The New Shape of IOP. A New, Modern, Patented Prism Designed for Your Goldmann Tonometer.
CATS® Tonometer Prism* features a unique, patented, dual-curved surface design that successfully reduces measurement errors caused by corneal biomechanics, corneal thickness, and tear film, which affect a large percentage of patients.1-4 Simply replace your traditional Goldmann prism with a new CATS Tonometer Prism to instantly overcome these error-causing factors.2-4
Why is CATS Tonometer Prism essential for your practice? It is widely accepted that for eyes with average corneas, Goldmann tonometry provides reliable IOP measurements. However, we now know that corneal properties such as Central Corneal Thickness (CCT), Corneal Hysteresis (CH), and tear film vary significantly from average in a large percentage of patients. These variations in corneal properties result in a clinically relevant negative impact on Goldmann Tonometer accuracy. The use of CCT-based IOP correction formulas, to determine individual IOP values, is neither valid nor useful, and as such not helpful in improving Goldmann accuracy or glaucoma decision making.5-6
Modernize your Goldmann tonometer today with CATS Tonometer Prism.2-4
CATS Tonometer Prism is made in the USA.
*This product is one reusable Goldmann prism.
The New Shape of IOP.
CATS Tonometer Prism features a unique, patented, dual-curved surface design that successfully reduces measurement errors caused by corneal biomechanics, corneal thickness, and tear film, which affect a large percentage of patients.1 Traditional Goldmann tonometer prisms "flatten" the cornea, which amplifies intracorneal stress during the measurement process. The curvature-matching design of CATS Tonometer Prism "cups" the cornea, reducing the impact of corneal thickness and corneal biomechanics on IOP measurements.2-4 In addition, CATS Tonometer Prism has a rolled outer edge which minimizes the tear film adhesion that plagues traditional Goldmann prisms.2-4 Simply replace your traditional Goldmann prism with a new CATS Tonometer Prism and instantly realize the benefits of the CATS design.
Designed to give you confidence in your Goldmann IOP readings.
In patients with average corneas, CATS Tonometer Prism will match traditional Goldmann prism IOP results closely because CATS Tonometer Prism was intentionally designed to measure the same as GAT in patients with average biomechanics and central corneal thickness. As patients' corneal properties deviate from average, the CATS prism will measure IOP more accurately.2-4,7,8 The clinician may note substantial differences between CATS Tonometer Prism and traditional Goldmann IOP results for patients with atypical corneal properties. These differences are due to the ability of the CATS Tonometer Prism to "ignore" corneal factors that affect the traditional Goldmann measurement. CATS Tonometer Prism and traditional Goldmann prism produce similar measurements for normal corneas which ensures long standing IOP benchmarks of normal ad high pressures are maintained, allowing clinicians to seamlessly integrate CATS IOP readings in comparison to their historic GAT IOP readings.2-4,7,8
Easily Integrate Into Any Practice.
CATS Tonometer Prism can be easily mounted on any Goldmann or Perkins tonometer. Simply replace your traditional Goldmann prism with the new CATS Tonometer Prism to immediately realize improved IOP measurements using the same technique you are already familiar with.2-4,7,8
Positioning that Self-Centers.
The flat surface of a traditional Goldmann prism tip permits IOP error resulting from sub-optimal positioning, because it is subjectively placed on the cornea. Due to the curvature-matching surface, CATS Tonometer Prism self-centers on the cornea, providing clearer and sharper mires when positioned on the apex of the cornea. Improper placement of CATS Tonometer Prism on the cornea results in obviously skewed mires which will not intersect for measurement. This immediately prompts the clinician to reposition the tip to obtain perfectly centered mires on the corneal apex, which ensures optimal accuracy and repeatability of IOP measured by CATS Tonometer Prism.
1 - McCafferty S, Lim G, Duncan W, et al. Goldmann tonometer prism with an optimized error correcting applanation surface. Transl Vis Sci Technol 2016; 5:4–5.
2 - McCafferty S, Tetrault K, McColgin A, Chue W, Levine J, Muller M. Modified Goldmann prism intraocular pressure measurement accuracy and correlation to corneal biomechanical metrics: multicentre randomised clinical trial. Br J Ophthalmol. 2019 Dec;103(12):1840-1844. doi: 10.1136/bjophthalmol-2018-313470.
3 - McCafferty S, Lim G, Duncan W, et al. Goldmann tonometer error correcting prism: clinical evaluation. Clin Ophthalmol 2017;11:835–40.
4 - McCafferty S, Enikov E, Schwiegerling J, et al. Goldmann tonometry tear-film error and partial correction with a shaped applanation surface. Clin Ophthal 2018;12:71–8.
5 - Pg 18. Robert N. Weinreb, James D. Brandt, David Garway-Heath and Felipe Medeiros, World Glaucoma Association on Intraocular Pressure; Consensus Series 4; May 5, 2007
6 - Brant JD, Gordon MO, Gao F, Beiser, JA, Miller JP, Kass MA. Ocular Hypertension Treatment Study Group, Adjusting intraocular pressure for central corneal thickness does not improve prediction models for primary open-angle glaucoma. Ophthalmology. 2012 Mar; 119(3): 437-42. doi: 10.1016/j.ophtha.2011.03.018.