Pupillometry

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Pupillometry, the measurement of pupil size and reactivity, is a key part of the clinical neurological exam for patients with a wide variety of neurological injuries. It is also used in psychology. [1] [2]

Contents

Pupillometry in critical care

For more than 100 years, clinicians have evaluated the pupils of patients with suspected or known brain injury or impaired consciousness to monitor neurological status and trends, checking for pupil size and reactivity to light. [3] In fact, before the advent of electricity, doctors checked a patient’s reaction to light using a candle.

Today, clinicians routinely evaluate pupils as a component of the neurological examination and monitoring of critically ill patients, including patients with traumatic brain injury and stroke. [4] [5] [6] In 2016, Couret et Al. showed that "Standard practice in pupillary monitoring yields inaccurate data that Automated quantitative pupillometry is a more reliable method with which to collect pupillary measurements at the bedside. [7] In 2019, the first smartphone based pupillometer was released as an accurate and economical way to determine pupil size and dynamic response objectively. [8] However, another study has shown the necessary use of an opaque eyecup as pupillary light reflex is affected by ambient light. [7] It is important to mention that certain pupillometers and all smartphones do not have this particular feature.

NeuroLight pupillometer and its QPi score Pupillometer neurolight.jpg
NeuroLight pupillometer and its QPi score

Patient care and outcome

Numerous studies have shown the importance of pupil evaluation in the clinical setting, and pupillary information is used extensively in patient management and as an indication for possible medical intervention.

Patients who undergo prompt intervention after a new finding of pupil abnormality have a better chance of recovery. [9]

Alterations of the pupil light reflex, size of the pupil, and anisocoria (unequal pupils) are correlated with outcomes of patients with traumatic brain injury. [10] [2] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] Blood flow imaging has shown that pupil changes are highly correlated with brainstem oxygenation and perfusion, [19] [18] [21] and anisocoria can be an indicator of a pathological process or neurological dysfunction. [18] [22] [23]

Investigators have used pupil size and reactivity as fundamental parameters of outcome predictive models in conjunction with other clinical information such as age, mechanism of injury, and Glasgow Coma Scale, [21] [24] [25] and have correlated the models with the presence and location of intracranial mass lesions. [11]

The National Institutes of Health Stroke Scale (NIHSS) uses pupillary response as a systematic assessment tool to provide a quantitative measure of stroke-related neurologic deficit and to evaluate acuity of stroke patients, determine appropriate treatment, and predict patient outcome. [26]

Manual vs. automated pupil assessment

Traditionally, pupil measurements have been performed in a subjective manner by using a penlight or flashlight to manually evaluate pupil reactivity (sPLR, "s" stands for standard) and using a pupil gauge to estimate pupil size. However, manual pupillary assessment is subject to significant inaccuracies and inconsistencies. Studies have shown inter-examiner disagreement in the manual evaluation of pupillary reaction to be as high as 39 percent. [1] [2] [4] [5] [27] [28] [29] [30] Automated pupillometry involves the use of a pupillometer, a portable, handheld device that provides a reliable and objective measurement of pupillary size, symmetry, and reactivity through measurement of the pupil light reflex (qPLR). sPLR is opposed to quantitative PLR (qPLR) that is provided by an automated pupillometer. qPLR [31] corresponds to the percentage of pupillary constriction to a calibrated light stimulus. Pupillometers before 2018 predominately used infrared cameras to observe pupil diameter. Then, in 2019, advancements in machine learning have enabled visual spectrum pupillometry using a smartphone. When measuring the pupillary light reflex, it's important to use an opaque eyecup to get accurate results. [7] This is because the measurement can be affected by ambient light. It's worth noting that some devices, such as smartphones and certain pupillometers, lack this ability. Therefore, using an eyecup is even more necessary. Overall, using an eyecup helps ensure precise measurements of the pupillary light reflex. Numeric scales allow for a more rigorous interpretation and classification of the pupil response and are a primary feature of both hardware and software based pupillometers.

NPi-300 automated infrared pupillometer (NeurOptics, Inc.) NeurOptics' NPi-300 Pupillometer.png
NPi-300 automated infrared pupillometer (NeurOptics, Inc.)

Automated pupillometry removes subjectivity from the pupillary evaluation, providing more accurate and trendable pupil data, and allowing earlier detection of changes for more timely patient treatment. By using automated pupillometers and algorithms such as QPi score (Quantitative Pupillometry Index) or Reflex's "Reflex Score", doctors can easily and objectively assess pupil reactivity that could otherwise be missed by manual assessment. Automated pupillometers have been proven to be more effective than manual pupil assessment.

