PubMed Health⌕ Search

Biomedical subjects

E A Swanson

Publications and source records attributed to E A Swanson.

At least 19 recordsLinked to original sources
PubMed1995

Optical coherence tomography of the human retina.

OBJECTIVE: To demonstrate optical coherence tomography for high-resolution, noninvasive imaging of the human retina. Optical coherence tomography is a new imaging technique analogous to ultrasound B scan that can provide cross-sectional images of the retina with micrometer-scale resolution. DESIGN: Survey optical coherence tomographic examination of the retina, including the macula and optic nerve head in normal human subjects. SETTING: Research laboratory. PARTICIPANTS: Convenience sample of normal human subjects. MAIN OUTCOME MEASURES: Correlation of optical coherence retinal tomographs with known normal retinal anatomy. RESULTS: Optical coherence tomographs can discriminate the cross-sectional morphologic features of the fovea and optic disc, the layered structure of the retina, and normal anatomic variations in retinal and retinal nerve fiber layer thicknesses with 10-microns depth resolution. CONCLUSION: Optical coherence tomography is a potentially useful technique for high depth resolution, cross-sectional examination of the fundus.

Fovea Centralis↗
PubMed1995

Quantification of nerve fiber layer thickness in normal and glaucomatous eyes using optical coherence tomography.

PURPOSE: Quantitative assessment of nerve fiber layer (NFL) thickness in normal and glaucomatous eyes, and correlation with conventional measurements of the optic nerve structure and function. METHODS: We studied 59 eyes of 33 subjects by conventional ophthalmologic physical examination, Humphrey 24-2 visual fields, stereoscopic optic nerve head photography, and optical coherence tomography. RESULTS: Nerve fiber layer thickness as measured by optical coherence tomography demonstrated a high degree of correlation with functional status of the optic nerve, as measured by visual field examination (P = .0001). Neither cupping of the optic nerve nor neuroretinal rim area were as strongly associated with visual field loss as was NFL thickness (P = .17 and P = .21, respectively). Cupping correlated with NFL thickness only when the cup was small (cup-to-diameter ratio, 0.1 to 0.3) or large (cup-to-diameter ratio, 0.8 to 1.0) (P = .006); there was no correlation between cupping and NFL thickness otherwise. Nerve fiber layer, especially in the inferior quadrant, was significantly thinner in glaucomatous eyes than in normal eyes (P = .04). Finally, we found a decrease in NFL thickness with aging, even when controlling for factors associated with the diagnosis of glaucoma (P = .03). CONCLUSIONS: Nerve fiber layer thickness can be measured using optical coherence tomography. These measurements provide good structural and functional correlation with known parameters.

Female↗
PubMed1995

Quantitative assessment of macular edema with optical coherence tomography.

OBJECTIVE: To evaluate optical coherence tomography, a new technique for high-resolution cross-sectional imaging of the retina, for quantitative assessment of retinal thickness in patients with macular edema. DESIGN: Survey examination with optical coherence tomography of patients with macular edema. SETTING: Referral eye center. PATIENTS: Forty-nine patients with the clinical diagnosis of diabetes or diabetic retinopathy and 25 patients with macular edema secondary to retinal vein occlusion, uveitis, epiretinal membrane formation, or cataract extraction. MAIN OUTCOME MEASURES: Correlation of optical coherence tomograms with slit-lamp biomicroscopy, fluorescein angiography, and visual acuity. RESULTS: Optical coherence tomograms of cystoid macular edema closely corresponded to known histopathologic characteristics. Quantitative measurement of retinal thickness is possible because of the well-defined boundaries in optical reflectivity at the inner and outer margins of the neurosensory retina. Serial optical coherence tomographic examinations allowed tracking of both the longitudinal progression of macular thickening and the resolution of macular edema after laser photocoagulation. In patients with diabetic retinopathy, measurements of central macular thickness with optical coherence tomography correlated with visual acuity, and optical coherence tomography was more sensitive than slit-lamp biomicroscopy to small changes in retinal thickness. CONCLUSIONS: Optical coherence tomography appears useful for objectively monitoring retinal thickness with high resolution in patients with macular edema. It may eventually prove to be a sensitive diagnostic test for the early detection of macular thickening in patients with diabetic retinopathy.

