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- Carcinoma-associated retinopathy in a young teenager with immature teratoma of the ovary. [JOURNAL ARTICLE]
- J AAPOS 2014 Aug; 18(4):396-398.
A 14-year-old African American girl presented with diminished vision in both eyes 1 week after undergoing an oophorectomy for a right ovarian mass. Systemic metastatic work-up was negative. Visual acuity was 20/40 in the right eye and 20/50 in the left eye. Slit-lamp biomicroscopy was unremarkable in both eyes. Fundus examination showed diffuse patchy areas of retinal pigment epithelial atrophy in the macula and peripheral retina bilaterally. Color vision had decreased in each eye. Electroretinography revealed nondetectable rod and cone responses. Both pattern and flash visual evoked potential (VEP) testing showed delayed latency in both eyes. She was treated with pulse intravenous methylprednisolone for 3 days along with intravenous immunoglobulins and rituximab, followed by systemic prednisolone and biweekly intravenous immunoglobulins and rituximab for 3 months. Antiretinal autoantibodies against 48-kDa (arrestin) and 64-kDa and 94-kDa proteins were positive, suggestive of carcinoma-associated retinopathy. After 3 months, visual acuity was 20/40 in each eye with improvement in color vision and VEP findings.
- Predictors of dementia in Parkinson disease: A prospective cohort study. [JOURNAL ARTICLE]
- Neurology 2014 Aug 29.
We investigated an array of possible markers of early dementia in Parkinson disease.We performed a comprehensive assessment of autonomic, sleep, psychiatric, visual, olfactory, and motor manifestations in 80 patients with Parkinson disease who were dementia-free at baseline. After 4.4 years' follow-up, patients were evaluated for dementia. Predictive variables were assessed using logistic regression adjusting for disease duration, follow-up duration, age, and sex.Of 80 patients, 27 (34%) developed dementia. Patients destined to develop dementia were older and more often male (odds ratio [OR] = 3.64, p = 0.023). Those with baseline mild cognitive impairment had increased dementia risk (OR = 22.5, p < 0.001). REM sleep behavior disorder at baseline dramatically increased dementia risk (OR = 49.7, p = 0.001); however, neither daytime sleepiness nor insomnia predicted dementia. Higher baseline blood pressure increased dementia risk (OR = 1.37 per 10 mm Hg, p = 0.032). Orthostatic blood pressure drop was strongly associated with dementia risk (OR = 1.84 per 10 mm Hg, p < 0.001); having a systolic drop of >10 mm Hg increased dementia odds 7-fold (OR = 7.3, p = 0.002). Abnormal color vision increased dementia risk (OR = 3.3, p = 0.014), but olfactory dysfunction did not. Among baseline motor variables, proportion of gait involvement (OR = 1.12, p = 0.023), falls (OR = 3.02, p = 0.042), and freezing (OR = 2.63, p = 0.013), as well as the Purdue Pegboard Test (OR = 0.67, p = 0.049) and alternate tap test (OR = 0.97, p = 0.033) predicted dementia.Cardiovascular autonomic dysfunction, REM sleep behavior disorder, color discrimination ability, and gait dysfunction strongly predict development of dementia in Parkinson disease.
- Evaluation of Acquired Color Vision Deficiency in Glaucoma Using the Rabin Cone Contrast Test. [JOURNAL ARTICLE]
- Invest Ophthalmol Vis Sci 2014 Aug 28.
