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Pupillary response is a physiological response that varies the size of the pupil between 1.5 mm and 8 mm, [1] via the optic and oculomotor cranial nerve. A constriction response , [2] is the narrowing of the pupil, which may be caused by scleral buckles or drugs such as opiates/opioids or anti-hypertension medications.
These can be due to concussion injury to the brain and is associated with subdural haemorrhage and unconsciousness. The parasympathetic fibers to the pupil are responsible for pupillary constriction. The fibers pass through the periphery of the oculomotor nerve, and hence are the first to be affected in case of compression of the nerve.
The Marcus Gunn pupil is a relative afferent pupillary defect indicating a decreased pupillary response to light in the affected eye. [3] In the swinging flashlight test, a light is alternately shone into the left and right eyes. A normal response would be equal constriction of both pupils, regardless of which eye the light is directed at.
Signs of increased ICP include decreasing level of consciousness, paralysis or weakness on one side of the body, and a blown pupil, one that fails to constrict in response to light or is slow to do so. [51] Cushing's triad, a slow heart rate with high blood pressure and respiratory depression is a classic manifestation of significantly raised ...
Horner's syndrome, also known as oculosympathetic paresis, [1] is a combination of symptoms that arises when a group of nerves known as the sympathetic trunk is damaged. The signs and symptoms occur on the same side (ipsilateral) as it is a lesion of the sympathetic trunk.
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]
Next, constriction of the pupil occurs. Because the lens cannot refract light rays at the edges well, the image produced by the lens is blurry around the edges so the pupil constricts when one attempts to focus on nearby objects. [citation needed] Lastly, accommodation of the lens occurs. This is an alteration in the curvature of the lens that ...
A concussion, also known as a mild traumatic brain injury (mTBI), is a head injury that temporarily affects brain functioning. [8] Symptoms may include headache, dizziness, difficulty with thinking and concentration, sleep disturbances, mood changes, a brief period of memory loss, brief loss of consciousness; problems with balance; nausea; blurred vision; and mood changes.