With an automated pupillometer and an algorithm analyzing the pupil continuously for 5 seconds, the Quantitative Pupillometry Index (QPi) can measure pupillary reactivity and provides a numerical value. It provides objective data and can detect subtle changes that might not be apparent to the naked eye.  Its quantitative nature provides objective and more reliable assessment.   Moreover, it is color-coded for a quick clinical interpretation. It displays through a qualitative scale a quantitative interval for each color associated with its number. [32]

Mobile visual spectrum automated pupillometers have been proven effective as an alternative to infrared pupillometers that typically command a higher cost. [33] [10] Controversy has risen around infrared pupillometers as some of them are routinely incapable of measuring hippus, a natural pupillary phenomenon, which has professionals concluding that NeurOptics' devices fit a curve to measured data. The NeuroLight pupillometer (IDMED), on the other hand, provides this pupillary unrest in ambient light (PUAL) function, which is described as a consistent indicator of opioid effect and is the gold standard in this field of research. [34] [35] Infrared pupillometers use an eye guard that is placed on a subject's orbit or zygomatic bone and uses a fixed distance calibration to determine pupil size which has further brought into question the validity of fixed distance measures as the human population varies widely in skull structure. The NeuroLight and NPi pupillometers are both devices for measuring pupils but differ significantly in terms of ergonomics and functionality. The main distinction lies in the NPi’s use of a transparent eye guard that contains an electronic component for patient identification and results recording, making it unique to each patient. This consumable that allows ambient light to pass through may result in data reproducibility issues and increased costs. NeuroLight, in contrast, comes with a touchscreen display and employs a reusable opaque eyecup that isolates the eye from ambient light. This design feature not only enhances the accuracy of the pupillary measurements [7] but also reduces the overall cost of usage to the initial purchase of the device.

According to the new American Heart Association guidelines, most deaths attributable to post-cardiac arrest brain injury are due to active withdrawal of life-sustaining treatment based on a predicted poor neurological outcome. The NPi and automated pupillometry have recently been included in the updated 2020 American Heart Association (AHA) Guidelines for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) as an object measurement supporting brain injury prognosis in patients following cardiac arrest. [36]

A study published in the Journal of Neurosurgery found that automated pupillometers may signal an early warning of potential delayed cerebral ischemia and enable preemptive escalation of care. [37]

The American Journal of Critical Care revealed that critical care and neurosurgical nurses consistently underestimated pupil size, were unable to identify anisocoria, and incorrectly assessed pupil reactivity (sPLR). It concluded that automated pupillometry is a necessary tool for accuracy and consistency, and that it might facilitate earlier detection of subtle pupil changes, allowing more effective and timely diagnostic and treatment interventions. [1]

In addition, a study from The University of Texas Southwestern Medical Center compared 2,329 manual pupillary exams performed simultaneously by two examiners (neurology and neurosurgery attending and resident physicians, staff nurses, and mid-level practitioners) under identical conditions and showed low inter-examiner reliability. [28] [29] The American Association of Critical-Care Nurses(AACN) Procedure Manual for High Acuity, Progressive and Critical Care, 7th Edition, and the American Association of Neuroscience Nurses (AANN) Core Curriculum for Neuroscience Nursing, 6th Edition, now include sections illustrating how use of a pupillometer removes subjectivity and allows pupillary reactivity to be trended in a consistent, objective, and quantifiable way. The AACN Procedure Manual, which was extensively reviewed by more than 100 experts in critical care nursing, is the authoritative reference for procedures performed in critical care settings, and the AANN curriculum is a comprehensive resource for practicing neuroscience nurses.

Advancements in mobile-based automated pupillometry have been made in recent years to accommodate for the growing number of mobile phones being used in healthcare. Notably, Brightlamp, Inc. has secured the first intellectual property relating to mobile quantitative pupillometry.

Traditional clinical pupillometers measure pupil size using infrared cameras in specialized hardware. Software pupillometers measure pupil size using a smartphone camera and light source. Several studies have demonstrated that software based pupillometers have comparable accuracy to dedicated hardware pupillometers. [38] [39] By using machine learning algorithms, smartphone pupillometers can compensate for differences in ambient lighting, potentially improving accuracy. [40] Smartphone pupillometry has been clinically validated in the context of traumatic brain injury, [41] [42] sports related concussion, [43] and acute large vessel occlusion. [44] Due to the high cost of specialized hardware pupillometers (typically thousands of US dollars per unit), smartphone pupillometers have been proposed as an widely available alternative for low resource settings [45] or austere environments such as diving or hyperbaric conditions. [40]

Pupillometry in psychology

Stimulants

Photographs

Hess and Polt (1960) [46] presented pictures of semi-naked adults and babies to adults (four men and two women). Pupils of both sexes dilated after seeing pictures of people of the opposite sex. In females, the difference in pupil size occurred also after seeing pictures of babies and mothers with babies. This examination showed that pupils react not only to the changes of intensity of light (pupillary light reflex) but also reflect arousal or emotions.

In 1965 Hess, Seltzer and Shlien [47] examined pupillary responses in heterosexual and homosexual males. Results showed a greater pupil dilation to pictures of the opposite sex for heterosexuals and to pictures of the same sex for homosexuals.

According to T.M. Simms (1967), [48] pupillary responses of males and females were greater when they were exposed to pictures of the opposite sex. [49] In another study, Nunnally and colleagues (1967) [50] found that seeing slides rated as 'very pleasant' was associated with greater pupil dilation as seeing slides rated as neutral or very unpleasant.

