Neurodegenerative eye diseases, such as glaucoma, cause irreversible vision loss in millions of patients worldwide, creating serious medical, economic and social issues. Like other mammalian central nervous system tra...Neurodegenerative eye diseases, such as glaucoma, cause irreversible vision loss in millions of patients worldwide, creating serious medical, economic and social issues. Like other mammalian central nervous system tracts, optic nerve intrinsically lacks the capacity for axonal growth and its surrounding environment is also non-permissive to regeneration. Any axonal damage also triggers a vicious cycle of retinal ganglion cell （RGC） death. Exploring methods that can enhance RGCs survival and promote axonal regeneration will not only enable vision restoration for millions of patients, but also shed light on the treatment of other neurodegenerative diseases. In this review article, we will go through three current approaches to cure neu- rodegenerative eye diseases, including cell based therapy, neuro-regeneration and neuro-rejuvenation.展开更多
Visual cortical prostheses have the potential to restore partial vision. Still limited by the low-resolution visual percepts provided by visual cortical prostheses, implant wearers can currently only ＂see＂ pixelized...Visual cortical prostheses have the potential to restore partial vision. Still limited by the low-resolution visual percepts provided by visual cortical prostheses, implant wearers can currently only ＂see＂ pixelized images, and how to obtain the specific brain responses to different pixelized images in the primary visual cortex（the implant area） is still unknown. We conducted a functional magnetic resonance imaging experiment on normal human participants to investigate the brain activation patterns in response to 18 different pixelized images. There were 100 voxels in the brain activation pattern that were selected from the primary visual cortex, and voxel size was 4 mm × 4 mm × 4 mm. Multi-voxel pattern analysis was used to test if these 18 different brain activation patterns were specific. We chose a Linear Support Vector Machine（LSVM） as the classifier in this study. The results showed that the classification accuracies of different brain activation patterns were significantly above chance level, which suggests that the classifier can successfully distinguish the brain activation patterns. Our results suggest that the specific brain activation patterns to different pixelized images can be obtained in the primary visual cortex using a 4 mm × 4 mm × 4 mm voxel size and a 100-voxel pattern.展开更多
Presbyopia correction is mainly concerned with the goal of regaining an uncorrected reading performance.Since historic reading charts do not provide a unique standard that is applicable for the analysis of clinical an...Presbyopia correction is mainly concerned with the goal of regaining an uncorrected reading performance.Since historic reading charts do not provide a unique standard that is applicable for the analysis of clinical and scientific reading performance,new standardized reading charts have been developed,in order to provide reading performance analyses analogous to modern single-optotype distance acuity measurements:the Bailey-Lovie Word Reading Chart,the Colenbrander English Continuous Text Near Vision Cards,the MNREAD Charts,and the RADNER Reading Charts.The last three are also meant to measure reading speed,thus allowing detailed analysis of the reading capabilities of the patient’s functional vision.Furthermore,these reading charts can be declared homologated,based on the standards that were published for reading charts by the Visual Function Committee of the International Council of Ophthalmology(ICO)in 1988.Many research studies have shown that by analyzing the reading performance with homologated reading charts,valuable insight into the reading performance of patients suffering from various diseases can be obtained.These reading charts have also been successfully used in presbyopia research.It therefore seems evident that homologated,standardized reading charts facilitate not only research concerning functional vision in many fields of ophthalmology but also international communication about near visual performance.Homologated reading charts are available in almost all languages and have become a valuable tool in analyzing reading performance.We argue in this review that homologated reading charts are clearly a necessity for presbyopia research.展开更多
In this paper, new solutions for the problem of pose estimation from correspondences between 3D model lines and 2D image lines are proposed. Traditional line-based pose estimation methods rely on the assumption that t...In this paper, new solutions for the problem of pose estimation from correspondences between 3D model lines and 2D image lines are proposed. Traditional line-based pose estimation methods rely on the assumption that the noises(perpendicular to the line) for the two endpoints are statistically independent. However, these two noises are in fact negatively correlated when the image line segment is fitted using the least-squares technique. Therefore, we design a new error function expressed by the average integral of the distance between line segments. Three least-squares techniques that optimize both the rotation and translation simultaneously are proposed in which the new error function is exploited. In addition, Lie group formalism is utilized to describe the pose parameters, and then, the optimization problem can be solved by means of a simple iterative least squares method. To enhance the robustness to outliers existing in the match data, an M-estimation method is developed to convert the pose optimization problem into an iterative reweighted least squares problem. The proposed methods are validated through experiments using both synthetic and real-world data. The experimental results show that the proposed methods yield a clearly higher precision than the traditional methods.展开更多
基金supported by the National Glaucoma Research Program of the Bright Focus Foundationsupported by an unrestricted research grant from Research to Prevent BlindnessNIH center grant EY014801
文摘Neurodegenerative eye diseases, such as glaucoma, cause irreversible vision loss in millions of patients worldwide, creating serious medical, economic and social issues. Like other mammalian central nervous system tracts, optic nerve intrinsically lacks the capacity for axonal growth and its surrounding environment is also non-permissive to regeneration. Any axonal damage also triggers a vicious cycle of retinal ganglion cell （RGC） death. Exploring methods that can enhance RGCs survival and promote axonal regeneration will not only enable vision restoration for millions of patients, but also shed light on the treatment of other neurodegenerative diseases. In this review article, we will go through three current approaches to cure neu- rodegenerative eye diseases, including cell based therapy, neuro-regeneration and neuro-rejuvenation.
