Purpose To evaluate the repeatability, reproducibility, and agreement of thickness profile measurements of eight intra-retinal layers determined by an automated algorithm applied to optical coherence tomography (OCT) images from two different instruments. Methods Twenty normal subjects (12 males, 8 females; 24 to 32 years old) were enrolled. Imaging was performed with a custom built ultra-high resolution OCT instrument (UHR-OCT, ~3 µm resolution) and a commercial RTVue100 OCT (~5 µm resolution) instrument. An automated algorithm was developed to segment the macular retina into eight layers and quantitate the thickness of each layer. The right eye of each subject was imaged two ...

Objective: Using a custom-developed segmentation algorithm, agreement of corneal epithelial thickness profile measurements between two spectral domain optical coherence tomography (SD-OCT) systems was assessed. Methods: Eighteen left eyes (18 subjects; mean+/-standard deviation; age, 23.2+/-0.9 years) were imaged twice on nonconsecutive days by a custom-built ultra-high resolution OCT (UHR-OCT) system and a commercial RTVue OCT system. A segmentation algorithm based on axial gradient information and a shortest path search was developed to measure corneal epithelial thickness profiles from the SD-OCT images. Results: There was good correlation between the automated and manual segmentation positions of the epithelium. The ...

An imager that can provide separated images corresponding to differing depths in a sample is presented. In accordance with some embodiments of the invention, an imager can include a light source; a sample arm that receives light from the light source, directs the light to a sample, and captures light returning from the sample; a modulation source that provides different modulations corresponding to differing imaging depths in the sample; a detector system to receive the captured light from the sample with the different modulations; and a processor that receives signals from the detector system and separates a plurality of images ...

AIM: To compare the regularity and accuracy of laser in situ keratomileusis (LASIK) flaps created by the Ziemer FEMTO LDV "Classic" (Ziemer "Classic") and Ziemer FEMTO LDV Crystal Line femtosecond laser (Ziemer Crystal Line). METHODS: Fourier-domain optical coherence tomography (RTVue OCT) was used to measure the morphology of 200 LASIK flaps of 100 consecutive patients created with the Ziemer Classic (100 flaps) or the Ziemer Crystal Line (100 flaps) at one week postoperatively. Flap thickness was evaluated at 36 specified measurement points on each flap. For all procedures with both lasers, the nominal flap thickness was 110µm. RESULTS: The ...

Purpose: To study the distribution of peripapillary retinal nerve fiber layer (RNFL) thickness in a population of 12-year-old children in central China using iVue-100 Spectral-domain optical coherence tomography (SD-OCT). Methods: 2105 of 12-year-old students from 4 randomly selected middle school in Anyang city participated in this study. Each child underwent ocular examinations including optical biometry, cycloplegic autorefraction and OCT (iVue-100). Glaucoma ONH scan was performed to measure the RNFL thickness. Only the children with signal strength higher than 45 were used for analyses. Multivariate analyses were performed to examine the distribution of RNFL with demographic (e.g., gender, age, body ...

Purpose: To evaluate the repeatability of corneal epithelial thickness (ET) and corneal thickness (CT) measurements in normal eyes and laser in situ keratomileusis (LASIK)-treated eyes using optical coherence tomography (RTVue system). Methods: In 35 right eyes of 35 normal subjects and 45 right eyes of 45 subjects who underwent a myopic LASIK, corneal ET and CT were evaluated in 17 areas: (1) 1 central zone within a 0- to 2.0-mm diameter, (2) 8 paracentral zones from a 2.0- to 5.0-mm diameter, and (3) 8 peripheral zones from a 5.0- to 6.0-mm diameter. The repeatability ...

Purposes We examined the relationships of ganglion cell complex (GCC) parameters determined on spectral-domain optical coherence tomography (SD-OCT), especially the width of abnormal areas, and its ability to detect various stages of glaucoma. Methods OCT parameters of glaucomatous and normal eyes were determined with the RTVue SD-OCT. Widths of abnormal GCC areas marked by either red or yellow on the OCT significance map were quantified with image J software. The relationships between the abnormal GCC area and other GCC parameters [thickness, focal loss volume (FLV), and global loss volume (GLV)] and the peripapillary retinal nerve fiber layer (RNFL) thickness were ...

Purpose: To test the effect of a novel signal normalization method for reducing systematic optical coherence tomography (OCT) measurement differences among multiple spectral-domain (SD-) OCT devices. Methods: One hundred and nine eyes from 59 subjects were scanned with two SD-OCT devices (Cirrus and RTVue) at the same visit. OCT image data were normalized to match their signal characteristics between the devices. To compensate signal strength differences, a custom high dynamic range (HDR) processing was also applied only to images with substantially lower signal strength. Global mean peripapillary RNFL thicknesses were then measured automatically from all images using custom segmentation software ...