Biomedical subjects

Hiroshi Ishikawa

Publications and source records attributed to Hiroshi Ishikawa.

At least 19 recordsLinked to original sources

PubMed2007

Glaucoma detection with matrix and standard achromatic perimetry.

BACKGROUND: Matrix perimetry is a new iteration of frequency-doubling technology (FDT) which uses a smaller target size in the standard achromatic perimetry presentation pattern. AIM: To compare the performance of matrix and Swedish interactive thresholding algorithm (SITA) perimetry in detecting glaucoma diagnosed by structural assessment. DESIGN: Prospective cross-sectional study. METHODS: 76 eyes from 15 healthy subjects and 61 consecutive glaucoma suspects and patients with glaucoma were included. All patients underwent optic nerve head (ONH) photography, SITA and matrix perimetries, and optical coherence tomography (OCT) within a 6-month period. Glaucoma diagnosis was established by either glaucomatous optic neuropathy or OCT by assessing retinal nerve fibre layer (RNFL) thickness. Mean deviation (MD), pattern standard deviation (PSD), glaucoma hemifield test and cluster of abnormal testing locations were recorded from matrix and SITA perimetries. RESULTS: Similar correlations were observed with matrix and SITA perimetry MD and PSD with either cup-to-disc ratio or OCT mean RNFL. The area under the receiver operating characteristic (AROC) curves of MD and PSD for discriminating between healthy and glaucomatous eyes ranged from 0.69 to 0.81 for matrix perimetry and from 0.75 to 0.77 for SITA perimetry. There were no significant differences among any corresponding matrix and SITA perimetry AROCs. CONCLUSIONS: Matrix and SITA perimetries had similar capabilities for distinguishing between healthy and glaucomatous eyes regardless of whether the diagnosis was established by ONH or OCT-RNFL assessment.

Adult↗

PubMed2006

Glaucoma detection with the Heidelberg retina tomograph 3.

PURPOSE: To compare the ability of the Heidelberg retina tomograph version 3 (HRT 3) and HRT version 2 (HRT 2) to discriminate between healthy and glaucomatous eyes. DESIGN: Retrospective cross-sectional study. PARTICIPANTS: Seventy-one eyes of 71 healthy volunteers and 50 eyes of 50 glaucoma patients were studied. The average visual field mean deviation of the glaucoma group was -6.03+/-5.78 dB. INTERVENTION: All participants had comprehensive ocular examinations, perimetry, and HRT scanning within 6 months. HRT 2 data were analyzed using HRT 3 software without modifying the disc margin. MAIN OUTCOME MEASURES: Discrimination capabilities between healthy and glaucomatous eyes were determined by areas under the receiver operating characteristics (AROCs) curves. Comparisons between corresponding AROCs obtained by HRT 2 and HRT 3 analyses were performed using the nonparametric DeLong method. Agreement between classifications as defined by the different analysis methods was quantified by kappa analysis. RESULTS: The individual stereometric parameters with the best discrimination were linear cup/disc ratio (AROC = 0.897; 95% confidence interval [CI], 0.836-0.958) for standard HRT 3 analysis and horizontal retinal nerve fiber layer curvature (0.905) for HRT 3 glaucoma probability score (GPS) analysis. Areas under the receiver operating characteristics for discrimination between glaucomatous and healthy eyes of the overall classification by HRT 2 Moorfields regression analysis (MRA), HRT 3 MRA, and GPS were 0.927 (95% CI, 0.877-0.977), 0.934 (0.888-0.980), and 0.880 (0.812-0.948), respectively. The difference between the 3 AROCs was not significant (P = 0.44). The agreement between HRT 2 and HRT 3 overall MRA classification was good (kappa = 0.70; CI, 0.59-0.80) with HRT 3 tending to report more abnormalities than HRT 2 analysis. The agreement between overall HRT 3 MRA and overall GPS was kappa = 0.58 (CI, 0.45-0.70). CONCLUSIONS: The glaucoma discriminating ability of the new HRT 3 software is similar to that of the previous generation HRT 2. The GPS analysis showed promising results in differentiating between healthy and glaucomatous eyes without the need for subjective operator input.

Adult↗

PubMed2006

Comparison of visual field defects using matrix perimetry and standard achromatic perimetry.

