Binocular Vision & Fusion Problems

February 13, 2023 | Category:

binocular vision

Binocular vision is vision in which both eyes are used together.

We have two eyes, each of which forms its own image. Yet we do not see an object double because our brain fuses the two images into one. Thus we possess ‘binocular vision’. It is because of good fusion that our vision is three dimensional and we are able to locate an object in space accurately.

It is an alarming fact that a full seventy per cent of the population have fusion problems of some kind. At its most severe degree, a fusion problem results in crossed eye; but a great many people have insufficiencies that are not so apparent.

When a person has poor binocular vision, he is under constant stress to maintain a balance of some sort to keep from becoming worse. Such a person is like someone on the verge of a breakdown, but fighting every step of the way to maintain equilibrium. It takes a lot of energy. He probably rubs his eyes frequently, rests his head on his arm when writing, cannot engage his eyes in a particular activity for a very long time and experiences sporadic double vision.

Without good depth perception, a person with poor binocular vision has difficulty in catching a ball, feels quite uneasy walking over a bridge or standing at the edge of a terrace and needs to hold onto a railing when going down steps because he is uncertain about the space in front of him and has difficulty in judging precisely where the edge of the step is.

Test: Do you have any Fusion Problems or Inefficient Binocular Vision?

For this test, you would need a small torch or pen-light (candle flame can be used instead), a 3 x 5 inch card, a dark room.

Perform the routine first without and then with glasses.


(1) Sit about 15 feet away from the light or the candle.

(2) Look at the light or the candle-flame with both the eyes.

(3) Hold the card in front of anyone eye so as to occlude its vision (the eye, however, should be kept open).

(4) Look at the light with the uncovered eye for ten counts.

(5) Keeping the gaze fixed on the light, rapidly remove the card to expose the covered eye.

(6) Do you momentarily see two lights? Do the two lights merge immediately or after some time ?

Evaluation of Test Results

Double vision (seeing two lights) is an indication of a certain degree of fusion problem.

If the two lights merge immediately, the fusion problem is slight.

If the two lights merge after some time, you have moderate fusion problem.

If the two lights merge after two seconds or more or if an effort is required on your part to bring about their fusion, you have marked fusion problem. Notes:

(1) Whichever eye is covered, the result turns out to be the same; that is to say that the problem is not specific to a particular eye.

(2) The problem gets aggravated and therefore can be elicited more easily when the eyes are tired (say following a session of reading or writing) or when a person is sick.

Guidelines For Eye Exercises

Before we go on to the details of eye exercises to improve binocular vision, there are a few points to take note of:

1. First, read and understand the steps of each eye exercise carefully.

2. Do not use glasses or contact unless you are instructed to.

3. Do the eye exercises in in non-glaring light. Vision chart or targets should be well lit at all times.

4. If the eye exercise requires you to close the eye, do so gently.

5. Do not strain your eyes while doing the eye exercise. The result would be better if you do not strain your eyes.

6. Rest your eyes after each eye exercise, and also at the end of the whole eye exercise. To relax your eyes, perform the eye relaxation exercises.

7. As our eyes are tired after a whole-day work, early morning is the best time for eye exercises.

8. If you do not have enough time to complete all the eye exercises for farsightedness, you can do some in the morning and finish the rest in the later part of the day.

9. Learn about the different stages that you will experience when you begin to build your visual habits: The different stages as you build your visual habit.

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