Pupillary control and approach to anisocoria cranial. Pupillary reflex measurement predicts insufficient. In the human visual system, the retina of each eye has a rodcone photoreceptorfree region where. Postganglionic parasympathetic fibers project from the ciliary ganglia to terminate on the sphincter pupillae mm. I propose to show that neither of these two schemes of the path of the fibers of the pupillary reflex is satisfactory, in that no proper provision is made for the consensual light reflex. This study has shown that latency and constriction. Since wernicke 1 publicized the matter in the 1880s, it has been considered practically a law of nature that the pupillary light reflex pathway is a simple brainstem reflex.
In order to elicit this reflex both eyes of the subject tested are adapted to a constant level of illumination in which darkness is a periodic stimulus. The pupillary light reflex plr describes the constriction and subsequent dilation of the pupil in response to light as a result of the antagonistic actions of the iris sphincter and dilator muscles. The pupillary light reflex neural pathway on each side has an afferent limb and two efferent limbs. Development of the pupil pupil is formed by the complete absorption of the central part of pupillary membrane. Light shined in one eye stimulates retinal photoreceptors, and subsequently retinal ganglion cells, whose axons travel through the optic nerve, chiasm, and tract to terminate in the pretectum pretectal nucleus. If a light is flashed near one eye, the pupils of both eyes contract. The pathway of pupillary constriction begins at the edingerwestphal nucleus near the occulomotor nerve nucleus. The pupillary light reflex was investigated using electrical stimulation along the pathway and recording in the short ciliary nerves. The pupils will offer substantial insight into ones ocular health and. Pupillary pathways american academy of ophthalmology.
Of note, the pupillary dark reflex involves a separate pathway, which ends with sympathetic fibers from long ciliary nerves innervating the dilator pupillae muscle. What is the pathway for the pupillary light reflex. Mechanism of pupillary reflex dilation in awake volunteers. A halving of the diameter cuts the amount of light to decrease by a factor of 4. Afferent pathway of pupillary light reflex solid yellow above. Pdf the paper presents the measurement system for quantitative investigation into the consensual reaction of pupil to light. Jun 06, 2014 the pupillary pathway and its clinical aspects slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Stimulation is relayed along the axons of the parasympathetic portion of cn iii out of the brainstem and to the ciliary ganglion. This is visual sensation, because the afferent branch of this reflex is simply sharing the special sense pathway. Further, we suggest a new strategy of lesion analysis by combining established techniques.
Dec 10, 2012 pupillary light reflex pathway made easy part 1 this video tutorial is brought to you by. If so, share your ppt presentation slides online with. Chromatic pupillary light reflex and its application in small. With the exception of one recent study gamlin et al. Pupillary reflex definition of pupillary reflex by medical. Increased pupillary constriction velocity in benign. Pupillary reflex size of pupil determined by balance between parasympathetic and sympathetic input parasympathetic constricts the pupil via sphincter muscle. Pupillary light reflex synonyms, pupillary light reflex pronunciation, pupillary light reflex translation, english dictionary definition of pupillary light reflex. This involves both edingerwestphal nucleus and relationships between the 3rd and 6th nerve. Mechanism of pupillary reflex dilation in awake volunteers and in organ donors. Lack of the pupillary reflex or an abnormal pupillary reflex can be caused by optic nerve damage, oculomotor nerve damage, brain stem death and depressant drugs, such as barbiturates. The pupillary light reflex pathway lecturer at the. Although pupillary response, where the pupil dilates or constricts due to light is not usually called a reflex, it is still usually considered a part of this topic.
The neuronal pathway subserving the pupillary light reflex. Decreased vision with pupillary light reflex deficits. Pupillary light reflex to light inside the natural blind spot. The pupillary light reflex is a test of the functional integrity of the subcortical afferent and efferent pathways and is reliably present after 31 weeks gestation. Feb 06, 2015 abnormalities of pupillary reflexes 27.
