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Abstract #14819 Published in IGR 8-4
Intraocular pressure and corneal thickness. A comparison between non-contact tonometry and applanation tonometry
Domke N; Hager A; Wiegand WOphthalmologe 2006; 103: 583-587
OBJECTIVE: Corneal thickness and deformation seem to have a considerable influence on intraocular pressure measurement. Due to differences in the corneal deformation in either non-contact tonometry or applanation tonometry, both methods should be compared in the same patient group depending on central corneal thickness. METHODS: In 106 eyes of 55 patients (18 males, 37 females, age 17-89 years, mean 63.3 years) with glaucoma and central corneal thickness between 409 and 644 μm (Orbscan II pachymetry) intraocular pressure was measured in each eye with non-contact tonometry (Reichert AT550) and 30 min later with Goldman applanation tonometry. RESULT: Non-contact tonometry as well as applanation tonometry showed a positive correlation between measured intraocular pressure and corneal thickness. The steepness of the line of regression was 0.33 mmHg per 10 μm of corneal thickness in non-contact tonometry and 0.17 mmHg per 10 μm of corneal thickness in applanation tonometry. CONCLUSION: Independently of the large differences in individual pressure measurements between non-contact tonometry and applanation tonometry, we found higher IOP values with non-contact tonometry in thicker corneas as compared with applanation tonometry. In thinner corneas there was a better correspondence between both methods. Thus, it seems very likely that corneal rigidity increases with corneal thickness. LA: German
Dr. N. Domke, Abteilung fur Augenheilkunde, Klinikum Nord-Heidberg, Tangstedter Landstrasse 400, 22417 Hamburg, Germany
Classification:
6.1 Intraocular pressure measurement; factors affecting IOP (Part of: 6 Clinical examination methods)
2.2 Cornea (Part of: 2 Anatomical structures in glaucoma)
