Pupils respond to three distinct kinds of stimuli: they constrict in response to brightness (the pupil light response), constrict in response to near fixation (the pupil near response), and dilate in ...response to increases in arousal and mental effort, either triggered by an external stimulus or spontaneously. In this review, I describe these three pupil responses, how they are related to high-level cognition, and the neural pathways that control them. I also discuss the functional relevance of pupil responses, that is, how pupil responses help us to better see the world. Although pupil responses likely serve many functions, not all of which are fully understood, one important function is to optimize vision either for acuity (small pupils see sharper) and depth of field (small pupils see sharply at a wider range of distances), or for sensitivity (large pupils are better able to detect faint stimuli); that is, pupils change their size to optimize vision for a particular situation. In many ways, pupil responses are similar to other eye movements, such as saccades and smooth pursuit: like these other eye movements, pupil responses have properties of both reflexive and voluntary action, and are part of active visual exploration.
This anthology presents successful examples of "research work" by teacher education students. Seminar concepts from the fields of natural sciences, music, educational science, mathematics and art, ...applied social psychology and the subject of German are presented. The volume is framed by a comprehensive theoretical introduction to the concept of research-based learning and its implementation at Leuphana University Lüneburg.
In diesem Sammelband werden gelungene Beispiele von „Forschungsarbeiten“ von Studierenden der Lehrkräftebildung dargestellt. Dazu werden Seminarkonzepte aus den Bereichen Naturwissenschaften, Musik, Bildungswissenschaft, Mathematik und Kunst, der angewandten Sozialpsychologie sowie dem Unterrichtsfach Deutsch vorgestellt. Gerahmt wird der Band durch eine umfangreiche theoretische Einführung in das Konzept des forschenden Lernens und seiner Umsetzung an der Leuphana Universität Lüneburg
Dilation devices in cataract surgery Sarnicola, Enrica; Sarnicola, Caterina; Sarnicola, Vincenzo
Current opinion in ophthalmology,
2023-Jan-01, 2023-01-00, 20230101, Letnik:
34, Številka:
1
Journal Article
Cataract surgery in the setting of small pupil represent a major challenge and it is associated with a higher risk of complications. When pharmacologic pupil dilation fails, mechanical pupil ...expansion devices are needed to obtain and maintain sufficient intraoperative mydriasis. The purpose of this review is to assess the pupil expansion devices currently available.
A variety of pupil expansion devices are offered on the market. They differ for design, material, shape, size, cost, and easiness of insertion/removal, nonetheless they all seem to be effective in improving the pupil size and easing the cataract surgery.
Mechanical pupil expansion can be effectively achieved with a variety of devices, which are well tolerated and can facilitate cataract surgery in the setting of poor mydriasis.
The purpose of this study was to determine the relative roles of the sympathetic (SNS) and parasympathetic nervous system (PNS) in pupillary hippus.
We used a paired-eye control study design with ...three cohorts receiving either 1.0% tropicamide (PNS antagonist) in light (TL), 1.0% tropicamide in dark (TD), or 10% phenylephrine (SNS) in light (PL), n = 12 in each. Each subject received one drop to the randomly determined treatment eye, while the other eye served as control. Bilateral measures of pupil size and dynamics were made over 2.6 seconds using an infrared eye-tracker sampling at 500 Hz. Measures were taken at baseline, then every 5 minutes for 40 minutes. Hippus, analyzed in both time and frequency domains, was compared between eyes and cohorts.
Pupillary hippus with a distinct dominant frequency was present in all measures at baseline (mean: 0.62 Hz, SD: 0.213 Hz), and that frequency did not change in any group (P = 0.971). Hippus magnitude (treatment eye relative to control eye) decreased in the TL (-72.8 ± 4.7%, P < 0.0001) and TD (-71.3 ± 2.6%, P < 0.0001) groups, but did not change in the PL (+5.4 ± 13.7%, P = 0.173) group, despite PL pupils dilating to a proportion similar to TD.
Pupillary hippus can be extinguished by antagonizing the PNS, whereas agonizing the SNS dilates the pupil without affecting hippus. This suggests that hippus originates from central PNS activity, and not from SNS activity, or oscillations in the balance between PNS and SNS at the pupil.