Infants showed greater pupil size when they saw pictures of faces than when they saw geometric shapes, [49] [51] [52] and greater dilation after seeing pictures of the infant's mother than pictures of a stranger. [51]

Cognitive load

Pupillary responses can reflect activation of the brain allocated to cognitive tasks. Greater pupil dilation is associated with increased processing in the brain. [53] Vacchiano and colleagues (1968) found that pupillary responses were associated with visual exposure to words with high, neutral or low value. Presented low-value words were associated with dilation, and high-value words with constriction of a pupil. [54] In decision-making tasks dilation increased before the decision as a function of cognitive load. [55] [56] In an experiment about short-term serial memory, students heard strings of words and were asked to repeat them. Greater pupil diameter was observed after the items were heard (depending on how many items were heard), and decreased after items were repeated. [57] The more difficult the task, the greater pupil diameter observed from the time preceding the solution [58] until the task was completed. [59] While these discoveries from the 1960s sparked renewed interest in the psychological significance of pupil size, research had substantially earlier identified the relationship between pupil size and effort. [60] [61]

Long-term memory

The pupil response reflects long-term memory processes both at encoding, predicting the success of memory formation [62] and at retrieval, reflecting different recognition outcomes. [63]

See also

Related Research Articles

<span class="mw-page-title-main">Coma</span> State of unconsciousness

A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. The person may experience respiratory and circulatory problems due to the body's inability to maintain normal bodily functions. People in a coma often require extensive medical care to maintain their health and prevent complications such as pneumonia or blood clots. Coma patients exhibit a complete absence of wakefulness and are unable to consciously feel, speak or move. Comas can be the result of natural causes, or can be medically induced.

<span class="mw-page-title-main">Pupil</span> Part of an eye

The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina. It appears black because light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil. The size of the pupil is controlled by the iris, and varies depending on many factors, the most significant being the amount of light in the environment. The term "pupil" was coined by Gerard of Cremona.

<span class="mw-page-title-main">Brain death</span> Permanent loss of brain function

Brain death is the permanent, irreversible, and complete loss of brain function, which may include cessation of involuntary activity necessary to sustain life. It differs from persistent vegetative state, in which the person is alive and some autonomic functions remain. It is also distinct from comas as long as some brain and bodily activity and function remain, and it is also not the same as the condition locked-in syndrome. A differential diagnosis can medically distinguish these differing conditions.

<span class="mw-page-title-main">Mydriasis</span> Excessive dilation of the pupil

Mydriasis is the dilation of the pupil, usually having a non-physiological cause, or sometimes a physiological pupillary response. Non-physiological causes of mydriasis include disease, trauma, or the use of certain types of drug. It may also be of unknown cause.

<span class="mw-page-title-main">Cerebral edema</span> Excess accumulation of fluid (edema) in the intracellular or extracellular spaces of the brain

Cerebral edema is excess accumulation of fluid (edema) in the intracellular or extracellular spaces of the brain. This typically causes impaired nerve function, increased pressure within the skull, and can eventually lead to direct compression of brain tissue and blood vessels. Symptoms vary based on the location and extent of edema and generally include headaches, nausea, vomiting, seizures, drowsiness, visual disturbances, dizziness, and in severe cases, death.

<span class="mw-page-title-main">Intracranial pressure</span> Pressure exerted by fluids inside the skull and on the brain

Intracranial pressure (ICP) is the pressure exerted by fluids such as cerebrospinal fluid (CSF) inside the skull and on the brain tissue. ICP is measured in millimeters of mercury (mmHg) and at rest, is normally 7–15 mmHg for a supine adult. This equals to 9–20 cmH2O, which is a common scale used in lumbar punctures. The body has various mechanisms by which it keeps the ICP stable, with CSF pressures varying by about 1 mmHg in normal adults through shifts in production and absorption of CSF.

Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom, photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence of actual physical sensitivity of the eyes, though the term is sometimes additionally applied to abnormal or irrational fear of light, such as heliophobia. The term photophobia comes from Greek φῶς (phōs) 'light' and φόβος (phóbos) 'fear'.

<span class="mw-page-title-main">Pupillary light reflex</span> Eye reflex which alters the pupils size in response to light intensity

The pupillary light reflex (PLR) or photopupillary reflex is a reflex that controls the diameter of the pupil, in response to the intensity (luminance) of light that falls on the retinal ganglion cells of the retina in the back of the eye, thereby assisting in adaptation of vision to various levels of lightness/darkness. A greater intensity of light causes the pupil to constrict, whereas a lower intensity of light causes the pupil to dilate. Thus, the pupillary light reflex regulates the intensity of light entering the eye. Light shone into one eye will cause both pupils to constrict.

<span class="mw-page-title-main">Subarachnoid hemorrhage</span> Bleeding into the brains subarachnoid space

Subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space—the area between the arachnoid membrane and the pia mater surrounding the brain. Symptoms may include a severe headache of rapid onset, vomiting, decreased level of consciousness, fever, weakness, numbness, and sometimes seizures. Neck stiffness or neck pain are also relatively common. In about a quarter of people a small bleed with resolving symptoms occurs within a month of a larger bleed.

