Visual Evoked Potentials of Blue-Sensitive Pathway after Cold-water Provocation and Ocular Cold Pressor Test in Glaucoma Low-Tension glaucoma
Schnitzler E., Michelson G., Horn F., Harazny J., Korth M., Jünemann A.
Augenklinik mit Poliklinik der Universität Erlangen-Nürnberg, Erlangen
Purpose: Measurement of the perfusion is a tool to show vascular dysregulation in open-angle glaucoma (POAG) [Gasser 1989]. The aim of our study was to investigate changes of the blue-yellow VEP due to cold-water provocation.
Method: 25 patients with ocular hypertension (OHT), 24 patients with preperimetric open-angle glaucoma, 24 patients with open-angle glaucoma, 25 patients with low-tension glaucoma (LTG) and 22 controls underwent a VEP using a blue on yellow stripe pattern[Horn et al.2002]. VEP was performed before cold-water provocation, 2 and 4 minutes after the beginning of the cold-water provocation. All patients with LTG underwent an additional measurement of the vascular reaction with pulsed Doppler flowmetrie of the A. ophthalmica, laser flowmetrie of the finger, measurement of blood pressure and pulse without and with cold-water provocation. Statistical evaluation was made by the paired t-Test.
Results: The amplitudes of the patients with low-tension glaucoma decreased from 4,17µV (mean) without cold-water test to 3,54 µV (mean) 4 minutes cold-water test. This difference was statistically significant (t-test: p=0,01). The other subjects showed no differences in amplitudes before or after cold-water provocation. In all groups the differences in peak times were insignifican
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