Intrasession repeatability of optical coherence tomography measures in active neovascular age-related macular degeneration.
ABSTRACT To determine the repeatability of Stratus optical coherence tomography fast macular thickness map analysis in patients with active neovascular age-related macular degeneration (nAMD).
Consecutive pairs of scans from 112 eyes of 112 consecutive patients with active nAMD were analyzed. The Bland-Altman coefficient of repeatability (CR) was calculated for each retinal thickness or volume measure.
The CR for the central 1 mm macular subfield was 59 μm (18% of retinal thickness) and did not exceed 69 μm in any subfield. There was much poorer repeatability for the center-point thickness (CPT) measure (CR of 78 μm; 24%). However, in the subgroup of 38 patients with no Stratus software low analysis confidence message on either analysis map, the revised CR (42 μm) for the CPT measure and the A1 subfield (40 μm) were similar.
Optical coherence tomography-derived retinal thickness measurements are subject to measurement variability in patients with active nAMD. The results suggest a change criterion of more than 59 μm in central 1 mm (A1) subfield macular thickness is necessary to distinguish true clinical change from measurement variability in these patients.
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ABSTRACT: To assess the reproducibility of retinal thickness measurement using commercially available mapping software of optical coherence tomography (OCT). Six radial scans, 6 mm long and centered on the fixation point, were performed on 10 eyes of 10 healthy volunteers and 10 eyes of 10 diabetic patients with clinically significant macular edema. Retinal thickness was measured automatically using the mapping software of OCT in the 9 macular Early Treatment Diabetic Retinopathy Study areas and in a central area 500 microm in diameter. Measurement reproducibility was tested by means of 3 series of scans performed by 2 different observers on 2 different days. Results were assessed by their repeatability and intraclass correlation coefficients (ICCs). In healthy subjects, intraobserver, interobserver, and intervisit reproducibility of retinal thickness measurements were excellent, with a repeatability coefficient of less than 7 microm and ICCs of greater than 0.89. In diabetic patients, the repeatability coefficient was less than 21 microm in all areas of the macula except one, with an ICC of greater than 0.98. Relative variations in measurements were small in both healthy and diabetic subjects, with reproducibilities of +/- 5% and +/- 6%, respectively. Retinal mapping software of OCT allows reproducible measurement of retinal thickness in both healthy subjects and diabetic patients with macular edema.Archives of Ophthalmology 09/2001; 119(8):1135-42. · 3.83 Impact Factor
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ABSTRACT: To demonstrate two novel ophthalmic imaging techniques based on fast Spectral Optical Coherence Tomography (SOCT). Prospective observation case report. Research laboratory. A normal human subject. Correlation of an optical coherence retinal tomogram with known retinal anatomy, reduction of eye exposure to the probing light beam during Optical Coherence Tomography (OCT) examination. High resolution (3- x 20-microm) cross-sectional 2-dimensional images of the human retina in vivo have been obtained with only 0.1-second total illumination time (for 1024 A-scans), and approximately 200- microW eye exposure. Details of the optic disk in vivo have been visualized at a rate of eight frames per second, which is sufficient to provide real time analysis. The 3-dimensional images of the optic nerve correspond to the images obtained from a fundus camera. Because of its short acquisition time and high sensitivity, SOCT uses a 100 times lower exposure/A-scan to obtain images of comparable quality to those obtained by the commercial instrument based on traditional time-domain OCT. Spectral Optical Coherence Tomography therefore provides a much wider safety margin than the traditional method and allows relaxation of the current safety precautions forbidding more than 10 minutes/day scanning of the same location of a retina. As a result of the high speed offered by the new technique, the 3-dimensional tomograms, which allow a surgeon access to a comprehensive and detailed view of relevant pathologies, are obtained in a much shorter, clinically more reasonable time.American Journal of Ophthalmology 10/2004; 138(3):412-9. · 3.63 Impact Factor
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ABSTRACT: To assess the intraobserver variability of optical coherence tomography (OCT) in patients with clinically stable maculas. Retrospective, observational case series using a diagnostic instrument. Retrospective study. setting. Private retina practice. patient population. Twenty-two eyes of 19 patients, each studied twice within 4 months. observation procedure. Optical coherence tomograph measurements of the macula obtained by two photographers. main outcome measures. Ordinary least products (OLP) and Bland-Altman analysis of OCT data. No fixed or proportional bias was detected in foveal zone thickness and total macular volume between measurements of either of the OCT operators. The coefficient of repeatability for foveal zone thickness was 37.0 microm for photographer 1 and 34.8 microm for photographer 2. The coefficient of repeatability for total macular volume was 0.29 mm(3) for photographer 1 and 0.10 mm(3) for photographer 2. Foveal zone thickness and total macular volume measurements show low intraobserver variability when analyzed by OLP and Bland-Altman techniques. Bounds are given for foveal zone thickness and total macular volume for which longitudinal OCT measurements by the same operator can be considered to reflect natural history or intervention effects rather than intraobserver variability.American Journal of Ophthalmology 10/2004; 138(3):477-9. · 3.63 Impact Factor