seven stimulus positions, 0.2 D hyperopic accommodative responses were observed and in two orientations, myopic responses were observed. For the other cat, weak accommodative responses including astigmatic changes were observed. In the sacrificed condition of the second cat, 0.1 D myopic response was observed for one stimulus orientation and the smaller responses were observed at six out of eight stimulus positions. No accommodative responses were elicited for the enucleated porcine eyes. Conclusions: In the anesthetized cats, electrical stimulation of the SSPC induced accommodative responses; the responses were unstable and weaker than the responses by the ciliary nerve stimulations we observed in our previous study. Small accommodative responses were observed after one of two cats had been sacrificed, but no accommodative responses were detected in the enucleated porcine eyes. Further studies are needed to confirm difference in the accommodation functions in the two species.

Circadian and wake-dependent effects on the pupil light reflex in response to narrow-bandwidth light pulses.

PURPOSE: Nonvisual light-dependent functions in humans are conveyed mainly by intrinsically photosensitive retinal ganglion cells, which express melanopsin as photopigment. We aimed to identify the effects of circadian phase and sleepiness across 24 hours on various aspects of the pupil response to light stimulation. METHODS: We tested 10 healthy adults hourly in two 12-hour sessions covering a 24-hour period. Pupil responses to narrow bandwidth red (635 ± 18 nm) and blue (463 ± 24 nm) light (duration of 1 and 30 seconds) at equal photon fluxes were recorded, and correlated with salivary melatonin concentrations at the same circadian phases and to subjective sleepiness ratings. The magnitude of pupil constriction was determined from minimal pupil size. The post-stimulus pupil response was assessed from the pupil size at 6 seconds following light offset, the area within the redilation curve, and the exponential rate of redilation. RESULTS: Among the measured parameters, the pupil size 6 seconds after light offset correlated with melatonin concentrations (P < 0.05) and showed a significant modulation over 24 hours with maximal values after the nocturnal peak of melatonin secretion. In contrast, the post-stimulus pupil response following red light stimulation correlated with subjective sleepiness (P < 0.05) without significant changes over 24 hours. CONCLUSIONS: The post-stimulus pupil response to blue light as a marker of intrinsic melanopsin activity demonstrated a circadian modulation. In contrast, the effect of sleepiness was more apparent in the cone contribution to the pupil response. Thus, pupillary responsiveness to light is under influence of the endogenous circadian clock and subjective sleepiness.

Test-retest repeatability of the pupil light response to blue and red light stimuli in normal human eyes using a novel pupillometer.

In this study, we evaluated the repeatability of pupil responses to colored light stimuli in healthy subjects using a prototype chromatic pupillometer. One eye of 10 healthy subjects was tested twice in the same day using monochromatic light exposure at two selected wavelengths (660 and 470 nm, intensity 300 cd/m(2)) presented continuously for 20 s. Pupil responses were recorded in real-time before, during, and after light exposure. Maximal contraction amplitude and sustained contraction amplitude were calculated. In addition, we quantified the summed pupil response during continuous light stimulation as the total area between a reference line representing baseline pupil size and the line representing actual pupil size over 20 s (area under the curve). There was no significant difference in the repeated measure compared to the first test for any of the pupil response parameters. In conclusion, we have developed a novel prototype of color pupillometer which demonstrates good repeatability in evoking and recording the pupillary response to a bright blue and red light stimulus.

An investigation into the relationship between pupil and accommodation responses during near vision

