How to Perrla Test Eyes Exam

Perrla Test Eyes is a series of examinations that involves checking a patient’s pupillary reactions to find out if there are larger threats to be aware of. A patient would be asked to sit in a room that is dimly lit prior to the commencement of the test. A bright light would be shined toward each eye and the examiner would take note of changes in pupillary responses accordingly. If the test shows normal signs, results would be recorded on a patient’s medical chart. If it shows any signs of abnormalities, a patient would be recommended to undergo further tests to properly discover what is going on with their body. The basics to the test are simple. It takes the way the pupils react to exposure to light into account when predicting a possible diagnosis and, in turn, helping with designing treatment plans for the conditions accordingly. Normal pupils always constrict themselves in the abundance of light and dilate in its absence or lack thereof. Anything else other than these normal responses is to be regarded as a sign of something wrong, which needs to be further examined.

How to Perrla Test Eyes Exam
How to Perrla Test Eyes Exam

Perrla Test Eyes is based on the movement of the pupils, which are controlled by nervous system. When the pupils are not capable of responding to stimulants the way they are expected to, it could be safe to assume that there is something to be worried about regarding a patient’s central nervous system. In a manner of speaking, discovering how the pupils react to light is the key to figuring out a larger problem that must be dealt with. In PERRLA test, there are factors that need to be taken into account before proper diagnosis can be derived. Those factors are:

The size

A medical examiner will conduct test under an environment that is bright and dark. He or she would measure the size of the pupils in both lighting conditions. The pupils are to be deemed abnormal if their sizes are different from one another or from that of the normal pupils.

The shape

Using a penlight, a medical examiner will see if the pupils are misshapen. A pupil should be in a shape of a perfect round. Anything else other than that is a sign of something to look deeper into.


This means reactivity to exposure to light source. Normal pupils would constrict in abundance of light. Even when there is only one pupil that does not react properly, cautions should be taken and further examinations must be conducted.

Reactivity also entails response to accommodations. This has anything to do with the eyes abilities to constrict their pupils when looking at objects in long distance which is then brought nearer. Normal pupils would dilate when a patient is looking at the object in long distance and constrict when the object is brought closer to the eyes, approximately closer to the nose.

Obviously, results derived from a PERRLA test is far from being set in stone. Abnormalities shown by the test should be taken as a sign that further exams are in order.

See also What Is PERRLA Eyes and Means in Eye Exam