Intravitreal triamcinolone for radiation-induced macular edema.
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Fluorescein Angiography↗
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Results for “Interferometry”
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Peripapillary detachment in pathologic myopia.
OBJECTIVE: To describe peripapillary detachment in pathologic myopia (PDPM), a newly recognized fundus lesion. DESIGN: Retrospective medical record review. METHODS: We evaluated a series of myopic eyes that had a yellow-orange elevation of the retina and retinal pigment epithelium at the inferior border of the myopic conus. RESULTS: Twenty eyes of 15 patients were identified during a 17-year period to have characteristic findings of PDPM. The mean age of the patients was 58 years. They were followed up for an average of 6 years. The mean spherical equivalent correction was -11.00 diopters (D) (range, -6.00 to -16.00 D). The mean axial length was 27.4 mm (range, 25.3-28.9 mm). In each case, ophthalmic coherence tomographic examination showed a localized detachment of the retinal pigment epithelium and retina corresponding to the PDPM lesion. During the follow-up period, the lesion remained stable in all cases except for 1. No apparent negative effect on visual function was noted. CONCLUSIONS: Peripapillary detachment in pathologic myopia is an asymptomatic, yellow-orange peripapillary detachment of the retinal pigment epithelium and retina in pathologic myopia. Recognition of this lesion is important to distinguish it from other fundus pathologic conditions, such as tumors or choroidal neovascularization, which require further investigation and treatment.
Adult↗
In vivo imaging of human retinal flow dynamics by color Doppler optical coherence tomography.
BACKGROUND: Color Doppler optical coherence tomography (CDOCT) combines laser Doppler velocimetry and optical coherence tomography for simultaneous micron-scale resolution cross-sectional imaging of tissue microstructure and blood flow. Recently, CDOCT was adapted to a slitlamp biomicroscope for imaging structure and blood flow in the human retina. OBJECTIVE: To demonstrate feasibility of CDOCT for imaging retinal hemodynamics. DESIGN: Enabling CDOCT to measure retinal blood flow pulsatility in humans. SETTING: Laboratory. MAIN OUTCOME MEASURES: Time-resolved flow profiles and images of retinal blood flow dynamics for measurement of pulsatility within retinal vessels. RESULTS: Rapid sequences of images were acquired over selected vessels near the optic nerve head. From these images, retinal blood flow profiles were extracted and synchronized to an external reference obtained with a photoplethysmograph. Each profile was acquired in less than 10 milliseconds. CONCLUSIONS: Our results indicate that CDOCT provides laser Doppler information in addition to conventional optical coherence tomography, allowing the observation of blood flow dynamics simultaneous to imaging retinal structure. CDOCT is a promising technology for research and clinical studies of retinal blood flow dynamics. CLINICAL RELEVANCE: Blood flow dynamics, such as pulsatility and autoregulation, have been shown to change throughout the progression of diabetic retinopathy and glaucoma. Enabling CDOCT to observe retinal dynamics improves its potential as a clinical diagnostic tool.
Blood Flow Velocity↗
Surgical ablation of retinal angiomatous proliferation.
Age-related macular degeneration (AMD) remains the leading cause of visual loss in adults older than 65 years. Retinal angiomatous proliferation (RAP) is a newly recognized manifestation of exudative AMD that has a poor natural history and demonstrated resistance to treatment with conventional laser photocoagulation. A novel surgical technique has been developed in this pilot series that shows promise in the treatment of this subtype of neovascular lesions. Through specific surgical lysis of the feeding arteriole and draining venule of an RAP lesion, improvement in visual acuity has been noted. This has been correlated with resolution of intraretinal edema and flattening of associated pigment epithelial detachment, which was confirmed by fluorescein angiography, optical coherence tomography, and high-speed indocyanine green angiography.
Aged↗
Enhanced visualization of macular pathology with the use of ultrahigh-resolution optical coherence tomography.
