La reconnaissance des objets et des scènes naturelles dans la dégénérescence maculaire liée à l'âge

Abstract : AMD (Age Related Macular Degeneration) is the leading cause of blindness in western countries. Quality of life Questionnaires indicate that people with AMD exhibit difficulties in finding objects and in mobility. In the natural environment, objects seldom appear in isolation. They appear in their natural setting in which they can be masked by other objects. The contrast of a scene may also change, as light varies as a function of the hour in the day and the light source. The objective of the study was to access objects and scene recognition impairments in people with AMD. We studied the perception of natural scenes, figure/ground discrimination, the effect of contrast on object recognition in achromatic scenes, and then navigation and spatial memory in a virtual environment. Performance was compared for people with AMD and age matched normally sighted controls. The results show that scene gist recognition can be accomplished with high accuracy with the low spatial resolution of peripheral vision, which supports the "scene centered approach" in scene recognition. Figure/ground discrimination is impaired in AMD. A white space surrounding the object is sufficient to improve its recognition and to facilitate figure/ground segregation. Performance is also improved when the object is displayed on its natural setting than when it appears on a non structured, non significant background. Sensitivity for the detection of a target object in achromatic scenes is impaired in AMD patients, who are more affected by contrast reductions than normally sighted people. A study on spatial nagigation showed a compression of space representation. People with AMD underestimate the virtual distance in a spatial navigation task. The results of our studies have implications for rehabilitation, for improving texts and magazines destined to people with low vision and for the improvement of the spatial environment of people suffering from AMD in order to facilitate mobility, object search and reduce the risk of falls.
Document type :
Theses
Human health and pathology. Université du Droit et de la Santé - Lille II, 2011. French. <NNT : 2011LIL2S010>


https://tel.archives-ouvertes.fr/tel-00638964
Contributor : ABES STAR <>
Submitted on : Monday, November 7, 2011 - 5:02:27 PM
Last modification on : Thursday, October 18, 2012 - 5:32:50 PM

File

thA_secomplA_te_tran.pdf
fileSource_public_star

Identifiers

  • HAL Id : tel-00638964, version 1

Collections

Citation

Thi Hà Châu Tran. La reconnaissance des objets et des scènes naturelles dans la dégénérescence maculaire liée à l'âge. Human health and pathology. Université du Droit et de la Santé - Lille II, 2011. French. <NNT : 2011LIL2S010>. <tel-00638964>

Export

Share

Metrics

Consultation de
la notice

274

Téléchargement du document

142