Abstract
Purpose::
Investigation of dynamic vessel behaviour of arteries and veins in patients with untreated and treated normal tension glaucoma (NTG) compared with normal values.
Methods::
In 14 patients with untreated and 31 patients with treated normal tension glaucoma the reaction of retinal vessels on flicker provocation was investigated with the Dynamic Retinal Vessel Analyzer (Imedos, Jena,Germany). The measurement procedure consisted of a 50 sec baseline measurement, a 20 sec flicker provocation and a rest period of 80 sec. The procedure was repeated three times and mean values were calculated.
Results::
In all patients with normal tension glaucoma, there was no adequate reaction of vessels during the flicker procedure. In comparison to normal vessel reaction, arteries and veins showed a reduced dilatation (Arteries: Normal: 6.9% ± 2.8; NTG: 3.6% ± 3.2; Veins: Normal: 6.5% ± 2.5; NTG: 3.6% ± 2.6). The arterial constriction following the flicker stimulation was reduced as well (Normal: -2.7% ± 1.4; NTG: 0.0% ± 2.3). In patients with treated NTG we did not find any influence of topical antiglaucoma therapy on vessel behaviour (Arteries: Dilatation: untreated NTG: 3.6% ± 3.4; treated NTG: 3.6% ± 3.1; Constriction: untreated NTG: -0.5% ± 1.7; treated NTG: 0.3% ± 2.4; Veins: untreated NTG: 3.6% ± 2.5; treated NTG: 3.6% ± 2.6).
Conclusions::
The dynamic vessel analysis in patients with NTG showed a significantly reduced vessel reaction. These results confirm the pathogenetic concept of vascular dysregulation in patients with NTG. The lack of any effect of topical antiglaucoma treatment on vessel behaviour might be caused by only moderate lowering of the intraocular pressure in these NTG-patients. This implies that new therapeutic strategies must be developed in the treatment of patients with normal tension glaucoma in order to improve vascular dynamics.
Keywords: blood supply • intraocular pressure