The Properties of Outer Retinal Band Three Investigated With Adaptive-Optics Optical Coherence Tomography.

PurposeOptical coherence tomography's (OCT) third outer retinal band has been attributed to the zone of interdigitation between RPE cells and cone outer segments. The purpose of this paper is to investigate the structure of this band with adaptive optics (AO)-OCT.MethodsUsing AO-OCT, images were obtained from two subjects. Axial structure was characterized by measuring band 3 thickness and separation between bands 2 and 3 in segmented cones. Lateral structure was characterized by correlation of band 3 with band 2 and comparison of their power spectra. Band thickness and separation were also measured in a clinical OCT image of one subject.ResultsBand 3 thickness ranged from 4.3 to 6.4 μm. Band 2 correlations ranged between 0.35 and 0.41 and power spectra of both bands confirmed peak frequencies that agree with histologic density measurements. In clinical images, band 3 thickness was between 14 and 19 μm. Measurements of AO-OCT of interband distance were lower than our corresponding clinical OCT measurements.ConclusionsBand 3 originates from a structure with axial extent similar to a single surface. Correlation with band 2 suggests an origin within the cone photoreceptor. These two observations indicate that band 3 corresponds predominantly to cone outer segment tips (COST). Conventional OCT may overestimate both the thickness of band 3 and outer segment length

Phase-sensitive imaging of the outer retina using optical coherence tomography and adaptive optics

The cone photoreceptor’s outer segment (OS) experiences changes in optical path length, both in response to visible stimuli and as a matter of its daily course of renewal and shedding. These changes are of interest, to quantify function in healthy cells and assess dysfunction in diseased ones. While optical coherence tomography (OCT), combined with adaptive optics (AO), has permitted unprecedented three-dimensional resolution in the living retina, it has not generally been able to measure these OS dynamics, whose scale is smaller than OCT’s axial resolution of a few microns. A possible solution is to take advantage of the phase information encoded in the OCT signal. Phase-sensitive implementations of spectral-domain optical coherence tomography (SD-OCT) have been demonstrated, capable of resolving sample axial displacements much smaller than the imaging wavelength, but these have been limited to ex vivo samples. In this paper we present a novel technique for retrieving phase information from OCT volumes of the outer retina. The key component of our technique is quantification of phase differences within the retina. We provide a quantitative analysis of such phase information and show that–when combined with appropriate methods for filtering and unwrapping–it can improve the sensitivity to OS length change by more than an order of magnitude, down to 45 nm, slightly thicker than a single OS disc. We further show that phase sensitivity drops off with retinal eccentricity, and that the best location for phase imaging is close to the fovea. We apply the technique to the measurement of sub-resolution changes in the OS over matters of hours. Using custom software for registration and tracking, these microscopic changes are monitored in hundreds of cones over time. In two subjects, the OS was found to have average elongation rates of 150 nm/hr, values which agree with our previous findings

Method for deriving visual field boundaries from OCT scans of patients with retinitis pigmentosa

The location of the loss of the inner segment (IS)/outer segment (OS) border, as seen with frequency domain optical coherence tomography (fdOCT), was determined on fdOCT scans from patients with retinitis pigmentosa. A comparison to visual field loss supported the hypothesis, based upon previous work, that the point at which the IS/OS border disappears provides a structural marker for the edge of the visual field. Repeat fdOCT measures showed good within day reproducibility, while data obtained on average 22.5 months later showed signs of progression. The IS/OS contour shows promise as a measure for following changes in patients undergoing treatment

Spatial and temporal variation of rod photoreceptor reflectance in the human retina

