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OCT System (oct + system)
Selected AbstractsUse of optical coherence tomography for assessment of dental caries: quantitative procedureJOURNAL OF ORAL REHABILITATION, Issue 12 2001B. T. Amaechi A method for quantitative assessment of dental caries using optical coherence tomography (OCT) was demonstrated. Development of caries lesions in 15 bovine teeth, by demineralization in acidic buffer solution, was quantitatively assessed daily for 3 days, using OCT. An OCT system which can collect A-scans (depth versus reflectivity curve), B-scans (longitudinal images) and C-scans (transverse images at constant depth) was used. While the B- and C-scans qualitatively described the lesion detected, the A-scan which showed the depth (mm) resolved reflectivity (dB) of the tooth tissue was used for the quantitative analysis. After a simple normalization procedure to determine the actual depth the light travelled into the tooth tissue, the area (R) under the A-scan was quantified as a measure of the degree of reflectivity of the tissue. The result showed that R (dB mm) decreased with increasing demineralization time. The percentage reflectivity loss (R%) in demineralized tissue, which related to the amount of mineral loss, was also calculated, and it was observed that R% increased with increasing demineralization time. It was concluded that with the above procedure, OCT could quantitatively monitor the mineral changes in a caries lesion on a longitudinal basis. [source] 4121: Combined OCT retinal nerve fibre layer analysis and VEP in neuro-ophthalmic diseaseACTA OPHTHALMOLOGICA, Issue 2010P GOOD Purpose Ocular Coherence Tomography (OCT) has become a valuable tool in assessing retinal nerve fibre layer thickness (RNFL) in Patients with optic nerve disease. This study is designed to compare RNFL thickness n with Visual Evoked Cortical Potentials (VECP)in patients with known optic nerve disease and comparing these to a group of patients with primary open angle glaucoma (POAG). Methods Twenty Patients (37 eyes) with clinically determined optic nerve disease underwent pattern reversal VECP and also OCT using a Spectralis OCT system. Assessment of global and segmental RNFL was made. Six Patients were diagnosed as Dominant Optic atrophy, 3 with Lebers Optic Neuropathy (LHON), 6 with Nutritional amblyopia, 3 with Anterior Ischaemic Optic Neuropathy (AION), and 2 with Demyelinating disease. These Patients were also compared to a group of 10 patients (20 eyes) with Primary Open Angle Glaucoma POAG. Results Pattern reversal VECP were abnormal in 32/37 eyes (86%): 26/32 (81%) of these being of reduced amplitude, and 20/32 (62%) being delayed. Amongst the patients with POAG only 4/20 eyes (20%) had abnormal VECP, and none were delayed. Thinning of the RNFL occurred in 36/37 eyes (97%) with optic nerve disease; 24 (65%) had global thinning, and the remainder segmental thinning only. All of the eyes with POAG had RNFL thinning but only 6/20 eyes (30%) had global thinning. Bipolar cell thinning of the central retina was noted in 6 eyes with optic nerve disease. Conclusion OCT is a valuable tool in the assessment of patients with optic nerve disease. Thinning of the RNFL was a more consistent finding than delay of the VECP in optic nerve disease, and a combination of VECP and OCT is helpful in the differential diagnosis of low tension glaucoma and optic nerve disease. [source] Slitlamp integrated OCT, what you can see, is what you can scanACTA OPHTHALMOLOGICA, Issue 2009FD VERBRAAK Purpose To present results of OCT images captured of the posterior and anterior segment of the eye using the SLSCAN-1, a new FD-OCT device integrated into a slit lamp. Methods Patients, seen in the outpatient clinic of the Academic Medical Center, were scanned with the SLSCAN-1, a newly developed OCT scanning device, integrated into a common slit lamp (figure 1). The OCT is a Fourier Domain OCT system (SLD light source, central wavelength 830 nm, bandwidth 30 nm, 1024 pixel CCD camera, scan speed 5k A-scans per second, 1024 A-scans per B-scan). The posterior segment scans have been captured using a standard indirect ophthalmic lens (Volk). A color fundus photography of the observed area is made at the same time (Topcon camera DC1, resolution = 3.24 Mp). Results For posterior segment imaging, the flexible optical arrangement of the slit lamp and the hand-held lens (Volk), allows the user to scan large areas of the retina (>45 degrees), depending on the pupil size of the patient. In all patients the macula and optic disk could be visualized without any difficulty. In the anterior segment mode, the SLSCAN-1 allows imaging of the cornea, anterior chamber, iris and parts of the lens. Conclusion The images made by the SLSCAN-, new slit lamp integrated FD-OCT, could be very useful to examine patients directly, both posterior and anterior, during regular slit lamp examinations. Commercial interest [source] Scanning beyond the limits of standard OCT: OCT scans of the peripheral retina and the anterior chamber angle with a slitlamp integtrated FD-OCT systemACTA OPHTHALMOLOGICA, Issue 2009M STEHOUWER Purpose Exploring the quality of OCT images of the peripheral retina and anterior chamber angle made through a 3-mirror contactlens and a new FD-OCT device integrated into a slit lamp. Methods Patients with peripheral lesions (n=10) and glaucoma (n=10), seen in the outpatient clinic of the Academic Medical Center, were scanned with a Fourier Domain OCT integrated into a common Topcon slitlamp (SLD light source, central wavelength 830 nm, bandwidth 30 nm, 1024 pixel CCD camera, scan speed 5k A-scans per second, up to 1024 A-scans per b-scan). For posterior segment scans a fast Z-tracking system in the reference arm compensates for the dynamic character (movements of patient, handheld lens, slitlamp) of the examination. Scans of peripheral lesions, and the anterior chamber angle were made with a 3-mirror lens, while simultaneously the lesions were observed with the slitlamp. Results Scans of the peripheral retina obtained with a 3-mirror lens with the FD-OCT integrated into the slitlamp were of reasonably good quality and lesions, like peripheral laser scars, could be clearly identified. Compared to stand alone OCT systems, the integrated OCT system reached more peripheral lesions. The anterior chamber angle scanned through a 3-mirror lens enabled scans of the angle structures. Conclusion It is possible to scan the peripheral retina and anterior chamber angle through a 3-mirror contact lens with the slitlamp with integrated OCT. These scans could be of clinical interest in patients with pathology in the peripheral retina pathology or the anterior chamber angle. [source] | ||||||||||