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The vergences are the movements that the ocular structures perform simultaneously, but in opposite directions, the ocular structure from one point to another at a given moment. Vergence flexibility is the ability of the eye to converge and diverge correctly in a given period of time. 

En Área Oftalmológica Avanzada We explain below what vergence flexibility is.

vergence flexibility

What is vergence flexibility?

Vergence flexibility (FV) is the ability of the eyes to perform fusional vergence movements for a certain time. During these movements the eyes focus simultaneously in different directions, quickly performing the action of vergence and accommodation. 

Vergence flexibility is a qualitative test that allows evaluating the daily behavior of the eyes during distance vision and near vision. VF is expressed in cycles per minute.

What does it measure? 

Vergence flexibility measures the ability of an individual's visual system to respond quickly and accurately to changes in vergence stimuli over a given period of time. In other words, VF calculates the ability of the eyes to converge and diverge quickly and accurately. 

How is this test performed? 

The vergence flexibility is one of the measures of the vergence system, therefore, to measure the VF it is necessary to use a flipper. The monocular flipper is an instrument that contains temporal base and nasal base cousins ​​that can be switched by rotating the flipper by its handle. 

During the test, the patient must observe through the BT and BN primes, which allow the individual to alternately converge and diverge. The medical specialist may also use loose prisms or a prism bar for the test. 

To measure the flexibility of vergence during near vision, an accommodative optotype located 40 cm away from the patient is used. This optotype contains of visual acuity 20/30 arranged vertically. 

At the beginning of the examination, BN prisms are placed in front of the eyes and then BT prisms. At the time of placing the BN premiums, the patient will see a blurred image that will progressively unify. When the patient states that he has been able to unify his image, the BN premiums will be exchanged for the BT premiums.  

The VF measurement is performed for 1 minute, and the number of cycles that the stimulus can fuse through the alternate presentation of the BT and BN prisms must be calculated. 

In interpreting the results of VF values, a value <8 cpm is considered an abnormal value. Abnormal results of this test may be an important indication of binocular dysfunctions not associated with squint

En Área Oftalmológica Avanzada we have the best human and technological team to measure the fusional vergencies. Do not hesitate to contact us if you need to check your binocular vision or measure your vergence flexibility. We will wait for you! 

Vergence flexibility
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Vergence flexibility
Vergence flexibility (FV) is the ability of the eyes to perform fusional vergence movements for a given time.
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Área Oftalmológica Avanzada
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vergential flexibility, vergences
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