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Biomedical subjects

Ann E Elsner

Publications and source records attributed to Ann E Elsner.

12 recordsLinked to original sources
PubMed2005

Imaging polarimetry in central serous chorioretinopathy.

PURPOSE: To evaluate a noninvasive technique to detect the leakage point of central serous chorioretinopathy (CSR), using a polarimetry method. DESIGN: Prospective cohort study. METHODS SETTING: Institutional practice. PATIENTS: We examined 30 eyes of 30 patients with CSR. MAIN OUTCOME MEASURES: Polarimetry images were recorded using the GDx-N (Laser Diagnostic Technologies). We computed four images that differed in their polarization content: a depolarized light image, an average reflectance image, a parallel polarized light image, and a birefringence image. Each polarimetry image was compared with abnormalities seen on fluorescein angiography. RESULTS: In all eyes, leakage area could be clearly visualized as a bright area in the depolarized light images. Michelson contrasts for the leakage areas were 0.58 +/- 0.28 in the depolarized light images, 0.17 +/- 0.11 in the average reflectance images, 0.09 +/- 0.09 in the parallel polarized light images, and 0.11 +/- 0.21 in the birefringence images from the same raw data. Michelson contrasts in depolarized light images were significantly higher than for the other three images (P < .0001, for all tests, paired t test). The fluid accumulated in the retina was well-visualized in the average and parallel polarized light images. CONCLUSIONS: Polarization-sensitive imaging could readily localize the leakage point and area of fluid in CSR. This may assist with the rapid, noninvasive assessment of CSR.

Adult↗
PubMed2005

Spectral imaging of the area of internal limiting membrane peeling.

PURPOSE: To evaluate a spectral imaging technique to detect the area of internal limiting membrane (ILM) peeling after vitrectomy for idiopathic macular hole. MATERIALS AND METHODS: In a prospective study, 15 eyes of 15 patients with idiopathic macular holes were tested. After vitrectomy with ILM peeling, retinal images were taken with color fundus photography, red-free fundus photography, and scanning laser ophthalmoscope imaging at 488 nm, 514 nm, 633 nm, and 780 nm. We calculated the Michelson contrast at the margin of ILM peeling, and each image was rank ordered for the ability to discern the margin of ILM peeling. RESULTS: The Michelson contrasts in scanning laser ophthalmoscope images at 488 nm and 514 nm were significantly larger than those in images at 633 nm and 780 nm and in the red-free fundus photograph. The scanning laser ophthalmoscope images at 488 nm and 514 nm were rated superior to images at 633 nm and 780 nm, the color fundus photograph, and the red-free fundus photograph. CONCLUSION: The scanning laser ophthalmoscope images at 488 nm and 514 nm provide a better tool than some of the common clinical means for detection of the area of ILM peeling. This may assist with rapid, noninvasive assessment of ILM peeling.

Aged↗
PubMed2005

Improved contrast of peripapillary hyperpigmentation using polarization analysis.

PURPOSE: To improve detection and quantification of peripapillary hyperpigmentation, associated with aging, open-angle glaucoma, and age-related macular degeneration. METHODS: A computational approach was implemented with a readily available polarimeter used in glaucoma diagnosis, a nerve fiber analyzer (GDx; Laser Diagnostic Technologies, San Diego, CA). Using near-infrared illumination at each of 20 input polarizations, a series of image pairs was digitized. One image is made from the light returning from the eye that is polarized parallel to the input light, and the other image is made from the light that is rotated by 90 degrees from the input polarization. Using raw data from these 40 images, and a simplified model of ocular polarization properties, images were computed based on their polarization content. Regions of hyperpigmentation, selected using stereo color fundus photographs, were quantified in three types of polarimetry images: (1) a depolarized light image resulting mainly from multiply scattered light; (2) an average image that is typical of confocal images; and (3) a birefringence image. Measurements on versus off hyperpigmentation were made in nine persons with suspected glaucoma or patients with primary open-angle glaucoma, selected to have clinically visible hyperpigmentation. RESULTS: In the depolarized light images, hyperpigmented regions were significantly brighter than comparison areas (P < 0.0425)-that is, had more scattered light and therefore more contrast (P < 0.037) than did color or other polarimetric images. CONCLUSIONS: With this polarimetry imaging method, subretinal tissues such as those with hyperpigmentation can be visualized with increased contrast.

Cross-Sectional Studies↗
PubMed2004

Birefringence of intraocular lenses.

PURPOSE: To determine the polarization properties of intraocular lenses (IOLs) in vitro and whether these properties contribute to significant intraindividual differences in the optical performance of the eye, including retinal imaging. SETTING: Tokyo Medical University, Shinjuku, Tokyo, Japan. METHODS: The single-pass linear birefringence was evaluated at 546.5 nm for the central 1.5 mm of the following IOLs: poly(methyl methacrylate) (MZ30BD, EZE55, UV-60SB, 824C, LS-106S), acrylic (MA60BM, VA-60CB, AR40e), and silicone (SI-40NB). To evaluate the influence of folding, models MA60BM, VA-60CB, AR40e, and SI-40NB were folded, unfolded, and measured for retardation values. To evaluate glistenings in vitro, experimental manipulation using the MA60BM was done to produce regions of glistenings. Retardation values were measured at the center of the micro-opacities and the adjacent clear areas. RESULTS: Striking polarization patterns were seen only in the compression-molded IOL, model 824C. Its retardation values ranged from 2.8 to 41.0 nm in the 30.0 diopter model. In other IOLs, the in vitro retardation values were minimal, even with folding, and barely nonuniform with glistening formation. CONCLUSIONS: The birefringence of the 824C IOL could be a source of error during polarization measurements of the fundus or with instruments that transmit polarized light through the IOL.

