Dynamic contour tonometry may be effective in glaucoma diagnosis

A novel biometrical parameter detected significant differences in ocular pulse amplitude in eyes with ocular hypertension vs. healthy eyes, according to researchers in Switzerland.

Timo Romppainen, MD, of Universitätsspital Zürich, and colleagues investigated the extent to which dynamic contour tonometry (DCT) could differentiate between different glaucoma types. The investigators used DCT to take transcorneal measurements of IOP and ocular pulse amplitude in 441 eyes of 222 patients. They found that ocular pulse amplitude averaged 3.1 mm Hg overall.

However, eyes with ocular hypertension had a significantly higher mean ocular pulse amplitude compared with healthy eyes and eyes with low-tension glaucoma. Ocular pulse amplitude averaged 3.6 mm Hg in eyes with ocular hypertension compared with 3.1 mm Hg in healthy eyes and 2.9 mm Hg in eyes with low-tension glaucoma, according to the study.

After trabeculectomy, mean ocular pulse amplitude dropped to 2.4 mm Hg, which was significantly lower than the ocular pulse amplitude in healthy eyes, the authors noted.

"The size of the [ocular pulse amplitude] seems to be characteristic for different types of glaucoma and directly dependent on intraocular pressure levels. Further investigation is indicated to clarify its diagnostic usefulness," the authors said.

The study is published in the March issue of Der Ophthalmologe.