The afferent arc is formed by the retinal receptors, bipolar and ganglion cells. As the occulomotor nerve of the uneffected eye is intact and it forms the efferent pathway of light reflex. The knee jerk is an example of the simplest type of reflex. Schematic overview of the anatomy of the pupillary light reflex arc.
The pupillary light reflex pathway cytoarchitectonic. We have examined both the time course for the development of the light reflex and pupil diameter before and after this event in 50 neonates. A reflex is built into the nervous system and does not need the intervention of conscious thought to take effect. From edingerwestphal nucleus, neurons project preganglionic parasympathetic fibers thru cniii to terminate in the ciliary ganglia. The diagram below shows the neuroanatomical pathways of the pupillary light reflex. On testing each reflex for each eye, several patterns are possible. Learn vocabulary, terms, and more with flashcards, games, and other study tools. In the current paper, we will examine the metrics of the pupillary light reflex in the monkey as a basis for understanding the behaviors of its constituent neurons. 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 to various levels of lightnessdarkness. Assessment of infant reflexes reflex description appearancedisappearance babinski stroking bottom of foot causes big toe to raise while other toes fan out and curl downward.
Jul 08, 2009 since wernicke 1 publicized the matter in the 1880s, it has been considered practically a law of nature that the pupillary light reflex pathway is a simple brainstem reflex. Pathway of accommodation reflex retina via optic nerve, chaisma optic tract lateral. Pupillary reflex psychology wiki fandom powered by wikia. The pupil has tight neurological control and abnormalities of this control correlate with underlying diagnoses. From here, the short ciliary nerves innervate the pupillary constrictor muscles to cause constriction of the pupil. This is achieved by a plr test using red and blue light sequentially,31 termed as a chromatic pupillary light reflex cplr test. We evaluated whether the pupillary light reflex is altered in benign essential blepharospasm patients. Pupillary reflexes are mediated through the iiird cranial nerve at the level of the superior colliculus. Pupillary light reflex, swinging flashlight test, marcus gunn pupil, direct light reflex, consensual light reflex, direct light pupillary reflex loss, relative afferent pupillary defect, afferent pupillary defect, pupil reactivity. Pupillary light reflex is the property of its rightful owner. Pupillary definition of pupillary by medical dictionary.
Merritt and moore claimed that their explanation of the production of the argyll robertson pupil explains the phenomena better than any hitherto offered. Although prd has many names in the medical literature, such as the ciliospinal reflex, 1 reflex pupillary dilation, 2 phasic pupil dilation, 10 and pupil dilation response, 10 we will use the term pupillary reflex dilation prd to indicate dilation of the pupil caused by nociceptive stimuli. This reflex serves to regulate the amount of light the retina receives under varying illuminations. The mechanism is not as clear cut, but as a finger draws closer from distant, both medial rectus contract, lens adopts a more convex shape followed by pupillary constriction. May 01, 2001 the pupillary response to light requires the presence of an intact reflex arc that passes through the brainstem fig. The afferent limb has nerve fibers running within the optic nerve.
The study, published in the journal nature communications, saw them investigate the pupillary light reflex a basic mechanism controlling the amount of light that reaches the retina in which the pupil contracts when the eye is exposed to sudden increases in brightness. Microsoft powerpoint chap 6 reflexes compatibility mode author. Ciliospinal reflex the ciliospinal reflex pupillaryskin reflex consists of dilation of the ipsilateral pupil in response to pain applied to. The consensual response results in pupillary constriction of the eye not directly stimulated by light, although the response is slightly reduced compared to the eye being directly tested. Jun 26, 2015 pupillary light reflex to light inside the natural blind spot. Pupillary reflexes involve the autonomic edingerwestphal component of the oculomotor nucleus.