Using adaptive optics imaging tools to image the living retina, numerous investigators have reported temporal fluctuation in the reflectivity of individual cone photoreceptors. In addition, there is cone-to-cone (spatial) variation in reflectivity. As it has only recently become possible to image the complete rod photoreceptor mosaic in the living human retina, we sought to characterize the reflectivity of individual rods and compare their behavior to that of foveal/parafoveal cones. Across two subjects, we were able to successfully track the reflectance behavior of 1,690 rods and 1,980 cones over 12 hours. Rod and cone photoreceptors showed similar regional and temporal variability in their reflectance profiles, suggesting the presence of a common governing physiological process. Within the rod and cone mosaics, there was no sign of spatial clumping of reflectance profile behavior; that is, the arrangement of cells of a given archetypal reflectance profile within the mosaic was indistinguishable from random. These data demonstrate the ability to track the behavior of rod reflectivity over time. Finally, as these and other reflectance changes may be an indicator of photoreceptor function, a future extension of this method will be to analyze this behavior in patients with rod photoreceptor dysfunction (e.g., retinitis pigmentosa, Usher’s syndrome, and congenital stationary night blindness)

Imaging retinal nerve fiber bundles using optical coherence tomography with adaptive optics

AbstractEarly detection of axonal tissue loss in retinal nerve fiber layer (RNFL) is critical for effective treatment and management of diseases such as glaucoma. This study aims to evaluate the capability of ultrahigh-resolution optical coherence tomography with adaptive optics (UHR-AO-OCT) for imaging the RNFL axonal bundles (RNFBs) with 3×3×3μm3 resolution in the eye. We used a research-grade UHR-AO-OCT system to acquire 3°×3° volumes in four normal subjects and one subject with an arcuate retinal nerve fiber layer defect (n=5; 29–62years). Cross section (B-scans) and en face (C-scan) slices extracted from the volumes were used to assess visibility and size distribution of individual RNFBs. In one subject, we reimaged the same RNFBs twice over a 7month interval and compared bundle width and thickness between the two imaging sessions. Lastly we compared images of an arcuate RNFL defect acquired with UHR-AO-OCT and commercial OCT (Heidelberg Spectralis). Individual RNFBs were distinguishable in all subjects at 3° retinal eccentricity in both cross-sectional and en face views (width: 30–50μm, thickness: 10–15μm). At 6° retinal eccentricity, RNFBs were distinguishable in three of the five subjects in both views (width: 30–45μm, thickness: 20–40μm). Width and thickness RNFB measurements taken 7months apart were strongly correlated (p<0.0005). Mean difference and standard deviation of the differences between the two measurement sessions were −0.1±4.0μm (width) and 0.3±1.5μm (thickness). UHR-AO-OCT outperformed commercial OCT in terms of clarity of the microscopic retina. To our knowledge, these are the first measurements of RNFB cross section reported in the living human eye

Heritability of Obsessive-Compulsive symptom dimensions.

Recent research has shown that obsessive-compulsive symptoms (OCS) differ remarkably among patients and can be divided into several symptom dimensions. OCS are influenced by genetic components, but it is unknown to what extent these symptom dimensions are heritable. The phenotypic heterogeneity also raises the question to what extent the symptom dimensions are influenced by specific or shared genetic factors. We studied a population sample of 1,383 female twins from the Virginia Twin Registry. OCS was measured by a questionnaire with 20 items from the Padua Inventory. After factor analysis, three reliable OC symptom dimensions were retained: Rumination, Contamination, and Checking. These OC dimensions were analyzed with multivariate genetic models to investigate both the overlap and uniqueness of genetic and environmental contributions underlying OC symptom dimensions. The multivariate common pathway model provided the best description of the data. All symptom dimensions share variation with a latent common factor, that is, OC behavior. Variation in this common factor was explained by both genes (36%) and environmental factors (64%). Only the Contamination dimension was influenced by specific genes and seemed to be a relatively independent dimension. The results suggest that a broad OC behavioral phenotype exists, influenced by both genes and nonshared environment. In addition, we found evidence for specific genetic and environmental factors underlying the Contamination dimension. Use of the Contamination dimension could therefore provide a powerful approach for the detection of genetic susceptibility loci that contribute to OCS. © 2007 Wiley-Liss, Inc

