Abstract A process for comparing sets of corneal measurements is disclosed. On a first occasion a photographic record of the cornea is made with a photoelectronic keratoscope. Using this photographic record, the dimensions of a desired corneal meridian are established. It has been discovered that a single parameter can be calculated from these dimensions which defines a reference curve to which the dimensions can be compared and a record of the comparison produced. The results of this comparison and this parameter are recorded or stored for later retrieval. At a subsequent occasion, a second photographic record of the eye is made. The parameter derived from the earlier reading is then recalled, the reference curve reconstructed, and the dimensions derived from the second record compared to the original reference curve. A comparison of the differences between each set of dimensions and the common reference curve is then available and indicates what changes have taken place in the shape of the cornea.
Inventors
👤 Malcolm G Townsley
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-05 13:09
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/107
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
106 words
A Method for ascertaining changes in corneal dimensions, comprising the steps of: a. measuring a corneal meridian at a first point in time to obtain a first set of data defining said corneal meridian; b. generating a reference curve from said first set of data; c. tabulating the differences between said first set of data and said reference curve; d. storing said tabulated differences and said reference curve; e. measuring the corneal meridian at a subsequent point in time to obtain a second set of data; f. regenerating said reference curve; and g. tabulating the differences between said reference curve and said second set of data.
Claim 2
Independent Claim
106 words
A Method for ascertaining changes in corneal dimensions, comprising the steps of: a. measuring a corneal meridian at a first point in time to obtain a first set of data defining said corneal meridian; b. generating a reference curve from said first set of data; c. tabulating the differences between said first set of data and said reference curve; d. storing said tabulated differences and said reference curve; e. measuring the corneal meridian at a subsequent point in time to obtain a second set of data; f. regenerating said reference curve; and g. tabulating the differences between said reference curve and said second set of data.
Claim 3
Dependent Claim
45 words
A method as in claim 1, wherein said reference curve is generated by deriving the vertex power of said corneal meridian or a parameter related to said vertex power from said first set of data and using said vertex power to derive said reference curve.
Claim 4
Dependent Claim
26 words
A method as in claim 2, wherein said reference curve is determined by said parameter and the mean eccentricity of a large population of corneal meridians.
Claim 5
Dependent Claim
17 words
A process as in claim 3, wherein said reference curve is stored by storing said vertex power.
Claim 6
Dependent Claim
73 words
A method for ascertaining changes in corneal dimensions as in claim 4, wherein said reference curve is defined by the equation: x2 - 2px + y2/Q 0 where x is the sagittal coordinate in millimeters, y is the semi-chord coordinate in millimeters, Q is greater than 0.50 and less than 1, and p is calculated from the equation: p ((64.9038/VcQ)) Square Root 26.042 + Q where Vc is the vertex power in diopters.