Method for determining the power of an intraocular lens used for the treatment of myopia

• US 6,626,538 B1
• Filed: 07/11/2001
• Issued: 09/30/2003
• Est. Priority Date: 07/12/2000
• Status: Expired due to Fees

• Current Assignee: Peter N. Arrowsmith
• Original Assignee: Peter N. Arrowsmith
• Inventors: Arrowsmith, Peter N.
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): SANDERS JR, JOHN R
• Application Number:
  US09/903,385
• Time in Patent Office: 811 Days
• Field of Search: 351/159, 351/177, 351/205, 351/216, 351/219, 351/246, 359/642, 600/398, 623/4, 623/6, 623/905
• US Class Current: 351/246
• CPC Class Codes: A61B 3/00 Apparatus for testing the eyes; Instruments for examining the eyes eye inspection using ultrasonic, sonic or infrasonic waves A61B8/10; devices for treatment of the eyes A61F9/00; exercisers for the eyes A61H5/00; optical systems in general G02B
• CPC Class Codes: A61B 3/0025 characterised by electronic signal processing, e.g. eye models
• CPC Class Codes: A61F 2/16 Intraocular lenses
• CPC Class Codes: Y10S 623/905 Eye

Abstract

A method of deriving a prediction model and calculating a predicted lens power to provide a desired post-operative spherical equivalent to correct myopia in a phakic eye of a patient using an intraocular lens includes measuring and determining the predictive significance of certain pre-operative characteristics of the eye, including cycloplegic and manifest spherical equivalent, vertex distance, anterior chamber depth, and keratometry. The prediction model is derived using multiple regression analysis on the pre-operative and post operative data. Measured data corresponding to a particular patient is used in the lens power prediction model to calculate the predicted lens power for implantation in the patient.

Claims

1. A method of designing an intraocular lens for surgical implantation in a phakic eye of a myopic patient wherein the design of the intraocular lens includes selecting a lens power to provide a predicted post-operative refraction in the eye of the patient, the method comprising the steps of:

a. using a first lens power prediction model to make a prediction of lens powers for a plurality of test lenses having a common lens configuration using a first set of pre-operative measurements for each of a corresponding number of myopic test patient eyes, the first set of pre-operative measurements selected from a group of patient factors that includes pre-operative refraction, anterior chamber depth, and vertex distance;

b. selecting test lenses having the predicted lens powers needed to provide the predicted post-operative refraction in the corresponding test patient eyes;

c. surgically implanting the test lenses in the corresponding test patient eyes;

d. obtaining post-operative measurements of the actual post-operative refraction achieved in each of the test patient eyes;

e. performing a multiple regression analysis of the actual post-operative measurements as compared to the corresponding first set of pre-operative measurements to identify and quantify which of the patient factors has a statistically significant effect on accuracy of the first predicted post-operative refraction as compared to the actual post-operative refraction;

f. using the identification and quantification of statistical significance determined by the multiple regression analysis to modify the first prediction model to create a second lens power prediction model using the identified patient factors;

g. obtaining from the patient the pre-operative measurements of the patient factors as identified and used in the second lens power prediction model; and

h. using the second lens power prediction model and pre-operative measurements obtained from the patient to select the lens power for the intraocular lens to be implanted in the patient.

2. A method of calculating a predicted lens power needed to provide a post-operative spherical equivalent to correct myopia in a phakic eye of a patient using an intraocular lens, the method comprising the steps of:

a. measuring pre-operative and post-operative characteristics of the eye, including spherical equivalent, vertex distance, anterior chamber depth, keratometry;

desired post-operative spherical equivalent, and first eye residual intraocular lens power; and

b. using each of the measured pre-operative characteristics and desired post-operative characteristics in a lens power prediction model to calculate the predicted lens power; and

c. wherein the lens power prediction model is a mathematical formula using the measured pre-operative and desired post-operative characteristics of the eye and corresponding coefficients substantially as follows