PURPOSE: To compare visual field (VF) defects found by Swedish interactive thresholding Algorithm (SITA) perimetry and Matrix perimetry, a new VF device that utilizes frequency doubling technology in a 24-2 test pattern. DESIGN: Prospective cross-sectional study. PARTICIPANTS: Fifty eyes from 50 subjects with SITA field defects were recruited for an observational study. METHODS: Swedish Interactive Threshold Algorithm and Matrix VF testing were performed on patients from a glaucoma practice. To evaluate the learning effect on the performance of the VF, we tested subsets of each group who had previous experience with standard automated perimetry (SAP). MAIN OUTCOME MEASURES: Test duration, mean threshold, mean deviation (MD), pattern standard deviation (PSD), glaucoma hemifield test, and number of abnormal points on the pattern deviation plot were evaluated for each device. RESULTS: Test duration was significantly shorter for Matrix (SITA, 357.0+/-85.6 seconds; Matrix, 319.5+/-16.5 seconds; P = 0.0002, paired t-test). Thirty-six percent of eyes with SITA VF defects showed a normal Matrix field. In 30 of 32 eyes (94%) where both devices showed VF defects, the defects were congruent. Mean threshold value was significantly lower with Matrix compared to SITA (P<0.0001, paired t-test), as was MD (-5.34+/-5.42 dB, -4.14+/-5.29 dB, respectively; P = 0.03, paired t-test). There was no significant difference in PSD between the 2 devices (P = 0.78, paired t-test). Matrix delineated significantly smaller (P = 0.005, Wilcoxon's test) and deeper (P<0.001, Wilcoxon's test) defects than those found with SITA. Similar results were observed in the subgroups with prior SAP experience. CONCLUSIONS: The Matrix examination did not detect 36% of abnormal SITA fields. Matrix field defects were smaller and deeper than those appearing in SITA perimetry.

Adult↗

PubMed2006

Independent origins of tetraploid cryptic species in the fern Ceratopteris thalictroides.

Ceratopteris thalictroides (L.) Brongn is a tetraploid fern species that contains at least three cryptic species, the south, the north and the third type. In this study we combined data from both chloroplast DNA (cpDNA) and nuclear DNA sequences of three diploid species and three cryptic species of C. thalictroides to unravel the origin of the cryptic species, particularly of the reticulate relationships among the diploid and tetraploid taxa in the genus Ceratopteris. Of the three diploid species examined, C. cornuta had cpDNA identical to that of the tetraploid third type plants, and this diploid species is a possible maternal ancestor of the tetraploid third type. Analysis of the homologue of the Arabidopsis thaliana LEAFY gene (CLFY1) identified ten alleles in the genus Ceratopteris, with six alleles found in C. thalictroides. The unrooted tree of the CLFY1 gene revealed four clusters. Each cryptic species showed fixed heterozygosity at the CLFY1 locus and had two alleles from different clusters of the CLFY1 tree. Consideration of the cpDNA sequences, CLFY1 genotypes of the cryptic species and CLFY1 gene tree in concert suggested that the cryptic species of C. thalictroides had originated through independent allopolyploidization events involving C. cornuta and two unknown hypothetical diploid species.

Base Sequence↗

PubMed2006

Oxidative stress causes heart failure with impaired mitochondrial respiration.

Elderly people insidiously manifest the symptoms of heart failure, such as dyspnea and/or physical disabilities in an age-dependent manner. Although previous studies suggested that oxidative stress plays a pathological role in the development of heart failure, no direct evidence has been documented so far. In order to investigate the pathological significance of oxidative stress in the heart, we generated heart/muscle-specific manganese superoxide dismutase-deficient mice. The mutant mice developed progressive congestive heart failure with specific molecular defects in mitochondrial respiration. In this paper, we showed for the first time that the oxidative stress caused specific morphological changes of mitochondria, excess formation of superoxide (O(2)(*)(-)), reduction of ATP, and transcriptional alterations of genes associated with heart failure in respect to cardiac contractility. Accordingly, administration of a superoxide dismutase mimetic significantly ameliorated the symptoms. These results implied that O(2)(*)(-) generated in mitochondria played a pivotal role in the development and progression of heart failure. We here present a bona fide model for human cardiac failure with oxidative stress valuable for therapeutic interventions.

Animals↗

PubMed2006

Abducens nerve palsy and postganglionic Horner syndrome with or without severe headache.

