According to the mechanism of spectral domain optical coherence tomography, this paper gives a design and development of a practical OCT imaging device based on slit-lamp microscopic widely-used in ophthalmology. The paper details the device's architecture and three key points in design: communication between PC and MCU, how to design modules of fixation lamp and reference arm and anti-interference measures.
Diagnostic Techniques, Ophthalmological ; instrumentation ; Equipment Design ; Tomography, Optical Coherence ; instrumentation ; methods

OBJECTIVEUsing the algorithm on the layered structure of the retina and quantitative analysis of the automatic segmentation technique is the key to the early diagnosis of glaucoma and other retinopathy on optical coherence tomography. Existing methods require high quality image and have low reliability. This paper used the improved complex nonlinear diffuse filtering and other methods to solve this problem.

METHODSThis paper includes algorithm such as automatic threshold, improved complex nonlinear diffusion filtering, morphological operations and peak detection. Use the method for the segmentation of 20 retinal layers images which acquired on the self-builder OCT system, the boundary of inner limiting membrane(ILM), outer nuclear layer(ONL), the photoreceptor segments(IS/ OS) and the RPE_ChCap layer are detected accurately. At last, the photoreceptor layer thickness is measured.

RESULTSThe results of segmentation and measurement are good corresponded with expert manual segmentation and measurements, retinal foveal measurements data is consistent with Zeiss Stratus OCT central retinal thickness 212+/-20 micro m.

CONCLUSIONThe algorithm proposed is prospective applied to clinical diagnosis of retinal diseases.

Algorithms ; Humans ; Retina ; anatomy & histology ; Software ; Tomography, Optical Coherence ; instrumentation ; methods

This investigation introduces GPU (Graphics Processing Unit)- based CUDA (Compute Unified Device Architecture) technology into signal processing of ophthalmic FD-OCT (Fourier-Domain Optical Coherence Tomography) imaging system, can realize parallel data processing, using CUDA to optimize relevant operations and algorithms, in order to solve the technical bottlenecks that currently affect ophthalmic real-time imaging in OCT system. Laboratory results showed that with GPU as a general parallel computing processor, the speed of imaging data processing using GPU+CPU mode is more than dozens times faster than traditional CPU platform based serial computing and imaging mode when executing the same data processing, which reaches the clinical requirements for two dimensional real-time imaging.
Computer Graphics ; Image Interpretation, Computer-Assisted ; Tomography, Optical Coherence ; instrumentation ; methods

INTRODUCTIONWe studied the automated intraretinal segmentation on Fourier domain optical coherence tomography (OCT).

MATERIALS AND METHODSThirty eyes from 30 normal subjects were studied using the RTVue-100. Both radial and raster scan protocol were performed 3 times on each subject. The OCT software performs automated intraretinal segmentation and provides macular thickness measurements.

RESULTSBoth scanning protocols provide reproducible inner, outer and full retinal thickness measurements. The inner, outer and full retinal thicknesses at the foveal central subfield were 67.31 +/- 12.27 microm, 151.67 +/- 12.96 microm, 219.33 +/- 23.19 microm, respectively by the raster scan, and 63.27 +/- 10.37 microm, 147.07 +/- 14.54 microm, 209.89 +/- 21.80 microm, respectively by the radial scan. Macular regional variations were consistently observed. The raster scan protocol gives greater retinal thickness measurements than the radial scan protocol (P <0.05), but the latter yields slightly more reproducible results.

CONCLUSIONSFourier domain OCT equipped with the ability to perform automatic intraretinal segmentation is a convenient tool in studying diseases that may differentially affect various parts of the retina. However, the establishment of normative values can be complicated by different scanning protocols, devices used, methods of data presentation and definition of intraretinal boundaries.

