How Much Superior Rectus Underaction is Considered Normal?

The majority of young healthy adults in this study showed some degree of superior rectus underaction. On ocular movement testing, -0.70 units of underaction, and on the synoptophore, -0.48 degrees of underaction are the mean levels of weakness to be expected. Superior rectus underactions greater than -1 units for ocular movement testing and -1 degrees on the synoptophore in healthy young adults should be carefully evaluated, together with other important clinical signs.