Purpose. To evaluate acquired color vision deficiency in glaucoma using the Rabin cone contrast test (RCCT). Methods. Twenty-seven eyes of 27 patients with glaucoma (glaucoma group) and 27 eyes of 27 normal subjects (control group) were included in this study. Long (L), medium (M), and short (S) CCT scores (L CCTs, M CCTs, and S CCTs, respectively) were measured using the RCCT in both groups. Visual field examinations were performed with Humphrey automated perimetry using the Swedish Interactive Thresholding Algorithm 30-2, and the mean deviation (MD) was evaluated. The macular ganglion cell/inner plexiform layer (GCIPL) thickness was measured using Cirrus high-definition optical coherence tomography in the glaucoma group. Results. The mean M CCTs and S CCTs in the glaucoma group were significantly (P<0.05 for both comparisons) lower than in the control group (M CCTs, 80.7±16.8 vs. 91.9± 8.22; S CCTs, 83.9±19.5 vs. 97.4± 3.77, respectively); the L CCTs did not differ significantly (P=0.065) from the controls (91.8±12.8 vs. 97.4± 3.50, respectively). The M CCTs and S CCTs were correlated significantly with MD (M CCTs, r=0.47; S CCTs, r=0.44, P<0.05 for both comparisons) and GCIPL thickness (M CCTs, r=0.70, P<0.0001; S CCTs, r=0.57, P<0.01). Conclusions. The chromatic discrimination thresholds measured by RCCT in the glaucoma group were significantly different from those measured in the control group and were correlated with the MD and GCIPL thickness. The RCCT may be useful for evaluating acquired color vision deficiency in glaucoma and may help advance current understanding of the pathophysiology of glaucomatous damage.
- Color properties of the motion detectors projecting to the goldfish tectum: I. A color matching study. [JOURNAL ARTICLE]
- J Integr Neurosci 2014 May 20.:1-20.
Responses of direction-selective and orientation-selective motion detectors were recorded extracellularly from the axon terminals of ganglion cells in the superficial layers of the tectum opticum of immobilized goldfish, Carassius gibelio (Bloch, 1782). Color stripes or edges moving on some color background (presented on the CRT monitor with known emission spectra of its phosphors) served as stimuli. It was shown that stimuli of any color can be more or less matched with the background by varying their intensities what is indicative of color blindness of the motion detectors. Sets of stimuli which matched the background proved to represent planes in the three-dimensional color space of the goldfish. A relative contribution of different types of cones to the spectral sensitivity was estimated according to orientation of the plane of color matches. The spectral sensitivity of any motion detector was shown to be determined mainly by long-wave cones with a weak negative (opponent) contributions of middle-wave and/or short-wave ones. This resulted in reduced sensitivity in the blue-green end of the spectrum, what may be considered as an adaptation to the aquatic environment where, because of the substantial light scattering of a blue-green light, acute vision is possible only in a red region of the spectrum.
- An Improved Mixture-of-Gaussians Background Model with Frame Difference and Blob Tracking in Video Stream. [JOURNAL ARTICLE]
- ScientificWorldJournal 2014.:424050.
Modeling background and segmenting moving objects are significant techniques for computer vision applications. Mixture-of-Gaussians (MoG) background model is commonly used in foreground extraction in video steam. However considering the case that the objects enter the scenery and stay for a while, the foreground extraction would fail as the objects stay still and gradually merge into the background. In this paper, we adopt a blob tracking method to cope with this situation. To construct the MoG model more quickly, we add frame difference method to the foreground extracted from MoG for very crowded situations. What is more, a new shadow removal method based on RGB color space is proposed.
- Curing Color Blindness-Mice and Nonhuman Primates. [JOURNAL ARTICLE]
- Cold Spring Harb Perspect Med 2014 Aug 21.
It has been possible to use viral-mediated gene therapy to transform dichromatic (red-green color-blind) primates to trichromatic. Even though the third cone type was added after the end of developmental critical periods, treated animals acquired red-green color vision. What happened in the treated animals may represent a recapitulation of the evolution of trichromacy, which seems to have evolved with the acquisition of a third cone type without the need for subsequent modification to the circuitry. Some transgenic mice in which a third cone type was added also acquired trichromacy. However, compared with treated primates, red-green color vision in mice is poor, indicating large differences between mice and monkeys in their ability to take advantage of the new input. These results have implications for understanding the limits and opportunities for using gene therapy to treat vision disorders caused by defects in cone function.
- A Malaria Diagnostic Tool Based on Computer Vision Screening and Visualization of Plasmodium falciparum Candidate Areas in Digitized Blood Smears. [Journal Article]
- PLoS One 2014; 9(8):e104855.