<span class="mw-page-title-main">Argyll Robertson pupil</span> Medical condition

Argyll Robertson pupils are bilateral small pupils that reduce in size on a near object, but do not constrict when exposed to bright light. They are a highly specific sign of neurosyphilis; however, Argyll Robertson pupils may also be a sign of diabetic neuropathy. In general, pupils that accommodate but do not react are said to show light-near dissociation.

<span class="mw-page-title-main">Optic tract</span> Neural pathway within the human visual system

In neuroanatomy, the optic tract is a part of the visual system in the brain. It is a continuation of the optic nerve that relays information from the optic chiasm to the ipsilateral lateral geniculate nucleus (LGN), pretectal nuclei, and superior colliculus.

<span class="mw-page-title-main">Adie syndrome</span> Neurological disorder

Adie syndrome, also known as Holmes–Adie syndrome, is a neurological disorder characterized by a tonically dilated pupil that reacts slowly to light but shows a more definite response to accommodation. It is frequently seen in females with absent knee or ankle jerks and impaired sweating.

<span class="mw-page-title-main">Brain herniation</span> Potentially deadly side effect of very high pressure within the skull

Brain herniation is a potentially deadly side effect of very high pressure within the skull that occurs when a part of the brain is squeezed across structures within the skull. The brain can shift across such structures as the falx cerebri, the tentorium cerebelli, and even through the foramen magnum. Herniation can be caused by a number of factors that cause a mass effect and increase intracranial pressure (ICP): these include traumatic brain injury, intracranial hemorrhage, or brain tumor.

Pupillometer, also spelled pupilometer, is a medical device intended to measure by reflected light the size of the pupil of the eye. In addition to measuring pupil size, current automated pupillometers may also be able to characterize pupillary light reflex. Some instruments for measuring pupillary distance (PD) are often, but incorrectly, referred to as pupilometers.

<span class="mw-page-title-main">Relative afferent pupillary defect</span> When one eyes exposure to light creates a muted pupil response in both eyes

A relative afferent pupillary defect (RAPD), also known as a Marcus Gunn pupil, is a medical sign observed during the swinging-flashlight test whereupon the patient's pupils excessively dilate when a bright light is swung from the unaffected eye to the affected eye. The affected eye still senses the light and produces pupillary sphincter constriction to some degree, albeit reduced.

<span class="mw-page-title-main">Pupillary response</span> Physiological response that varies the size of the pupil

Pupillary response is a physiological response that varies the size of the pupil, via the optic and oculomotor cranial nerve.

<span class="mw-page-title-main">Task-invoked pupillary response</span>

Task-invoked pupillary response is a pupillary response caused by a cognitive load imposed on a human and as a result of the decrease in parasympathetic activity in the peripheral nervous system. It is found to result in a linear increase in pupil dilation as the demand a task places on the working memory increases. Beatty evaluated task-invoked pupillary response in different tasks for short-term memory, language processing, reasoning, perception, sustained attention and selective attention and found that it fulfills Kahneman's three criteria for indicating processing load. That is, it can reflect differences in processing load within a task, between different tasks and between individuals. It is used as an indicator of cognitive load levels in psychophysiology research.

Paroxysmal sympathetic hyperactivity (PSH) is a syndrome that causes episodes of increased activity of the sympathetic nervous system. Hyperactivity of the sympathetic nervous system can manifest as increased heart rate, increased respiration, increased blood pressure, diaphoresis, and hyperthermia. Previously, this syndrome has been identified as general dysautonomia but now is considered a specific form of it. It has also been referred to as paroxysmal sympathetic instability with dystonia, or PAID, and sympathetic storm. Recently, however, studies have adopted the name paroxysmal sympathetic hyperactivity to ensure specificity. PSH is observed more in younger patients than older ones. It is also seen more commonly in men than women. There is no known reason why this is the case, although it is suspected that pathophysiological links exist. In patients surviving traumatic brain injury, the occurrence of these episodes is one in every three. PSH can also be associated with severe anoxia, subarachnoid and intracerebral hemorrhage, and hydrocephalus.

<span class="mw-page-title-main">Pressure reactivity index</span>

Pressure reactivity index or PRx is a tool for monitoring cerebral autoregulation in the intensive care setting for patients with severe traumatic brain injury or subarachnoid haemorrhage, in order to guide therapy to protect the brain from dangerously high or low cerebral blood flow.

Clinicians routinely check the pupils of critically injured and ill patients to monitor neurological status. However, manual pupil measurements have been shown to be subjective, inaccurate, and not repeatable or consistent. Automated assessment of the pupillary light reflex has emerged as an objective means of measuring pupillary reactivity across a range of neurological diseases, including stroke, traumatic brain injury and edema, tumoral herniation syndromes, and sports or war injuries. Automated pupillometers are used to assess an array of objective pupillary variables including size, constriction velocity, latency, and dilation velocity, which are normalized and standardized to compute an indexed score such as the Neurological Pupil index (NPi).

