If you see two of whatever you are looking at, you may have a condition known as diplopia, also referred to as double vision. Diplopia may be the result of a refractive error, where light from an object is split into two images by a defect in the eye’s optical system. Cataracts might, for example, cause such a defect.
Diplopia may also result from failure of both eyes to point at the object being viewed, a condition referred to as ocular misalignment. In normal vision, both eyes look at the same object. The images seen by the two eyes are fused into a single picture by the brain. If the eyes do not point at the same object, the image seen by each eye is different and cannot be fused. This results in double vision.
Double and blurred vision are often thought to be the same, but they are not. In blurred vision, a single image seen by one eye appears unclear. In double vision, two images are seen at the same time (one from each eye), creating understandable confusion for anyone who has it.
Treatment of double vision consists of eye exercises, surgical straightening of the eye or a combination of the two. Therapy is aimed at re-aligning the misaligned eye where possible without surgery and re-stimulating the part of the visual pathway to the brain which is not working correctly.