Microscopy is the gold standard for diagnosis of malaria, however, manual evaluation of blood films is highly dependent on skilled personnel in a time-consuming, error-prone and repetitive process. In this study we propose a method using computer vision detection and visualization of only the diagnostically most relevant sample regions in digitized blood smears.Giemsa-stained thin blood films with P. falciparum ring-stage trophozoites (n = 27) and uninfected controls (n = 20) were digitally scanned with an oil immersion objective (0.1 µm/pixel) to capture approximately 50,000 erythrocytes per sample. Parasite candidate regions were identified based on color and object size, followed by extraction of image features (local binary patterns, local contrast and Scale-invariant feature transform descriptors) used as input to a support vector machine classifier. The classifier was trained on digital slides from ten patients and validated on six samples.The diagnostic accuracy was tested on 31 samples (19 infected and 12 controls). From each digitized area of a blood smear, a panel with the 128 most probable parasite candidate regions was generated. Two expert microscopists were asked to visually inspect the panel on a tablet computer and to judge whether the patient was infected with P. falciparum. The method achieved a diagnostic sensitivity and specificity of 95% and 100% as well as 90% and 100% for the two readers respectively using the diagnostic tool. Parasitemia was separately calculated by the automated system and the correlation coefficient between manual and automated parasitemia counts was 0.97.We developed a decision support system for detecting malaria parasites using a computer vision algorithm combined with visualization of sample areas with the highest probability of malaria infection. The system provides a novel method for blood smear screening with a significantly reduced need for visual examination and has a potential to increase the throughput in malaria diagnostics.
- Color vision. The “geopolitics” of basic color terms. [Comment, News]
- Atten Percept Psychophys 2014 Jul; 76(5):1255-6.
- Johannes Vermeer of Delft [1632-1675] and vision in neuroendoscopy. [Journal Article, Review]
- Surg Neurol Int 2014.:123.
Johannes Vermeer of Delft [1632-1675] was one of the greatest Masters of the Dutch Golden Age who was intensely preoccupied with the behavior of light and other optical effects and was entitled "The Master of Light". He fastidiously attended to the subtleties of visual expression through geometry, composition, and precise mastery of the rules of perspective. It has been our impression that some visual similarity does exist between neuroendoscopic images and some of Vermeer's paintings. Such a relation could be explained by the fact that optical devices are utilized in producing both types of display.We reviewed the pertinent medical and art literature, observed some video clips of our endoscopy cases, and inspected digital high resolution images of Vermeer's paintings in order to elaborate on shared optical phenomena between neuroendoscopic views and Vermeer's paintings.Specific optical phenomena are indeed shared by Johannes Vermeer's works and neuroendoscopic vision, namely light and color effects as well as the rules of perspective.From the physical point of view, the possibility that a camera obscura inspired Vermeer's artistic creation makes the existence of a visual link between his paintings and the endoscopic views of the intracranial cavity comprehensible.
- Feature integration and object representations along the dorsal stream visual hierarchy. [Journal Article, Review]
- Front Comput Neurosci 2014.:84.
a ventral stream that receives color and form information and a dorsal stream that receives motion information. Each stream processes that information hierarchically, with each stage building upon the previous. In the ventral stream this leads to the formation of object representations that ultimately allow for object recognition regardless of changes in the surrounding environment. In the dorsal stream, this hierarchical processing has classically been thought to lead to the computation of complex motion in three dimensions. However, there is evidence to suggest that there is integration of both dorsal and ventral stream information into motion computation processes, giving rise to intermediate object representations, which facilitate object selection and decision making mechanisms in the dorsal stream. First we review the hierarchical processing of motion along the dorsal stream and the building up of object representations along the ventral stream. Then we discuss recent work on the integration of ventral and dorsal stream features that lead to intermediate object representations in the dorsal stream. Finally we propose a framework describing how and at what stage different features are integrated into dorsal visual stream object representations. Determining the integration of features along the dorsal stream is necessary to understand not only how the dorsal stream builds up an object representation but also which computations are performed on object representations instead of local features.