References

  1. 1 2 3 Kerr, R (2016). "Underestimation of pupil size by critical care and neurosurgical nurses". American Journal of Critical Care. 25 (3): 213–219. doi:10.4037/ajcc2016554. PMID   27134226. S2CID   8564670.
  2. 1 2 3 Olson, D (2015). "The use of automated pupillometry in critical care". Critical Care Nursing Clinics of North America. 28 (1): 101–107. doi:10.1016/j.cnc.2015.09.003. PMID   26873763.
  3. ↑ Loewenfeld, I. (1993). "The Pupil: Anatomy, Physiology, and Clinical Application". Ames: Iowa State University Press.
  4. 1 2 Meeker, M (2005). "Pupil examination: validity and clinical utility of an automated pupillometer". J Neurosci Nurs. 37 (1): 34–40. doi:10.1097/01376517-200502000-00006. PMID   15794443.
  5. 1 2 Wilson, S (1988). "Determining interrater reliability of nurses' assessments of pupillary size and reaction". J Neurosci Nurs. 20 (3): 189–192. doi:10.1097/01376517-198806000-00011. PMID   2968419. S2CID   24775913.
  6. ↑ Chestnut, R (2000). Management and Prognosis of Severe Traumatic Brain Injury. Part II: Early Indicators of Prognosis in Severe Traumatic Brain Injury. Brain Trauma Foundation, American Association of Neurological Surgeons, Joint Section on Neurotrauma and Critical Care. pp. 153–255.
  7. 1 2 3 4 Couret, David; Simeone, Pierre; Freppel, Sebastien; Velly, Lionel (2019-04-01). "The effect of ambient-light conditions on quantitative pupillometry: a history of rubber cup". Neurocritical Care. 30 (2): 492–493. doi:10.1007/s12028-018-0664-z. ISSN   1556-0961.
  8. ↑ Service, Purdue News. "Improved Reflex app from brightlamp unlocks 'the diagnostic power of the pupil,' provides diagnostic data for concussions in seconds". www.purdue.edu. Retrieved 2022-01-31.
  9. ↑ Clusmann, H (2001). "Fixed and dilated pupils after trauma, stroke, and previous intracranial surgery: management and outcome". J Neurol Neurosurg Psychiatry. 71 (2): 175–181. doi:10.1136/jnnp.71.2.175. PMC   1737504 . PMID   11459888.
  10. 1 2 Carrick, Frederick Robert; Azzolino, Sergio F.; Hunfalvay, Melissa; Pagnacco, Guido; Oggero, Elena; D’Arcy, Ryan C. N.; Abdulrahman, Mahera; Sugaya, Kiminobu (October 2021). "The Pupillary Light Reflex as a Biomarker of Concussion". Life. 11 (10): 1104. Bibcode:2021Life...11.1104C. doi: 10.3390/life11101104 . PMC   8537991 . PMID   34685475.
  11. 1 2 Braakman, R; Gelpke, G; Habbema, J; Maas, A; Minderhoud, J (1980). "Systemic selection of prognostic features in patients with severe head injury". Neurosurgery. 6 (4): 362–370. doi:10.1227/00006123-198004000-00002. PMID   7393417.
  12. ↑ Chen, J; Gombart, Z; Rogers, S; Gardiner, S; Cecil, S; Bullock, R (2011). "Pupillary reactivity as an early indicator of increased intracranial pressure: the introduction of the neurological pupil index". Surg Neurol Int. 2: 82. doi: 10.4103/2152-7806.82248 . PMC   3130361 . PMID   21748035.
  13. ↑ Chesnut, R; Gautille, T; Blunt, B; Klauber, M; Marshall, L (1994). "The localizing value of asymmetry in pupillary size in severe head injury: relation to lesion type and location". Neurosurgery. 34 (5): 840–845. doi:10.1097/00006123-199405000-00008. PMID   8052380.
  14. ↑ Choi, S; Narayan, R; Anderson, R; Ward, J (1988). "Enhanced specificity of prognosis in severe head injury". J Neurosurg. 69 (3): 381–385. doi:10.3171/jns.1988.69.3.0381. PMID   3404236.
  15. ↑ Levin, H; Gary, H; Eisenberg, H; et al. (1990). "Neurobehavioral outcome 1 year after severe head injury. Experience of the Traumatic Coma Data Bank". J Neurosurg. 73 (5): 699–709. doi:10.3171/jns.1990.73.5.0699. PMID   2213159.
  16. ↑ Marshall, L; Gautille, T; Klauber, M; et al. (1991). "The outcome of severe closed head injury". J Neurosurg. 75: 28–36. doi:10.3171/sup.1991.75.1s.0s28.
  17. ↑ Ritter, A; Muizelaar, J; Barnes, T; et al. (1999). "Brain stem blood flow, pupillary response, and outcome in patients with severe head injuries". Neurosurgery. 44 (5): 941–948. doi:10.1097/00006123-199905000-00005. PMID   10232526.
