Poor spatial vision is often caused by gradual increase in light scatter in older eyes. When this is large, the loss of vision is described as ‘disability glare,’ i.e., visual discomfort and failure to see fine spatial detail in low contrast. Large amounts of scattered light also cause discomfort in addition to loss of spatial vision, particularly during night driving. The test measures the amount and angular distribution of scattered light in the eye and has been used in several studies.
