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At least 19 recordsLinked to original sources

PubMedDate not supplied

Pupil in clinical diagnosis. Light reflex anatomy and the afferent pupil defect.

The neuroanatomy for the light reflex has been reviewed. The importance of the semidecussation of visual pathways in the afferent portion of the system has been emphasized. The anatomy of the near synkinesis and its relation to the anatomy of the light reflex have been reviewed. The various abnormalities of sensory pupil function have been outlined. Particular stress has been placed on the value of the afferent pupil defect in the diagnosis of sensory lesions affecting the eye because of retinal or optic nerve disease. In addition, the value of the consensual pupil in the diagnosis of afferent defects has received special comment.

Accommodation, Ocular↗

PubMed1978

Pupil cycle time in optic neuritis.

A thin slit-lamp beam illuminating the pupil margin produced clearly visible pupil oscillations. These oscillations were timed with a stopwatch, thus producing a measurement of the "pupil cycle time". The pupil cycle time was remarkably stable in various testing situations and repeatable within +/- 3% over extended periods of time. When the iris muscles were normally innervated and responsive, the pupil cycle time was dependent on the speed of conduction and the number and strength of optic nerve impulses. Pupil cycle time can be measured in most persons with active or inactive optic neuritis. In the few patients whose light reflex is so poor that the pupil cycle time cannot be measured, the inability to induce cycling can itself be taken as a definite abnormality of the light reflex arc. Only 5% of normal persons 12 to 50 years of age are expected to have a pupil cycle time in either eye longer than 954 msec, or a difference in pupil cycle time between the two eyes longer than 70 msec. Pupil cycle time was significantly longer in patients with optic neuritis, with a P-value less than .001. The pupil cycle time is similar to visual evoked response latency time in that it can detect and quantitate subclinical defects in optic nerve conduction time. Pupil cycle time is objective and quantitative for each eye individually. It is a fast, simple, and reliable clinic test of optic nerve function.

Adult↗

PubMed2026

Identification Matters: How Data Sharing Affects Pupil Honesty and Engagement in Universal School Well-Being Assessments.

PURPOSE: Universal well-being assessments in schools may support early identification of pupils needing mental health support. However, little is known about how privacy and confidentiality concerns influence pupils' acceptability of assessments and willingness to engage authentically. This study examined how hypothetical identification, where responses are linked to pupils and shared with key stakeholders, affects pupils' anticipated honesty and engagement, and whether known help-seeking barriers predict negative responses. METHODS: Cross-sectional data were collected from 12,377 primary (ages 8-10) and secondary pupils (ages 11-17) across 55 schools in England. Pupils reported whether their responses would change if identifiable and shared with school staff, parents/guardians, or external professionals. Responses indicating reduced honesty or likelihood of disengagement were coded as negative. Predictors were examined using mixed-effects logistic regression models, including demographics, school connectedness, and mental well-being. RESULTS: Identification and data sharing influenced pupils' anticipated engagement, particularly in secondary schools. Identification by school staff elicited the highest proportion of negative responses in both phases, whereas external professionals elicited the fewest. Most primary pupils reported they would respond authentically, while a larger proportion of secondary pupils indicated they would respond less honestly or disengage when responses were identifiable and shared. Across primary and secondary samples, low well-being, low school connectedness, and being female were associated with greater likelihood of negative response. DISCUSSION: Pupils' anticipated engagement with well-being assessments is shaped by who accesses their data, with marked developmental differences. Strengthening trust, privacy, and connectedness, and supporting pupils' autonomy, may improve the acceptability and response accuracy.

Humans↗

PubMed1979

The effect of pupil size on visual acuity in uncorrected and corrected myopia.

The effect of pupil size on the relation between Snellen visual acuity and corrected and uncorrected myopia was examined for 22 young subjects with degrees of myopia ranging from 0.75 D to 7.5 D. Effective pupil size was varied by inducing mydriasis and then placing artificial pupils of between 1.0 and 8.0 mm diameter before the eye. Both a constant chart luminance of 120 cd/m2 and a constant retinal illuminance of 2150 trolands were used. There was little difference in results for the two lighting conditions. For the corrected myopes considered as a group, maximum visual acuity occurred for 2--3 mm diameter pupils, but larger pupils reduced acuity only marginally. For the uncorrected myopes, variation in pupil size produced a large variation in visual acuity, and for refractive errors greater than about 1.5 D, the optimum pupil diameter was less than 1 mm. For uncorrected myopes of 3.0 D or less, visual acuity was nearly as good with a 1-mm pupil as for corrected myopes. The presented data are a useful guide to the clinician.