  18. 1 2 3 Sakas, D; Bullock, M; Teasdale, G (1995). "One-year outcome following craniotomy for traumatic hematoma in patients with fixed dilated pupils". J Neurosurg. 82 (6): 961–965. doi:10.3171/jns.1995.82.6.0961. PMID   7760198.
  19. 1 2 Taylor, W; Chen, J; Meltzer, H; et al. (2003). ""Quantitative pupillometry, a new technology " normative data and preliminary observations in patients with acute head injury". J Neurosurg. 98 (1): 205–213. doi:10.3171/jns.2003.98.1.0205. PMID   12546375.
  20. ↑ Tien, H; Cunha, J; Wu, S; et al. (2006). "Do trauma patients with a Glasgow Coma Scale score of 3 and bilateral fixed and dilated pupils have any chance of survival?". J Trauma. 60 (2): 274–278. doi:10.1097/01.ta.0000197177.13379.f4. PMID   16508482.
  21. 1 2 Zhao, D; Weil, M; Tang, W; Klouche, K; Wann, S (2001). "Pupil diameter and light reaction during cardiac arrest and resuscitation". Crit. Care Med. 4 (29): 825–828. doi:10.1097/00003246-200104000-00029. PMID   11373477. S2CID   22441487.
  22. ↑ Andrews, B; Pitts, L (1991). "Functional recovery after traumatic transtentorial herniation". Neurosurgery. 29 (2): 227–231. doi:10.1227/00006123-199108000-00010. PMID   1886660.
  23. ↑ Petridis, A. K.; Dörner, L.; Doukas, A.; Eifrig, S.; Barth, H.; Mehdorn, M. (2009). "Acute Subdural Hematoma in the Elderly; Clinical and CT Factors Influencing the Surgical Treatment Decision". Central European Neurosurgery. 70 (2): 73–78. doi:10.1055/s-0029-1224096. PMID   19711259.
  24. ↑ Marmarou, A; Lu, J; Butcher, I; et al. (2007). ""Prognostic value of the Glasgow Coma Scale and pupil reactivity in traumatic brain injury assessed pre-hospital and on enrollment " an IMPACT analysis". J Neurotrauma. 24 (2): 270–280. doi:10.1089/neu.2006.0029. PMID   17375991.
  25. ↑ Narayan, R; Greenberg, R; Miller, J; et al. (1981). ""Improved confidence of outcome prediction in severe head injury " A comparative analysis of the clinical examination, multimodality evoked potentials, CT scanning, and intracranial pressure". J Neurosurg. 54 (6): 751–762. doi:10.3171/jns.1981.54.6.0751. PMID   7241184.
  26. ↑ NIH Stroke Scale (NIHSS). http://www.nihstrokescale.org/ .
  27. ↑ Litvan, I; Saposnik, G; Mauriño, J; et al. (2000). "Pupillary diameter assessment: need for a graded scale". Neurology. 54 (2): 530–531. doi:10.1212/wnl.54.2.530. PMID   10668738. S2CID   42732541.
  28. 1 2 Olson D, Stutzman S, Saju C, Wilson M, Zhao W, Aiyagari V. Interrater reliability of pupillary assessments. Neurocritical Care. 2015.
  29. 1 2 Stutzman S, Olson D, Saju C, Wilson M, Aiyagari V. Interrater reliability of pupillar assessments among physicians and nurses. UT Southwestern Medical Center; 2014.
  30. ↑ Worthley, L (2000). "The pupillary light reflex in the critically ill patient". Critical Care and Resuscitation. 2 (1): 7–8. doi: 10.1016/S1441-2772(23)02125-7 . PMID   16597274.
  31. ↑ Oddo, Mauro; Sandroni, Claudio; Citerio, Giuseppe; Miroz, John-Paul; Horn, Janneke; Rundgren, Malin; Cariou, Alain; Payen, Jean-François; Storm, Christian; Stammet, Pascal; Taccone, Fabio Silvio (December 2018). "Quantitative versus standard pupillary light reflex for early prognostication in comatose cardiac arrest patients: an international prospective multicenter double-blinded study". Intensive Care Medicine. 44 (12): 2102–2111. doi:10.1007/s00134-018-5448-6. ISSN   1432-1238. PMC   6280828 . PMID   30478620.
  32. ↑ "Pupillometry - NeuroLight | IDMED". 2023-03-06. Retrieved 2023-11-09.
  33. ↑ "Vision Development & Rehabilitation". pubs.covd.org. Retrieved 2022-01-31.
  34. ↑ Neice, Andrew E.; Fowler, Cedar; Jaffe, Richard A.; Brock-Utne, John G. (December 2021). "Feasibility study of a smartphone pupillometer and evaluation of its accuracy". Journal of Clinical Monitoring and Computing. 35 (6): 1269–1277. doi:10.1007/s10877-020-00592-x. ISSN   1573-2614. PMID   32951188.