Adult↗
PubMed1995

Optical coherence tomography of central serous chorioretinopathy.

PURPOSE: To assess the potential of a new imaging technique, optical coherence tomography, for the diagnosis and monitoring of central serous chorioretinopathy. Optical coherence tomography is a novel noninvasive, noncontact imaging modality that produces high longitudinal resolution, cross-sectional tomographs of ocular tissue. METHODS: Optical coherence tomography is analogous to ultrasound, except that it uses light rather than sound to obtain higher image resolution in the retina. Cross-sectional tomographs of optical reflectivity within the retina are produced with longitudinal resolution of 10 microns. Optical coherence tomography was used to examine 16 patients at a referral eye center whose initial examination disclosed the clinical diagnosis of central serous chorioretinopathy. The optical coherence tomography results were correlated with slit-lamp biomicroscopy, fundus photography, and fluorescein angiography. RESULTS: The cross-sectional view produced by optical coherence tomography was effective in objectively quantifying the amount of serous retinal detachment in the disease. Optical coherence tomography disclosed detachments that were undetected by slit-lamp biomicroscopy. Longitudinal measurements with optical coherence tomography were successfully able to track the resolution of subretinal fluid accumulation. CONCLUSION: Optical coherence tomography is potentially useful as a new, noninvasive diagnostic technique for quantitative examination of patients with central serous chorioretinopathy and objectively monitoring the clinical course of the serous retinal detachment in this disease.

Adult↗
PubMed1995

Optical coherence tomography of macular holes.

PURPOSE: To assess the potential of a new diagnostic technique called optical coherence tomography (OCT) for diagnosing and monitoring macular holes. This technique is a novel noninvasive, noncontact imaging modality that produces high longitudinal resolution (10-micron) cross-sectional tomographs of ocular tissue. METHODS: Optical coherence tomography is analogous to ultrasound except that optical rather than acoustic reflectivity is measured. Cross-sectional tomographs of the retina profiling optical reflectivity in a thin, optical slice of tissue are obtained with a longitudinal resolution of 10 microns. Optical coherence tomography was used to examine 49 patients with the clinical diagnosis of idiopathic full-thickness macular hole, impending macular hole, epimacular membrane with macular pseudohole, or partial-thickness hole. The resulting OCTs were correlated with contact lens and slit-lamp biomicroscopy, fundus photography, and fluorescein angiography. RESULTS: The cross-sectional view produced by OCT was effective in distinguishing full-thickness macular holes from partial-thickness holes, macular pseudoholes, and cysts. Optical coherence tomography was successful in staging macular holes and provided a quantitative measure of hole diameter and the amount of surrounding macular edema. Optical coherence tomography also was used to evaluate the vitreoretinal interface in patients' fellow eyes and was able to detect small separations of the posterior hyaloid from the retina. CONCLUSION: Optical coherence tomography appears potentially useful as a new, noninvasive, diagnostic technique for visualizing and quantitatively characterizing macular holes and assessing fellow eyes of patients with a macular hole. The tomographic information provided by OCT eventually may lead to a better understanding of the pathogenesis of macular hole formation.

Adult↗
PubMed1995

Imaging of macular diseases with optical coherence tomography.

