Generating a refractive ophthalmic nomogram

A method for generating an ophthalmic nomogram for treating an eye, comprising:

• storing, by a computer, a computer program and post-operation refraction data for generating the ophthalmic nomogram, the post-operation refraction data comprising a plurality of notations, each notation comprising a sphere and a cylinder, each notation describing a post-operation correction associated with a target correction, the target correction having a target sphere;
• executing, by the computer, the computer program to create a nomogram data set comprising a plurality of selected spheres, the computer executing the computer program comprising:
• performing the following for each notation of the plurality of notations to yield the plurality of selected spheres:
• when the notation is expressed as a plus notation, determining a minus notation corresponding to the plus notation;
• when the notation is expressed as a minus notation, determining a plus notation corresponding to the minus notation;
• identifying whether the plus notation or the minus notation has a lower absolute sphere;
• designating the lower absolute sphere of the identified notation as a candidate sphere;
• and
• determining whether to designate the candidate sphere as a selected sphere;
• and
• calculating the ophthalmic nomogram from the plurality of selected spheres.

A system for generating an ophthalmic nomogram for treating an eye, comprising:

• a computer comprising:
• a memory configured to store a computer program and post-operation refraction data for generating the ophthalmic nomogram, the post-operation refraction data comprising a plurality of notations, each notation comprising a sphere and a cylinder, each notation describing a post-operation correction associated with a target correction, the target correction having a target sphere;
• and
• logic configured to execute the computer program to create a nomogram data set comprising a plurality of selected spheres, the logic executing the computer program configured to:
• perform the following for each notation of the plurality of notations to yield the plurality of selected spheres:
• when the notation is expressed as a plus notation, determine a minus notation corresponding to the plus notation;
• when the notation is expressed as a minus notation, determine a plus notation corresponding to the minus notation;
• identify whether the plus notation or the minus notation has a lower absolute sphere;
• designate the lower absolute sphere of the identified notation as a candidate sphere;
• and
• determine whether to designate the candidate sphere as a selected sphere by:
• when an absolute cylinder of the notation is equal to two times an absolute sphere of the notation, determining whether to include or exclude the candidate sphere from the plurality of selected spheres;
• when an absolute cylinder of the notation is not equal to two times an absolute sphere of the notation, determining whether the notation describes a mixed astigmatism;
• and
• when the notation describes a mixed astigmatism, determining whether to include or exclude the candidate sphere;
• determine that an absolute cylinder of the notation is equal to two times an absolute sphere of the notation;
• and
• perform a distribution procedure to distribute plus notations and minus notations of the plurality of selected spheres by:
• when a sphere of a previous iteration was from the minus notation, selecting the sphere of the plus notation, and if the sphere of the previous iteration was from the plus notation, selecting the sphere of the minus notation;
• or
• randomly selecting the sphere of either the plus notation or the minus notation as the selected sphere;
• calculate the ophthalmic nomogram from the plurality of selected spheres by:
• performing the following for each selected sphere of the nomogram
• data set:
• determining a post-operation correction corresponding to a selected sphere;
• and
• identifying the target sphere of the target correction associated with the post-operation correction;
• creating a graph of the post-operation spheres versus the target spheres by:
• performing a regression analysis of the post-operation spheres versus the target spheres in order to determine a line that describes a relationship between the post-operation spheres and the target spheres;
• and
• performing a first regression analysis for a first diopter range of the post-operation spheres versus the target spheres to determine a first line that describes a relationship between the post-operation spheres and the target spheres in the first diopter range, and performing a second regression analysis for a second diopter range of the post-operation spheres versus the target spheres to determine a second line that describes a relationship between the post-operation spheres and the target spheres in the second diopter range;
• and
• identifying a subset of the plurality of selected spheres corresponding to a class of patients, and calculating the ophthalmic nomogram from the subset of the plurality of selected spheres;
• and
• plan a treatment for the eye according to the ophthalmic nomogram;
• and a laser device configured to perform the treatment for the eye.