Adult ; Humans ; Image Interpretation, Computer-Assisted ; methods ; Macula Lutea ; anatomy & histology ; Middle Aged ; Reference Values ; Retinal Diseases ; diagnosis ; Tomography, Optical Coherence ; instrumentation ; methods ; Young Adult

We report the application of optical coherence tomography (OCT) to the diagnosis and evaluation of otitis media (OM). Whereas conventional diagnostic modalities for OM, including standard and pneumatic otoscopy, are limited to visualizing the surface of the tympanic membrane (TM), OCT effectively reveals the depth-resolved microstructure below the TM with very high spatial resolution, with the potential advantage of its use for diagnosing different types of OM. We examined the use of 840-nm spectral domain-OCT (SD-OCT) clinically, using normal ears and ears with the adhesive and effusion types of OM. Specific features were identified in two-dimensional OCT images of abnormal TMs, compared to images of healthy TMs. Analysis of the A-scan (axial depth scan) identified unique patterns of constituents within the effusions. The OCT images could not only be used to construct a database for the diagnosis and classification of OM but OCT might also represent an upgrade over current otoscopy techniques.
Adult ; Ear Canal/anatomy & histology ; Eustachian Tube/physiology ; Female ; Humans ; Male ; Middle Aged ; Otitis Media/classification/*diagnosis ; Tomography, Optical Coherence/instrumentation/*methods ; Tympanic Membrane/*physiology

We report the application of optical coherence tomography (OCT) to the diagnosis and evaluation of otitis media (OM). Whereas conventional diagnostic modalities for OM, including standard and pneumatic otoscopy, are limited to visualizing the surface of the tympanic membrane (TM), OCT effectively reveals the depth-resolved microstructure below the TM with very high spatial resolution, with the potential advantage of its use for diagnosing different types of OM. We examined the use of 840-nm spectral domain-OCT (SD-OCT) clinically, using normal ears and ears with the adhesive and effusion types of OM. Specific features were identified in two-dimensional OCT images of abnormal TMs, compared to images of healthy TMs. Analysis of the A-scan (axial depth scan) identified unique patterns of constituents within the effusions. The OCT images could not only be used to construct a database for the diagnosis and classification of OM but OCT might also represent an upgrade over current otoscopy techniques.
Adult ; Ear Canal/anatomy & histology ; Eustachian Tube/physiology ; Female ; Humans ; Male ; Middle Aged ; Otitis Media/classification/*diagnosis ; Tomography, Optical Coherence/instrumentation/*methods ; Tympanic Membrane/*physiology

BACKGROUNDMeasurement of anterior segment parameters plays an important role in diagnosis and treatment of glaucoma. The objective of this study was to evaluate the repeatability and reproducibility of anterior chamber volume (ACV) measurements with rotating scheimpflug camera (RSC) and to examine agreement with anterior segment optical coherence tomography (AS-OCT).

METHODSThirty nine healthy normal subjects were recruited from the Eye Center of Tongren Hospital. ACV was measured using RSC and AS-OCT in a randomly selected eye for each subject. For RSC measurements, both automatic and manual ACV measurements and 2 independent operators' ACV measurements were obtained. All subjects were invited for 3 visits within a week to evaluate repeatability and reproducibility of ACV measurement by RSC. Agreement was evaluated between RSC and AS-OCT.

RESULTSGood repeatability and reproducibility were found for both automatic and manual ACV measurements obtained by RSC. For intrasession repeatability, coefficient of variation (CVw) and intraclass correlation coefficient (ICC) values for automatic were 3.52% and 0.98; the values for manual were 3.44% and 0.97, respectively. For intersession reproducibility, the respective CVw and ICC values were 3.96% and 0.96. Good agreement was also found in 2 operators for both automatic and manual ACV measurements; nevertheless, poor agreement was found between RSC and AS-OCT (95% confidence interval (CI) for agreement of automatic RSC measurement versus AS-OCT were -96.3 to 72.8 microl and 95% CI for agreement of manual RSC measurement versus AS-OCT were between -41.7 to 10.1 microl).

CONCLUSIONSBoth RSC automatic and manual ACV measurements showed good repeatability and reproducibility, and showed comparable agreement between 2 independent operators, but poor agreement was found between RSC and AS-OCT.

Adult ; Anterior Chamber ; anatomy & histology ; Anterior Eye Segment ; anatomy & histology ; Cornea ; anatomy & histology ; Diagnostic Techniques, Ophthalmological ; instrumentation ; Female ; Glaucoma ; diagnosis ; Humans ; Male ; Reproducibility of Results ; Tomography, Optical Coherence ; methods ; Young Adult