Why do doctors shine a light in your eyes when they are unconscious?

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.

Why do I see lights when I hit my head?

If you get hit on the head, the tissue in your occipital lobe gets shaken up. Brain cells then send out random electrical impulses, which your brain interprets as flashes of light that may seem like stars.

What does shining a light in your eye do?

In bright light, it contracts. Light detected by the retina of your eye is converted to nerve impulses that travel down the optic nerve. Some of these nerve impulses go from the optic nerve to the muscles that control the size of the pupil. More light creates more impulses, causing the muscles to close the pupil.

How does head injury affect pupils?

Objective: Acute pupillary dilation in a head-injured patient is a neurological emergency. Pupil dilation is thought to be the result of uncal herniation causing mechanical compression of the IIIrd cranial nerve and subsequent brain stem compromise.

Do pupils react when unconscious?

The pupils should constrict immediately and equally bilaterally; after you remove the light, they should immediately dilate back to baseline. Document the response: Is it brisk, sluggish, nonreactive, or fixed? Immediately report any changes from baseline.

What receives light in the eye?

Light passes through the front of the eye (cornea) to the lens. The cornea and the lens help to focus the light rays onto the back of the eye (retina). The cells in the retina absorb and convert the light to electrochemical impulses which are transferred along the optic nerve and then to the brain.

How do pupils look after head injury?

After more serious head injuries are excluded, a diagnosis of concussion can be made. Medical professionals have long used the pupillary light reflex — usually in the form of a penlight test where they shine a light into a patient’s eyes — to assess severe forms of brain injury.

How do pupils react with concussion?

Vision or eye disturbances, such as pupils that are bigger than normal (dilated pupils) or pupils of unequal sizes. Ringing in the ears that doesn’t go away. Weakness in the arms or legs. Appearing very pale for longer than an hour.