A free powerpoint ppt presentation displayed as a flash slide show on id. Nerve impulses follow routes through the nervous system called nerve pathways. The afferent component is the anterior visual pathway from which fibres pass to synapse in the pretectal nucleus in the mid. The details of the pathway are detailed below the diagram. Find powerpoint presentations and slides using the power of, find free. The pathway is by way of fibers of these sensory nerves and their central connections in the brain stem and spinal cord and then by way of the sympathetic outflow from the intermediolateral column to. Pupillary reflex size of pupil determined by balance between parasympathetic and sympathetic input parasympathetic constricts the pupil via sphincter muscle sympathetic dilates the pupil via dilator muscle response to light mediated by parasympathetic. Pdf how to test for a relative afferent pupillary defect. The pupillary light reflex was absent in all neonates of less than 30 weeks gestational age, it gradually developed from this age and by 35 weeks it was present in all. Chromatic pupillary light reflex and its application in. Increasing stimulus intensity was associated with an increase in direct light reflex amplitude and maximum rate of constriction and redilatation. The swinging light test is used to detect a relative afferent pupil defect rapd. The afferent pupillary light reflex fibers travel through the optic nerves, optic chiasm, and optic tracts, and then separate from the optic tracts to proceed to the pretectal.
The efferent path is the same as that of the light reflex for innervation of the. Since these muscles are innervated by the parasympathetic and sympathetic nervous systems, respectively, different parameters of the plr can be used as indicators for either sympathetic or. Right consensual pupillary reflex is the right pupils indirect response to light entering the left eye, the contralateral eye. Pupillary light reflex pathway, is a reflex that controls the diameter of the pupil, in response to the intensity luminance of light that falls on the retina of the eye, thereby assisting in adaptation to various levels of darkness and light, in addition to retinal sensitivity.
The fibers of the sphincter pupillae encompass the pupil. Afferent limb light stimulates photoreceptors and the signal is conveyed to a special set of ganglion cells that send their nerve impulses thru the. Ppt pupillary pathways powerpoint presentation free to. Pupillary light reflex pathway video lecture made easy. What it assesses the integrity of the pupillary light reflex pathway. Some of the simplest nerve pathways consist of little more than two neurons that communicate across a single synapse. In 19 normal subjects the pupillary reflex to light was studied over a range of stimulus intensities by infrared electronic pupillography and analysed by a computer technique. Eyeing up the future of the pupillary light reflex in.
Pupillary reflex pathway the pupillary reflex can be thought of as an afferent limb, a parasympathetic efferent limb, and a sympathetic efferent limb. There are a handful of pupillary abnormalities that every clinician should know. The data pupil size, rate of contraction and relaxation are stored on the device and can be downloaded to a computer. Pupillary responses can signal potentially serious problems. Request pdf the pupillary light reflex pathway cytoarchitectonic probabilistic maps in hemianopic patients the anatomy of the human pupillary light reflex plr pathway is a matter of debate.
Pathway of light reflex initiated by retinal photoreceptors. This study aimed to evaluate the pupillary dilatation reflex pdr during a tetanic stimulation to predict insufficient analgesia before nociceptive stimulation in the intensive care unit icu. By way of the optic tract the afferent path 1 of the pupil lary system projects to the dorsal. In 1939 one of us lowenstein1 described a pupillary reflex which he called the reflex to darkness. Schematic drawing of the pupillary light reflex pathway. Edingerwestphal neurons project preganglionic parasympathetic fibers through cn iii to terminate in the ciliary ganglia.
Important pupillary disorders include physiologic anisocoria, relative afferent pupillary defect, amaurotic pupil, argyll robertson pupils, cranial nerve iii palsy, pharmacologic mydriasis, tonic pupil, and horner syndrome. Pupillary light reflexrelated parameters were measured under mesopic 10 lux and photopic illuminance 200 lux using an infrared pupillometer. A light stimulating the left retina generates impulses that travel up the left optic nerve and divide at the chiasm. Medical pharmacology and therapeutics fifth edition, 2018. The pupillary light reflex plr regulates the amount of light that reaches the retina, and the reflex pathway involves the ganglion cells of the retina, the pretectal nucleus, the edinger. A reflex is a relatively simple motor response that does not involve a large number of interneurons or association neurons. The pupillary light reflex in normal subjects british journal of.