基金supported by the National Natural Science Foundation of China,No.31070758,31271060the Natural Science Foundation of Chongqing in China,No.cstc2013jcyj A10085
文摘Visual cortical prostheses have the potential to restore partial vision. Still limited by the low-resolution visual percepts provided by visual cortical prostheses, implant wearers can currently only ＂see＂ pixelized images, and how to obtain the specific brain responses to different pixelized images in the primary visual cortex（the implant area） is still unknown. We conducted a functional magnetic resonance imaging experiment on normal human participants to investigate the brain activation patterns in response to 18 different pixelized images. There were 100 voxels in the brain activation pattern that were selected from the primary visual cortex, and voxel size was 4 mm × 4 mm × 4 mm. Multi-voxel pattern analysis was used to test if these 18 different brain activation patterns were specific. We chose a Linear Support Vector Machine（LSVM） as the classifier in this study. The results showed that the classification accuracies of different brain activation patterns were significantly above chance level, which suggests that the classifier can successfully distinguish the brain activation patterns. Our results suggest that the specific brain activation patterns to different pixelized images can be obtained in the primary visual cortex using a 4 mm × 4 mm × 4 mm voxel size and a 100-voxel pattern.
文摘Presbyopia correction is mainly concerned with the goal of regaining an uncorrected reading performance.Since historic reading charts do not provide a unique standard that is applicable for the analysis of clinical and scientific reading performance,new standardized reading charts have been developed,in order to provide reading performance analyses analogous to modern single-optotype distance acuity measurements:the Bailey-Lovie Word Reading Chart,the Colenbrander English Continuous Text Near Vision Cards,the MNREAD Charts,and the RADNER Reading Charts.The last three are also meant to measure reading speed,thus allowing detailed analysis of the reading capabilities of the patient’s functional vision.Furthermore,these reading charts can be declared homologated,based on the standards that were published for reading charts by the Visual Function Committee of the International Council of Ophthalmology(ICO)in 1988.Many research studies have shown that by analyzing the reading performance with homologated reading charts,valuable insight into the reading performance of patients suffering from various diseases can be obtained.These reading charts have also been successfully used in presbyopia research.It therefore seems evident that homologated,standardized reading charts facilitate not only research concerning functional vision in many fields of ophthalmology but also international communication about near visual performance.Homologated reading charts are available in almost all languages and have become a valuable tool in analyzing reading performance.We argue in this review that homologated reading charts are clearly a necessity for presbyopia research.
基金supported by the National Basic Research Program of China(“973”Project)(Grant No.2013CB733100)National Natural Science Foundation of China(Grant No.11332012)
文摘In this paper, new solutions for the problem of pose estimation from correspondences between 3D model lines and 2D image lines are proposed. Traditional line-based pose estimation methods rely on the assumption that the noises(perpendicular to the line) for the two endpoints are statistically independent. However, these two noises are in fact negatively correlated when the image line segment is fitted using the least-squares technique. Therefore, we design a new error function expressed by the average integral of the distance between line segments. Three least-squares techniques that optimize both the rotation and translation simultaneously are proposed in which the new error function is exploited. In addition, Lie group formalism is utilized to describe the pose parameters, and then, the optimization problem can be solved by means of a simple iterative least squares method. To enhance the robustness to outliers existing in the match data, an M-estimation method is developed to convert the pose optimization problem into an iterative reweighted least squares problem. The proposed methods are validated through experiments using both synthetic and real-world data. The experimental results show that the proposed methods yield a clearly higher precision than the traditional methods.
