Abstract
Purpose::
To investigate in patients with Normal Tension Glaucoma (NTG): 1. The frequency and degree of extracranial internal carotid artery stenosis using extracranial carotid artery doppler sonography. 2. Whether there is any association between the degree of stenosis of the carotid artery and the stage of visual field loss (VFL)
Methods::
Retrospective evaluation of 69 consecutive patients with NTG with VFL stage I-V (Aulhorn classification) or preperimetric NTG at time of diagnosis. For staging the eye with the more severe VFL was used. If both eyes had the same stage of VFL, a randomized selection of the eye included was performed. All eyes had consistently an intraocular pressure equal or less than 21 mmHg on diurnal testing without medication and during the entire observation time with topical medication. For evaluation three patient groups were formed: patients with no hemodynamic relevant stenosis, with stenosis degree up to 60% and with stenosis between 60-90%. For statistics Jonckheere-Terpstra test was used.
Results::
20.3% of 69 eyes had a preperimetric NTG, stage I had 11,6%, stage II 10,1%, stage III 37,7%, stage IV 18,8%, stage V 1,5%. Stage III of VFL was most frequent at the first examination. 62 of 69 patients (89,9%) had no stenosis of the carotid artery, 8,6% had a stenosis up to 60% and 1 patient (1,5%) had a stenosis of 60-90%. This shows that extracranial carotid arteries are usually normal in patients with NTG.There was no significant relation between the degree of stenosis of the carotid artery and the stage of VFL at time of diagnosis. (p=0,270; Jonckheere-Terpstra test; two sided).
Conclusions::
Our results suggest that it is not necessary in all NTG patients to routinely perform a doppler carotid artery sonography. So far we referred all patients with NTG to the department of neurology for cranial MRI and for doppler carotid artery sonography. In case of severe asymmetric VFL, systemic arterial hypertension, amaurosis fugax etc. doppler carotid artery sonography remains essential in patients with NTG.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • blood supply • visual fields