Pupil Evaluation And Trauma Recovery


Located in the center of the inside of an iris, a pupil is a circular black hole allowing light to pass to the retina. The tissue around the pupil absorbs the light reaching it, making it appear black.

The pupil is surrounded by the iris’s soft muscles that help protect the pupil from light and provides better vision in the dark—the muscles around the pupil help in its dilation or contraction by avoiding light.

Why do pupils change sizes?

The pupil changes size as a response to light. The pupil grows, i.e., dilates when the light is dim. And the pupil shrinks in size with bright light. The normal size of the contracted pupil is between two to four mm. At the same time, the dilated pupil size is between three to eight mm.

Though in humans, the size of pupils varies for different ages. 

The pupils are light-sensitive. The contraction and dilation depend on the oculomotor nerve. Thus the evaluation of pupillary light reflex is extremely important during any brain or head injury.

If there is any serious head injury, then it can easily detect based on its pupillary light reflex. The pupil will dilate in low light and contract in bright light. This light reflex is a vital function of the brainstem.

Pupilometer and its functions:

So, what is a pupilometer? Evaluation of pupils means assessment and changes in a pupil. A pupilometer is an electronic pupil-size measuring device. Also spelled pupillometer, it is a combination of two devices:

1.     To measure the pupils’ response to light.

2.     Used in ophthalmology, i.e., in measuring the length between the pupils to visual stimuli.

A pupilometer is a portable device. They are used as peripheral devices with various IBM-friendly personal computers.

Routine pupil evaluation is a protocol for patients in critical conditions. Or those with severe injury or illness. 

Pupillary light reflex and pupillary size measurement are traditional clinical methods. They are used for predicting nerve or head injury.

The neurological experts suggest a regular pupillary examination, especially for patients with any sort of head, brain, or nerve injury.

A pupilometer, in addition, helps in facilitating pupil dynamics of patients on drugs.

In such cases, the pupils are exceedingly constricted. And also known as pinpoint pupils. Measuring the pupil dynamics at a time like this is impossible with naked eyes. Pupil’s size is also measured with video or photography with a suitable calibration method.


Pupilometer is a handheld device that electronically measures pupil diameter with its infrared sensors. It has the capability of stimulating the pupil with the pulse of programmable light. Further, it records the resulting response of pupils. 

Then a comparison between the report in the present and fixed pupil diameter size with the one obtained with infrared pupilometer occurs.

The infrared pupilometer is also used in documenting the light response of the pupil. This helps to research patients in various drug-related aspects. 

The infrared measurements of pupil diameter per photographic measurements take place.

The results and effects of drugs and medicines are also checked and researched with changes in pupil diameter measurements.

Pupils size measurement is possible via photography or video after appropriate calibration of the method as well.

Pupillometer functions:

· They are used in the measurement of the diameter of a pupil as well as its size.

· A pupillometer provides objective, reliable, and accurate pupillary reflex measurement for reactivity and size.

· It has an infrared camera, a light source- LED, and a processor in a handheld device.

· Over time, the trends and monitors change.

· No calibration is required. 

· Portable hand-handled device 

Pupillary responses during head injury:

Traumatic brain injuries are a significant cause of death worldwide. About 30% of the world’s population dies as a result of brain injury. And about 1.4 million Americans die annually due to TBIs.

Pupillary Response in Traumatic Brain Injury (TBI)is an effective way of understanding the extent of the injury. The first thing that the clinical check during ahead injury is the pupil light reflex and response. It plays an indispensable role in this regard and has both prognostic and diagnostic value. 

The clinical with the case of trauma patients perform routine neurological examinations. This examination begins with a pupillary examination. The process does not only have a medical reason but has a physiological basis to it as well. 

Let’s get to know if the reason behind this assessment:

  • Traumatic brain injuries are likely to cause change or rise in emotions—an analysis of the pupillary reaction to light happens.
  • Elevated ICP can cause a change in the function of the brainstem, resulting in abnormalities in the size of pupils. 
  • The pupillary reaction to light can inform of any abnormalities like changes in ICP. At the same time, newfound or upheld papillary would mean worse aftermath.
  • It helps to predict corticosteroid Randomization after Significant Head Injury. 
  • Pupillary assessments these days takes place with the help of a handheld electronic pupilometer. Thus helping in getting a precise assessment. 
  • Pupil assessment provides Intra and inter-observation of head injury.
  • Pupillary dilatation in head injury can even identify acute severe cases of traumatic subdural hematoma. And if the pupils are non-reactive to light after a head injury, the speculation confirms.
  • With the help of a pupillometer, detecting a shift in the intracranial midline is possible. 
  • An assessment of pupil size will help regulate the effect of ICP osmotic medication on the pupillary process.


Today, various methods and technologies are available for treatment. 

In cases of neural health, a pupillometer is an adequate model of comprehending the extent of the stimuli damage. This is important from both physical and psychological health perspectives.

It has proven itself a crucial tool for clinical—an easy method to assess the situation as quickly as possible. Pupils’ reaction to light is an easy and quick method of identifying the health of a patient. All you need is quality treatment on time.