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The objective measurement of the visual acuity is one of the most important issues in ophthalmology clinics, and the optokinetic nystagmus (OKN) can be a good candidate for this purpose. In this paper, an eyeglasses-based electrooculogram (EOG) for the detection of the OKN is introduced. It is convenient to use and allows the refractive error correction for the visual acuity measurement.

A key problem of artificial visual prosthesis is the low resolution due to the limited number of electrodes. Various methods such as edge detection, contrast enhancement have been studied as the solutions of the low resolution problem and these methods have been performed to face or object recognition in the close-up image. In this paper, we proposed the region-of-interest detection method using a context-based model, which is appropriate for real situations. The visually-salient region was detected by combining the saliency map with color information. In experiment, to evaluate the proposed model, gaze was estimated using an eye tracker when subjects watch the original image and two types of 10 × 10 pixelized images produced by conventional and saliency based method, respectively. Each gaze of pixelized images was compared with the gaze of the original image. The experiment showed that the gaze using the proposed context based model much more correlates with the gaze of the original image than that of conventional model.

This article reports on a retinal stimulation system for long-term use in animal electrical stimulation experiments. The presented system consisted of an implantable stimulator which provided continuous electrical stimulation, and an external component which provided preset stimulation patterns and power to the implanted stimulator via a paired radio frequency (RF) coil. A rechargeable internal battery and a parameter memory component were introduced to the implanted retinal stimulator. As a result, the external component was not necessary during the stimulation mode. The inductive coil pair was used to pass the parameter data and to recharge the battery. A switch circuit was used to separate the stimulation mode from the battery recharging mode. The implantable stimulator was implemented with IC chips and the electronics, except for the stimulation electrodes, were hermetically packaged in a biocompatible metal case. A polyimide-based gold electrode array was used. Surgical implantation into rabbits was performed to verify the functionality and safety of this newly designed system. The electrodes were implanted in the suprachoroidal space. Evoked cortical potentials were recorded during electrical stimulation of the retina. Long-term follow-up using OCT showed no chorioretinal abnormality after implantation of the electrodes.

We perform the measurement of accommodation response in viewing stereoscopic images. The results indicate the possibility that the viewer gazes between the convergence point of images and the display device.

Glaucoma is the second leading cause of blindness, and the retinal nerve fiber layer (RNFL) defect is the early sign of the glaucomatous optic nerve damage. To evaluate the RNFL, segmentation of the optic nerve head on the RNFL photograph should be the first step. This paper presents segmentation of optic nerve head using warping and random sample consensus (RANSAC). Sensitivity and positive predictability of the proposed method were 91% and 78% respectively.

To improve the usability of conventional indirect ophthalmoscope, we propose the newly designed binocular indirect ophthalmoscope which is inexpensive, comfortable, light-weighted, long-lasting, and provides stereopsis not only to examiner but also to observers. Our new system shows good performance compared to conventional indirect ophthalmoscope and also presents the stereoscopic assistant view through special visualization system.

Hessian matrix is the square matrix of second partial derivatives of a scalar-valued function and is well known for object recognition in computer vision and medical shape analysis. Previous curvature based polyp detection algorithms generate myriad of false positives. Hessian-matrix based method, however, is more sensitive to local shape features, so easily reduce false positives. Calculation of Hessian matrix on 3D CT data and Eigen decomposition of the matrix gives three Eigen values and vectors at each voxel. Using these Eigen values, we can figure out which type of intensity structures (blob, line, and sheet-like) is on the given voxel. We focus on detecting blob-like object automatically. In the inner colonic wall structures, blob-like, line-like, and sheet-like objects represent polyps, folds and wall, respectively. In addition, to improve the performance of the algorithm, Gaussian blurring factor and shape threshold parameters are optimized. Before Hessian matrix calculation, smoothing the given region using Gaussian kernel with small deviation is necessary to enhance local intensity structures. To optimize the parameters and validate this method, we have produced anthropomorphic pig phantoms. Fourteen phantoms with 103 polyps (16 polyps = 6mm) were used. CT scan was performed with 1mm slice thickness. Our detection algorithm found 84 polyps (81.6%) correctly. Average number of false positives is 7.9 at each CT scan. This results show that our algorithm is clinically applicable for polyp detection, because of high sensitivity and relatively low false positive detections.