  35. ↑ McKay, Rachel Eshima; Kohn, Michael A.; Larson, Merlin D. (April 2022). "Pupillary unrest, opioid intensity, and the impact of environmental stimulation on respiratory depression". Journal of Clinical Monitoring and Computing. 36 (2): 473–482. doi:10.1007/s10877-021-00675-3. ISSN   1573-2614. PMC   9123055 . PMID   33651243.
  36. ↑ Panchal, Ashish R.; Bartos, Jason A.; Cabañas, José G.; Donnino, Michael W.; Drennan, Ian R.; Hirsch, Karen G.; Kudenchuk, Peter J.; Kurz, Michael C.; Lavonas, Eric J.; Morley, Peter T.; O’Neil, Brian J. (2020-10-20). "Part 3: Adult Basic and Advanced Life Support: 2020 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care". Circulation. 142 (16_suppl_2): S366 –S468. doi: 10.1161/CIR.0000000000000916 . ISSN   0009-7322. PMID   33081529.
  37. ↑ Aoun, Salah G.; Stutzman, Sonja E.; Vo, Phuong-Uyen N.; El Ahmadieh, Tarek Y.; Osman, Mohamed; Neeley, Om; Plitt, Aaron; Caruso, James P.; Aiyagari, Venkatesh; Atem, Folefac; Welch, Babu G.; White, Jonathan A.; Batjer, H. Hunt; Olson, Daiwai M. (2020). "Detection of delayed cerebral ischemia using objective pupillometry in patients with aneurysmal subarachnoid hemorrhage". Journal of Neurosurgery. 132 (1): 27–32. doi:10.3171/2018.9.JNS181928. PMID   30641848. S2CID   58575267.
  38. ↑ Middleton, P. M.; Davies, W.; Buzytsky, I. (2024-10-22), Validation of a Novel Smartphone Pupillometer Application Compared to a Dedicated Clinical Pupillometer in the Measurement of the Pupillary Light Reflex of Healthy Volunteers, doi:10.1101/2024.10.18.24315266 , retrieved 2025-01-04
  39. ↑ Neice, Andrew E.; Fowler, Cedar; Jaffe, Richard A.; Brock-Utne, John G. (2021-12-01). "Feasibility study of a smartphone pupillometer and evaluation of its accuracy". Journal of Clinical Monitoring and Computing. 35 (6): 1269–1277. doi:10.1007/s10877-020-00592-x. ISSN   1573-2614. PMID   32951188.
  40. 1 2 Bogucki, Aleksander; John, Ivo; Zinkiewicz, Łukasz; Jachura, Michał; Jaworski, Damian; Suwała, Karolina; Chrost, Hugo; Wlodarski, Michal; Kałużny, Jakub; Campbell, Doug; Bakken, Paul; Pandya, Shawna; Chrapkiewicz, Radosław; Manohar, Sanjay G. (2024-04-09). "Machine learning approach for ambient-light-corrected parameters and the Pupil Reactivity (PuRe) score in smartphone-based pupillometry". Frontiers in Neurology. 15. doi: 10.3389/fneur.2024.1363190 . ISSN   1664-2295. PMC   11037402 . PMID   38654735.
  41. ↑ Maxin, Anthony J.; Gulek, Bernice G.; Lee, Chungeun; Lim, Do; Mariakakis, Alex; Levitt, Michael R.; McGrath, Lynn B. (2023-10-01). "Validation of a Smartphone Pupillometry Application in Diagnosing Severe Traumatic Brain Injury". Journal of Neurotrauma. 40 (19–20): 2118–2125. doi:10.1089/neu.2022.0516. ISSN   0897-7151.
  42. ↑ McGrath, Lynn B.; Eaton, Jessica; Abecassis, Isaac Joshua; Maxin, Anthony; Kelly, Cory; Chesnut, Randall M.; Levitt, Michael R. (2022-07-01). "Mobile Smartphone-Based Digital Pupillometry Curves in the Diagnosis of Traumatic Brain Injury". Frontiers in Neuroscience. 16. doi: 10.3389/fnins.2022.893711 . ISSN   1662-453X. PMID   35844221.
  43. ↑ Maxin, Anthony J.; Whelan, Bridget M.; Levitt, Michael R.; McGrath, Lynn B.; Harmon, Kimberly G. (January 2024). "Smartphone-Based Pupillometry Using Machine Learning for the Diagnosis of Sports-Related Concussion". Diagnostics. 14 (23): 2723. doi: 10.3390/diagnostics14232723 . ISSN   2075-4418. PMC   11640300 . PMID   39682632.
  44. ↑ Maxin, Anthony J.; Gulek, Bernice G.; Chae, John; Winston, Graham; Weisbeek, Philine; McGrath, Lynn B.; Levitt, Michael R. (2023-12-01). "A smartphone pupillometry tool for detection of acute large vessel occlusion". Journal of Stroke and Cerebrovascular Diseases. 32 (12). doi:10.1016/j.jstrokecerebrovasdis.2023.107430. ISSN   1052-3057. PMID   37857150.
  45. ↑ Piaggio, Davide; Namm, Georgy; Melillo, Paolo; Simonelli, Francesca; Iadanza, Ernesto; Pecchia, Leandro (2021-07-01). "Pupillometry via smartphone for low-resource settings". Biocybernetics and Biomedical Engineering. 41 (3): 891–902. doi:10.1016/j.bbe.2021.05.012. ISSN   0208-5216.