Pupillary diameter and reaction to light in preterm neonates. Pupillary constriction in response to light requires transmission of light information from the retina to the brain afferent pathway, and signals from the brain to constrict the pupils efferent pathway fig. Efferent pathway pretectal nucleus nerve fibres partially decussate to. This page includes the following topics and synonyms. Pdf approach to pupillary abnormalities via anatomical pathways. Pupillary evaluation for differential diagnosis of coma.
Pupillary light reflex definition of pupillary light. Pupillary reflex to darkness jama ophthalmology jama network. Apr 15, 2016 it controls light exposure of the retina. Enhanced pupillary light reflex in infancy is associated with. Approach to pupillary abnormalities via anatomical pathways. Postganglionic fibers in the short ciliary nerves innervate the ciliary muscles and the pupillary constrictor muscles. Sympathetic innervation leads to pupillary dilation. Normally, both pupils should constrict with light shone into either eye alone. In the light reflex, the pupils constrict when light is shone on the retina. Swinging flashlight test for afferent papillary defect. The fibers enter the orbit with cniii nerve fibers and ultimately synapse at the cilliary ganglion.
Pupillary reflex refers to one of the reflexes associated with pupillary function types include. Pupillary light reflex pathway part 1 including sample. Logistic regression analysis was used to test for independence of pupillary light reflex testing and presence of anisocoria in discrimination of structural versus metabolic aetiology of coma. The afferents are optic nerve fibres which pass to both pretectal nuclei, crossing in. The pupillary light reflex or haab reflex is the reduction of pupil size in response to light the pupillary accommodation reflex is the reduction of pupil size in response to an object coming close to the eye both these reflexes affect both eyes, even if only one eye is stimulated. If you continue browsing the site, you agree to the use of cookies on this website. The pupillary light reflex figure 1 begins when light hits the retina and causes a signal to travel along the optic nerve.
View and download powerpoint presentations on pupillary reflex ppt. Assessment of patient suitability for contact lenses. The pupillary light reflex requires cn ii, cn iii, and central brain stem connections. The pupillary pathway and its clinical aspects slideshare. In bright light causing a smaller pupil opening, the eye has better sharpness and depth of field. Pupiliary pathway free download as powerpoint presentation. Pupillary light reflex definition of pupillary light reflex. The discharge of single units in the ciliary ganglion was compared during diffuse light stimuli and electrical stimuli. The light reflex is the primary determinant of pupil size, with increased light causing the pupil to constrict and reduce the amount of light that reaches the retina. The sympathetic innervation to the pupil consists of a three. If one eye only is stimulated, both pupils constrict, the socalled consensual reflex.
Assessment and diagnosis tomy rm kerala j ophthalmol. Postganglionic parasympathetic fibers project from the ciliary ganglia to terminate on the sphincter pupillae muscles, causing bilateral pupillary constriction. In practice, a negative cplr when evaluated with red light in the 630nm wavelength spectrum, along. Characteristics of the pupillary light reflex in the macaque. Concurrent impaired vision and pupillary light reflex deficits are suggestive of a lesion affecting the proximal portion of the visual pathway, from the retina to just prior to the lateral geniculate nucleus, which is common to both the visual pathways and the pupillary light reflex pathway. The pupillary reflexes are tested clinically using a pen torch fig. The keen practitioner can gain helpful information simply by assessing pupillary responses. Pdf autonomic components of the pupillary light reflex. In this prospective noninterventional study in a surgical icu of a university hospital, pdr was assessed during tetanic stimulation of 10, 20 or 40 ma immediately before 40 endotracheal suctionings. The optic nerve then forms the optic chiasm, which diverges into a left and.
Twentythree patients with benign essential blepharospasm, 47 with reflex blepharospasm, and 29 dry eye disease controls were included. And, because of the crossing fibers, there is not only a direct pupillary reflex but also a consensual pupillary light reflex. The anatomy of the human pupillary light reflex plr pathway is a matter of debate. Ppt pupillary light reflex powerpoint presentation. Mechanism of pupillary reflex dilation in awake volunteers and in organ donors laura l. Pdf system for measurement of the consensual pupil light reflex.
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