Photoreceptor loss as a result of retinal degenerative diseases, such as age-related macular degeneration and retinitis pigmentosa is a leading cause of blindness in adult (1). Despite a near-total loss of the photoreceptors, the inner nuclear and ganglion cell layers survive at fairly high rates in the patients with retinitis pigmentosa (2) and age-related macular degeneration (3). Retinal prostheses have great potential in alleviating the problems and disabilities produced by these diseases. The feasibility of the electrical stimulation of the remaining retinal neurons is supported by clinical studies which showed that controlled electrical signals applied to a small area of the retina of a blind volunteer through a microelectrode resulted in the perception of a small spot of light (4).

In the present study, we performed the retrograde tracing method using the neurotropic pseudorabies virus bartha strain (PRV-Ba) and immunohistochemistry against CGRP, to identify whether CGRP exists in the gastric monosynaptic vagal circuit between dorsal motor nucleus of vagus nerve (DMV) and nucleus tractus solitarius (NTS). At the results, PRV immunoreactive neurons were found in both DMV and NTS. However, CGRP-immunoreactive cells were present only in NTS, which contained no double-labeled neurons for PRV and CGRP. These results suggest that CGRP may not have a neuronal function in gastric vagal circuit of rat.

We developed the asymmetry analyzing system for facial palsy patient's rehabilitation progress study. Using PC standard imaging device, captured 640*480 RGB image is converted into HSV space. A Lip-shape mask is extracted by thresholding. By taking 5 regions consisted in one region on lip and four regions on face skin, reasonable thresholds are determined by Fuzzy C-Means clustering. The extreme points on the lip shape mask are extracted to get the seeds for tracking. Segmented seed points are tracking by Iterative Lucas-Kanade tracking method in pyramids at 30 fps and recording simultaneously. To reduce the disk writing load on computer, we use asynchronous mode file writing, which is going to transfer to and review by clinician. Tracking shows quite reliable results, but sometimes the tracked points are following along the lip line because of the similar contrasts. Therefore, the first strategy to improve the reliability of tracking is using the high contrast points, such as left and right maximal point of lip shape. The second is clustering some points near the maximal points and eliminating outlying tracking points. The third is rechecking the lip shape using lip segmentation when the operator confirms that subject's maximal lip moving. Left and right tracking points are compared in forms of trajectory plot.

This paper presents an integrated neural probe that can be used as a neural signal recorder as well as a chemical stimulator. The single unit integrated probe features in-plane shanks with buried microchannels and low impedance microelectrodes. The fabricated neural probe has three 3 mm-long shanks with a 10 /spl mu/m-diameter microchannel and six 30 /spl mu/m /spl times/ 30 /spl mu/m square gold microelectrodes per shank. The measured impedance magnitude and the phase shift of the microelectrodes are 23.1 k/spl Omega//900 /spl mu/m/sup 2/ and 52.9/spl deg/ at 1 kHz, respectively.

A three-dimensional array of single-crystalline silicon microspikes with protruded barbs is developed for microscale biopsy. The developed microbiopsy tool is designed to replace the conventional endoscopic biopsy tool and to reduce patient discomfort and risk during the endoscopic operation. For fabrication we extend the SBM (Sacrificial Bulk Micromachining) process and apply the SBM process to both sides of the wafer. Shanks of the fabricated 3D microspikes are 1.5 mm long, 150 /spl mu/m thick and 150 /spl mu/m wide. The developed microbiopsy tools are evaluated in-vivo experiment by extracting tissues from live anesthetized rabbits and examining the tissue with the hematoxylin and eosin (H&E) staining protocol. In addition, the clinical test of extracting gastric adenocarcinoma tissue samples is also performed. The 3D microspikes successfully extracted tissue samples from the small intestines of the anesthetized rabbits and gastric adenocarcinoma tissue. The evaluation reveals that the biopsy with the 3D microspike can be applied to the medical examination.

This paper presents a novel 3D 8/spl times/8 multi-electrode array for artificial retina application. Each electrode features a triangular pyramidal structure that composed of one (111) plane and two vertical planes. The coneangle between the (111) plane and the vertical plane is 19.5/spl deg/. The sharp triangular pyramidal structure makes the minimal invasive penetration for the inner limiting membrane. The characteristic measurement of impedance magnitude and the phase shift of a single electrode are 1.19 M/spl Omega/ and 80.8/spl deg/ at 1 kHz, respectively.