A Hamamatsu Video Area Analyser has been coupled with a modified Canon IR automatic optometer. This has allowed simultaneous recording of pupil diameter and accommodation response to be made both statically and continuously, a feature not common in previous studies. Experimental work concerned pupil and accommodation responses during near vision tasks under a variety of conditions. The effects of sustained near vision tasks on accommodation have usually been demonstrated by taking post-task measures under darkroom conditions. The possibility of similar effects on pupil diameter was assessed using static and continuous recordings following a near vision task. Results showed that is luminance levels remained unchanged by using a pre-and post-task bright-empty field then, although accommodation regressed to pre-task levels,pupil diameter remained for several minutes at the contstricted level induced by the task. An investigation into the effect of a sinusoidally-modulated blur-only accommodative stimulus on pupil response demonstrated that response may be reduced or absent despite robust accommodation responses. This suggests that blur-driven acommodation alone may not be sufficient to produce a pupil near response and that the presence of other cues may be necessary. Pupil response was investigated using a looming stimulus which produced an inferred-proximity cue. It was found that a pupil response could be induced which was in synchrony with the stimulus while closed-loop accommodation response was kept constant by the constraints of optical blur. The pupil diameter of young and elderly subjects undertaking a 5 minute reading task was measured to assess the contribution of pupil constriction to near vision function in terms of depth-of-focus. Results showed that in the young subjects pupil diameter was too large to have a significant effect on depth-of-focus although it may be increased in the elderly subjects. Pupil and accommodation reponses to a temporally-modulated stimulus containing all cues present in a normal visual environment was assessed and results showed that as stimulus temporal frequency increased, pupil response showed increasing phase lag relative to closed-loop accommodation. The results of this study suggest that it may be necessary to change the accepted view of the function of pupil response as part of the near vision triad and that further study would be of benefit in particular to designers of vision aids such as, for example, bifocal contact lenses.

A digital signal processing approach for affective sensing of a computer user through pupil diameter monitoring

Recent research has indicated that the pupil diameter (PD) in humans varies with their affective states. However, this signal has not been fully investigated for affective sensing purposes in human-computer interaction systems. This may be due to the dominant separate effect of the pupillary light reflex (PLR), which shrinks the pupil when light intensity increases. In this dissertation, an adaptive interference canceller (AIC) system using the H∞ time-varying (HITV) adaptive algorithm was developed to minimize the impact of the PLR on the measured pupil diameter signal. The modified pupil diameter (MPD) signal, obtained from the AIC was expected to reflect primarily the pupillary affective responses (PAR) of the subject. Additional manipulations of the AIC output resulted in a processed MPD (PMPD) signal, from which a classification feature, PMPDmean, was extracted. This feature was used to train and test a support vector machine (SVM), for the identification of stress states in the subject from whom the pupil diameter signal was recorded, achieving an accuracy rate of 77.78%. The advantages of affective recognition through the PD signal were verified by comparatively investigating the classification of stress and relaxation states through features derived from the simultaneously recorded galvanic skin response (GSR) and blood volume pulse (BVP) signals, with and without the PD feature. The discriminating potential of each individual feature extracted from GSR, BVP and PD was studied by analysis of its receiver operating characteristic (ROC) curve. The ROC curve found for the PMPDmean feature encompassed the largest area (0.8546) of all the single-feature ROCs investigated. The encouraging results seen in affective sensing based on pupil diameter monitoring were obtained in spite of intermittent illumination increases purposely introduced during the experiments. Therefore, these results confirmed the benefits of using the AIC implementation with the HITV adaptive algorithm to isolate the PAR and the potential of using PD monitoring to sense the evolving affective states of a computer user.

A Digital Signal Processing Approach for Affective Sensing of a Computer User through Pupil Diameter Monitoring

Recent research has indicated that the pupil diameter (PD) in humans varies with their affective states. However, this signal has not been fully investigated for affective sensing purposes in human-computer interaction systems. This may be due to the dominant separate effect of the pupillary light reflex (PLR), which shrinks the pupil when light intensity increases. In this dissertation, an adaptive interference canceller (AIC) system using the H∞ time-varying (HITV) adaptive algorithm was developed to minimize the impact of the PLR on the measured pupil diameter signal. The modified pupil diameter (MPD) signal, obtained from the AIC was expected to reflect primarily the pupillary affective responses (PAR) of the subject. Additional manipulations of the AIC output resulted in a processed MPD (PMPD) signal, from which a classification feature, PMPDmean, was extracted. This feature was used to train and test a support vector machine (SVM), for the identification of stress states in the subject from whom the pupil diameter signal was recorded, achieving an accuracy rate of 77.78%. The advantages of affective recognition through the PD signal were verified by comparatively investigating the classification of stress and relaxation states through features derived from the simultaneously recorded galvanic skin response (GSR) and blood volume pulse (BVP) signals, with and without the PD feature. The discriminating potential of each individual feature extracted from GSR, BVP and PD was studied by analysis of its receiver operating characteristic (ROC) curve. The ROC curve found for the PMPDmean feature encompassed the largest area (0.8546) of all the single-feature ROCs investigated. The encouraging results seen in affective sensing based on pupil diameter monitoring were obtained in spite of intermittent illumination increases purposely introduced during the experiments. Therefore, these results confirmed the benefits of using the AIC implementation with the HITV adaptive algorithm to isolate the PAR and the potential of using PD monitoring to sense the evolving affective states of a computer user.

