Monocular double or triple vision occurs secondary to some disturbance along the visual axis. The visual axis implies all the structures that light has to pass in order to reach the retina. For the sake of this discussion, I will refer to the problem as diplopia
) since the number of images seen is usually irrelevant. The pathology lies in seeing more than one image. It is very rare for a retinal problem to cause diplopia.
The most common reason for this phenomenon, is an optical irregularity in either the cornea (the front of the eye) or the lens
(behind the pupil, used for proper focusing).
In the cornea, one can suffer from irregular astigmatism. This is a type of astigmatism that causes two or three images to be detected by the retinal cells. Irregular astigmatism may be caused by a condition termed keratoconus
. Another reason may be a decentered contact lens
on the eye. About 40% of monocular diplopia is caused by cornal problems such as the ones just described.
Another common reason for monocular diplopia occurs when cataracts
affect the lens of the eye. In particular, nuclear sclerotic cataracts can cause this type of symptom.
I recommend a complete eye exam including a corneal topography
that will help determine if irregular astigmatism is present. Also the lens of the eye can be carefully examined.
I hope this is helpful....