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Abstract #46921 Published in IGR 13-3
Comparison of Goldmann and Pascal tonometry in relation to corneal hysteresis and central corneal thickness in nonglaucomatous eyes
Mangouritsas G; Mourtzoukos S; Mantzounis A; Alexopoulos LClinical Ophthalmology 2011; 5: 1071-1077
Objective: To compare measurements obtained by Goldmann applanation tonometry (GAT) and Pascal dynamic contour tonometry (DCT), and to study their relationship to corneal thickness and biomechanical properties in nonglaucomatous eyes. Methods: This is a prospective and randomized study of 200 eyes from 200 non-glaucomatous subjects who underwent intraocular pressure (IOP) measurements by GAT and DCT. The two methods were compared and assessed for agreement by means of the Bland-Altman plot. Central corneal thickness (CCT) and corneal hysteresis (CH) were obtained by ultrasound pachymeter and Ocular Response Analyzer, respectively. The effect of CH and CCT was correlated with the DCT/GAT IOP differences. Results: Mean age was 57.4 (plus or minus) 14.7 years (range 24-82 years). Mean IOP measurements obtained were 16.7 (plus or minus) 3.2 mmHg by GAT and 19.4 (plus or minus) 3.3 mmHg by DCT. DCT showed a statistically significant higher mean IOP (2.7 (plus or minus) 1.9 mmHg, P< 0.001) compared with GAT. Mean CCT and CH were 546.5 (plus or minus) 40 (mu)m and 10.85 (plus or minus) 2.0 mmHg, respectively. The differences in IOP (DCT - GAT) were significantly correlated with CCT and CH (Pearson's correlation coefficient r = -0.517 and -0.355, P< 0.0001, respectively). The difference between the two correlation coefficients was statistically significant (P< 0.05, Z-statistic). According to the Bland-Altman plot, the results of the two methods were clinically different. Conclusion: Significantly higher IOP readings were obtained by DCT than by GAT in nonglaucomatous subjects. The IOP differences between the two methods were associated with CCT and CH, suggesting that DCT was less dependent on corneal parameters. Each method provides clinically different IOP values, indicating that DCT and GAT should not be used interchangeably.
G. Mangouritsas. Glaucoma Department, Eye Clinic, 'Hellenic Red Cross' General Hospital, Athens, Greece.
Classification:
6.1.1 Devices, techniques (Part of: 6 Clinical examination methods > 6.1 Intraocular pressure measurement; factors affecting IOP)
2.2 Cornea (Part of: 2 Anatomical structures in glaucoma)
