Abstract

P 122

In NTG patients the optic radiation volume measured by tractography is correlated with presence of arterial hypertension

Georg Michelson1, Simone Wärntges1, Tobias Engelhorn2, Arnd Dörfler2
1Universitäts-Augenklinik Erlangen; 2Neuroradiologie, Klinik für Radiologie, Universitätsklinikum Erlangen, Erlangen

Background and goal
Arterial hypertension is known to cause cerebral microangiopathy, which may induce optic atrophy. The extent of systemic effects of hypertension on the optic radiation (OR) volume in primary open angle glaucoma (POAG) and particularly, its subgroup normal tension glaucoma (NTG) is not clear. We examined the correlation of arterial hypertension with the damage of the optic radiation volume in both groups in relation to the presence of arterial hypertensive disease.
Method
In this prospective observational study 21 patients with POAG and 11 patients diagnosed with NTG (age 58±12 years and 59±13 years, respectively, p=0.63) were randomly selected from the glaucoma consultation hours. Subjects were examined by T2-weighted magnetic resonance imaging (MRI) for cerebral microangiopathy and by diffusion tensor imaging (DTI) for a rarefied optic radiation. No stroke or cerebral tumour was diagnosed in the MRI. The optic radiation in the DTI was manually outlined and the volume was calculated and compared to age-adjusted controls.
Results
In both groups the presence of arterial hypertension was correlated positively with the presence of cerebral microangiopathy (Kendall-tau-b for both groups p<0.001). In NTG patients the volume of the optic radiation correlated negatively with the presence of arterial hypertension (Kendall-tau-b -0.520, p=0.013 for both OR). Likewise, the optic radiation volume correlated with the microangiopathy stage (Kendall-tau-b for right OR: -0.501, p<0.001 and left OR: -0.691, p=0.003). In POAG patients without NTG this correlations were absent. Notably, the mean of the reduced optic radiation volume was not different between POAG patients (right OR: 87±16% and left OR: 86±17%) and NTG patients (right OR: 86±16% and left OR: 86±17%).
Conclusion
The presence of arterial hypertension and the stage of microangiopathy are more important for the reduction of the optic radiation volume in NTG patients than in POAG patients without NTG. In the latter group other mechanisms might prevail, which cause the same degree of optic radiation damage.

Copyright: 2009 Porstmann Kongresse GmbH. All rights reserved. Impressum, Disclaimer.