Nomogram-Based Sphere Correction for Laser Vision Refractive Errors
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Solution Overview
Problem
Current laser vision correction systems, such as the Zyoptix® system, often result in overcorrection of refractive errors due to the use of preprogrammed instructions that do not account for individual variations in higher-order aberrations, leading to suboptimal postoperative outcomes, with a significant percentage of patients requiring re-treatment and experiencing residual refractive errors.
Innovation Solution
A nomogram-based system that calculates the amount of sphere correction using preoperative manifest refraction and higher-order aberrations data, specifically accounting for interactions between lower- and higher-order aberrations to refine the laser ablation process, reducing spherical overcorrection and improving postoperative refractive outcomes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If preprogrammed instructions are used for laser ablation, then the surgical process is simplified and faster, but manufacturing precision deteriorates due to overcorrection of refractive errors
Solution Approach 1:
The patent modifies the preprogrammed instruction parameters by introducing nomogram-based calculations that adjust the amount of sphere correction based on preoperative manifest refraction and higher-order aberrations data. This changes the ablation parameters dynamically rather than using fixed preprogrammed values, resolving the contradiction by maintaining surgical efficiency while improving correction accuracy through personalized parameter adjustment
Solution Approach 2:
The patent performs preliminary calculations using nomograms before the actual laser ablation to determine the precise amount of sphere correction needed. This preliminary action accounts for individual variations in higher-order aberrations and their interactions with lower-order aberrations, allowing the surgical process to proceed efficiently with pre-calculated accurate parameters that prevent overcorrection
2Device complexity
If preprogrammed instructions are used for laser ablation, then device complexity is reduced, but measurement precision deteriorates in predicting postoperative refractive error
Solution Approach 1:
The patent introduces nomograms as an intermediary computational tool between the preprogrammed instruction system and the actual laser ablation process. These nomograms serve as a mediator that translates preoperative data (manifest refraction and higher-order aberrations) into corrected ablation parameters, thereby improving prediction accuracy without significantly increasing the complexity of the laser system itself
Solution Approach 2:
The patent replaces the mechanical reliance on fixed preprogrammed instructions with a computational approach using nomogram-based calculations. This substitution introduces mathematical models that account for higher-order aberration interactions, improving measurement precision while keeping the physical laser system relatively simple
3Ease of operation
If individual variations in higher-order aberrations are not accounted for, then ease of operation is maintained, but reliability deteriorates with significant percentage of patients requiring re-treatment
Solution Approach 1:
The patent performs preliminary nomogram-based calculations before surgery to account for individual variations in higher-order aberrations. This preliminary action ensures that each patient's unique optical characteristics are considered in advance, improving reliability by preventing overcorrection while maintaining ease of operation during the actual surgical procedure
Solution Approach 2:
The patent incorporates feedback mechanisms by using preoperative manifest refraction and higher-order aberrations data to adjust the ablation plan. This feedback loop allows the system to learn from individual patient characteristics and optimize treatment parameters accordingly, improving reliability without significantly complicating the surgical workflow
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed system achieves a higher percentage of patients with uncorrected visual acuity of 20/20 or better, minimizing the need for re-treatment and reducing the range of postoperative refractive errors to within ±1 diopter, thereby enhancing the precision and effectiveness of customized LASIK procedures.
Implementation Method 1
a programmed series of ablating laser pulses are directed onto a patient's eye to reshape the cornea
Data Source
AI summary
Disclosed is a computer-implemented method for correcting refractive errors in a living eye using a laser vision correction system that involves first calculating an amount of sphere based on preoperative manifest refraction and higher order aberrations data associated with the eye, and then correcting for the calculated amount of sphere by ablating at least a portion of the eye. The preoperative manifest refraction may include preoperative manifest sphere, preoperative spherical equivalent, regular astigmatism, and oblique astigmatism, and the preoperative higher-order aberrations may include 4th-order spherical and 3rd root mean square. Other factors may also be used to adjust the calculated amount of sphere. A device readable medium for storing the calculation and instructions for operating a laser vision correction system for practicing the method is also disclosed, as is a method of treating refractive errors.