eye disorders
Diplopia
Etiology of Diplopia
Monocular diplopiacan occur when something distorts light transmission through the eye to the retina. There may be>2 images. One of the images is of normal quality (eg, brightness, contrast, clarity); the rest are of inferior quality. The most common causes of monocular diplopia are Cataract None Corneal shape problems, such as Keratoconus or surface irregularity Uncorrected Overview of Refractive Error , usually astigmatism Other causes include corneal scarring and dislocated lens. Complaints also may represent malingering. Binocular diplopiasuggests disconjugate alignment of the eyes. There are only 2 images, and they are of equal quality. There are many possible causes of binocular diplopia (see table). The most common are Cranial nerve (third, fourth, or sixth) palsy Myasthenia Gravis None Orbital infiltration (eg, thyroid infiltrative ophthalmopathy, orbital pseudotumor) Most commonly, the eyes are misaligned because of a disorder affecting the cranial nerves innervating the extraocular muscles (third, fourth, or sixth cranial nerves). These palsies may be isolated and idiopathic or the result of various disorders involving the cranial nerve nuclei or the infranuclear nerve or nerves. Whether pain is present depends on the disorder. Other causes involve mechanical interference with ocular motion (which often cause pain) or a generalized disorder of neuromuscular transmission (which typically do not cause pain). 