Retinal implant is aimed at electronic stimulation of remaining retinal neurons in patients with degenerated photoreceptors. The Korean group for retina implants started development in year 2000, aiming for the rehabilitation of patients suffering from photoreceptor loss due to diseases such as aged-related macular degeneration (AMD) and retinitis pigmentosa (RP). To minimize the damage during ophthalmic surgery and to get better contact to the retina, flexible polyimide is selected as the substrate material of microelectrode arrays. Both the subretinal and epiretinal approaches are investigated in the group. For stimulation, we have considered both direct optical stimulation using unbiased photodiodes, and ordinary electrical stimulation based on cochlear implant-like electronics. The implanted retina produces EEPs (electrically evoked potentials) with typical peaks present, but with smaller latencies. In this presentation, we will describe the neuron-microelectronics interface, the stimulation methods, and the results of in-vitro and in-vivo animal tests.

Introduction: Indocyanin green fundus angiographic images (ICGA) of the eyes is useful method in detecting and characterizing the choroidal neovascularization (CNV), which is the major cause of the blindness over 65 years of age. To investigate the quantitative analysis of the blood flow on ICGA, systematic approach for automatic registration of using mutual information and a quantitative analysis was developed. Methods: Intermittent sequential images of indocyanin green angiography were acquired by Heidelberg retinal angiography that uses the laser scanning system for the image acquisition. Misalignment of each image generated by the minute eye movement of the patients was corrected by the mutual information method because the distribution of the contrast media on image is changing throughout the time sequences. Several region of interest (ROI) were selected by a physician and the intensities of the selected region were plotted according to the time sequences. Results: The registration of ICGA time sequential images is required not only translate transform but also rotational transform. Signal intensities showed variation based on gamma-variate function depending on ROIs and capillary vessels show more variance of signal intensity than major vessels. CNV showed intermediate variance of signal intensity and prolonged transit time. Conclusion: The resulting registered images can be used not only for quantitative analysis, but also for perfusion analysis. Various investigative approached on CNV using this method will be helpful in the characterization of the lesion and follow-up.

A new optical link method for the retinal prosthesis is proposed. A laser diode system was chosen to transfer image into the eye and the new optical system was designed and evaluated in silico and ex vivo. The use of laser diode array in artificial retina system makes system simple by deleting signal processing part inside of the eyeball. The designed optical system is enough to focus laser beam on photodiode array in 20 /spl times/ 20 application on simulation using Code V program, and about 200 /spl mu/m focusing of laser beam was possible on experiment with porcine eye.

AlamarBlue is used to induce color and fluorescence in the microenvironment of activated cells. The alamarBlue assay was studied to determine if it could be used as a method of evaluating the number of retinal pigment epithelial (RPE) cells. A series of two-fold dilutions of RPE cells were placed into 96-well culture plates. The alamarBlue was added to the culture media after attaching the cells. The absorbance and fluorescence were measured consecutively at various intervals over a period of 24 hr. Cell viability were evaluated by means of the trypan blue exclusion method and flow cytometry using a combination of propidium iodide and annexin V was done to prove the safety of alamarBlue assay to the cells. Both the absorbance and the fluorescence had a linear relationship with the number of RPE cells. Exposing the RPE cells to alamarBlue was not detrimental to the cells. In conclusion, the alamarBlue assay constitutes a one-step, extremely simple, reproducible, economical and non-toxic procedure for evaluating the number of viable RPE cells.

We employed the retrograde neural tracing method using the pseudorabies virus bartha strain (PRV-Ba) to investigate the projection from accessory trigeminal nucleus (Acc5) or accessary facial nucleus (Acc7) to hypoglossal nucleus (HP). After injection of PRV-Ba into the bellies of the digastric muscle, the PRV-Ba containing neurones were observed in Acc5 of the cranial belly injected rats and Acc7 of caudal belly injected rats ipsilaterally, but not in HP. These results suggest that Acc5 and Acc7 may not project to HP and that movements of the digastric muscle are not related to cooperation with tongue movements during mastication.