OBJECTIVE: To report the clinical features of 9 patients with both abducens nerve palsy and postganglionic Horner syndrome. PATIENTS AND METHODS: Nine patients with this symptom combination were examined by our Neuro-ophthalmology Clinic in Nihon University Itabashi Hospital between 1978 and 2004. Patient ages ranged from 28 to 63 years (average 47.2+/-8.7 years). Six patients were males and 3 were females. Primary diseases, accompanying symptoms and prognoses were surveyed. RESULTS: In primary diseases, neoplasm in the cavernous sinus was observed in 2 patients, sphenoidal sinus cyst in 2, intra-cavernous carotid aneurysm in 2, epipharynx carcinoma in 1, chordoma in the base of the skull in 1, and meningioma in the middle cranial fossa in 1. Five patients with extra-cavernous sinus lesions; sphenoidal sinus cyst, epipharynx carcinoma, chordoma and meningioma, complained of severe headache. However, in patients without severe headache, intra-cavernous sinus lesions such as carotid aneurysm and metastatic carcinoma were detected. After therapy, abducens nerve palsy improved in 5 patients, however, Horner syndrome persisted in all patients. CONCLUSION: We emphasize that this symptom combination is an important sign of lesions in the posterior portion of the cavernous sinus or in its vicinity. Moreover, the presence or absence of severe headache depends on whether the lesion is in the intra-cavernous or extra-cavernous sinus.

Abducens Nerve Diseases↗

PubMed2006

Complete hydatidiform mole and normal live birth following intracytoplasmic sperm injection.

A twin pregnancy with complete hydatidiform mole (HM) and preterm birth of a normal female infant after intracytoplasmic sperm injection (ICSI) conception was experienced. ICSI due to severe oligozoospermia was performed on three ova, and three embryos with confirmed two proneclei (2PN) were subsequently transferred to the uterus. At 7 weeks of gestation, molar pregnancy as well as a viable fetus was recognized. At 33 weeks, the pregnancy was terminated due to preterm labor. Dichorionic pregnancy consisting of a normal fetus and placenta in one chorionic membrane and complete HM in the other was recognized. Cytomolecular analysis indicated that the complete HM genome was derived from duplication of a single sperm, and a normal neonate was from biparental genomes. It should be noted that ICSI can avoid incomplete HM (mostly triploid) due to multi-sperm fertilization but might not be able to avoid complete HM (paternal diploid) although such a risk is very low. This is the second report of this condition and is accompanied by the first well-described molecular analysis.

Adult↗

PubMed2006

Persistence of Cloquet's canal in normal healthy eyes.

PURPOSE: Optic nerve head (ONH) structural imaging with state-of-the-art, high-speed, ultra-high-resolution optical coherence tomography (hsUHR-OCT). DESIGN: Observational cohort study. METHODS: ONH centered 3-dimensional (94,371,840 voxel measurements in a 6- x 6- x 1.4-mm tissue volume) hsUHR-OCT data were obtained in one eye from each of six males and nine females normal healthy volunteers (40 +/- 9 years of age). The presence of structures projecting anteriorly from the disk into the vitreous was noted. RESULTS: Structures were noted in 14 of 15 (93%) examined eyes, emanating from the rim of the ONH at the nasal inferior sector, presenting as thin tissue meandering into the vitreous. CONCLUSIONS: Previous technologies provided limited visualization of ONH structures. The ability to scan the entire disk using 3-dimensional OCT (3D-OCT) in a high-density raster pattern reveals a high frequency of persistence of Cloquet's canal in the normal healthy eye.

Adult↗

PubMed2006

Effect of corneal drying on optical coherence tomography.

PURPOSE: To determine the effect of corneal drying on the outcome of optical coherence tomography (OCT). DESIGN: Cohort study. PARTICIPANTS: Seventeen normal participants (mean age, 39+/-12 years). METHODS: Subjects underwent a series of peripapillary circular StratusOCT scans (version 3.0; Carl Zeiss Meditec, Inc., Dublin, CA) in a randomly selected eye. Baseline scan sets were acquired, and thereafter, blinking was prevented by taping the eyelid. Eyelid taping was immediately followed by 6 to 8 serial scan sets, each separated by 20 seconds. After removing the eyelid tape, 3 additional scans were acquired at 1, 2, and 4 minutes of blinking freely. MAIN OUTCOME MEASURES: The analyzed outcome measures were scan quality as defined by signal-to-noise ratio (SNR) and signal strength (SS) provided by the built-in OCT software and mean nerve fiber layer (NFL) thickness. RESULTS: Significant reductions in SNR, SS, and NFL were noted at each scanning point in the drying phase (for each, P<0.015, paired t test) except for NFL thickness measurements acquired at 140 and 160 seconds. The reduction in NFL thickness exceeded the 95% confidence limit of the reported reproducibility error of StratusOCT after 15 seconds of corneal drying. After 1 and 2 minutes of blinking freely, there was still a significant reduction in NFL thickness compared with the baseline value, which was no longer evident at the 4-minute scan. CONCLUSIONS: Corneal dryness affects OCT scan quality and measured NFL thickness after a short exposure time. It is recommended to instruct those who are scanned to blink frequently or to instill artificial tears.

