Subsequent projects

Prof. Dr. Mark Greenlee
University of Regensburg

Prof. Dr. John S. Werner
University of California, Davis
Department of Ophthalmology and Vision Science

Compensatory effect of contrast gain in preferred retinal locus (PRL) of AMD patients

Following blindness in central vision, patients often learn to use a different part of the retina for visual fixation and attention. This is known as their preferred retinal locus (PRL).  It is unclear what processes mediate the PRL and the extent of compensation for visual losses. The purpose of this research is to understand compensation processes in patients with macular degeneration. We propose to measure contrast response functions as they quantify what people actually see, while constraining models of the underlying neural changes. We have developed a method based on Maximum Likelihood Difference Scaling (MLDS) which is simple for the observer.  We will first identify the location of PRL using NIDEK MP-1 Microperimeter by means of fixation stability assessment test. Afterwards, a triad of stimuli will be presented to study participants. The observer’s task is to judge which of three stimuli is most dissimilar. We will also plan to test the same stimuli at a non-preferred location at the same retinal eccentricity. Eye fixation is monitored and trials with unstable fixation will be removed. Macular degeneration occurs in several inherited conditions that lead to permanent losses of central vision.  As a result, many tasks of everyday vision such as reading and driving are impaired. In our first period of BaCaTec support, we (Malania et al., IOVS, 2017) used diffusion-tensor imaging and high-resolution T1-weighted imaging to demonstrate that the changes in the visual pathways are not restricted to the retina but extend into the central white matter. We expect to obtain new and exciting results concerning the involvement of the visual pathways in macular degeneration. As a consequence of deafferentation, the optic tract and optic radiations are compromised. Using diffusion-tensor imaging it is now possible to visualize and quantify these alterations in patients with AMD. As such these results will be important for future planning of rehabilitation in AMD patients.

Malania, M., Konrad, J., Jägle, H., Werner, J. S., & Greenlee, M. W. (2017). Compromised Integrity of Central Visual Pathways in Patients with Macular Degeneration. Investigative Ophthalmology & Visual Science, 58(7), 2939–9.


Primary project: Retinal and cortical pathways in age-related macular degeneration


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