Visual psychophysics and Rehabilitation : Investigation of low vision
Reading – Low vision – Age-related Macular Degeneration (AMD) – fMRI – MNREAD
My research interests focus on low vision and its impact on reading. The general purpose of my studies is to investigate reading processes in patients with central field loss (CFL), and more broadly low vision, using psychophysical tools, fMRI technique and mixed-effects models analysis. One potential goal of these studies is to find some ways to enhance text display and improve visual readaptation.
Since April 2011, I have been working as a Post-Doctoral Research Associate under the supervision of Dr. Gordon Legge at the Minnesota Laboratory for Low Vision Research (University of Minnesota; Psychology Department). One of our ongoing projects aims at optimizing reading training for patients with central scotomas. In the mean time, I have been using MRI to investigate the cortical sites involved in perceptual learning of peripheral reading in normal observers. Lately, I also dedicated a lot of my time in the design and testing of the MNREAD app, an iPad version of the MNREAD acuity chart.
From November 2007 to February 2011, I have been a PhD candidate under the supervision of Dr. Eric Castet, at the Mediterranean Institute for Cognitive Neuroscience (INCM-CNRS) and collaborated with the low-vision clinic of the hospital La Timone in Marseilles, France. Among other projects, I studied the relationship between oculomotor patterns and PRL position in patients with Macular Degeneration.
What is AMD?
Age-related Macular Degeneration (AMD) is the most common cause of vision loss in the industrialized country in those 50 or older. The macula (central retina) degenerates and becomes non-functional. As a consequence, the individual perceives a black spot at the center of his/her visual field. For more information on AMD: http://www.allaboutvision.com/conditions/amd.htm
Reading & AMD…
To compensate for this impairment, patients have to use parts of their peripheral vision to substitute their missing central vision. But such re-adaptive strategies are not perfect and leads to a dissociation between oculomotor and attentional behaviors. Patients report difficulties in face recognition, orientation and mobility, but their major complaint is that reading is either impossible or very slow. Indeed, even with the best optical correction and an appropriate magnification, AMD patients still read significantly slower than healthy readers. My thesis work focused on understanding the difficulties encountered by AMD patients during reading tasks. Long term goal is to find some ways to enhance or customize text display to improve their comfort and reading performances.
MP1 – Microperimeter
To understand the functional impairment, the first step is to examine the anatomical one. The Microperimeter MP1 (Nidek Technologies) is used to assess characteristics of each scotoma, such as its position, size and shape, or the position of the preferred retinal location(s) (PRL) used to fixate. All this information is useful to analyse reading performances.
In addition to reading performances recordings, the eye-tracker EyeLink II (SR Research) allows to record in real time oculomotor patterns of patients. Collecting eye-tracking data is crucial to understand reading patterns and strategies.