OBJECTIVES: To demonstrate a new generation of ophthalmic optical coherence tomography (OCT) technology with unprecedented axial resolution for enhanced imaging of intraretinal microstructures and to investigate its clinical feasibility to visualize intraretinal morphology of macular pathology. METHODS: A clinically viable ultrahigh-resolution ophthalmic OCT system was developed and used in clinical imaging for the first time. Fifty-six eyes of 40 selected patients with different macular diseases including macular hole, macular edema, age-related macular degeneration, central serous chorioretinopathy, epiretinal membranes, and detachment of pigment epithelium and sensory retina were included. OUTCOME MEASURES: Ultrahigh-resolution tomograms visualizing intraretinal morphologic features in different retinal diseases. RESULTS: An axial image resolution of approximately 3 micro m was achieved in the eyes examined, nearly 2 orders of magnitude better than conventional ophthalmic ultrasound. Ultrahigh-resolution OCT images provided additional diagnostically important information on intraretinal morphologic features that could not have been obtained by standard techniques. CONCLUSIONS: Ultrahigh-resolution ophthalmic OCT enables unprecedented visualization of intraretinal morphologic features and therefore has the potential to contribute to a better understanding of ocular pathogenesis, as well as to enhance the sensitivity and specificity for early ophthalmic diagnosis and to monitor the efficacy of therapy. This study establishes a baseline for the interpretation of ultrahigh-resolution ophthalmic OCT imaging of macular diseases.
Adult↗
Central serous chorioretinopathy imaged by optical coherence tomography.
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Adult↗
Optic disc traction syndrome associated with central retinal vein occlusion.
OBJECTIVE: To describe the association between ischemic central retinal vein occlusion (CRVO) and the development of optic disc (vitreopapillary) traction, as verified by optical coherence tomography (OCT). METHODS: In a prospective, noncomparative, observational patient series, 3 women aged 51 to 64 years developed an ischemic type of CRVO. One patient underwent cannulation of the central retinal vein with injection of a tissue plasminogen activator. In each eye, the contour of the optic nerve head could not be accurately detected because of overlying fibrous tissue. Each patient underwent OCT examination 6 to 10 months (average, 8.3 months) after the occlusive event. RESULTS: Optic disc traction was found by OCT in the 3 patients. In each, the disc was elevated, associated with either incomplete posterior vitreous detachment (2 eyes) or vitreopapillary fibrous membrane (1 eye). Secondary peripapillary retinal traction and macular or retinal detachment developed ("optic disc traction syndrome"). These findings were less marked, or not evident, on both clinical examination and ocular ultrasonography. CONCLUSIONS: Optic disc traction and secondary localized retinal detachment can develop after ischemic CRVO and may contribute to the poor visual acuity. This syndrome should merit special attention before surgery for CRVO is planned. The use of OCT was helpful to diagnose this syndrome.
Diagnostic Imaging↗
Fourier analysis of optical coherence tomography and scanning laser polarimetry retinal nerve fiber layer measurements in the diagnosis of glaucoma.
OBJECTIVE: To evaluate a new Fourier-based analysis method for diagnosing glaucoma using retinal nerve fiber layer (RNFL) thickness estimates obtained from the optical coherence tomograph (OCT) (OCT 2000) and the scanning laser polarimeter (GDx). METHODS: We obtained RNFL thickness estimates from 1 eye of 38 healthy individuals and 42 patients with early glaucomatous visual field loss using the OCT and GDx devices. The shape of the RNFL double-hump pattern was assessed using Fourier analysis, and values were entered into a linear discriminant analysis. Receiver operating characteristic (ROC) curves were used to compare the performance of the Fourier-based metrics against other commonly used RNFL analytical procedures. Reliability was assessed on independent samples by the split-half method. Correlations were calculated to determine the extent to which the Fourier discriminant measures and other RNFL measures covaried between the 2 devices and the relationship between these RNFL measures and visual field measures. RESULTS: Sensitivity and specificity for the linear discriminant function (LDF) based on the Fourier analysis of the OCT data were 76% and 90%, respectively, and the area under the ROC curve was 0.925 (SEM, 0.028). For the GDx data, the Fourier-based LDF yielded sensitivity and specificity of 82% and 90%, respectively, with an ROC curve area of 0.928 (SEM, 0.029). These values were better than those determined using the GDx number, a previous discriminant function using GDx variables and OCT thickness values. The Fourier-based LDFs and numerous other measures were significantly correlated between the 2 devices. For each device, the visual field measures correlated most highly with the Fourier-based LDF measure. CONCLUSIONS: For both devices, the LDF based on the output from a Fourier analysis of RNFL data resulted in better diagnostic capability compared with other common RNFL analytical procedures. That this technique improves RNFL analysis is also supported by the better correlations between visual field measures and the Fourier-based LDF measures.
Diagnostic Techniques, Ophthalmological↗
Interpretation of objectively acquired retinal thickness values.
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Diabetes Mellitus, Type 2↗
Interferometric visual acuity testing in anterior segment disease.
