Abstract
Purpose: :
One of the clinical signs observed at the funduscopic examination of the eye of the intracranial hypertension patients, apart from the papillary edema is the reduction, even the disappearance of the spontaneous pulsatility of the retinal vessels. This sign known since a long time was to date not measurable in an objective way.A new device, Retinal Vessel Analyzer (Imedos) now makes it possible to measure negligible variations of the vascular diameter (arteriolar and venular) during the cardiac cycle and thus to appreciate in an objective way the "retinal vascular pulse". We thus measured the retinal vascular pulsatility found among patients having a benign intracranial hypertension (BIH) which we compared with a control population.
Methods: :
We included 6 patients presenting a benign intracranial hypertension. For each participant, an examination with RVA was carried out right before the lumbar puncture (J0) then at 1 month (M1) and 3 months intervals (3M). The measurement of the amplitude of the retinal vascular pulse was made at the level of the temporal vessels (diameter higher than 100 microns), within one papillary diameter of the optical nerve. We compared these results with a control population (n=76).
Results: :
The mean venous pulsatility found at the 76 controls was 5,07m ± 1,57. Our 6 patients presenting a BIH, had a venous pulsatility that was lower than 0,5m at D0 (p < 0,05), lower than 0,8m± 0,52 at M1 (p < 0,05) and between 0,5 and 3m at m3. All the 6 patients had an abnormal measurement of the intracranial pressure (values ranging between 21 and 26 mm H2O) at the time of the lumbar puncture (normal < 20 mm H2O). It was not found a correlation between the value of the venous pulsatility and the value of the intracranial pressure.
Conclusions: :
The variation of the vascular diameter during the cardiac cycle, measured by RVA, is an indirect reflection of the vascular transmural pressure. Pulsatility is the resultant of the intra and extravascular pressure and of the vascular rigidity. Our results show that even in the case of a moderate BIH it exist an early, identifiable repercussion at the level of the retinal vascular network quantifiable by RVA. This reduction in the venous pulsatility can be explained by an increase in the intravascular pressure and/or by a parietal remodeling, especially at the later stage.RVA, a noninvasive examination, could be, after validation of this first study, considered a new examination technique to be proposed in the diagnosis and the follow-up of the patients having an intracranial hypertension. Indeed, by measuring only the venous pulsatility, it is possible on the one hand to evoke the diagnosis of BIH and on the other hand to evaluate in an objective way the effectiveness of the treatments proposed
Keywords: neuro-ophthalmology: optic nerve