Intraocular Pressure Measurement Accuracy and Repeatability of a Modified Goldmann Prism: Multicenter Randomized Clinical Trial

McCafferty, Sean; Tetrault, Kyle; McColgin, Ann Z; Chue, Warren; Levine, Jason; Müller, Melissa

doi:10.1016/j.ajo.2018.08.051

Cited by 12 publications

(40 citation statements)

References 19 publications

(35 reference statements)

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“…23,24 The modified CATS prism surface equalizes this pressure distribution across the applanation surface and demonstrates a significantly decreased sensitivity to alterations in the major sources of corneal biomechanical error. 22,[25][26][27][28][29] Decreased non-responder rates were also demonstrated with a modified Goldmann (CATS) prism in patients using the PGA latanoprost and not with timolol use. Part of the latanoprost non-response may be latanoprost induced alterations in corneal biomechanics which dampen the actual IOP reduction measured with a standard GAT prism.…”

Section: Discussionmentioning

confidence: 95%

“…16,18,19,23,24 CATS tonometer prism IOP measurements have been shown substantially equivalent to flat surfaced GAT prism IOP measurements in patients without disease such as glaucoma and having nominal CCTs between 500 and 600 microns. 26,27 Initial differential CATS minus GAT IOP measurements indicated an average of 1.95 ± 2.23 mm Hg higher IOP with the CATS prism compared to the GAT prism. Additionally, 22% of the patients would be reclassified as primary open-angle glaucoma from normal tension glaucoma based upon the higher IOP measurement with the CATS prism.…”

Section: Discussionmentioning

confidence: 98%

“…Pressure measurements spaced by 5 minutes were made two (2) times with each a CATS and GAT prism (consisting of averaged measurements at 180 and 90 degrees to correct for astigmatism). 26 Measurements were completed before treatment and at 1, 3, and 6 months following the institution of topical medication.…”

Section: Protocolmentioning

confidence: 99%

“…(Figure 1) Several studies, including intracameral pressure comparisons, have shown the CATS prism to have significantly decreased sensitivity to variations in corneal biomechanical properties when compared to the GAT prism. 22,[25][26][27][28][29] The design differences were described in detail previously. 22 Differences in IOP between the CATS and GAT measurements were strongly correlated with variations in corneal biomechanical properties such as CCT and CH.…”

Section: Introductionmentioning

confidence: 99%

“…22,[25][26][27][28][29] Since both prisms measure the same pressure for a cornea with nominal biomechanical properties, it is likely that the difference in CATS and GAT IOP is a direct measurement (in mm Hg) of those combined corneal biomechanical properties affecting its deformation. 25,26 The present study was completed to evaluate the effect of PGAs on IOP measurement accuracy and measure changes in corneal biomechanical properties. In addition, the study participants were equally randomized to timolol maleate treatment to delineate the effects of lowering IOP on the corneal biomechanics and IOP differences.…”

Section: Introductionmentioning

confidence: 99%

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<p>Improved Efficacy of Topical Latanoprost 0.005% Demonstrated by Corneal Biomechanical Correcting Modified Goldmann Prism</p>

Radcliffe¹,

Berdahl²,

Ibach³

et al. 2020

OPTH

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To evaluate intraocular pressure (IOP) reduction measured by a Goldmann applanation tonometer (GAT) prism and a modified surface Goldmann (CATS) prism with the institution of a topical prostaglandin analog (PGA) or alternatively a topical beta blocker. Design: Prospective, open-label, randomized, controlled, and reference device comparison. Methods: Thirty-six (36) treatment naïve glaucoma patients (72 eyes) were randomized equally to treatment with latanoprost 0.005% or timolol maleate 0.5%. Each patient underwent IOP measurement with standard GAT and CATS prisms before and at 1, 3, and 6 months of treatment. Central corneal thickness (CCT) and corneal hysteresis (CH) were also measured. Medication response was defined as a 20% reduction in IOP from baseline. Results: The CATS prism demonstrated the IOP reduction with topical latanoprost at a mean of 1.9 mmHg lower than the IOP measured with GAT (p=0.01). The CATS and GAT prisms detected no difference in IOP reduction with timolol (p=0.23). The number of latanoprost treatment nonresponders was reduced from 36.1% measured with GAT to 13.8% when measured with the CATS prism (p=0.005). Timolol indicated no difference in the treatment non-response rate at 22.2% (p=0.999). CH increased significantly with latanoprost treatment by an average of 0.55 mmHg (p=0.014) and remained unchanged with timolol at −0.014 mmHg (p=0.68). Discussion: IOP reduction and responder rates were increased when measured with a CATS prism in patients using latanoprost and not with timolol use. Latanoprost-induced alterations in corneal biomechanics may dampen the actual IOP reduction measured with a standard GAT prism. Clinical Trial Registration: ClinicalTrials.gov NCT04178863.

