Low vision and
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Low vision refers to any visual impairment that is not correctable by glasses or contacts. The causes include macular degeneration, glaucoma, cataract, retinitis pigmentosa, and many more. My focus is to design training methods or assistive tools for people with Age-related Macular Degeneration, or AMD.
Macular degeneration is a leading cause of vision loss in the United States. It affects 6.5% of U.S. population aged 40 years or older. This is a disease related to the retina in the eye. The retina is a thin layer of tissue at the back of the eye, responsible for sensing the light. The macula is at the center of the retina, and the center of the macula has the highest density of cone cells and the best visual acuity. In macular degeneration, the macula region is impaired. In more advanced cases, the patients will lose their central vision and therefore have to use their peripheral for many daily tasks, such as reading. Reading in peripheral vision is difficult and slow, which motivates researchers, including me, to develop rehabilitation protocols to improve peripheral reading. |
Minnesota Laboratory for Low Vision Research, September 2011 - August 2017.
Advisor: Dr. Gordon Legge
Advisor: Dr. Gordon Legge
Sensory bottleneck of peripheral reading(Source: Legge, 2007. Taylor & Francis Group)
One proposed sensory bottleneck for reading is the visual span, i.e. the number of letters that can be seen clearly within a glimpse. What are the sensory factors limiting the size of the visual span, and can they be changed through training?
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Cognitive constraints: attentional bottleneck(Source: http://patrikrowinski.se/pay-attention-on-where-you-are-aiming-your-spotlight/?lang=en)
The visual span may not be the only bottleneck for reading. There may also be an attentional bottleneck. How does spatial attention interact with the visual span to determine reading speed?
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Developing a video game as trainingAlthough some previous training protocols are shown to be effective, the procedure was tedious and may discourage patients from keep training. To increase subjective enjoyment, we developed a word-puzzle game where the training was imbedded. Is it fun and effective?
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Visual span:
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Universal constraints for symbol recognitionAre there common constraints limiting both Korean and English recognition, and can training benefits generalize to untrained conditions?
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Comparing Korean and English reading speedEnglish reading speed increases with print size until a critical print size (CPS) is reached, and then remains constant at a maximum reading speed (MRS). As eccentricity increases, MRS decreases and CPS increases. How does the reading curve look like for Korean, a language with more complex orthography?
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Engel Vision and Imaging Laboratory, January 2019 - present.
Advisor: Dr. Stephen Engel
Advisor: Dr. Stephen Engel
Designing and testing a text remapping toolWith the rapid advances in technology, it is time to seek for high-tech solutions to difficulties caused by impaired vision. This research aims at designing and testing a novel text remapping tool for people with central field loss. The system displays text on a screen and uses eye tracking to determine the location of the person’s blind spot. Any text that falls in this blind spot will be shifted or “remapped” in real-time to a place where the person can see. Our current work involves 1) improving the tool by testing it in both normally-sighted participants and people with central-field loss, and 2) investigating the sensory, cognitive, and oculomotor factors affecting the utility of this tool.
An earlier version of the algorithm has been tested in normally-sighted subjects. Read more >> |
Assume the patient has a blind spot demonstrated by the black circle in this graph. If the patient is reading the word "between", the letters "ween" will be blocked by the blind spot without remapping. With remapping, the algorithm will then shift these letters to a place outside of the blind spot, in this case below the lower boundary of the blind spot. In this way, the patients can access information that would otherwise be unavailable to them.
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