Geochemistry Of Acid Mine Drainage From A Coal Mining Area And Processes Controlling Metal Attenuation In Stream Waters, Southern Brazil.

Acid drainage influence on the water and sediment quality was investigated in a coal mining area (southern Brazil). Mine drainage showed pH between 3.2 and 4.6 and elevated concentrations of sulfate, As and metals, of which, Fe, Mn and Zn exceeded the limits for the emission of effluents stated in the Brazilian legislation. Arsenic also exceeded the limit, but only slightly. Groundwater monitoring wells from active mines and tailings piles showed pH interval and chemical concentrations similar to those of mine drainage. However, the river and ground water samples of municipal public water supplies revealed a pH range from 7.2 to 7.5 and low chemical concentrations, although Cd concentration slightly exceeded the limit adopted by Brazilian legislation for groundwater. In general, surface waters showed large pH range (6 to 10.8), and changes caused by acid drainage in the chemical composition of these waters were not very significant. Locally, acid drainage seemed to have dissolved carbonate rocks present in the local stratigraphic sequence, attenuating the dispersion of metals and As. Stream sediments presented anomalies of these elements, which were strongly dependent on the proximity of tailings piles and abandoned mines. We found that precipitation processes in sediments and the dilution of dissolved phases were responsible for the attenuation of the concentrations of the metals and As in the acid drainage and river water mixing zone. In general, a larger influence of mining activities on the chemical composition of the surface waters and sediments was observed when enrichment factors in relation to regional background levels were used.

Imported Malaria In A Non-endemic Area: The Experience Of The University Of Campinas Hospital In The Brazilian Southeast.

Although malaria in Brazil almost exclusively occurs within the boundaries of the Amazon Region, some concerns are raised regarding imported malaria to non-endemic areas of the country, notably increased incidence of complications due to delayed diagnoses. However, although imported malaria in Brazil represents a major health problem, only a few studies have addressed this subject. A retrospective case series is presented in which 263 medical charts were analysed to investigate the clinical and epidemiological characterization of malaria cases that were diagnosed and treated at Hospital & Clinics, State University of Campinas between 1998 and 2011. Amongst all medical charts analysed, 224 patients had a parasitological confirmed diagnosis of malaria. Plasmodium vivax and Plasmodium falciparum were responsible for 67% and 30% of the infections, respectively. The majority of patients were male (83%) of a productive age (median, 37 years old). Importantly, severe complications did not differ significantly between P. vivax (14 cases, 9%) and P. falciparum (7 cases, 10%) infections. Severe malaria cases were frequent among imported cases in Brazil outside of the Amazon area. The findings reinforce the idea that P. vivax infections in Brazil are not benign, regardless the endemicity of the area studied. Moreover, as the hospital is located in a privileged site, it could be used for future studies of malaria relapses and primaquine resistance mechanisms. Finally, based on the volume of cases treated and the secondary complications, referral malaria services are needed in the non-endemic areas of Brazil for a rapid and efficient and treatment.

[construction Of Measurement Instruments In The Area Of Health].