If a mental image is a rerepresentation of a perception, then properties such as luminance or brightness should also be conjured up in the image. We monitored pupil diameters with an infrared eye ...tracker while participants first saw and then generated mental images of shapes that varied in luminance or complexity, while looking at an empty gray background. Participants also imagined familiar scenarios (e.g., a "sunny sky" or a "dark room") while looking at the same neutral screen. In all experiments, participants' eye pupils dilated or constricted, respectively, in response to dark and bright imagined objects and scenarios. Shape complexity increased mental effort and pupillary sizes independently of shapes' luminance. Because the participants were unable to voluntarily constrict their eyes' pupils, the observed pupillary adjustments to imaginary light present a strong case for accounts of mental imagery as a process based on brain states similar to those that arise during perception.
When the pupil dilates, the amount of light that falls onto the retina increases. However, in daily life, this does not make the world look brighter. Here we asked whether pupil size (resulting from ...active pupil movement) influences subjective brightness in the absence of indirect cues that, in daily life, support brightness constancy. We measured the subjective brightness of a tester stimulus relative to a referent as a function of pupil size during tester presentation. In Experiment 1, we manipulated pupil size through a secondary working-memory task (larger pupils with higher load and after errors). We found some evidence that the tester was perceived as darker, rather than brighter, when pupils were larger. In Experiment 2, we presented a red or blue display (larger pupils following red displays). We again found that the tester was perceived as darker when pupils were larger. We speculate that the visual system takes pupil size into account when making brightness judgments. Finally, we highlight the challenges associated with manipulating pupil size. In summary, the current study (as well as a recent pharmacological study on the same topic by another team) is intriguing first steps towards understanding the role of pupil size in brightness perception.
The size of the pupil has a large effect on visual function, and pupil size depends mainly on the adapting luminance, modulated by other factors. Over the last century, a number of formulas have been ...proposed to describe this dependence. Here we review seven published formulas and develop a new unified formula that incorporates the effects of luminance, size of the adapting field, age of the observer, and whether one or both eyes are adapted. We provide interactive demonstrations and software implementations of the unified formula.
Since COVID-19 was first reported, different neurological complications have been acknowledged, but their description is constantly evolving. We report a case of concurrent tonic pupil and trochlear ...nerve palsy in this context. A 62-year-old man reported a 5-day history of binocular vertical diplopia and blurred vision in his left eye, noticing that his left pupil was dilated. He had suffered a flu-like syndrome 2 weeks before. Clinical exam showed a right trochlear nerve palsy and a left mydriatic pupil. MRI, X chest ray, and analytical results were normal. Antibodies for SARS-CoV-2 were positive (low IgM and high IgG titers). Antiganglioside antibodies were negative. A 0.125% pilocarpine test confirmed Adie’s pupil diagnosis. The patient was treated with a tapered prednisone dose with resolution of his diplopia but no change in Adie’s pupil. This is the first case reporting Adie’s pupil as a postinfectious manifestation of COVID-19. An immune-mediated mechanism is presumed.
This study presented the practices of pupil behaviour management of Vietnamese primary teachers with a focus on primary pupils' misbehaviours, and the activities the primary teachers implemented to ...manage this misbehaviour. 1,545 primary pupils' parents and teachers from all three main areas in Vietnam took part in the questionnaire surveys. Mathematical statistical methods were used to analyse data along with collating the perceptions between primary teachers and parents. The results showed that pupil behaviour management had been implemented to a positive extent by the primary teachers in classroom practices. The primary teachers frequently implemented the activities of pupil behaviour management to deal with pupils' misbehaviours, and this could help prevent misbehaviour in classroom practices. Nevertheless, the study also revealed that one of the emergent problems that needs to be solved in order to achieve better pupil behaviour management is pupils' inattentive attitudes in learning. A possible reason was attributed to the teachers' less cares and the lower frequency with which interactive instruction was implemented by the primary teachers in their teaching practices. The study suggested that an appropriate strategy of pupil behaviour management for Vietnamese primary teachers needed to be designed in order to help better engage pupils in learning and to meet the requirements of the ongoing implementation of competence-based curricula. A social constructivist approach with its interactive and meaningful features was recommended for further studies to work on designing an appropriate behaviour management strategy for pupils in a Confucian heritage culture such as Vietnam.
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