Disruption of Inter-hemispheric Transfer in Early Glaucoma
Glaucoma is known as the “silent killer of vision” because a large proportion of people are not aware they have it until the late stages of the disease, and therefore it is very important to detect the disease early so these patients get help. It is also important to understand the disease in order to develop new lines of treatments. There are new indications that changes occur not only in the eyes but also in the brain of these patients, particularly in a structure that connects the two brain hemispheres. We plan to study the function of this brain structure in humans with glaucoma using a series of non-invasive tests.
This grant was transferred to Dr. Esther G. Gonzalez upon the passing of the original PI, Dr. Martin Steinbach in June 2017. The research project is being continued in Martin's memory.
There is new research showing that glaucoma changes occur not only in the eyes but also in the brain, particularly in a structure that connects the two brain hemispheres called the corpus callosum. We plan to test the function of this brain structure with a series of noninvasive tests using a phenomenon called a binocular rivalry.
Briefly, binocular rivalry occurs when one stimulus is presented to one eye and a different stimulus to the other eye. Under this circumstance, the brain cannot combine the two stimuli into a stable binocular percept and the two images compete for perceptual dominance. Changes in eye dominance happen in a wave-like fashion and the initiation and speed of these “traveling waves” can be measured.
We plan to test rivalry dominance of stimuli presented centrally and in the periphery in eyes of individuals living with glaucoma. We will also measure intra and inter-hemispheric propagation of the traveling waves during rivalry. We have preliminary data showing that even in the early stages, the binocular rivalry of people with glaucoma is different from that experienced by people without this disease.
This project will examine the function of a brain structure that is not part of the primary visual pathway. Its dysfunction may suggest that additional degenerative mechanisms of glaucoma exist, which would be similar to those found in Alzheimer’s disease, for example.
If the hypotheses of this project are confirmed, in addition to broadening our understanding of glaucoma, the techniques introduced here may also be used for early diagnosis and for new approaches to glaucoma research and treatment. Our technique is easy to set up, requiring minimal equipment, and we will make available to others the methods we developed that enabled us to conduct our studies.
Glaucoma is known as the “silent killer of vision” because a large proportion of people are not aware that they have it until the late stages of the disease. It is therefore very important to detect glaucoma early so these patients can get help. It is also important to understand the disease in order to develop new lines of treatment.
About the Researcher
I obtained a bachelor’s degree with honors in experimental psychology from the National Autonomous University of Mexico (UNAM) in 1976. My master’s (1978) and PhD degrees (1984), also in experimental psychology, were both from the University of Toronto. I am most interested in studying the changes undergone by the brain when we lose parts of our visual field, when our two eyes do not work well together, or when we lose one eye. These interests have led me to do research on the visual and ocular motor functions of patients with central vision loss from age-related macular degeneration with a view towards rehabilitation. A second area of interest is the binocular integration of people who suffer from glaucoma, given that recent findings have shown neurodegeneration of the body and splenium of the corpus callosum in these patients. Finally, I find my research with one-eyed patients very important because of what it tells us about brain plasticity. Scientists provide explanation, interpretation and prediction of the phenomena that comprise our brain’s activity and that most complex of all senses, which is vision. I believe in the value of the interaction between basic and applied science which, in my field of research, involves the collaboration with ophthalmologists. Clinicians provide us with insights that we, as scientists, can put to the test.
Only cancer is more feared than the loss of sight, and one of the most regretted losses from low vision is the inability to read. Few things are more gratifying than helping a person regain some of that lost visual function and our lab has dedicated a lot of time to understand how to do this. Glaucoma is another important area of our research. This is a complex, not fully understood the disease that affects people in their prime and maybe earlier. These two areas form the core of our current scientific activity.
We believe in the interplay of basic and applied research because the more we know about the disease, the better equipped we will be for finding a cure. We also believe that knowing the “normal" informs us about pathology, while pathology clarifies what the "normal" should be. The BrightFocus Foundation stands out for their far-sightedness as a supporter of basic scientific and applied research, knowing full well that the two nourish each other. Our present research into the neuroscience of glaucoma could not have proceeded without the support of BrightFocus and its donors.
First published on: November 28, 2017
Last modified on: June 30, 2019