Temporal changes of human cone photoreceptors observed in vivo with SLO/OCT

In this study we use our previously introduced scanning laser ophthalmoscope (SLO) / transverse scanning optical coherence tomography (TS-OCT) instrument to investigate long term changes in cone photoreceptors. The instrument is capable to provide 3D information of the human cone photoreceptors with negligible eye motion artifacts due to an implemented 3D motion correction on a cellular level. This allows for an in vivo investigation of exactly the same location on the retina with cellular resolution over several days. Temporal changes in the backscattered intensity are observed and quantified within the junction between inner and outer segments of cone photoreceptors, the cone outer segments, the end tips of cone photoreceptors and the retinal pigment epithelium. Furthermore, the length of individual cone outer segments is measured and observed over time. We show, to the best of our knowledge for the first time, that bright reflection spots which are located within the outer segment of cone photoreceptors change their position when observed over extended time periods. The average measured bright reflection spot motion speed corresponds well to the expected cone growth speed. We believe that this observation can be associated with the first direct in vivo imaging of the cone renewal process

Images of photoreceptors in living primate eyes using adaptive optics two-photon ophthalmoscopy

In vivo two-photon imaging through the pupil of the primate eye has the potential to become a useful tool for functional imaging of the retina. Two-photon excited fluorescence images of the macaque cone mosaic were obtained using a fluorescence adaptive optics scanning laser ophthalmoscope, overcoming the challenges of a low numerical aperture, imperfect optics of the eye, high required light levels, and eye motion. Although the specific fluorophores are as yet unknown, strong in vivo intrinsic fluorescence allowed images of the cone mosaic. Imaging intact ex vivo retina revealed that the strongest two-photon excited fluorescence signal comes from the cone inner segments. The fluorescence response increased following light stimulation, which could provide a functional measure of the effects of light on photoreceptors

Analisis Pemetaan dan Pengembangan Potensi Komoditas Tanaman Obat di Kabupaten Pacitan

: This aims of this study are determining the commodity of medicinal plants base and non-base in Pacitan Regency with LQ (Location Quotient) analysis and formulating alternative and priorities development strategies of medicinal plants base commodity in Pacitan Regency with AHP (Analytical Hierarchy Process) analysis. Location were selected in Pacitan Regency as one potential area ofmedicinal plants commodity development. This study was using descriptive method. The data collections were using primary and secondary data. The data were analyzed by LQ and AHP. The study shown that medicinal plants commodity with value of LQ base for 3 consecutive years in 2011-2013 amounted to 1,545; 1,329 and 1,099 in Pacitan Regency is ginger commodity. AHP analysis formulating alternative and priorities development strategies of ginger commodity in Pacitan Regency through five criteria: production, capital, technology, price and market linkages. Alternative and priorities development strategies of ginger commodity in Pacitan Regency are 1) procuring and improving of capital aid that right on target and support appropriate technologies with a priority value of 0,33; 2) increasing availability of adequate market information with a priority value of 0,27;3) increasing ginger commodity processing skills and expanding market of ginger products processed with a priority value of 0,22; 4) improving quality of ginger harvest through the seeds certification process that evenly distributed throughout ginger producers region with a priority value of 0,20

Noninvasive imaging of the human rod photoreceptor mosaic using a confocal adaptive optics scanning ophthalmoscope

The rod photoreceptors are implicated in a number of devastating retinal diseases. However, routine imaging of these cells has remained elusive, even with the advent of adaptive optics imaging. Here, we present the first in vivo images of the contiguous rod photoreceptor mosaic in nine healthy human subjects. The images were collected with three different confocal adaptive optics scanning ophthalmoscopes at two different institutions, using 680 and 775 nm superluminescent diodes for illumination. Estimates of photoreceptor density and rod:cone ratios in the 5°–15° retinal eccentricity range are consistent with histological findings, confirming our ability to resolve the rod mosaic by averaging multiple registered images, without the need for additional image processing. In one subject, we were able to identify the emergence of the first rods at approximately 190 μm from the foveal center, in agreement with previous histological studies. The rod and cone photoreceptor mosaics appear in focus at different retinal depths, with the rod mosaic best focus (i.e., brightest and sharpest) being at least 10 μm shallower than the cones at retinal eccentricities larger than 8°. This study represents an important step in bringing high-resolution imaging to bear on the study of rod disorders