The oculocardiac reflex, also known as Aschner phenomenon, Aschner reflex, or Aschner–Dagnini reflex, is a decrease in pulse rate associated with traction applied to

extraocular muscles The extraocular muscles, or extrinsic ocular muscles, are the seven extrinsic muscles of the eye in human eye, humans and other animals. Six of the extraocular muscles, the four recti muscles, and the superior oblique muscle, superior and inferior ...

and/or compression of the

eyeball An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the eye ...

. The reflex is mediated by nerve connections between the ophthalmic branch of the trigeminal cranial nerve via the

ciliary ganglion The ciliary ganglion is a parasympathetic ganglion located just behind the eye in the posterior orbit. It is 1–2 mm in diameter and in humans contains approximately 2,500 neurons. The ganglion contains postganglionic parasympathetic neurons. T ...

, and the

vagus nerve The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fibe ...

of the

parasympathetic nervous system The parasympathetic nervous system (PSNS) is one of the three divisions of the autonomic nervous system, the others being the sympathetic nervous system and the enteric nervous system. The autonomic nervous system is responsible for regulat ...

. Nerve fibres from the maxillary and mandibular divisions of the trigeminal nerve have also been documented. These afferents synapse with the visceral motor nucleus of the vagus nerve, located in the

reticular formation The reticular formation is a set of interconnected nuclei in the brainstem that spans from the lower end of the medulla oblongata to the upper end of the midbrain. The neurons of the reticular formation make up a complex set of neural networks ...

of the brain stem. The efferent portion is carried by the vagus nerve from the cardiovascular center of the medulla to the heart, of which increased stimulation leads to decreased output of the

sinoatrial node The sinoatrial node (also known as the sinuatrial node, SA node, sinus node or Keith–Flack node) is an ellipse, oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of Cell (biology), cells known as pa ...

. This reflex is especially sensitive in

neonates In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to Juvenile (orga ...

and children, particularly during strabismus correction surgery. Oculocardiac reflex can be profound during eye examination for retinopathy of prematurity.Schumacher AC, Ball M, Arnold AW, Grendahl RL, Winkle RK, Arnold RW. Oculocardiac reflex during ROP exams. Clin Ophthalmol. 2020;14:4263-4269. doi:https://doi.org/10.2147/OPTH.S288578 However, this reflex may also occur with adults.

Bradycardia Bradycardia, also called bradyarrhythmia, is a resting heart rate under 60 beats per minute (BPM). While bradycardia can result from various pathological processes, it is commonly a physiological response to cardiovascular conditioning or due ...

junctional rhythm Junctional rhythm also called nodal rhythm describes an abnormal heart rhythm resulting from impulses coming from a locus of tissue in the area of the atrioventricular node (AV node), the "junction" between atria and ventricles. Under normal cond ...

and

asystole Asystole (New Latin, from Greek privative a "not, without" + ''systolē'' "contraction") is the absence of ventricular contractions in the context of a lethal heart arrhythmia (in contrast to an induced asystole on a cooled patient on a heart-lun ...

, all of which may be life-threatening, can be induced through this reflex. This reflex has been seen to occur during many pan facial trauma surgeries due to stimulation of any of the three branches of trigeminal nerve.

Treatment

The reflex can be blocked by intravenous injection of an anti-muscarinic

acetylcholine Acetylcholine (ACh) is an organic compound that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Par ...

(ACh)

antagonist An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.atropine Atropine is a tropane alkaloid and anticholinergic medication used to treat certain types of nerve agent and pesticide poisonings as well as some types of slow heart rate, and to decrease saliva production during surgery. It is typically give ...

glycopyrrolate Glycopyrronium bromide is a medication of the muscarinic anticholinergic group. It does not cross the blood–brain barrier and consequently has few to no central effects. It is given by mouth, via intravenous injection, on the skin, and via in ...

. If bradycardia does occur, removal of the stimulus is immediately indicated. This often results in the restoration of normal sinus rhythm of the heart. If not, the use of atropine or glycopyrrolate will usually be successful and permit continuation of the surgical procedure. Caution should be used with fast-push, intravenous opioids and dexmedetomidine which exacerbate the bradycardia. In extreme cases, such as asystole,

cardiopulmonary resuscitation Cardiopulmonary resuscitation (CPR) is an emergency procedure used during Cardiac arrest, cardiac or Respiratory arrest, respiratory arrest that involves chest compressions, often combined with artificial ventilation, to preserve brain function ...

may be required.

In psychology

A commonly-used technique in the field of

brainspotting Brainspotting is a psychotherapy technique that attempts to help people process psychological trauma or other problems via eye movements. Practitioners of this technique use a pointer to direct a client’s eye gaze in order to send signals to the ...

called "vergence" deliberately triggers this reflex in order to calm patients.

External links

* * Video Example
Video abstract
to

References

{{DEFAULTSORT:Oculocardiac Reflex Ophthalmology Reflexes

Treatment

In psychology

See also

External links

References