Preoperative and posteroperative visual acuities for Landolt ring targets and for a grating target of comparable retinal illuminance produced by two-beam interference were assessed in patients with anterior segment disease. Good preoperative interferometric acuities (6/12 or better) were found in over half of the cases in which Landolt acuities were 6/90 or worse. In general, good preoperative interferometric acuities were predictive of good postoperative Landolt acuities. However, poor interferometric acuities in patients with opacified media did not preclude good Landolt acuities postoperatively. We conclude that interferometric acuity testing can provide valuable information about potential macular resolution capacity in some cases. Both the strengths and weaknesses of interferometric acuity testing must be appreciated for successful application.
Cataract↗
Laser interferometric visual acuity in senile macular degeneration.
Twenty-nine eyes from 15 patients were affected by senile macular degeneration and had clear ocular media. Tests with retinal interference fringe patterns produced by a low-energy helium-neon laser and Snellen's charts showed that in 13 eyes, interferometric and Snellen's acuities were within one line. In the remaining 16 eyes, laser interferometric acuities were notably better than Snellen's acuities. Our results suggest that laser interferometric visual acuities, prior to lens extraction, will prove inconsistent in accurately predicting postoperative Snellen's acuities in patients with senile macular degeneration.
Aging↗
Instruments for predicting visual acuity. A clinical comparison.
A series of 54 eyes in 50 patients had preoperative predictions of postoperative visual acuity, using both a white-light interferometer (Lotmar Visometer) and a Snellen chart projector (Guyton-Minkowski Potential Acuity Meter). The predicted vision by each instrument was compared with the actual postoperative vision. Forty eyes in 36 of these patients, 25 with concurrent eye disease, had cataract extraction with intraocular lens implantation. Fifteen eyes in 15 patients, 11 with concurrent eye disease, had neodymium-YAG laser posterior capsulotomy. The Visometer gave more accurate predictions than the Potential Acuity Meter in cataract patients with open angle glaucoma, even with glaucomatous visual field loss, and in patients with a visual acuity of less than 20/400 due to advanced cataract formation.
Adult↗
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↗
An improved technique for optical interferometric imaging of isolated cells.
We have improved the optical interferometric imaging technique that was recently used to measure local organic material concentrations in quasicylindrical cells. This allowed similar measurements for cells of arbitrary shape. The setup was used to measure the thickness of skin corneocytes.
Animals↗
Optical biosensors.
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Biosensing Techniques↗
Quantification and evaluation of Joule heating in on-chip capillary electrophoresis.
We present the use of a novel, picoliter volume interferometer to measure, for the first time, the extent of Joule heating in chip-scale capillary electrophoresis (CE). The simple optical configuration for the on-chip interferometric backscatter detector (OCIBD) consists of an unfocused laser, an unaltered silica chip with a half-cylinder channel and a photodetector. Using OCIBD for millidegree-level noninvasive thermometry, temperature changes associated with Joule heating (2.81 degrees C above ambient) in on-chip CE have been observed in 90 microm wide and 40 microm deep separation channels. The temporal response of Joule heating in isotropically etched channels was exponential, with it taking an excess of 2.7 s to reach equilibrium. Buffer viscosity changes have also been derived from empirical on-chip thermometry data, allowing for the determination of diffusion coefficients for solutes when separated in heated buffers. In addition, OCIBD has allowed the reduction in separation efficiency to be estimated in the absence of laminar flow and due to increased molecular diffusion and lower buffer viscosity. A 7% reduction in separation efficiency was determined for a high current drawing buffer such as Tris-boric acid under an applied field of just 400 V/cm. Results indicate that heating effects in on-chip CE have been underestimated and there is a need to readdress the theoretical model.
Buffers↗
Formaldehyde activity on historical glass objects in museum microclimate.
Degradation of some cultural heritage monuments has been caused by interaction with the closest environment (micro-climate). Amount of separate compounds is very small and because of it, this fact becomes neglected. Time and temperature can induce their activity finally causing deterioration. In this category organic compounds can be interpreted as one of museum show - case element. This statement has been improved by testing glass objects and their suitable sensors (model glasses). Destructive activity of formaldehyde on historical glasses belonging to the XVIII-th c. objects with totally different compositions has been confirmed by carried out experiments. For historical material which is very limited, sensor glass method has been applied. Sensors are prepared on the base of results of chemical analyses of original glass chemical analyses and melted on laboratory scale (according to historical data). Induced corrosion for sensor supports knowledge about deterioration process in real micro-environmental conditions. The following testing methods were used: scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), optical interferometer (OI), inductively couple plasma (ICP).
Formaldehyde↗