Adult↗

PubMed1978

Edge-light pupil cycle time.

A thin slit-lamp beam illuminating the pupil margin produces clearly visible pupil oscillations. These oscillations can be timed with a stopwatch, thus producing a measurement of the "edge-light" pupil cycle time'. The pupil cycle time is remarkably stable in various testing situations and is repeatable within about +/- 3% over extended periods of time. Expected normal distribution and 95% confidence intervals are given in Table 3. When the iris muscles are normally innervated and responsive, the pupil cycle time is dependent on the speed of nerve conduction and the number and strength of optic nerve impulses. Only 5% of normal persons aged 12 to 50 years are expected to have a pupil cycle time in either eye longer than 954 ms or a difference in pupil cycle time between the two eyes longer than 70 ms.

Adolescent↗

PubMed1979

Static and kinetic properties of the dolphin pupil.

In dim illumination, adult human pupil area becomes asymptotic at about 51 mm2 whereas the dolphin pupil achieves an area of about 70 mm2 under equivalent conditions. At moderate illumination levels (greater than 100 lx), the dolphin pupil becomes a horizontally oriented ellipse and develops a pronounced central constriction with additional light. The relative relationship between pupil area and illumination copmares closely with published human data. Rates of pupil response to step increments in illumination are very similar for the two species. Although the pupil has been proposed as a mechanism for correction of the dolphins' high aerial myopia, correlation of the laboratory findings on static and kinetic pupil properties with visually controlled aerial behaviors disclosed no special interdependence.

Adaptation, Ocular↗

PubMed1979

[The role of the pupil's size in the perception of other persons].

Studies by Hess (1975) show that the pupil serves as a source of information in perception of the emotional state of another person. Large pupils are interpreted in a positive sense. Basing on the results of Hess, the hypothesis that pupil size does not become a relevant variable in person perception until after puberty, was formed. The following result would be interpreted as supporting the hypothesis: since girls reach puberty before boys, more girls should react to pupil size than boys of the same age. 121 students between the ages of 11 and 16 years judged in several statements which of two face photos of a teacher expressed a greater degree of positive attention and esteem towards the students. The two face photos were identical with the exception of pupil size. All age groups rated the photos with larger pupils more positively. Sex differences occurred in the ratings of the 11 to 12-year-olds. Some basic differences between this experiment and that of Hess are discussed.

Adolescent↗

PubMed1977

Sex differences in behavior ratings: male and female teachers rate male and female pupils.

Male and female primary school teachers rated their male and female pupils using a 16-item classroom behavior rating scale (Modified AML). Male pupils were generally rated more poorly than femal pupils by both male and female teachers. Male teachers rated both male and female pupils more conservatively than did female teachers on the separate factors of the AML scale. There was no difference in ratings by male and femal teachers of the overall adjustment of pupils, where the extreme scale point called for a professional decision as to whether the child should be referred to child guidance services. The findings have methodological implications for epidemiological studies, and for longitudinal studies. The findings fail to support the view that male pupils have more difficulty in school because they are taught by female teachers.

Aggression↗

PubMed2025

Pupil dynamics in macaque recognition memory tasks: investigating physiological mechanisms.

Cognitive deficits are common in primates, particularly in memory and emotional processes. Rhesus monkey (Macaca mulatta), widely used in cognitive and behavioral research, are central to memory studies. The relationship between recognition memory performance and pupillary dynamics in rhesus monkeys remains underexplored. This study investigated pupil dynamics during recognition memory tasks and their physiological correlates in five sexually mature male rhesus monkeys. We measured pupil diameter and oscillatory features during tasks and analyzed the relationship between behavioral performance and physiological indicators. We found that the average correct response rate exceeded the random success level, and reaction times were significantly shorter during successful recognition than failures, highlighting their cognitive efficiency. During recognition of familiar scenes, average pupil diameter increased, while maximum change in pupil size decreased, indicating reduced cognitive load. Both the frequency and amplitude of pupillary oscillation were lower during successful trials, reflecting decreased cognitive conflict and effective processing. This change reflects a decrease in cognitive conflict and suggests that information processing was more effective. The absolute value of the pupil peak slope decreased during successful recognition, indicating more stable cognitive state. These results support that pupillary dynamics can serve as physiological markers of cognitive effort in rhesus monkeys. Future studies should investigate how stimulus characteristics influence recognition and incorporate measures, such as intracranial EEG and fMRI, to enhance our understanding of their neural mechanisms. This research supports the rhesus monkey model in cognitive neuroscience and contributes to understanding primate cognition and its physiological foundations, with implications for clinical and translational research.