Adult↗

PubMed2006

Retinal nerve fiber layer assessment using optical coherence tomography with active optic nerve head tracking.

PURPOSE: To develop an eye-motion-tracking optical coherence tomographic (OCT) method and assess its effect on image registration and nerve fiber layer (NFL) thickness measurement reproducibility. METHODS: A system capable of tracking common fundus features based on reflectance changes was integrated into a commercial OCT unit (OCT II; Carl Zeiss Meditec, Inc., Dublin, CA) and tested on healthy subjects and patients with glaucoma. Twenty successive peripapillary NFL scans were obtained with tracking and 20 without tracking, for 40 images in each session for each eye. Subjects participated in one session on three different days. Composite OCT scans and composite fundus images were generated for assessment of eye tracking. NFL thickness measurement reproducibility was also assessed. RESULTS: Seven healthy and nine glaucomatous eyes of 16 subjects were recruited. A qualitative assessment of composite OCT scans and composite fundus images showed little motion artifact or blurring along edges and blood vessels during tracking; however, those structures were less clearly defined when tracking was disengaged. There was no significant reproducibility difference with and without tracking in both intra- and intersession NFL measurement SD calculations in any location. The mean retinal pixel SD was significantly smaller with tracking than without (490.9 +/- 19.3 microm vs. 506.4 +/- 31.8 microm, P = 0.005, paired t-test). CONCLUSIONS: A retinal-tracking system was successfully developed and integrated into a commercial OCT unit. Tracking OCT improved the consistency of scan registration, but did not influence NFL thickness measurement reproducibility in this small sample study.

Adult↗

PubMed2006

Involvement of radical species in inactivation of Vibrio parahaemolyticus in saline solutions by direct-current electric treatment.

The effect of pulsed low-direct-current (DC) electric treatment on the viability of Vibrio parahaemolyticus in artificial seawater and 3.0% (w/v) NaCl solution was studied as a function of available chlorine (AC) concentration. The amount of AC generated during the DC electric treatment increased in proportion to the amount of passed DC. The survival fraction of V. parahaemolyticus cells decreased depending on AC concentration. When the generated AC components were completely reduced in the presence of sufficient sodium thiosulfate, no inactivation of V. parahaemolyticus in the NaCl solution was observed during the DC electric treatment. Based on the AC concentration, the inactivation efficacies of the DC electric treatment of the seawater and NaCl solution were approximately 4-fold and 30-fold that of the exogenous addition of sodium hypochlorite, respectively. Fluorometric analysis using 2-[6-(4'-hydroxy)phenoxy-3H-xanthen-3-on-9-yl]benzoic acid showed that the generation of highly reactive radical species such as hydroxyl radical in the seawater and NaCl solution occurred during the DC electric treatment. The amount of generated radical species depended on the amount of passed DC. It is concluded that pulsed low-DC electric treatment of saline solutions exerts superior inactivation efficacy against V. parahaemolyticus to sodium hypochlorite owing to the generation of radical species.

Electricity↗

PubMed2006

Radiographic evaluation of caudal vena cava size as a useful parameter for the diagnosis of heart disease in dairy cattle.

To quantify the radiographic parameters of the caudal vena cava (CVC) in healthy cattle and demonstrate their clinical usefulness, the present study compared the ratios of the diameter of the thoracic CVC to the diameter of the aorta (Ao) and length of the thoracic vertebrae (VL), which are all positioned in the same intercostal space, in 81 healthy control cattle (43 growing, 38 adult) and 10 cattle with heart disease. The average diameter of the CVC (CVCave) was correlated with the size of the Ao and VL in the control cows. Although the diameter and pulsation index of the CVC differed significantly between the growing and adult cows, the ratios of CVC/Ao and CVC/VL were fixed values for both the growing and mature cattle. However, in the cattle with heart disease, the pulsation index of the CVC was significantly lower or there was absence of pulsation due to a dilated CVC, and the ratio of CVCave/Ao and CVCave/VL were significantly higher than those in the healthy cattle.