Measurement instruments are an integral part of clinical practice, health evaluation and research. These instruments are only useful and able to present scientifically robust results when they are developed properly and have appropriate psychometric properties. Despite the significant increase of rating scales, the literature suggests that many of them have not been adequately developed and validated. The scope of this study was to conduct a narrative review on the process of developing new measurement instruments and to present some tools which can be used in some stages of the development process. The steps described were: I-The establishment of a conceptual framework, and the definition of the objectives of the instrument and the population involved; II-Development of the items and of the response scales; III-Selection and organization of the items and structuring of the instrument; IV-Content validity, V-Pre-test. This study also included a brief discussion on the evaluation of the psychometric properties due to their importance for the instruments to be accepted and acknowledged in both scientific and clinical environments.

Ambiência aérea em alojamento de frangos de corte: poeira e gases

Air quality in animal production environment has been refereed as an interesting point for studies in environmental control systems with the focus both to the animal health which live in total confinement, as to the workers. The objective of this research was to determine the variation on the aerial environmental quality in two types of broiler housing: conventional (Gc) and tunnel type (Gt). The total dust values in both houses offered adequate rearing conditions to the birds; however, regarding the inhale dust in the air was above the limits recommended for humans. Carbon monoxide concentration in the heating phase during the evaluated period was above the 10 ppm maximum recommended, and it was higher during the cold season in Gt house (30 ppm) when compared to the Gc house (18 ppm). Ammonia concentration peaks in the air were above the 20 ppm recommended from the 20th day of production in both houses and in daily average, for a period higher in Gt (4h30) when compared to Gt (2h45). Only traces of nitrate oxide and methane were found while carbonic dioxide gas concentration evaluated during daytime met the limits allowed for both birds and labor.

Ambiências térmica, aérea e acústica para reprodutores suínos

The swine breeder rearing environment directly affects the animal's performance. This research had the objective of developing a thermal, aerial and acoustic environmental evaluation pattern for boar housing. The experiment was carried on a commercial swine farm in Salto County -SP, Brazil. Thermal, aerial and acoustic environment data of rearing conditions were registered. Data were statistically analyzed using as threshold the ideal housing environment that leads to animal welfare. Results showed that ambient temperature was around 70% beyond normal range, while air relative humidity, air speed and gases concentration were within threshold values. Noise level data besides being within normal range did not present large variation. In relation to the fuzzy logic analysis it was possible to build up a scenario which indicated that the best welfare indexes to male swine breeders happens when thermal comfort index are close to 80%, and noise level is lower than 40 dB. In the other hand the worst welfare index occur in the sector where the thermal comfort values are below 40% at the same time that the noise level is higher than 80 dB leading to inadequate conditions to the animal, and may directly interfere in the reproduction system performance.

Efeitos da constrição pupilar na perimetria de freqüência dupla em olhos normais

Purpose: To study the effects of pupillary constriction on frequency doubling perimetry in a group of normal subjects. Methods: Eighteen healthy volunteers participated in the study. Only one eye per patient (right eye) underwent frequency doubling perimetry (Full Threshold C-20 strategy). For the second session, one drop of 2% pilocarpine was administered to the volunteers' right eye and the examination was repeated after 60 minutes. Results: Sixty minutes after administration of 2% pilocarpine, there was a significant reduction of the pupillary diameter from 4.22 ± 0.17 mm to 1.55 ± 0.51 mm (p<0.05). There was a significant reduction of the mean retinal sensibility after pupillary constriction. The threshold sensitivity of the central 5º worsened by 5.67 ± 2.49 dB; the area between 2.5º and 10º worsened by 4.49 ± 2.73 dB; and the area between 10º and 20º worsened by 5.10 ± 3.55 dB (p<0.01). A reduction of 4.06 ± 2.67 dB was observed in the mean deviation, as well as an increase of 0.64 ± 0.94 dB in the pattern standard deviation (p<0.01). No differences were observed regarding the number of fixation losses, false-positive and false-negatives responses, and duration of the examination. Conclusion: Changes in pupillary diameter may produce significant declines in threshold sensitivities of the 20º visual field tested by frequency doubling perimetry. These results suggest that is important to maintain a constant pupillary diameter in seriate examinations.

Interesses fisicos no lazer como area de intervenção do profissional da educação fisica

Universidade Estadual de Campinas. Faculdade de Educação Física