It is very difficult to measure the human eye properties directly, such as the accommodation mechanism, intraocular pressure distribution, the dynamics of aqueous humor flow and the bio-heat transfer in human eyes. Modeling and simulation may, therefore, play an increasingly important role in the ophthalmologic investigation. The major computer modeling methods, including geometric modeling, physical modeling and mathematical modeling, are introduced in this paper. Modeling and simulation anatomy properties and physiological properties of eye tissues, such as the cornea, aqueous humor and crystalline lens, vitreous, optic nerve head, sclera, are analyzed in the order from global to local, from front to back, from outside to inside. Finally, the problems of computer modeling in ophthalmologic investigation are discussed, and the development trends of the future are pointed out.
Aqueous Humor ; physiology ; Computer Simulation ; Cornea ; physiology ; Eye ; anatomy & histology ; Humans ; Lens, Crystalline ; physiology ; Ophthalmology ; trends ; Sclera ; physiology

In view of the evaluation of fundus image segmentation, a new evaluation method was proposed to make up insufficiency of the traditional evaluation method which only considers the overlap of pixels and neglects topology structure of the retinal vessel. Mathematical morphology and thinning algorithm were used to obtain the retinal vascular topology structure. Then three features of retinal vessel, including mutual information, correlation coefficient and ratio of nodes, were calculated. The features of the thinned images taken as topology structure of blood vessel were used to evaluate retinal image segmentation. The manually-labeled images and their eroded ones of STARE database were used in the experiment. The result showed that these features, including mutual information, correlation coefficient and ratio of nodes, could be used to evaluate the segmentation quality of retinal vessel on fundus image through topology structure, and the algorithm was simple. The method is of significance to the supplement of traditional segmentation evaluation of retinal vessel on fundus image.
Algorithms ; Databases, Factual ; Diagnostic Imaging ; methods ; Diagnostic Techniques, Ophthalmological ; Fundus Oculi ; Humans ; Image Processing, Computer-Assisted ; Retina ; Retinal Vessels ; anatomy & histology

Objective: To compare and analyze functional brain response characteristics by applying acupuncture or moxibustion to Zusanli (ST 36) in patients with functional dyspepsia (FD) and investigate the differences of central action mechanism resulting from acupuncture or moxibustion. Methods: A total of eligible 24 FD cases were divided into two blood-oxygen-level dependent (BOLD) sequences for functional magnetic resonance imaging (fMRI) scan. The amplitude of low frequency fluctuation (ALFF) analyses were conducted on the data of location phase, structure phase, resting state before acupuncture/moxibustion, working state during acupuncture/moxibustion and resting state after acupuncture/moxibustion using Data Processing Assistant for Resting-State fMRI (DPARSF) software. Results: Acupuncture and moxibustion produced significant differences in functional brain response. The working state during acupuncture/moxibustion mainly decreased ALFF values in the right supramarginal gyrus, right superior parietal lobule, right frontal gyrus, upper right occipital lobe, right precuneus and right cingulate gyrus. At the same time, it increased ALFF values in the left cerebellum, right caudate nucleus, right cerebellum and left inferior gyrus. The differences during the resting state after acupuncture/moxibustion were significantly smaller than the working state in intensity and size. It mainly resulted in decrease in ALFF values in the right postcentral gyrus and right supramarginal gyrus and increase in ALFF values in the left precuneus, orbital part of inferior frontal gyrus and right cerebellar peduncles. Conclusion: Needling and moxibustion at Zusanli (ST 36) can produce significant differences in immediate functional brain response.

Objective To explore whether the pattern of dysphagia verified using videofluoroscopic swallowing study (VFSS) was associated with the Iocation of the infarction in stroke patients.Methods Ninety-two patients with dysphagia (admitted between January 2015 and August 2016) who had first onset of cerebral infarction confirmed by magnetic resonance imaging were included in this study.They were divided into a unilateral brainstem group (n =29),a left hemisphere (cortex + white matter) group (n =37) and a right hemisphere (cortex + white matter) group (n=26) according to the location of the stroke.All subjects were evaluated using VFSS,and the oral transit time (OTT),triggering of pharyngeal swallowing (TPS),presence of residue in the vallecular and pyriform sinus,penetration,aspiration,cough reaction and upper esophageal sphincter (UES) opening were recorded and compared among the three groups.Results There were no significant differences among the three groups in OTT (X2 =0.712,P=0.918),TPS (1.564,P =0.458),penetration (X2 =5.615,P=0.060) and cough reaction (X2 =5.882,P=0.053).The unilateral brainstem group had significantly more residue in the vallecular and pyriform sinus than the left hemisphere group (X2=6.508,P=0.011).Aspiration was significantly more frequently found in the unilateral brainstem group than in the left hemisphere group (X2=7.803,P =0.005).The unilateral brainstem group was more likely to have insufficient UES opening than the left hemisphere (X2=29.555,P＜0.001) and right hemisphere groups (X2=24.630,P＜0.001).Conclusions Unilateral brainstem stroke is more likely to cause dysphagia than the unilateral cerebral hemisphere stroke,characterized by the abnormal residue in the vallecular and pyriform sinus,aspiration and the degree of UES opening.No significant differences were found in the dysphagia between stroke survivors with stroke in right and left hemispheres.