Pericellular arborization is reported to be the self-regulating structure in sensory ganglia. Although the calcitonin gene-related peptide (CGRP) or substance P (SP) immunoreactive pericellular arborization appeared in the sensory ganglia, there was no available information that CGRP and SP colocalize in this structure. As the attempts to resolve the question described above, the present study was undertaken to identify the coexistence of CGRP and SP in pericellular arborizations of the goat nodose and trigeminal ganglia by double immunohistochemistry. As the results show, CGRP immunoreactivity was present in every pericellular arborization containing SP immunoreactivity in trigeminal ganglia, however, pericellular network containing CGRP or SP immunoreactivity was not present in nodose ganglia. Unexpectedly, a few small satellite elements were observed to contain intense CGRP and SP immunoreactivity at the periphery of CGRP and SP immunoreactive neurones in nodose ganglia. Therefore, these results suggest that CGRP and SP coexist in pericellular arborizations, and that satellite cell as well as pericellular arborization may be involved in intraganglionic regulation of goat sensory ganglia.

PURPOSE. We present a computerized method of measuring binocular alignment using a selective wavelength filter and an infrared camera, and validate the efficacy of automated image analysis compared to the gold standard prism and alternate cover test (PCT). METHODS. A prospective observational pilot study was performed on 30 subjects with intermittent exotropia, 30 subjects with esotropia, and 30 orthotropic subjects who were able to cooperate with the PCT. Two independent ophthalmologists examined the angle of deviation using the PCT. Full-face images were obtained with an infrared camera while a selective wavelength filter was placed in front of either eye. Images were analyzed using the 3D Strabismus Photo Analyzer. Interobserver variability, test‐retest reliability and correlation between the angles of deviation were determined for both methods. RESULTS. The 95% limit of agreement of interobserver variability was 64.8 prism diopters (PD) for the PCT and 64.3 PD for the selective wavelength filter analysis. The 95% limit of agreement of test‐retest reliability between the PCT and selective wavelength filter analysis was 68.5 PD. Results of the PCT and selective wavelength filter analysis showed a strong positive correlation (R ¼ 0.900, P < 0.001). CONCLUSIONS. Infrared images acquired with a selective wavelength filter can detect the latent components of strabismus, and automated image analysis showed excellent agreement with the standard PCT. This automated method is an accurate and reliable tool for measuring ocular deviation with minimal observer dependency.

A dual-band mobile phone antenna with dual feeders is proposed to improve antenna radiation efficiency in the CDMA band of 824–894 MHz and the GSM band of 880–960 MHz. The proposed antenna consists of two planar inverted-F antennas and a common ground plane with a slot. The electric fields are more confined on each radiating element region at each band in this configuration. Measured results show that radiation efficiencies of the proposed antenna are improved by up to 20% compared to those of the antenna without a slot.

To develop a liquid crystal polymer (LCP)-based, long-term implantable, retinal stimulation microelectrode array using a novel fabrication method.The fabrication process used laser micromachining and customized thermal-press bonding to produce LCP-based microelectrode arrays. To evaluate the fabrication process and the resultant electrode arrays, in vitro reliability tests and in vivo animal experiments were performed. The in vitro tests consisted of electrode site impedance recording and electrode interlayer adhesion monitoring during accelerated soak tests. For in vivo testing, the fabricated electrode arrays were implanted in the suprachoroidal space of rabbit eyes. Optical coherence tomography (OCT) and electrically evoked cortical potentials (EECPs) were used to determine long-term biocompatibility and functionality of the implant.The fabricated structure had a smooth, rounded edge profile and exhibited moderate flexibility, which are advantageous features for safe implantation without guide tools. After accelerated soak tests at 75 degrees C in phosphate-buffered saline, the electrode sites showed no degradation, and the interlayer adhesion of the structure showed acceptable stability for more than 2 months. The electrode arrays were safely implanted in the suprachoroidal space of rabbit eyes, and EECP waveforms were recorded. Over a 3-month postoperative period, no chorioretinal inflammation or structural deformities were observed by OCT and histologic examination.LCP-based flexible microelectrode arrays can be successfully applied as retinal prostheses. The results demonstrate that such electrode arrays are safe, biocompatible, and mechanically stable and that they can be effective as part of a chronic retinal implant system.

