Purpose: We evaluate solutions for an applanating surface modification to the Goldmann tonometer prism, which substantially negates the errors due to patient variability in biomechanics. Methods: A modified Goldmann or correcting applanation tonometry surface (CATS) prism is presented which was optimized to minimize the intraocular pressure (lOP) error due to corneal thickness, stiffness, curvature, and tear film. Mathematical modeling with finite element analysis (FEA) and manometric lOP referenced cadaver eyes were used to optimize and validate the design. Results: Mathematical modeling of the optimized CATS prism indicates an approximate 50% reduction in each of the corneal biomechanical and tear film errors. Manometric lOP referenced pressure in cadaveric eyes demonstrates substantial equivalence to GAT in nominal eyes with the CATS prism as predicted by modeling theory. Conclusion: A CATS modified Goldmann prism is theoretically able to significantly improve the accuracy of lOP measurement without changing Goldmann measurement technique or interpretation. Clinical validation is needed but the analysis indicates a reduction in CCT error alone to less than +/- 2 mm Hg using the CATS prism in 100% of a standard population compared to only 54% less than +/- 2 mm Hg error with the present Goldmann prism. Translational Relevance: This article presents an easily adopted novel approach and critical design parameters to improve the accuracy of a Goldmann applanating tonometer.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/622594 |
| Date | 09 September 2016 |
| Creators | McCafferty, Sean, Lim, Garrett, Duncan, William, Enikov, Eniko, Schwiegerling, Jim |
| Contributors | Univ Arizona, Dept Ophthalmol, Univ Arizona, Coll Opt Sci, Univ Arizona, Coll Engn, Dept Mech & Aerosp, Intuor Technolgies, Tucson, AZ, USA 2University of Arizona Department of Ophthalmology, Tucson, AZ, USA 3University of Arizona College of Optical Science, Tucson, AZ, USA, Intuor Technolgies, Tucson, AZ, USA, Intuor Technolgies, Tucson, AZ, USA 3University of Arizona College of Optical Science, Tucson, AZ, USA, University of Arizona College of Engineering - Department of Mechanical and Aerospace, Tucson, AZ, USA, University of Arizona Department of Ophthalmology, Tucson, AZ, USA 3University of Arizona College of Optical Science, Tucson, AZ, USA |
| Publisher | ASSOC RESEARCH VISION OPHTHALMOLOGY INC |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. |
| Relation | http://tvst.arvojournals.org/article.aspx?doi=10.1167/tvst.5.5.4 |
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