Animals↗

PubMed2006

[A case of preeclampsia-eclampsia reversible posterior leukoencephalopathy syndrome].

BACKGROUND: We report a case of preeclampsiaeclampsia reversible posterior leukoencephalopathy syndrome (P-ERPLS). CASE: The patient was a 26-year-old Ethiopian woman in the 30th week of her pregnancy. She consulted internal medicine and ophthalmology department doctors in our university hospital for headache on August 7, 2004. Her visual acuity was counting fingers in both eyes. On August 9, she underwent urgent cesarean section after eclampsia developed. The fluid-attenuated inversion recovery (FLAIR) images of magnetic resonance imaging (MRI) showed a high signal intensity on white matter in both occipital lobes. The patient visited our ophthalmology clinic again on August 20. We detected minor decreased visual acuity in her left eye, and minor left homonymous hemianopia was diagnosed by the confrontation visual field test. On August 31, the abnormal findings in the FLAIR image had completely disappeared. Her blood pressure returned to the normal range, and her general and visual symptoms improved. CONCLUSION: Since a patient with eclampsia is in poor general condition, ophthalmologic examination is limited. However, this syndrome should be considered in a pregnant patient with visual symptoms.

Adult↗

PubMed2006

[Clinical evaluation of primary position downbeat nystagmus].

PURPOSE: Primary position downbeat nystagmus is a vertical nystagmus with a rapid phase downwards presenting in any gaze. We evaluated causative lesions, etiology, and incidence by age groups. MATERIALS AND METHODS: Twenty-five patients with primary position downbeat nystagmus were enrolled in this study. Their causative lesions, etiology, and frequency by age group were investigated. We divided the patients into 3 groups depending on age; under 30, from 30 to 60, and over 60 years. RESULT: Cerebrovascular disorder was diagnosed in 5 patients. Four patients had cerebellar degeneration. Three patients had multiple sclerosis or Arnold-Chiari malformation. Two patients had cerebellar tumor. In the young group under 30, etiology was mainly cerebellar tumor or multiple sclerosis. Especially cerebellar tumor was limited to this group. In the middle age group, there was no distinctive tendency. In the older group over 60 years, cerebrovascular disorder was predominant. In 10 patients with intracranial lesions, the foci were located in the cerebellum, pons, or medulla oblongata. CONCLUSION: The causes of primary position down beat nystagmus tended to be age-dependent. The locations of causative lesions were the cerebellum and the inferior brain stem.

Adolescent↗

PubMed2006

[A case of N3 gastric cancer successfully treated by TS-1 followed by curative resection].

We report a case of N 3 gastric cancer successfully treated by TS-1 followed by curative resection. The patient was a 64-year-old male. Gastrointestinal endoscopic examination showed advanced gastric cancer. Examination by computed tomography revealed gastric cancer and swollen para-aortic lymph nodes. This patient was treated by neoadjuvant chemotherapy with oral administration of TS-1 (120 mg/day, day 1-28 with 2 weeks rest). After 3 courses of TS-1, the primary lesion and swollen lymph nodes were remarkably reduced. This chemotherapy enabled pancreatoduodenectomy with D 3 lymph node dissection in curative resection. The pathological diagnosis was por, pT 2, pMP and pap, pT 1, pSM 2, pPM(-), pDM(-), pN 1, pStage II and curability A. This neoadjuvant chemotherapy regimen seems to be an effective and promising therapy for patients with advanced gastric cancer.

Adenocarcinoma↗

PubMed2006

Characterization of mitochondria in cisplatin-resistant human ovarian carcinoma cells.

