[Transorbital echography for assessment of optical nerve atrophy in demyelinating diseases: a pilot study]

INTRODUCTION. Demielinating diseases are a group of heterogenic diseases in whom mieline is attacked. The optic nerve (ON) is one of the most commonly affected. SUBJECTS AND METHODS. An observational prospective case-control study with ON orbital echography was developed. The case group was formed by 31 demielinating diseases patients and the control group was formed by 24 healthy people. Mean age of cases: 48.3 ± 11.8 years old, controls 48.7 ± 9.9 years old. 46% of controls and 35% of cases were males. RESULTS. We found statistical significance differences between cases and controls regarding the diameter of right (controls 3.64 ± 0.58 mm vs patients 2.84 ± 0.56 mm; p < 0.001) and left ON (controls 3.95 ± 0.84 mm vs patients 2.74 ± 0.54 mm; p < 0.001). We found no differences between maximum systolic and median velocities regarding ophthalmic arteries in both groups, neither for previous acute optical neuritis history or visual evocated potentials. CONCLUSIONS. ON evaluation with transorbital echography is an easy, feasible, non invasive, useful and costless technique for the evaluation of the ON atrophy. As for visual evocated potentials are abnormal in a huge number of patients without previous optical neuritis evidence, the diameter of ON measured by transorbital Doppler could be a consistent paraclinic marker of these diseases.