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Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 98%

Section: Protocolmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

<p>Improved Efficacy of Topical Latanoprost 0.005% Demonstrated by Corneal Biomechanical Correcting Modified Goldmann Prism</p>

Radcliffe¹,

Berdahl²,

Ibach³

et al. 2020

OPTH

Self Cite

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New applanation tonometer for myopic patients after laser refractive surgery

Iglesias

Yebra

Kudsieh

et al. 2020

Sci Rep

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this study assesses the agreement between intraocular pressure (iop) measurements taken with the Goldmann applanation tonometer (GAt) and a new experimental applanation tonometer with a convexly shaped apex (CT) after laser myopic refractive surgery. Two different CT radii (CT1 and CT2) were designed with a finite element analyser, and a prospective double masked study on 102 eyes from 102 patients was carried out. A Bland-Altman plot and intra-class correlation coefficient (ICC) were calculated to assess the agreement between GAT measurements and the measurements of both CT1 and CT2 before and after myopic laser assisted in situ keratomileusis (LASiK; n = 73) and photorefractive keratectomy (pRK; n = 29). We evaluated a subset of two subgroups (n = 36 each) for intra and interobserver (iA/ie) error. from the whole cohort, the best iop agreement was observed between GAtpre and CT1post surgery: 16.09 ± 2.92 vs 16.42 ± 2.87 (p < 0.001); ICC = 0.675 (95% CI: 0.554-0.768). In the analysis of LASiK vs PRK, GATpre and CT1post showed the highest agreement, although LASIK measurements were more accurate than pRK, as the icc = 0.718 (95% CI: 0.594-0.812) and ICC = 0.578 (95% CI: 0.182-0.795) respectively. Excellent agreement was observed for IA/IE, and there was an icc > 0.8 (95% CI) in all cases. CT1 proved more accurate in the LASIK subgroup. In conclusion, our new version of GAt could be used with post-surgery LASiK patients as a more accurate measurement device compared to the current reference tonometer. The Goldmann applanation tonometer (GAT; Haag-Streit, Switzerland) is the current reference tonometer for measuring intraocular pressure (IOP) in daily clinical practice due to its acceptably accurate measurements, reproducibility and reliability 1-4. However, GAT readings are influenced by corneal central thickness (CCT) and corneal biomechanics (CB), which vary widely among normal individuals 1,5,6. In myopic laser refractive surgery (LRS) patients, variations induced in both CCT and CB lead to differences in GAT readings. This change in IOP has been inconsistent in previous studies regardless of the type of surgery: Mardelli et al. 7 found a significant reduction of 1 ± 2.8 mmHg in IOP measurements after ablating 23 μm in photorefractive keratectomy (PRK) patients; while Duch et al. 8 found an underestimation of about 2.9 mmHg per 70 μm ablation in CCT after laser assisted in situ keratomileusis (LASIK). These IOP underestimations affect the reliability of GAT as gold standard after LASIK and PRK procedures 9-11. LASIK is one of the most frequent types of eye surgery and a total of 40 million people had this operation worldwide between 1991 and 2016 12. Moreover, the prevalence of glaucoma is 2 to 4 times higher among the myopic population 13. Thus, it is very important to obtain an accurate and real estimation of IOP in order not to miss ocular hypertension after myopic LRS. The aim of our study is to describe a new modified GAT as well as its translational application and clinical outcomes by evaluating IOP meas...

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Corneal Crosslinking Biomechanics Evaluated by a Novel and Easily Implemented Differential Tonometry Method

Wang

Berdahl

McCafferty

2021

Current Eye Research

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Purpose: Evaluate potential corneal biomechanical changes following corneal crosslinking (CXL) by paired differential tonometry intraocular pressure (IOP) measurements with a Goldmann tonometer (GAT) prism and corneal compensating, correcting applanation tonometry surface (CATS) prism. Methods: IOP was measured prospectively on 23 unique eyes undergoing CXL for keratoconus with a GAT using a standard flat GAT prism and a curved corneal error correcting CATS prism before treatment and at 2 weeks, 2 months and 6 months after treatment. Concurrent measurements of central corneal thickness (CCT) and corneal hysteresis (CH) were completed. Results: Paired IOP measurements with standard GAT and corneal correcting CATS prisms indicated a significant sustained relative increase in the differential IOP between the two prisms after CXL (p = .002,0.051,0.062). CH initially decreased at two weeks post-CXL then returned to sustained pre-op levels (p = .033,0.20,0.20). CCT progressively decreased following CXL (p = .005). Discussion: Differential tonometry between standard GAT and corneal biomechanical compensating CATS prisms indicates findings consistent with increased corneal rigidity following CXL and may demonstrate a simple and sensitive method for measurement of relative corneal biomechanical changes due to pharmacologic agents and procedures.

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Intraocular Pressure Measurement Accuracy and Repeatability of a Modified Goldmann Prism: Multicenter Randomized Clinical Trial

Abstract: A modified surface replacement prism is statistically equivalent to a flat-surfaced prism. The modified surface prism indicated statistically significant correction for CCT requiring further testing outside the ANSI standard limits (0.500 mm < CCT < 0.600 mm) to examine its full potential.

Cited by 12 publications

References 19 publications

<p>Improved Efficacy of Topical Latanoprost 0.005% Demonstrated by Corneal Biomechanical Correcting Modified Goldmann Prism</p>

<p>Improved Efficacy of Topical Latanoprost 0.005% Demonstrated by Corneal Biomechanical Correcting Modified Goldmann Prism</p>

New applanation tonometer for myopic patients after laser refractive surgery

Corneal Crosslinking Biomechanics Evaluated by a Novel and Easily Implemented Differential Tonometry Method

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