One of the mechanisms of cisplatin cell cytotoxicity is the mitochondria-associated induction of apoptosis. The morphological or functional change of mitochondria in cisplatin-resistant cells has already been reported. Herein we present additional data describing the mitochondrial genomic and functional changes in cisplatin- resistant cells. Cisplatin increased the level of apoptotic cells in cisplatin-sensitive human ovarian carcinoma OV 2008 and C13 cells by 3.90+/-1.01 (SD; N=3) (p<0.01)-fold and 2.03+/-0.20 (SD; N=3) (p<0.01)-fold compared to the basal apoptotic level. This indicates a lower level induction of apoptosis by 50% in cisplatin-resistant OV 2008/C13 *5.25 variant (C13) cells. In both cell types, cisplatin cytotoxicity is mostly inhibited by the caspase-9 inhibitor as well as the caspase-3 inhibitor, Ac-DEVD-CHO, suggesting that the mitochondrial downstream event was functioning well in both the C13 cells and in OV 2008 cells. Mitochondrial transmembrane potential (DeltaPsim) determined by flow cytometry using DiOC6-stained cells revealed a significant depolarization of C13 cells as compared to OV 2008 cells. Treatment of these cells with cisplatin or hydrogen peroxide induces complete mitochondrial DNA damage in OV 2008 cells, while only partial DNA-destruction is observed in C13 cells, strongly suggesting that mitochondria are resistant to cisplatin and oxidative stress response. Continuous oxygen consumption of these cells monitored by a multi-channel dissolved oxygen meter is 1.70-fold higher in OV 2008 cells than C13 cells and the oxygen consumption was decreased by 30% in C13 cells, suggesting mitochondrial respiratory malfunction in these cells. The hypothesis generated here is that mitochondrial DNA resistance to cisplatin and oxidative stress response might be one of the main characteristics concerning the lower level of apoptosis induced by cisplatin. However, the mechanism by which the mitochondrial DNA encoded molecule is involved in cisplatin resistance remains to be determined.

Apoptosis↗

PubMed2005

Comparison of ultrahigh- and standard-resolution optical coherence tomography for imaging macular pathology.

OBJECTIVE: To compare ultrahigh-resolution optical coherence tomography (UHR OCT) with standard-resolution OCT for imaging macular diseases, develop baselines for interpreting OCT images, and identify situations where UHR OCT can provide additional information on disease morphology. DESIGN: Cross-sectional study. PARTICIPANTS: One thousand two eyes of 555 patients with different macular diseases including macular hole, macular edema, central serous chorioretinopathy, age-related macular degeneration (AMD), choroidal neovascularization, epiretinal membrane, retinal pigment epithelium (RPE) detachment, and retinitis pigmentosa. METHODS: A UHR ophthalmic OCT system that achieves 3-microm axial image resolution was developed for imaging in the ophthalmology clinic. Comparative studies were performed with both UHR OCT and standard 10-microm-resolution OCT. Standard scanning protocols of 6 radial 6-mm scans through the fovea were obtained with both systems. Ultrahigh-resolution OCT and standard-resolution OCT images were correlated with standard ophthalmic examination techniques (dilated ophthalmoscopy, fluorescein angiography, indocyanine green angiograms) to assess morphological information contained in the images. MAIN OUTCOME MEASURES: Ultrahigh-resolution and standard-resolution OCT images of macular pathologies. RESULTS: Correlations of UHR OCT images, standard-resolution images, fundus examination, and/or fluorescein angiography were demonstrated in full-thickness macular hole, central serous chorioretinopathy, macular edema, AMD, RPE detachment, epiretinal membrane, vitreal macular traction, and retinitis pigmentosa. Ultrahigh-resolution OCT and standard-resolution OCT exhibited comparable performance in differentiating thicker retinal layers, such as the retinal nerve fiber, inner and outer plexiform, and inner and outer nuclear. Ultrahigh-resolution OCT had improved performance differentiating finer structures or structures with lower contrast, such as the ganglion cell layer and external limiting membrane. Ultrahigh-resolution OCT confirmed the interpretation of features, such as the boundary between the photoreceptor inner and outer segments, which is also visible in standard-resolution OCT. The improved resolution of UHR OCT is especially advantageous in assessing photoreceptor morphology. CONCLUSIONS: Ultrahigh-resolution OCT enhances the visualization of intraretinal architectural morphology relative to standard-resolution OCT. Ultrahigh-resolution OCT images can provide a baseline for defining the interpretation of standard-resolution images, thus enhancing the clinical utility of standard OCT imaging. In addition, UHR OCT can provide additional information on macular disease morphology that promises to improve understanding of disease progression and management.

Adult↗

PubMed2005

Illusory volumes in human stereo perception.

Any complete theory of human stereopsis must model not only how the correspondences between locations in the two views are determined and the depths are recovered from their disparity, but also how the ambiguity arising from such factors as noise, periodicity, and large regions of constant intensity are resolved and missing data are interpolated. In investigating this process of recovering surface structure from sparse disparity information, using stereo pairs with sparse identifiable features, we made an observation that contradicts all extant models. It suggests the inadequacy of retinotopic representation in modeling surface perception in this stage. We also suggest a possible alternative theory, which is a minimization of the modulus of Gaussian curvature.

Depth Perception↗