Distance ESO Deviation—A Basic Deviation or Paralysis of Divergence

A Group of one hundred patients is described with the condition of distance eso deviation or convergent squint which is present for distance viewing together with an exo deviation for near viewing and in-between distance and near there is a neutral point or crossing distance where there is no deviation. The crossing distance determines the distance at which an exo deviation will be present. Accommodation increases the degree of eso deviation and shortens the crossing distance, especially in younger patients, but does not have much effect in presbyopic patients. Distance eso deviation occurs at all ages and varies in degree from a small phoria to an obvious tropia. It is a cause of diplopia in elderly patients, and may be the underlying cause of convergent squint in young patients. It is distinct from the rare condition of divergence paresis.