Animals↗

PubMed1977

Fisher's syndrome: a pharmacological study of the pupils.

A pharmacological study was performed in the involved pupils to demonstrate the site of lesion in a patient with Fisher's syndrome who showed marked ptosis, complete external ophthalmoplegia, pupillary involvement with anisocoria, facial paresis, ataxia, areflexia, and albuminocytological dissociation in the cerebrospinal fluid. The instillation of 2.5% methacholine produced mild constriction of one pupil. This response was not detectable in the recovery stage. The instillation of 1.25% l-epinephrine produced marked bilateral dilation of the pupils, in both the early and recovery stages. Instillation of 5% tyramine produced pupillary dilation as in the normal pupil. The response to 5% cocaine, tested only in the recovery stage, was weak in one pupil. These results imply that the pupillary involvement was due to peripheral involvement of the sympathetic and parasympathetic nervous systems. The lesion in the sympathetic nervous system was preganglionic, but in the parasympathetic nervous system the precise localization could not be determined.

Aged↗

PubMed1977

Actions of amphetamine and antagonists on pupil diameter in the chronic sympathectomized dog.

The left superior cervical ganglia were removed from 5 dogs. Beginning 30 days postoperatively, epinephrine (10 microgram/kg/min), norepinephrine (10 microgram/kg/min), and d-amphetamine (1.0 mg/kg) were infused i.v. for 10 min following either vehicle, phenoxybenzamine, pimozide, or haloperidol. Epinephrine and norepinephrine dilated the pupil and retracted the nictitating membrane of the denervated side, whereas amphetamine dilated both pupils and retracted both nictitating membranes. Phenoxybenzamine (4 mg/kg) constricted primarily the pupil of the innervated iris and completely antagonized the effects of the catecholamines on the irides and amphetamine on the nictitating membranes, but only partially antagonized amphetamine-induced mydriasis. Haloperidol (1.0 mg/kg) constricted both pupils, possessed only modest alpha-adrenergic blocking activity, and was as effective as phenoxybenzamine in antagonizing amphetamine-induced mydriasis. Pimozide (0.1 mg/kg) constricted both pupils, had no significant alpha-adrenergic blocking activity, and did not antagonize amphetamine-induced mydriasis. Pimozide and haloperidol, but not phenoxybenzamine, blocked amphetamine-induced stereotyped head bobbing. These results suggest that amphetamine produces mydriasis in the dog through a peripheral sympathetic action and also through a central mechanism involving inhibition of the oculomotor nucleus. However, the role of dopamine is not clear.

Animals↗

PubMed1979

Pupil dilation, sex of stimulus, and age and sex of observer.

10-yr.-old, 16-yr.-old, and 20-yr.-old male and female observers (ns = 10; N = 60) rated a number of male and female faces for how 'good-looking' they were. Some of these faces were identical save that in one version the pupils were larger. Pupil dilation in the photographs of males produced no significant effects, whereas pupil dilation in the female photographs caused such faces to be rated as more good-looking by the two oldest groups of male observers. The 10-yr.-old boys and the 16- and 20-yr.-old women rated the female faces with enlarged pupils as significantly less 'good-looking' than the same faces with smaller pupils.

Adolescent↗

PubMed1978

A displaced Stiles-Crawford effect associated with an eccentric pupil.

Receptors tend to be oriented toward a point near the center of the pupil in the normal eye. We report psychophysical studies of receptor orientation and directional sensitivity in a subject whose right pupil is displaced nearly 3 mm nasally as a result of injury sustained 25 years ago. The Stiles-Crawford effect was measured for foveal cones and for parafoveal cones and rods. Greatest sensitivity was found in all cases at a point close to the center of the natural pupil, indicating that the receptors in this eye are trained toward the abnormally situated pupil. At large angles of incidence, foveal cones exhibited a clear asymptote of sensitivity 0.83 log units below the sensitivity for axially incident light. Parafoveal cones were more directionally sensitive, with a suggestion of an asymptote for oblique incidence about 1.2 log units below the sensitivity for axial incidence. Rods showed a sensitivity pattern decentered like that of the cones, with a greatest observed sensitivity loss of 0.28 log units. Best acuity for cones was observed for entrance pupils close to the optical axis of the eye, remote from the pupillary region for best sensitivity.

