Yes / Although their eyes are pointing in different directions, people with long-standing strabismic amblyopia typically do not experience double-vision or indeed any visual symptoms arising from their condition. It is generally believed that the phenomenon of suppression plays a major role in dealing with the consequences of amblyopia and strabismus, by preventing images from the weaker/deviating eye from reaching conscious awareness. Suppression is thus a highly sophisticated coping mechanism. Although suppression has been studied for over 100 years the literature is equivocal in relation to the extent of the retina that is suppressed, though the method used to investigate suppression is crucial to the outcome. There is growing evidence that some measurement methods lead to artefactual claims that suppression exists when it does not. Methodology/Results: Here we present the results of an experiment conducted with a new method to examine the prevalence, depth and extent of suppression in ten individuals with strabismic amblyopia. Seven subjects (70%) showed no evidence whatsoever for suppression and in the three individuals who did (30%), the depth and extent of suppression was small. Conclusions: Suppression may play a much smaller role in dealing with the negative consequences of strabismic amblyopia than previously thought. Whereas recent claims of this nature have been made only in those with micro-strabismus our results show extremely limited evidence for suppression across the central visual field in strabismic amblyopes more generally. Instead of suppressing the image from the weaker/deviating eye, we suggest the visual system of individuals with strabismic amblyopia may act to maximise the possibilities for binocular co-operation. This is consistent with recent evidence from strabismic and amblyopic individuals that their binocular mechanisms are intact, and that, just as in visual normals, performance with two eyes is better than with the better eye alone in these individuals.

La présence d'un scotome maculaire oblige les patients à utiliser la vision excentrée ce qui provoque une difficulté à coordonner les systèmes oculomoteur et visuo-attentionnel. La lecture devient alors une des plaintes majeures chez ces patients, et les processus impliqués dans la baisse des performances de lecture restent mal connus. Dans la plupart des cas, le patient développe une ou plusieurs zones de la rétine excentrée dites préférentielles, et dénommées couramment PRLs. Nous nous proposons ici d'utiliser une approche psychophysique afin d'étudier les processus de la lecture en vision excentrée. Nous avons tout d'abord élaboré un test de lecture francophone informatisé suivant les principes des MNRead Acuity Charts afin de pouvoir évaluer la vitesse maximale de lecture chez des patients porteurs de scotomes centraux binoculaires dont l'atteinte avait été mesurée à l'aide d'un micropérimètre MP-1. Deux analyses utilisant des modèles statistiques à effets mixtes nous ont permis de mettre en évidence des prédicteurs efficaces de la vitesse maximale de lecture: 1) l'espace interligne; 2) le type de DMLA ; 3) la surface du scot; 4) la distance entre la PRL de fixation et la fovéa; 5) le statut du cristallin. Puis, nous nous sommes intéressés aux stratégies de lecture déployées par les patients. L'analyse de la distribution verticale des fixations enregistrées pendant la lecture nous a permis de mettre en évidence que dans 97% des cas, les patients utilisent une zone préférentielle de la rétine unique dans le plan vertical.Ces résultats présentent des intérêts théoriques et pratiques dans la création de nouveaux supports visuels et techniques de réadaptation. / Patients with central field loss (CFL) have to use eccentric vision and complain particularly about reading. The purpose of this thesis is to investigate reading processes in those patients using psychophysical tools. First, we investigated predictors of reading performances. We developed a French computerized version of the MNRead Acuity Charts to assess Maximum Reading Speed in patients with binocular scotomas, measured with the microperimeter MP-1. Two distinct analyses using mixed effects models allowed us to estimate the influence of predictors of Maximum Reading Speed: 1) interline spacing; 2) AMD type; 3) scotoma size; 4) distance between fixation PRL and fovea; 5) lens status. Then, we investigated oculomotor patterns of patients during sentence reading. Analysing the vertical distribution of fixations lead us to the conclusion that in most cases (97%), patients use a single eccentric preferred retinal locus (PRL) in the vertical meridian during reading. One potential goal of these studies is to find some ways to enhance text display and improve visual readaptation.