Vertical Scans Research Articles

Electromagnetic biaxial microscanner with mechanical amplification at resonance.

We present the design, fabrication, and measurement results of an electromagnetic biaxial microscanner with mechanical amplification mechanism. A gimbaled scanner with two distinct single-crystal silicon layer thicknesses and integrated copper coils has been fabricated with combination of surface and bulk micromachining processes. A magnet assembly consisting of an array of permanent magnets and a pole piece has been placed under the substrate to provide high strength lateral magnetic field oriented 45° to two perpendicular scanning axes. Micromirror has been supported by additional gimbal to implement a mechanical amplification. A 1.2mm-diameter mirror with aluminum reflective surface has been actuated at 60Hz for vertical scan and at 21kHz for horizontal scan. Maximum scan angle of 36.12° at 21.19kHz and 17.62° at 60Hz have been obtained for horizontal and vertical scans, respectively.

Outer retinal tubulation in diabetic macular edema following anti-VEGF treatment

BackgroundTo address the presence and features of outer retinal tubulation (ORT) found in diabetic macular edema (DME) treated with anti-vascular endothelial growth factor (anti-VEGF) and to differentiate between ORT and cystoid DME, which have different plans of management.MethodsThis was a retrospective review of a total of 514 patients investigated with spectral domain optical coherence tomography (OCT) in patients with diabetic macular edema treated with anti-VEGF. ORT was seen in 12 eyes of 11 patients. The morphologic characteristics of ORT and its progress over time were examined using OCT data. The retinal images were obtained by horizontal and vertical scans to analyze the possible presence of ORT and to explore their morphologic features and location in the retinal layers.ResultsORT was seen in DME treated with anti-VEGF. ORT was shown as round or ovoid hyporeflective spaces with hyperreflective borders on the B-scans, measuring 30 to 120 μm high and 30 to 1775 μm wide. The tubules generally remained stable over time. In a retinal practice specializing in advanced diabetic retinopathy clinic, this ORT was seen in 12 eyes of 11 patients during a 12-month period. ORT presented either after receiving 0.05 mL open-label intravitreal injections of 0.5 mg ranibizumab or 1.25 mg bevacizumab.ConclusionORT is found in DME treated with anti-VEGF that may show damage to the outer retina secondary to the severity and chronicity of the DME. ORT may be a result of underlying chronic and severe diabetic macular edema that may occur later possibly secondary to retinal layers rearrangement after several anti-VEGF injections. It is important to differentiate between ORT and cystoids DME. The presence of the ORT entity alone without the presence of DME does not require further anti-VEGF re-injections.

Application of the Ultraviolet Scanning Elastic Backscatter LiDAR for the Investigation of Aerosol Variability

In order to investigate the aerosol variability over the southwest region of Slovenia, an ultraviolet scanning elastic backscatter LiDAR was utilized to make the vertical scan for atmospheric probing. With the assumption of horizontal atmospheric homogeneity, aerosol optical variables were retrieved from the horizontal pixel data points of two-dimensional range-height-indicator (RHI) diagrams by using a multiangle retrieval method, in which optical depth is defined as the slope of the resulting linear function when height is kept constant. To make the data retrieval feasible and precise, a series of key procedures complemented the data processing, including construction of the RHI diagram, correction of Rayleigh scattering, assessment of horizontal atmospheric homogeneity and retrieval of aerosol optical variables. The measurement example demonstrated the feasibility of the ultraviolet scanning elastic backscatter LiDAR in the applications of the retrieval of aerosol extinction and determination of the atmospheric boundary layer height. Three months’ data combined with the modeling of air flow trajectories using Hybrid Single Particle Lagrangian Integrated Trajectory Model were analyzed to investigate aerosol variability. The average value of aerosol extinction with the presence of land-based air masses from the European continent was found to be two-times larger than that influenced by marine aerosols from the Mediterranean or Adriatic Sea.

