Association Between Plasma Endothelin-1 and Severity of Different Types of Glaucoma

PURPOSE: Endothelin-1 (ET-1) has been suggested to play an important role in the pathogenesis of glaucoma. Herein, we studied whether increased levels of plasma ET-1 are associated with changes in the visual field and changes in optical coherence tomography (OCT)-measured retinal nerve fiber layer (RNFL) thickness in patients with different types of glaucoma. PATIENTS AND METHODS: : Plasma concentration of ET-1 was determined in 31 patients with primary open-angle glaucoma, 18 patients with normal tension glaucoma, 16 patients with primary angle-closure glaucoma, and in 37 normal controls. In all participants, visual field testing was performed and OCT was used to measure RNFL thickness. The correlation between mean ET-1 level and changes in the visual field (mean deviation, dB) and changes in OCT-measured RNFL thickness in 1 randomly selected eye from each patient in each group was then evaluated. RESULTS: The ET-1 level was 3.27±1.25 pg/mL in the primary open-angle glaucoma group (-14.09±8.76 dB), 3.12±1.46 pg/mL in the normal tension glaucoma group (-8.87±6.15 dB), 2.58±.22pg/mL in the primary angle-closure glaucoma group (-14.55±10.2 dB), and 1.53±1.49 pg/mL in the control group. Although mean ET-1 levels were significantly higher in all 3 of the glaucoma groups than in the control group, there was no significant difference in ET-1 level among the 3 glaucoma groups. In addition, no significant correlation was found between levels of plasma ET-1 and structural or functional changes in patients with different types of glaucoma. CONCLUSIONS: : There was no correlation between plasma levels of ET-1 and severity of glaucoma. The role ET-1 plays in the pathogenesis of glaucoma remains to be determined.