To adopt micropatterning technology in manufacturing silicone elastomer-based microelectrode arrays for retinal stimulation, a silicone-polyimide hybrid microelectrode array was proposed and tested in vivo.Gold microelectrodes were created by semiconductor manufacturing technology based on polyimide and were hybridized with silicone elastomer by spin coating. The stability of the hybrid between the two materials was flex and blister tested. The feasibility of the hybrid electrode was evaluated in the rabbit eye by reviewing optical coherence tomography (OCT) findings after suprachoroidal implantation.The flex test showed no dehiscence between the two materials for 24 hours of alternative flexion and extension from -45.0 degrees to +45.0 degrees . During the blister test, delamination was observed at 8.33 +/- 1.36 psi of pressure stress; however, this property was improved to 11.50 +/- 1.04 psi by oxygen plasma treatment before hybridization. OCT examination revealed that the implanted electrodes were safely located in the suprachoroidal space during the 4-week follow-up period.The silicone-polyimide hybrid microelectrode array showed moderate physical properties, which are suitable for in vivo application. Appropriate pretreatment before hybridization improved electrode stability. In vivo testing indicated that this electrode is suitable as a stimulation electrode in artificial retina.

To identify characteristics measured by optical coherence tomography (OCT) that are correlated with visual outcome after epiretinal membrane (ERM) removal by pars plana vitrectomy (PPV).Interventional, prospective, randomized case series.One hundred and one eyes of 101 patients with idiopathic ERM underwent PPV for ERM removal. Ophthalmic evaluations included best-corrected visual acuity (BCVA) and Stratus OCT preoperatively at 3 and 6 months postoperatively. Relations between three OCT features including integrity of junction between inner and outer segments of photoreceptors (IS/OS junction), macular thickness, foveal contour and the three visual acuity parameters such as preoperative BCVAs, postoperative BCVAs, and the differences between preoperative and postoperative BCVAs (BCVA differences) were evaluated with respect to time.Eyes with disruption of IS/OS junction had significantly lower postoperative BCVA and BCVA differences than those without disruption (P.0001, respectively). "Same" (increment or decrement of BCVA up to 1 Snellen line) and "Better" (visual increment of at least 2 Snellen lines) BCVA outcome groups were significantly different with respect to the status of IS/OS junction (P.005). An increase in the proportion of eyes with photoreceptor disruption was observed at 3 months postoperatively, and this proportion was maintained afterward. Preoperative macular thicknesses showed a positive correlation with BCVA differences, and postoperative macular thicknesses negatively correlated with postoperative BCVA (r0.25; P.05, respectively). Thickness difference and foveal contour were not correlated with the three parameters of visual outcome (P.05, respectively).Photoreceptor disruption detected by OCT was found to be a predictor of poor visual outcome in eyes with idiopathic ERM, and it was found that this disruption may be irreversible. Thus, early membrane removals may beneficially prevent further progression of photoreceptor damage in ERM patients with photoreceptor disruption.

To investigate the effects of combined low-dose cyclosporine and prednisone (Cs/Pd) treatment on circulating CD56+ T cells in patients with Behçet's uveitis.Ten patients with Behçet's uveitis and 10 healthy control subjects were prospectively recruited. The patients were treated with Cs/Pd for 2 months. Phenotypic and functional changes in circulating CD56+ T cells were assayed before and after treatment. CD56+ T-cell subsets were determined by flow cytometric analysis with monoclonal antibodies for CD3, CD4, CD8, CD56, pan gammadelta TCR, and Valpha24. The absolute numbers of cells in the lymphocyte subsets were calculated. Cytokine (IFN-gamma, IL-4, and IL-10) expressions were measured by ELISA and by intracellular cytokine staining.The proportions of CD56+ T cells, specifically CD8highCD56+ and CD56+gammadelta T-cell subsets, were significantly higher in active Behçet's uveitis but normalized after treatment, whereas the total T-lymphocyte count and the absolute numbers of CD56- T cells were unaffected by treatment. The levels of IFN-gamma and IL-4 were elevated in aqueous humor and serum in Behçet's uveitis (P0.001), whereas IL-10 was not detected. After treatment, serum IL-4 levels markedly increased (P0.001), and IFN-gamma production by circulating CD56+ T cells was then suppressed. IL-4 and -10 production by CD56+ T cells was increased by treatment, but in contrast, minimal changes were found in CD56- T cells.The results imply that Cs/Pd treatment for Behçet's uveitis selectively affects the population of and the cytokine expression in CD56+ T cells, but without significant changes in CD56- T cells, and that IFN-gamma-producing CD56+ T cells are the central pathogenic immune cells in Behçet's uveitis.