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Finite element simulation of Goldmann tonometry after refractive surgery
Magdalena Asejczyk-Widlicka1, Wieslaw Srodka2
1Department of Optics & Photonics, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
Clinical Biomechanics (Bristol, Avon)
|November 3, 2019
Summary
Accurate intraocular pressure (IOP) measurement after refractive surgery remains a challenge. A new correction formula for Goldmann Applanation Tonometry (GAT) improves IOP readings by accounting for corneal changes, enhancing patient care.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Computational Modeling
Background:
- Accurate intraocular pressure (IOP) measurement after refractive surgery is critical but unresolved.
- Goldmann Applanation Tonometry (GAT) accuracy is affected by post-surgical corneal changes.
- A validated correction formula for GAT is needed.
Purpose of the Study:
- To evaluate the accuracy of a correction formula for Goldmann Applanation Tonometry (GAT) readings after refractive surgery.
- To assess GAT accuracy considering altered corneal curvature and thickness.
- To provide a reliable method for IOP measurement in post-refractive surgery patients.
Main Methods:
- Numerical simulation of refractive surgery and GAT.
- Finite element analysis incorporating corneal shell buckling.
- Simulation of GAT across various ablation depths and IOP levels.
Main Results:
- A strong correlation between GAT readings and IOP was observed, especially above 16 mmHg.
- The proposed correction formula demonstrated low estimation errors: <1 mmHg at 32 mmHg IOP and <3 mmHg at 48 mmHg IOP.
- The simulation accounted for nonlinearities in GAT measurements due to corneal geometry changes.
Conclusions:
- The developed correction formula for GAT is effective for post-refractive surgery eyes.
- The formula maintains accuracy irrespective of IOP levels and ablation depth.
- This method enhances the reliability of IOP measurements in a challenging clinical scenario.
