Evaluation of the Visual Field on the Ground

Overview

Retinopathy pigmentosa (which affects about 40,000 patients in France) leads to destruction of the peripheral retina. This condition, often familial, frequently affects young patients. Visual acuity is excellent for a long time, the disease affecting the central macular region only belatedly. On the other hand, the visual field is very quickly narrowed to a central or paracentral zone. For the patient, knowing the limits of his visual field and learning to adapt is necessary especially when traveling. The management of these patients is twofold: * an orthoptist carries out an overall evaluation of the visual field using the Goldmann device (30 cm projection of the areas seen and not seen by the patient's eye), then performs rehabilitation over several weeks * an instructor of locomotion (open specialization: occupational therapist, case of this project,...) carries out an evaluation in situation, followed by a personalized reeducation over several weeks. The first sessions consist in establishing a climate of confidence, presenting the objectives of the management of locomotion and begin to understand the movements inside and outside accompanied. The following of the rehabilitation is an apprenticeship of the optimal use of the residual field of vision and the proposed technical aids (white cane), in the whole of the displacements, inside and outside. The residual field of vision is evaluated by a device at the first appointment at the specialized center. This examination, necessary for the professional, is not informative for the patient. It is sometimes supplemented by the evaluation of the visual field of view (ECVS). The ECVS, done jointly by the orthoptist and the locomotion instructor, consists in evaluating the functional visual field on a horizontal plane at 1m (meter) and 5m, and vertical at 5m. The field of vision of the patient, immobile, is materialized by targets deposited at each limit of the zones seen that it indicates. The investigators believe that the passing of a visual field on the ground, thanks to the projection of the zones of vision, allows the patient to improve his knowledge on his visual possibilities (and gaps) and thus to make his reeducation more efficient.