Birefringence↗
PubMed2003

Compact scanning laser ophthalmoscope with high-speed retinal tracker.

The effectiveness of image stabilization with a retinal tracker in a multifunction, compact scanning laser ophthalmoscope (TSLO) was demonstrated in initial human subject tests. The retinal tracking system uses a co confocal reflectometer with a closed-loop optical servo system to lock onto features in the fundus. The system is multifarious and modular to allow configuration for many research a clinical applications. Adult volunteers were tested without mydriasis to optimize the tracking instrumentation and to characterize imaging performance. The retinal tracking system achieves a bandwidth of greater than 1 kHz, which permits tracking at rates that greatly exceed the maximum rate of motion of the human eye. The TSLO system stabilized images to an accuracy of 0.05 deg in all test subjects during ordinary saccades with a velocity up to approximately 500 deg/s. Feature lock was maintained for minutes despite subject eye blinking. Even when nearly 1000 frames were coadded, image blur was minimal. Successful frame coaddition allowed image acquisition with decreased noise in low-light applications. The retinal tracking system significantly enhances the imaging capabilities of the scanning laser ophthalmoscope.

Equipment Design↗
PubMed2003

Improved contrast of subretinal structures using polarization analysis.

PURPOSE: To improve the ability to detect and quantify the early retinal changes associated with aging, age-related maculopathy, and age-related macular degeneration. METHODS: A computational approach was implemented for analyzing images using a readily available polarimeter that is used for glaucoma diagnosis. This device, the GDx Nerve Fiber Analyzer (Laser Diagnostic Technologies, Inc., San Diego, CA), takes a series of images as a function of the polarization angle of the illuminating light. For each of 20 input polarizations, pairs of retinal images are digitized. One image is made of the light returning from the eye that is polarized parallel to the input light, and the other image is made of the light that is rotated by 90 degrees from the input polarization. Using the raw data from these 40 images, and a simplified model of the polarization properties of the eye, we calculated the amount of light that returns in a parallel polarized state, and the amount of light that is depolarized by multiple scattering. Measurements were made in seven subjects with small drusen. RESULTS: The depolarized light image produced a 3.4 times higher contrast of drusen and subretinal changes than the parallel polarized light images. CONCLUSIONS: Polarization-sensitive imaging combined with a simple computational approach allows the measurement of the retinal distribution of multiply scattered light. With this technique, retinal imaging of age-related changes in retinal and subretinal tissue can be improved.

Contrast Sensitivity↗
PubMed2002

Identifying live nematodes in diffuse unilateral subacute neuroretinitis by using the scanning laser ophthalmoscope.

OBJECTIVE: To describe use of the scanning laser ophthalmoscope (SLO) to identify live nematodes in patients with diffuse unilateral subacute neuroretinitis. METHODS: Infrared, red, and blue illumination (780, 633, and 488 nm, respectively) in an SLO were used to image and evaluate functional retinal status in patients with late-stage diffuse unilateral subacute neuroretinitis. An examination to identify live nematodes was performed in the affected eyes. RESULTS: Using blue illumination, the ocular fundus appeared dark and provided a high-contrast background for the white image of the worm. The red laser was used to perform red-on-red perimetry. We also used perimetry stimulus to stimulate the worm's movement and pinpoint its location. We precisely defined the relation between the fixation point and the worm to plan accurate laser treatment. The infrared laser is safe and comfortable for prolonged examination. Using the SLO, several physicians simultaneously visualized the ocular fundus. Video output from the SLO provided temporal information, excellent for enhancing detection of worms, which was displayed dynamically on video. CONCLUSIONS: Although examination with a fundus contact lens by skilled ophthalmologists is the method of choice, the SLO provides a new examination modality with distinct advantages for identifying live worms in young patients with diffuse unilateral subacute neuroretinitis.

Adolescent↗
PubMed2002

Cone photopigment in older subjects: decreased optical density in early age-related macular degeneration.

We measured changes to cone photoreceptors in patients with early age-related macular degeneration. The data of 53 patients were compared with normative data for color matching measurements of long- and middle-wavelength-sensitive cones in the central macula. A four-parameter model quantified cone photopigment optical density and kinetics. Cone photopigment optical density was on average less for the patients than for normal subjects and was uncorrelated with visual acuity. More light was needed to reduce the photopigment density by 50% in the steady state for patients. These results imply that cone photopigment optical density is reduced by factors other than slowed kinetics.

Aged↗
PubMed2002

Imaging and visualization of pathology beneath the retinal surface.

Pathology beneath the highly reflective surface, such as the human retina, is key in the detection and management of disease. Advanced imaging techniques can help reveal these. Visualization and guiding the imaging to the appropriate area still remain as problems, in part due to the small scale of the pathology with respect to the potential area to be covered.

Aged↗