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Abstract #24391 Published in IGR 11-3
Comparison of dynamic contour tonometry and Goldmann applanation tonometry and their relationship to corneal properties, refractive error, and ocular pulse amplitude
Erickson DH; Goodwin D; Rollins M; Belaustegui A; Anderson COptometry 2009; 80: 169-174
BACKGROUND: Accurate intraocular pressure (IOP) measurement is essential in diagnosing and managing glaucoma. Dynamic contour tonometry (DCT) is less dependent on corneal properties, such as thickness, elasticity, and rigidity, than Goldmann applanation tonometry (GAT). This study examined the relationship between GAT and DCT as well as their relationship with corneal properties and ocular pulse amplitude (OPA). METHODS: GAT, DCT, OPA, pachymetry, refractive error, and corneal curvature measurements were obtained on 115 healthy volunteers. RESULTS: Participants with thicker corneas (≥580 μm) had higher IOP measurements with GAT than DCT (P = 0.005). Those with thinner corneas (≤520 μm) had lower IOP with GAT versus DCT (P = 0.008). GAT and DCT readings did not differ significantly in corneas with average thickness (521 to 579 μm). A clinically significant IOP difference between DCT and GAT was found in 18.2% of subjects. A correlation was found between OPA and both refractive error and IOP (R2 = .343, P < 0.0001). OPA was higher with increased IOP and decreased myopia. CONCLUSION: DCT provides IOP measurements that are less dependent on corneal factors than GAT, aiding in diagnosis and treatment of patients with ocular hypertension and glaucoma. Additional studies are necessary to examine the relationship between OPA, refractive error, and IOP and its possible association with increased incidence of glaucoma in myopic patients.
Dr. D.H. Erickson, Pacific University College of Optometry, Forest Grove, OR, USA. derickson@pacificu.edu
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)
8.1 Myopia (Part of: 8 Refractive errors in relation to glaucoma)
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)