#$%^&*AU2016200874A120160225.pdf#####ASSESSMENT OF TOPOGRAPHIC SEMI-MERIDIAN PARAMETERS FOR CORNEAL ASTIGMATISM ANALYS IS AND VECTOR PLANNING TREATMENT Abstract Techniques are disclosed in which a topographic parameter is determined in each hemidivision of the eye by considering the topography of reflected images from a multiplicity of illuminated concentric rings of the cornea. A simulated spherocylinder is produced to fit into each ring and conform to the topography thereof from which a topographic parameter for each ring can be obtained. All of the topographic parameters of each ring are combined and a mean summated value is obtained representing magnitude and meridian of each hemidivision. From these parameters, a single topographic value for the entire eye (CarT) can be found as well as a value representing topographic disparity (TD) between the two hemidivisions. The topography values for the hemidivisions are used in a vector planning system to obtain treatment parameters in a single step operation. 10980226_1
