Étude des atteintes posturales chez les patients déficients visuels

Abstract

IntroductionBalance is an active system allowing the body to maintain individual stability despite external stimuli. It relies on many senses which provide data to compensate for external variations such as visual information. It is thus necessary that the senses be in good condition and transmit accurate data. We wished to study postural adaptations made by visually impaired people. Material and methodsWe performed a prospective study of patients with macular degeneration with visual acuity less than 20/40, glaucoma with a mean visual field defect less 12 decibels, and a control population. All subjects underwent a dynamic equilibrium test on a stabilometric platform with Win-Posturo software. We assessed their postural profile in various situations : eyes open, eyes closed, balance, anteroposterior displacement and lateral displacement. ResultsThe first group consisted of 16 patients with age macular degeneration (AMD), the second of 17 patients with glaucoma and the third of 18 control subjects. In static equilibrium, for the parameter “length vs. surface area,” all groups had an improvement in their performance with eyes open (P=0.05). There was a significant difference between the subject and control groups (P<0.01). In addition, subjects in the group with peripheral visual impairment had significantly greater tendency to lean forward. In dynamic equilibrium, we did not demonstrate any significant difference between the groups. DiscussionIn static equilibrium, patients with poor peripheral vision have better quality somatosensory compensation, but they have a tendency to lean forward, which increases the risk of falling forward. For the three groups, the tests showed that the subjects are vision-dependent, which implies that somatosensory compensation could be developed to limit this dependency. In dynamic equilibrium, the subjects in the disease groups perform significantly worse than the controls. All the visually impaired have a more developed somatosensory mechanism than the controls. The subjects in the first and third groups have the same postural profile, they are vision-dependent. Subjects in the second group have an instability and change in their postural strategy, increasing the risk of falling. Visual acuity has a lesser impact on the risk of falling than the visual field. ConclusionComparing postural responses in these different situations, it appears that postural profiles are modified in the case of visual disability, although the postural profile of the group with central visual loss is similar to that of the controls. Retinal involvement, whether central or peripheral, leads to postural imbalance that may result in falls in certain cases. To limit the prevalence of these falls, it would be interesting to address visually impaired patients by examination and postural rehabilitation to decrease the effects of this visual impairment.