Repeatability of ocular blood flow pneumotonometry

Bhan, A; Bhargava, J S; Vernon, S A; Armstrong, Sarah; Bhan, Kanchan; Tong, Louis; Sung, Velota

doi:10.1016/s0161-6420(03)00492-5

Cited by 14 publications

(9 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…*Oculab Tono-Pen; **Mentor Tono-Pen XL; ***Bio-Rad Tono-Pen XL; OBF tonograph (OBF Labs). ÀOverall value: tonometer overestimates GAT at low IOPs and underestimates at high IOPs.Overall value: tonometer underestimates GAT at low IOPs and overestimates at high IOPs.GAT/OBF comparisons On average, the OBF slightly underestimated IOP measurements by the GAT(table 1), in agreement with Yang et al8 In contrast, an overestimation by the OBF was reported by Bafa et al 9 and Bhan et al19 The 95% limits of agreement were similar to previous findings (table 4). The OBF underestimated GAT IOP by 2.6 mm Hg at 15 mm Hg and overestimated GAT IOP by 2.6 mm Hg at 25 mm Hg (table 3).…”

supporting

confidence: 88%

A comparison of four methods of tonometry: method agreement and interobserver variability

Tonnu

2005

British Journal of Ophthalmology

191

149

View full text Add to dashboard Cite

Aim: To compare the inter-method agreement in intraocular pressure (IOP) measurements made with four different tonometric methods. Methods: IOP was measured with the Goldmann applanation tonometer (GAT), Tono-Pen XL, ocular blood flow tonograph (OBF), and Canon TX-10 non-contact tonometer (NCT) in a randomised order in one eye of each of 105 patients with ocular hypertension or glaucoma. Three measurements were made with each method, and by each of two independent GAT observers. GAT interobserver and tonometer inter-method agreement was assessed by the Bland-Altman method. The outcome measures were 95% limits of agreement for IOP measurements between GAT observers and between tonometric methods, and 95% confidence intervals for intra-session repeated measurements. Results: The mean differences (bias) in IOP measurements were 0.4 mm Hg between GAT observers, and 0.6 mm Hg, 0.1 mm Hg, and 0.7 mm Hg between GAT and Tono-Pen, OBF, and NCT, respectively. The 95% limits of agreement were smallest (bias ¡2.6 mm Hg) between GAT observers, and larger for agreement between the GAT and the Tono-Pen, OBF, and NCT (bias ¡6.7, ¡5.5, and ¡4.8 mm Hg, respectively). The OBF and NCT significantly underestimated GAT measurements at lower IOP and overestimated these at higher IOP. The repeatability coefficients for intra-session repeated measurement for each method were ¡2.2 mm Hg and ¡2.5 mm Hg for the GAT, ¡4.3 mm Hg for the Tono-Pen, ¡3.7 mm Hg for the OBF, and ¡3.2 mm Hg for the NCT. Conclusions: There was good interobserver agreement with the GAT and moderate agreement between the NCT and GAT. The differences between the GAT and OBF and between the GAT and Tono-Pen probably preclude the OBF and Tono-Pen from routine clinical use as objective methods to measure IOP in normal adult eyes.

show abstract

supporting

confidence: 88%

A comparison of four methods of tonometry: method agreement and interobserver variability

Tonnu

2005

British Journal of Ophthalmology

191

149

View full text Add to dashboard Cite

show abstract

“…These values are not substantially different from those reported in other studies. In one of the earlier studies, the coefficients reported for the Goldmann tonometer were 5.2 mmHg (right eye) and 4.8 mmHg (left eye) (Phelps and Phelps, 1976) whereas slightly lower coefficients have been reported more recently (4.81 and 3.87 mmHg for the right and left eyes, respectively) (Bhan et al ., 2003). The variability observed reflects the variability of the measurement error.…”

Section: Discussionmentioning

confidence: 86%

Validity and limitations of the Nidek NT‐4000 non‐contact tonometer: a clinical study

Regine

Scuderi

Cesareo

et al. 2005

Ophthalmic Physiologic Optic

View full text Add to dashboard Cite

Using Goldmann applanation tonometry (GAT) as a gold standard, we evaluated the accuracy of Nidek NT-4000 pneumotonometry (NPT) in adults without corneal disease. Bland and Altman analysis of serial intra-ocular pressures (IOPs) measured with NPT and GAT in 10 healthy subjects revealed that the repeatability coefficients for the two methods were similar. NPT, GAT and ultrasonic pachymetry were then performed in 100 patients. Bland and Altman analysis showed that NPT yielded significantly higher readings than GAT [mean biases for right and left eye measurements were 1.37 mmHg (95% limits of agreement: -3.02-5.76) and 1.17 mmHg (95% limits of agreement: -2.76-5.11) respectively] and was more affected by corneal thickness variations. For detection of IOPs > or =21 mmHg, NPT displayed very high sensitivity (0.90) and good specificity (0.95). NPT may be useful in screening and clinical settings but borderline-high IOP readings should be confirmed with GAT.

show abstract

“…Henson and Harper 27 have proposed that an explanation for the discrepancy between the published clinical evaluations of NCTs and the observations noted in ophthalmic departments could be the way in which optometrists select cases for referral, combined with the variability inherent in the measurement of IOP. The instrument has been shown to provide reproducible measures; 29 however, a more recent study has questioned the value of the OBF pneumotonometer as a tool for measuring IOP, 30 and, contrary to expectations, based on the mechanism of measurement of IOP, corneal thickness appears to affect measures obtained with the OBF tonometer more than they affect Goldmann measures. 8.4).…”

Section: Regression Towards the Mean Effectmentioning

confidence: 98%