BACKGROUND/PURPOSE: To assess the potential of a new diagnostic technique called optical coherence tomography for imaging macular disease. Optical coherence tomography is a novel noninvasive, noncontact imaging modality which produces high depth resolution (10 microns) cross-sectional tomographs of ocular tissue. It is analogous to ultrasound, except that optical rather than acoustic reflectivity is measured. METHODS: Optical coherence tomography images of the macula were obtained in 51 eyes of 44 patients with selected macular diseases. Imaging is performed in a manner compatible with slit-lamp indirect biomicroscopy so that high-resolution optical tomography may be accomplished simultaneously with normal ophthalmic examination. The time-of-flight delay of light backscattered from different layers in the retina is determined using low-coherence interferometry. Cross-sectional tomographs of the retina profiling optical reflectivity versus distance into the tissue are obtained in 2.5 seconds and with a longitudinal resolution of 10 microns. RESULTS: Correlation of fundus examination and fluorescein angiography with optical coherence tomography tomographs was demonstrated in 12 eyes with the following pathologies: full- and partial-thickness macular hole, epiretinal membrane, macular edema, intraretinal exudate, idiopathic central serous chorioretinopathy, and detachments of the pigment epithelium and neurosensory retina. CONCLUSION: Optical coherence tomography is potentially a powerful tool for detecting and monitoring a variety of macular diseases, including macular edema, macular holes, and detachments of the neurosensory retina and pigment epithelium.

Adult↗
PubMed1995

Optical biopsy and imaging using optical coherence tomography.

Optical coherence tomography is a new imaging technique that can perform high-resolution, micrometre-scale, cross-sectional imaging in biological systems. The technology has been developed, and reduced to, preliminary clinical practice in ophthalmology. The challenging problem that OCT may address is the development of 'optical biopsy' techniques. These techniques can provide diagnostic imaging of tissue morphology without the need for excision of specimens. Many investigations remain to identify optimal areas for clinical application, and additional engineering must be done to integrate vertically the technology and to reduce it to clinical practice. Nevertheless, preliminary studies indicate the feasibility of developing this technology for a wide range of clinical and research diagnostic imaging applications. The ability to non-excisionally evaluate tissue morphology using a catheter or an endoscope could have a significant impact on the diagnosis and management of a wide range of diseases.

Arteries↗
PubMed1995

Reliability and validity of a new preadmission acuity tool for long-term care.

The purpose of this project was to develop a new tool designed to assess the acuity of applicants to long-term facilities. Using a known groups method, residents of long-term care facilities were categorized as independent (n = 68), assist (n = 71), and dependent (n = 65) and assessed using the Preadmission Acuity Inquiry Tool (PAI) to generate the data base for examining its psychometric properties. The progression of the mean scores from independent to assist to dependent demonstrates the ability of the tool to differentiate across varying levels of functional independence. Using discriminant analysis, the degree of accuracy in predicting group membership for the independent group was 88%, for the dependent group 75%, and for the assist group 17% with the overall agreement between PAI scores and a priori classifications at 60%. Kappa coefficients for interrater reliability ranged from .54 to 1.0 with a mean of .90. The Cronbach's alpha coefficient was .81. The PAI has demonstrated sufficient reliability and validity to warrant further refinement and testing. This new instrument may enable health care professionals to provide the appropriate level of care in a cost-effective manner.

Activities of Daily Living↗
PubMed1994

Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography.

OBJECTIVE: To demonstrate a new diagnostic technique, optical coherence tomography, for high-resolution cross-sectional imaging of structures in the anterior segment of the human eye in vivo. Optical coherence tomography is a new, noninvasive, noncontact optical imaging modality that has spatial resolution superior to that of conventional clinical ultrasonography (< 20 microns) and high sensitivity (dynamic range, > 90 dB). DESIGN: Survey of intraocular structure and dimension measurements. SETTING: Laboratory. PATIENTS: Convenience sample. MAIN OUTCOME MEASURES: Correlation with range of accepted normal intraocular structure profiles and dimensions. RESULTS: Direct in vivo measurements with micrometer-scale resolution were performed of corneal thickness and surface profile (including visualization of the corneal epithelium), anterior chamber depth and angle, and iris thickness and surface profile. Dense nuclear cataracts were successfully imaged through their full thickness in a cold cataract model in calf eyes in vitro. CONCLUSIONS: Optical coherence tomography has potential as a diagnostic tool for applications in noncontact biometry, anterior chamber angle assessment, identification and monitoring of intraocular masses and tumors, and elucidation of abnormalities of the cornea, iris, and crystalline lens.

Anterior Chamber↗
PubMed1994

Alzheimer's residents' cognitive and functional measures: special and traditional care unit comparison.