Child, Preschool↗

PubMed1977

Orientation of slit pupil and visual streak in the eye of the cat.

The orientation of the visual streak of the cat's retina was compared to that of the long axis of the slit pupil in the same eye. In five paralyzed, anesthetized cats, the retinal projection to the superior colliculus was mapped with electrophysiological techniques. The orientation of the visual streak was estimated from the projection in visual space of the collicular region of high magnification which corresponds to the central projection of the streak. The angle by which the streak was tilted from absolute horizontal was always within one or two degree of the angle by which the pupil axis was tilted from absolute vertical. This relationship was confirmed in three of the animals in which small retinal lesions were placed a known distance from the histologically determined axis of the streak. From the visual coordinates of these lesions, an independent estimate of the streak's orientation was obtained. In each case, the tilt of streak axis from horizontal differed by no more than 0.5 degrees from the tilt of the pupil axis from vertical. The results support the hypothesis that planes containing the long axis of the cat's slit pupil are perpendicular to planes containing the long axis of the visual streak of the same eye.

Animals↗

PubMed1979

The influence of 1,3,7-trimethyl-xanthine (caffeine) on the pain-caused dilation of pupil.

The pupil dilation in man caused by pain was investigated. The pain stimulus was induced electrically. The size of the pupil was measured according to the "flying spot scanning method". The accuracy of measurement was increased by computer-assisted addition of repeated responses as well as by elimination of the, usually not considered constriction due to light compensation over Maxwellian view. The pure psycho-sensory dilation shows no initial contraction. The central stimulant 1,3,7-trimethyl-xanthine (caffeine) does not influence the course and adaption of the pupil reaction by a pain stimulus over the threshold. The pupil reaction correlates with the subjective feeling of pain. This suggests that caffeine does not influence the feeling of pain.

Adult↗

PubMed1978

A small pupil binocular indirect ophthalmoscope.

A description of a lightweight small pupil binocular indirect ophthalmoscope is presented. This instrument can be used with well dilated pupils and clear media as any stereoscopic indirect ophthalmoscope. However, the instrument can be simply and easily adjusted for usage in patients with small pupils or opacities of the media. The optical and mechanical principles employed are presented. The technique of utilization for small pupil viewing is outlined.

Dilatation↗

PubMed1978

The refraction of the eye in the relation to spherical aberration and pupil size.

Available theoretical and experimental data on the dependence of the subjective refraction of the eye on spherical aberration and pupil size are reviewed and additional experimental results are presented. Under photopic conditions, refraction varies little (similar to 0.3 DS) with pupil diameter, even when substantial amounts of spherical aberration are present (similar to 1.0 DS). It is argued that this result may be attributed to the insensitivity of optimal focus to spherical aberration at the spatial frequencies involved in photopic refraction, to the Stiles-Crawford effect and to the influence of aberrations other than primary spherical aberration in the outer zones of the pupil. The signficance of these findings is indicated in relation to possible discrepancies between the results of objective and subjective refractions when large pupils are in use.

Humans↗

PubMed1978

[The effect of the pupil as aperture and field stop on the various components of the human electroretinogram (author's transl)].

The electroretinogram (ERG) was recorded in 10 normal subjects under scotopic and photopic conditions with the pupil of one eye constricted and that of the other eye dilated. The human iris, being displaced from the nodal point of the eye, acts not only as an aperture, regulating the retinal illumination, but also as a field stop, limiting the visual angle, especially for large object fields, as in Ganzfeld illumination. This double effect of a constricted pupil clearly influences the Ganzfeld ERG, not only shifting the intensity response functions to higher luminances but also diminishing the maximal responses. Control experiments with smaller test fields, which are less affected by the pupillary field-stop properties, reveal no diminution of the scotopic b-wave amplitudes. Implicit time functions, being nearly independent of the number of receptors stimulated, can be matched by taking into account the pupillary diameter and calculating the actual retinal illumination (Troland). Amplitudes, being highly affected by a decrease of responding neurons due to the angle-limiting field-stop character of the pupil, cannot be matched with regard to the pupillary diameter. This effect is most noticeable in Ganzfeld illumination for the scotopic b-wave, generated mainly by neurons of the peripheral retina, and has less effect on the photopic responses that are generated more centrally.

Adaptation, Ocular↗