«Back to the glossary index

El squint is an alteration of binocular vision characterized by the deviation of the eye axes towards a certain direction. The phoria are also known as the false squint, are a disorder that causes misalignment of the axes of the eye in certain circumstances. 

Factors like Stress, tiredness and visual fatigue  They can make a phoria appear and cause symptoms in the vision. In Área Oftalmológica Avanzada We explain below, what are phorias, how they are detected and what is the ideal treatment. 


What are phoria?

Ocular phoria is the hidden deviation of the visual axes that usually manifests itself in special circumstances such as episodes of chronic stress and fatigue. 

The phorias remain, most of the time, hidden because they are compensated by complementary reflections. These reflexes are called fusional reserves and they are the ones in charge of keeping the eyes aligned despite the existence of a phoria. 

When a person is very tired or stressed, the fusional reserves are not enough to compensate for the phoria, causing it to become noticeable and cause symptoms such as blurred vision, double vision y headache

It is important to note that phorias are not the same as trophies. The tropias are what we know as strabismus, an alteration of the binocular vision It causes misalignment of the axes of the eye and prevents both structures from focusing on the same point at the same time. 

Types of phoria

The phoria are classified according to the direction in which the ocular axis deviates, let's see: 

  • Exophoria: the ocular axis deviates outwards.
  • Endophoria: the eye axis deviates inward.
  • Hyperphoria: the ocular axis deviates upwards. 
  • Hypophoria: the ocular axis deviates downwards.

How to detect the presence or deviation of the ocular phoria?

There are many diagnostic tests to diagnose phorias, tropias or strabismus, however, the most effective method is cover test. This test consists of occluding an eye and uncovering it intermittently while the patient stares at an object with both eye structures. 

The cover test can also be performed alternately. In this case, one eye is covered and then the other immediately, while the patient constantly observes an object from near or far.  

The movements of the eyeball during the examination allow the ophthalmologist to diagnose the phoria, measure the level of deviation and determine its magnitude and direction. 


Ocular phoria that are compensated by fusional reflexes and do not cause any symptoms in the patient do not need to be treated. 

When a patient presents a decompensated phoria that is affecting his vision, we recommend performing exercises visual therapy in our unit specially dedicated to it. The visual therapy It is a set of eye exercises that are performed in order to strengthen and improve the functioning of the extrinsic muscles of the eye, which are responsible for the movement of the eyeball. 

The use of glasses with prisms is also a great help to compensate for the phoria and avoid eye strain.

Article name
Ocular phoria is the hidden deviation of the visual axes that usually manifests itself in special circumstances such as episodes of chronic stress and fatigue.
Name of the editor
Área Oftalmológica Avanzada
Editor's logo
False strabismus, ocular phoria
«Back to the glossary index