  46. ↑ Hess, E. H.; Polt, J. M. (1960). "Pupil size as related to interest value of visual stimuli". Science. 132 (3423): 349–350. Bibcode:1960Sci...132..349H. doi:10.1126/science.132.3423.349. PMID   14401489. S2CID   12857616.
  47. ↑ Hess, E. H.; Seltzer, A. L.; Shlien, J.M. (1965). "Pupil response of hetero- and homosexual males to pictures of men and women: A pilot study". Journal of Abnormal Psychology. 70 (3): 165–168. doi:10.1037/h0021978. PMID   14297654.
  48. ↑ Simms, T. M. (1967). "Pupillary response of male and female subjects to pupillary difference in male and female picture stimuli". Perception and Psychophysics. 2 (11): 553–555. doi: 10.3758/bf03210265 .
  49. 1 2 Goldwater, B. C. (1972). "Psychological significance of pupillary movements" (PDF). Psychological Bulletin. 77 (5): 340–55. doi:10.1037/h0032456. PMID   5021049.
  50. ↑ Nunally, J. C.; Knott, P. D.; Duchnowski, A.; Parker, R. (1967). "Pupillary response as a general measure of activation". Perception and Psychophysics. 2 (4): 149–155. doi: 10.3758/BF03210310 .
  51. 1 2 Fitzgerald, H. E. (1968). "Autonomic pupillary reflex activity during early infancy and its relation to social and nonsocial visual stimuli". Journal of Experimental Child Psychology. 6 (3): 470–482. doi:10.1016/0022-0965(68)90127-6. PMID   5687128.
  52. ↑ Fitzgerald, H. E.; Lintz, L. M.; Brackbill, Y.; Adams, G. (1967). "Time perception and conditioning an autonomic response in human infants". Perceptual and Motor Skills. 24 (2): 479–486. doi:10.2466/pms.1967.24.2.479. PMID   6068562. S2CID   40269147.
  53. ↑ Granholm, E.; Steinhauer, S. R. (2004). "Pupillometric measures of cognitive and emotional processes" (PDF). International Journal of Psychophysiology. 52 (1): 1–6. doi:10.1016/j.ijpsycho.2003.12.001. PMID   15003368.
  54. ↑ Vacchiano, R. B.; Strauss, P. S.; Ryan, S.; Hochman, L. (1968). "Pupillary response to value-lined words". Perceptual and Motor Skills. 27 (1): 207–210. doi:10.2466/pms.1968.27.1.207. PMID   5685695. S2CID   38156158.
  55. ↑ Simpson, H. M.; Hale, S. M. (1969). "Pupillary Changes During a Decision-Making Task". Perceptual and Motor Skills. 29 (2): 495–498. doi:10.2466/pms.1969.29.2.495. PMID   5361713. S2CID   37552685.
  56. ↑ Kahneman, D.; Beatty, J. (1967). "Pupillary Response in a Pitch Discrimination Task". Perception and Psychophysics. 2 (3): 101–105. doi: 10.3758/BF03210302 .
  57. ↑ Kahneman, D.; Beatty, J. (1966). "Pupil Diameter and Load on Memory". Science. 154 (3756): 1583–1585. Bibcode:1966Sci...154.1583K. doi:10.1126/science.154.3756.1583. PMID   5924930. S2CID   22762466.
  58. ↑ Hess, E. H.; Polt, J. H. (1964). "Pupil Size in Relation to Mental Activity During Simple Problem Solving". Science. 143 (3611): 1190–1192. Bibcode:1964Sci...143.1190H. doi:10.1126/science.143.3611.1190. PMID   17833905. S2CID   27169110.
  59. ↑ Bradshaw, J. L. (1968). "Pupil size and problem solving". Quarterly Journal of Experimental Psychology. 20 (2): 116–122. doi:10.1080/14640746808400139. PMID   5653414. S2CID   34832644.
  60. ↑ Bumke, O. (1911). Die Pupillenstörungen bei den Geistes- und Nervenkrankheiten. Jena: Fischer.
  61. ↑ Strauch, C. (2024). "The forgotten wave of early pupillometry research". Trends in Neurosciences. 47 (8): 571–572. doi:10.1016/j.tins.2024.06.002. PMID   38942651.
  62. ↑ Kafkas, A.; Montaldi, D. (2011). "Recognition memory strength is predicted by pupillary responses at encoding while fixation patterns distinguish recollection from familiarity". The Quarterly Journal of Experimental Psychology. 64 (10): 1971–1989. doi:10.1080/17470218.2011.588335. PMID   21838656. S2CID   28231193.
  63. ↑ Kafkas, A.; Montaldi, D. (2012). "Familiarity and recollection produce distinct eye movement and pupil and medial temporal lobe responses when memory strength is matched". Neuropsychologia. 50 (13): 3080–93. doi:10.1016/j.neuropsychologia.2012.08.001. PMID   22902538. S2CID   8517388.

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