The optic nerve, or more precisely, the photosensitive ganglion cells through the retinohypothalamic tract, is responsible for the afferent limb of the pupillary reflex; it senses the incoming light.
What can cause afferent pupillary defect?
Common causes of unilateral optic nerve disorders that can be associated with a RAPD include ischaemic optic neuropathy, optic neuritis, optic nerve compression (orbital tumours or dysthyroid eye disease), trauma, and asymmetric glaucoma.
What is an efferent pupillary defect?
Efferent pupillary defects are caused by problems of sympathetic or parasympathetic innervation or structural iris changes presenting as anisocoria or impaired pupillary light reaction. This overview describes the diagnostic steps for evaluating efferent pupillary disorders and outlines further steps of work-up.
What does APD mean in ophthalmology?
An Afferent Pupillary Defect (APD) is caused by damage to the neuropathway connecting the eyes and the brain. Your doctor or technician will check for this by shining a handheld light into your eyes and looking for an equal response.
What is a Marcus Gunn pupil?
Marcus Gunn pupil (MGP) is the term given to an abnormal pupil showing aberrant pupillary response in certain ocular disorders. In literature, the term is often used synonymously with Marcus Gunn phenomenon or relative afferent pupillary defect (RAPD). [1] After exposure to bright light, a normal pupil constricts.
What nerve is responsible for pupil dilation?
Therefore, the oculomotor nerve is responsible not only for a wide variety of eye movements but also for pupillary constriction and lens accommodation. A variety of pathologies may affect this nerve, but it will result in ptosis, the eye rotated downward and outward and with a fixed, dilated pupil.
Can RAPD be treated?
If RAPD is caused by a tumor in the optic nerve, such as optic nerve glioma, your treatment plan may include radiation and surgery. The cause of the Marcus Gunn pupil will determine when or if it can be resolved.
Why do doctors test pupil response?
Pupil dilation is performed to purposefully increase the size of the pupils during an eye exam so that the eye doctor can fully examine the health of the optic nerve and retina. The exam is critical to preventing and treating eye conditions that could potentially lead to vision loss.
What is the function of these pupillary reflexes?
The pupillary light reflex allows the eye to adjust the amount of light reaching the retina and protects the photoreceptors from bright lights. The iris contains two sets of smooth muscles that control the size of the pupil (Figure 7.2).
What is Adie’s tonic pupil?
The tonic pupil, sometimes called Adie tonic pupil or simply the Adie pupil, is the term used to denote a pupil with parasympathetic denervation that constricts poorly to light but reacts better to accommodation (near response), such that the initially larger Adie pupil becomes smaller than its normal fellow and …
What causes Marcus Gunn pupil?
Marcus Gunn pupil refers to the unequal pupillary response to light due to damage or disease in the retina or optic nerve. Examples include retinal detachment, retinal ischemia, optic neuritis, severe glaucoma, trauma, and tumor of the optic nerve, among other causes.
What is Holmes Adie syndrome?
Definition. Holmes-Adie syndrome (HAS) is a neurological disorder affecting the pupil of the eye and the autonomic nervous system.
What does Perrla mean in medical?
PERRLA is an acronym that stands for the pupil qualities your doctor should review during an eye exam. The list includes Pupils, Equal, Round, Reactive (to), Light, Accomodation.
What is RAPD or APD?
June 15, 2020. Relative afferent pupillary defect (RAPD or APD): RAPD is a condition in which the left and right pupils respond differently to a bright light stimulus (shown in one eye at a time) due to unilateral or asymmetrical disease of the retina or optic nerve.
What is hippus pupil reaction?
Hippus is a state of physiologic unrest. The pupil constricts to direct light stimulus but cannot maintain constriction and dilates. Each eye has dual innervation of both sympathetic and parasympathetic systems. The normal resting pupil size is not constant.
What is the Argyll Robertson pupil?
The Argyll Robertson (AR) pupil has been defined as a pupil that is small and constricts poorly to direct light but briskly when a target within reading distance is viewed (light-near dissociation).
What is reverse Argyll Robertson pupil?
Inverse Argyll Robertson Pupil (IARP), absence of pupillary constriction to near stimuli with retention of pupillary light reflex, has rarely been described. Chrousosandcolleagues( 1985 ) reported a child with absence of complete near reflex triad.
What is Papillitis?
Papillitis, also known as optic neuritis, is characterized by inflammation and deterioration of the portion of the optic nerve known as the optic disk.
Which nervous system regulates our pupillary response Brainly?
The autonomic nervous system is a control system that acts largely unconsciously and regulates bodily functions such as the heart rate, digestion, respiratory rate, pupillary response, urination, and sexual arousal. … Within the brain, theautonomic nervous system is regulated by the hypothalamus.
How do you test Marcus Gunn’s pupil?
The Marcus Gunn pupil can be detected by swinging a flashlight between both eyes. Of course, normally, if you flash light in one eye, both pupils will constrict.
Why is there RAPD in CRVO?
3. The relative afferent pupillary defect (RAPD) is very helpful in separating the ischemic type from the nonischemic type, during both the early and the late stages of the disease.
Can you have an APD in both eyes?
In case if both pupils do not show a similar response to the light stimuli, shone in one eye at a time, the patient will be diagnosed with RAPD or Marcus Gunn pupils. off note if the condition is bilateral and symmetrical, there will not be a RAPD but bilateral APD.
What is normal pupil reaction?
The normal pupil size in adults varies from 2 to 4 mm in diameter in bright light to 4 to 8 mm in the dark. … Both pupils constrict when the eye is focused on a near object (accommodative response). The pupil is abnormal if it fails to dilate to the dark or fails to constrict to light or accommodation.
Do pupils react in coma?
All cranial nerve or brain stem reflexes must be absent without any spontaneous respirations. The pupils do not react to light and the corneal, oculocephalic (doll’s eyes), oculovestibular (cold caloric) and gag reflexes are absent.
Why do doctors flashlight eyes?
You’ve seen it on television: A doctor shines a bright light into an unconscious patient’s eye to check for brain death. If the pupil constricts, the brain is OK, because in mammals, the brain controls the pupil.
What type of reflex is the pupillary light reflex?
Pupillary reflexes involve the autonomic (Edinger-Westphal) component of the oculomotor nucleus. In the light reflex, the pupils constrict when light is shone on the retina. If one eye only is stimulated, both pupils constrict, the so-called consensual reflex.
What is pupillary pathway?
Pathway: Afferent pupillary fibers start at the retinal ganglion cell layer and then travel through the optic nerve, optic chiasm, and optic tract, join the brachium of the superior colliculus, and travel to the pretectal area of the midbrain, which sends fibers bilaterally to the efferent Edinger-Westphal nuclei of …
Is pupillary light reflex cranial or spinal?
Similar reflex arcs exist between cranial nerves with sensory and motor function. Because most of the cranial nerves are arranged along the brainstem, these reflex arcs are referred to as brainstem reflexes. Pupillary light reflex is an example of a brainstem reflex.
Graduated from ENSAT (national agronomic school of Toulouse) in plant sciences in 2018, I pursued a CIFRE doctorate under contract with Sun’Agri and INRAE in Avignon between 2019 and 2022. My thesis aimed to study dynamic agrivoltaic systems, in my case in arboriculture. I love to write and share science related Stuff Here on my Website. I am currently continuing at Sun’Agri as an R&D engineer.