Hess chart detects the amount of underaction and overaction of muscles therefore it helps in diagnosis of ocular motility defects. Further by comparing subsequent Hess charts, one can find out improvement or deterioration of a condition. This test can give us repeated and reliable results. Modification of the Hess screen is a Lees screen which uses double sided mirror instead of color dissociation method used by Hess chart. This pg snippet manuscript demonstrates various conditions where Hess or Lees chart can be used and help in diagnosis along with decision making in the management of various ocular motility defects.