A concussion is a mild traumatic brain injury from a sudden jolt or blow to the head or body, causing the brain to move rapidly within the skull. This movement can lead to temporary disruptions in normal brain function. While a medical diagnosis from a healthcare professional is always necessary, observing how pupils respond to light can offer preliminary indications of a possible head injury, helping determine if professional medical evaluation is needed.
Understanding Pupil Response
The eyes provide insight into neurological function, with pupils serving as a key indicator of brain activity. Pupil size continuously adjusts in response to varying light levels, a process known as the pupillary light reflex (PLR). This reflex is controlled by a complex interplay between the optic nerve, the midbrain, and the oculomotor nerve. A concussion can disrupt these neurological pathways, impacting the brain’s ability to regulate pupil size and reaction. This disruption might lead to abnormal pupil responses, such as changes in size, delayed reactions to light, or asymmetry between the two eyes.
How to Perform a Pupil Check
Performing a basic pupil check involves a few simple steps:
Find a dimly lit room, which allows pupils to naturally dilate for easier observation.
Explain to the individual that you will be shining a light into their eyes and ask them to look straight ahead.
Use a penlight or a phone flashlight, ideally with adjustable brightness, as a very bright light can be uncomfortable.
Gently shine the light into one eye from a 45-degree angle, not directly head-on, and observe if the pupil constricts and holds that constriction for a few seconds.
Repeat this process for the other eye.
Observe both eyes for any differences in their response.
What Pupil Responses Indicate
A normal pupil response involves both pupils constricting briskly and equally when exposed to light. They should remain constricted for about 3-5 seconds until the light is removed. The pupil in the eye not directly exposed to the light should also constrict in a consensual response. Abnormal responses can suggest a concussion or a more serious head injury. A sluggish response, where the pupil constricts slowly or dilates quickly after constriction, can be a sign of neurological disruption. Unequal pupil size, medically known as anisocoria, where one pupil is noticeably larger than the other, may indicate a more severe brain injury and warrants immediate medical attention. While a small difference in pupil size (less than 1 millimeter) can be normal, a significant difference or pupils that are fixed and dilated and do not react to light are concerning signs.
Seeking Professional Medical Evaluation
Observing pupil responses at home can be a helpful preliminary step, but it is not a substitute for a thorough medical assessment by a healthcare professional. A definitive diagnosis of a concussion requires a comprehensive evaluation that includes medical history, physical examination, and neurological tests. Healthcare providers can also conduct specialized tests to determine the extent of the injury and rule out more severe conditions like skull fractures or bleeding in the brain. If there is any suspicion of a concussion, especially if abnormal pupil responses are observed, or if other symptoms such as severe headache, repeated vomiting, loss of consciousness, or balance problems are present, immediate medical attention is necessary. Contacting emergency services or visiting an urgent care center or hospital ensures appropriate care and monitoring.