Why Alignment Of Bird Watching Binoculars Is Necessary?

Have you ever felt that your eyes are being squeezed when you are using your binoculars? Immediately after using you binoculars have you ever felt cross-eyed? Do you suffer from severe headaches after using binoculars for long?

These are some of the after effects of using bird watching binoculars which are not aligned properly.
What is alignment?
Binoculars are a pair of telescopes placed side by side to offer equal vision to both eyes. The eyes and brain blend both the images and for this to happen thus, both these telescopes have to be in alignment.
However, there is a possibility that the alignment can be disturbed when they are knocked or dropped. As a result they do not point in the same direction, which causes your eyes and brain to strain to align both the images.
One cannot tell by simply looking at a pair of binoculars with their naked eyes whether they are perfectly aligned. For this high-end equipment is required, however one can check their pair for overall misalignment. All you need to do is choose a horizontal line, like a roof line or power line which is completely straight. Look at it through your binoculars, focus for a minute or two and pull away the binoculars from your eyes for two to three inches but do not change their position. The image formed is separated into two circles.
Alignment
When the binoculars are aligned, the line appears straight in both circles.
Out of alignment
In case both telescopes are not in alignment, the horizontal line might step up or step down between both circles.
When your binoculars are not in alignment, both images will be struggling with each other. All your eye muscles and brain try to combine both pictures to form a single image. However, this is fairly difficult for your brain, which is why your head starts aching.
Other conditions
Even if you are unable to hold the binoculars straight and tilt the entire device you will be able to tell whether or not it is in alignment. The two circles will not remain at the same level and even then the line will be continuous if it is in alignment.
How to correct misalignment?
You cannot repair your bird watching binoculars, when it is out of alignment. You might be able to contact the manufacturer and send it back for repair if it is still within warranty period. During this time period you might get a proper repair done for little to no charge. If it is not under the warranty period you should replace it. The cost for having a binocular realigned is fairly high, so if the pair is not valuable, buy a new pair as it will cost less.