Commonly is referred to as a squint and is medically known as strabismus, derived from the Greek word (strab-is-mos).

The eyes are not aligned with each other eye.  The position of one eye may look:-

It may be a combination of both, for example inwards AND upwards.


There are 6 extra-ocular muscles in each eye and they have to work together with the other eye as a pair to achieve single vision when staring at something in space.

For example:  Looking to the right

What causes a squint?

The reasons squint develops is due to some of the following:

A squint may  affect vision.  The brain ignores the image coming from the squinting eye and starts to become lazy otherwise known as amblyopia (am-bly-opia) meaning lazy  or poor vision not blind vision.

This test is crucial to assess the presence and type of a squint.  It is a simple procedure using a cover to occlude one eye and see the movement of the other eye.

If  one of the eye is covered with the black cover (occluder)  the other eye will move to view the object/image.