The Oculocardiac Reflex, also known as the Aschner Reflex, is a phenomenon where stimulation of the eye can cause a decrease in heart rate. The spelling of this word can be explained using the International Phonetic Alphabet (IPA). The first part of the word, "oculo", is pronounced as "ɑ.kjʊ.loʊ". The second part, "cardiac", is pronounced as "ˈkɑɹ.di.æk". And the final part, "reflex", is pronounced as "ˈɹiː.flɛks". Therefore, the IPA transcription for "Oculocardiac Reflex" would be "ɑ.kjʊ.loʊ.ˈkɑɹ.di.æk.ˈɹiː.flɛks".
The oculocardiac reflex, also known as the Aschner reflex or 'eye-heart' reflex, refers to a natural physiological response characterized by a decrease in heart rate that occurs when pressure is applied to the eyeball or surrounding structures. This reflexive response is mediated by the trigeminal nerve, specifically the ophthalmic branch (V1), which carries sensory information from the eye to the brainstem. The oculocardiac reflex is a parasympathetic reflex, meaning that it involves the activation of the parasympathetic nervous system.
When pressure is applied to the eye, the reflex is triggered, leading to the stimulation of the ophthalmic division of the trigeminal nerve. This stimulation then activates the parasympathetic fibers of the vagus nerve (cranial nerve X), which innervate the heart. The parasympathetic fibers release acetylcholine, a neurotransmitter that slows down the heart rate by inhibiting the electrical conduction through the sinoatrial (SA) node, which regulates the heart's rhythm.
The oculocardiac reflex typically causes a decrease in heart rate by 10-20%, but in some cases, it can be more significant, leading to bradycardia (abnormally slow heart rate) or even cardiac arrest. This reflex can be triggered by various stimuli, such as pressure on the eye during eye surgery, trauma to the eye, or even eye examinations involving manipulation or pressure on the globe. It is important for medical professionals to be aware of this reflex and take necessary precautions to monitor and manage any potential complications that may arise during procedures involving the eye.
A change in the pulse-rate, usually a slowing, following compression of the eyeball.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The term "Oculocardiac Reflex" is derived from Latin and Greek roots.
1. Oculo-: This prefix is derived from the Latin word "oculus", meaning "eye". It pertains to anything related to the eye.
2. -cardiac: This suffix is derived from the Greek word "kardia", meaning "heart". It pertains to anything related to the heart.
3. Reflex: This word is derived from the Latin word "reflexus", meaning "bent back" or "reflected". It refers to an involuntary response or reaction to a stimulus.
Therefore, the etymology of "Oculocardiac Reflex" combines Latin and Greek to describe the involuntary heart response caused by eye stimuli.