The aim of this field experiment was to compare the effects of a special care unit (SCU) on residents with Alzheimer's disease (AD) who lived on the SCU and on traditional (integrated) nursing home units. Twenty-two subjects, 13 on the SCU and 9 on traditional integrated units were compared. Repeated measures ANOVA was used to assess differences between the two groups and within the groups over two bimonthly pretests and two bimonthly posttests. No significant differences on cognitive or functional abilities scores were evident for the groups and no significant differences were found over time. However, consistent with the prediction of the Progressively Lower Stress Threshold Model, the SCU subjects' function was better than subjects on traditional units when measured by socially accessible behaviors.

Activities of Daily Living↗
PubMed1994

A nursing perspective on SCUs.

Much of what is in the literature regarding nursing of AD patients and their families is anecdotal, has not been validated by systematic research, and is atheoretical. The majority of nursing research in AD has focused on patient characteristics and problem behaviors or on the needs and experiences of family care givers rather than on characteristics of SCUs. Research should continue in these areas, along with testing nursing interventions to maintain the optimal cognitive, physical, social, and emotional function of residents with AD in institutional settings. Explanatory theories should be devised and tested to advance the development of nursing knowledge in the care of residents with AD and family care givers. Finally, more evaluation research is needed to test the cost effectiveness of SCU programs, including effects on residents with AD, family members, and staff care givers.

Aged↗
PubMed1993

Effects of individualized music on confused and agitated elderly patients.

The Progressively Lowered Stress Threshold Model in conjunction with an identified theoretical basis provides a framework for the use of individualized music in individuals with Dementia of the Alzheimer's Type (DAT). The effects of individualized music is explored in five elderly patients who are confused and agitated and residing in a long-term care facility. The Modified Cohen-Mansfield Agitation Inventory is used to measure the outcome. The immediate and 1-hour residual effects suggest the potential of individualized music as an alternative approach to the management of agitation in confused elderly patients.

Aged↗
PubMed1993

Catastrophic reactions and other behaviors of Alzheimer's residents: special unit compared with traditional units.

Using a quasi-experimental pretest/posttest design, the effects of a Special Care Unit (SCU) on the incidence of catastrophic reactions and other behaviors of nursing home residents with Alzheimer's disease (AD) were examined. Findings indicate significantly fewer catastrophic reactions and other selected behavior changes occurred during the posttest period for subjects in the experimental group compared with the subjects in the control group. Implications for psychiatric consultation/liaison nurses (PCLNs) working with this vulnerable population are discussed.

Activities of Daily Living↗
PubMed1992

A nursing camp--a multi-agency cooperative effort.

A summer nursing camp for junior and senior high school youth, planned and implemented by a multi-agency advisory group, demonstrates one way to attract future nurses into the profession. To effectively solve the problem of the nurse shortage, the efforts of nurse administrators in education and practice must be coordinated.

Adolescent↗
PubMed1991

Optical coherence tomography.

A technique called optical coherence tomography (OCT) has been developed for noninvasive cross-sectional imaging in biological systems. OCT uses low-coherence interferometry to produce a two-dimensional image of optical scattering from internal tissue microstructures in a way that is analogous to ultrasonic pulse-echo imaging. OCT has longitudinal and lateral spatial resolutions of a few micrometers and can detect reflected signals as small as approximately 10(-10) of the incident optical power. Tomographic imaging is demonstrated in vitro in the peripapillary area of the retina and in the coronary artery, two clinically relevant examples that are representative of transparent and turbid media, respectively.

Coronary Disease↗
PubMed1981

Hair follicles in the canine tongue.

At least three normal-appearing and mature hair follicles containing hairs were found to be growing in a coiled manner within the intrinsic musculature of the anterior two thirds of a dog's tongue. An extensive review of the literature has shown that hair follicles are, indeed, found in some unusual places, but previous finding of their presence in the tongue has not been reported. Microscopic examination of serial sections failed to produce any evidence that these follicles were the result of some form of foreign body accident or teratomatous process. They appeared histologically normal in all respects and are assumed to be endogenous to the tongue. The embryologic development of these follicles is briefly commented upon.

Animals↗