Walsh & Hoyt: Blurred Vision

Misalignment of the visual axes does not always produce diplopia or visual confusion. In some patients, the images of an object seen by noncorresponding parts of the retina are so close together that the patient does not recognize diplopia but instead complains that the vision is blurred when both eyes are open. Similarly, some patients interpret visual confusion not as image superimposition but as simple ""blurred vision."" Blurred vision that exists only with both eyes viewing is quite common in the early stages of an ocular motor nerve paresis. In such patients, the blurred vision clears completely if either eye is closed.