Goldmann and error correcting tonometry prisms compared to intracameral pressure
AffiliationUniv Arizona, Coll Opt Sci LLC, Coll Med, Dept Ophthalmol Intuor Technol
Univ Arizona, Coll Med, Dept Ophthalmol
Univ Arizona, Coll Optic Sci, Dept Ophthalmol
Univ Arizona, Coll Engn, Dept Aerosp & Mech
Central corneal thickness
Corneal resistance factor
MetadataShow full item record
PublisherBIOMED CENTRAL LTD
CitationGoldmann and error correcting tonometry prisms compared to intracameral pressure 2018, 18 (1) BMC Ophthalmology
Rights© The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License.
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AbstractBackground: Compare Goldmann applanation tonometer (GAT) prism and correcting applanation tonometry surface (CATS) prism to intracameral intraocular pressure (IOP), in vivo and in vitro. Methods: Pressure transducer intracameral IOP was measured on fifty-eight (58) eyes undergoing cataract surgery and the IOP was modulated manometrically to 10, 20, and 40 mmHg. Simultaneously, IOP was measured using a Perkins tonometer with a standard GAT prism and a CATS prism at each of the intracameral pressures. Statistical comparison was made between true intracameral pressures and the two prism measurements. Differences between the two prism measurements were correlated to central corneal thickness (CCT) and corneal resistance factor (CRF). Human cadaver eyes were used to assess measurement repeatability. Results: The CATS tonometer prism measured closer to true intracameral IOP than the GAT prism by 1.7+/-2.7 mmHg across all pressures and corneal properties. The difference in CATS and GAT measurements was greater in thin CCT corneas (2.7+/-1.9 mmHg) and low resistance (CRF) corneas (2.8+/-2.1 mmHg). The difference in prisms was negligible at high CCT and CRF values. No difference was seen in measurement repeatability between the two prisms. Conclusion: A CATS prism in Goldmann tonometer armatures significantly improve the accuracy of IOP measurement compared to true intracameral pressure across a physiologic range of IOP values. The CATS prism is significantly more accurate compared to the GAT prism in thin and less rigid corneas. The in vivo intracameral study validates mathematical models and clinical findings in IOP measurement between the GAT and CATS prisms.
VersionFinal published version
SponsorsNIH SBIR Grant [R43 EY026821-01]; Arizona Eye Consultants, Tucson, AZ; Abbott Medical Optics
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