Comparison of Clinical Features in Highly Myopic Eyes with and without a Dome-Shaped Macula

To compare the clinical features of highly myopic eyes with a dome-shaped macula (DSM) with those without a DSM and to identify the funduscopic clues to suspect the presence of DSM. Retrospective case series. A total of 586 patients (1118 eyes) with high myopia (refractive error <-8 diopters [D] or axial length ≥26.5 mm) who had optical coherence tomography (OCT) examinations through the central fovea at our High Myopia Clinic between February 2012 and November2013. Vertical and horizontal OCT scans across the central fovea were retrospectively analyzed. A DSM was defined by the presence of an inward bulge of >50 μm in the vertical OCT image. Fundus photographs also were analyzed to identify the funduscopic clues to suspect the presence of DSM. The rate of DSM in 1118 highly myopic eyes. The rate of DSM in highly myopic eyes with macular complications. Funduscopic features to suggest the presence of DSM. Among the 1118 eyes, 225 (20.1%) had a DSM. A DSM was present in both vertical and horizontal OCT sections in 20% of eyes, along only the vertical section in 77% of eyes, and in only the horizontal section in 2% of eyes. The results of multiple regression analyses showed that serous retinal detachment and foveal and extrafoveal retinoschisis were significantly associated with the presence of DSM and that choroidal neovascularization was not. Ophthalmoscopically, 91.4% of the eyes with the appearance of a horizontal ridge connecting the optic disc and the fovea had a DSM. A DSM is found in as many as 20% of highly myopic individuals. Horizontal ridges connecting the optic disc and the fovea might be an important clue to suspect the presence of a DSM on the basis of fundus photographs.

En face imaging of posterior precortical vitreous pockets using swept-source optical coherence tomography.

To obtain sequential flat (en face) images of posterior precortical vitreous pockets (PPVPs) using swept-source optical coherence tomography (SS-OCT). We performed SS-OCT in the right eyes of 112 volunteers (mean age, 30.1 years; mean refraction, -2.5 diopters) while sitting using 12-mm horizontal, vertical scans of the 12- × 9-mm plane × 2.6-mm depth through the macula and optic disc. En face images of the posterior vitreous were obtained by En-View, a SS-OCT program. Swept-source OCT visualized the PPVPs and Cloquet's canals in all subjects; the PPVPs appeared as boat-shaped lacunae in the horizontal scan and extended superiorly as clefts in the vertical scan. En face imaging showed PPVPs and Cloquet's canals as two oval lacunae near the vitreoretinal interface and a septum between the nasal border of the PPVPs and Cloquet's canals. In all cases, the lacunas of the PPVPs were larger than those of Cloquet's canals. In 99 (88.4%) of 112 eyes, the PPVPs and Cloquet's canals were fused by connecting channels. The mean width of the connecting channels was 920.2 ± 37.4 μm, and the mean height was 288.6 ± 20.0 μm. On the anterior en face images, the PPVPs became crescent-shaped in all eyes. Using SS-OCT, we obtained en face images of PPVPs and Cloquet's canals in vivo. The en face images of the PPVPs near the retina showed oval shapes that changed to crescents, which corresponded to the superior edge of the PPVPs. The PPVPs were fused with Cloquet's canal by a flat-shaped connecting channel.

Georeferenced Scanning System to Estimate the Leaf Wall Area in Tree Crops

This paper presents the use of a terrestrial light detection and ranging (LiDAR) system to scan the vegetation of tree crops to estimate the so-called pixelated leaf wall area (PLWA). Scanning rows laterally and considering only the half-canopy vegetation to the line of the trunks, PLWA refers to the vertical projected area without gaps detected by LiDAR. As defined, PLWA may be different depending on the side from which the LiDAR is applied. The system is completed by a real-time kinematic global positioning system (RTK-GPS) sensor and an inertial measurement unit (IMU) sensor for positioning. At the end, a total leaf wall area (LWA) is computed and assigned to the X, Y position of each vertical scan. The final value of the area depends on the distance between two consecutive scans (or horizontal resolution), as well as the number of intercepted points within each scan, since PLWA is only computed when the laser beam detects vegetation. To verify system performance, tests were conducted related to the georeferencing task and synchronization problems between GPS time and central processing unit (CPU) time. Despite this, the overall accuracy of the system is generally acceptable. The Leaf Area Index (LAI) can then be estimated using PLWA as an explanatory variable in appropriate linear regression models.

Observation of the Vitreous in Diabetic Macular Edema Using Swept-Source OCT

Purpose: This study describes the relationship between the vitreous and diabetic macular edema (DME) using swept source OCT (SS-OCT). Method: We examined 81 eyes of 58 consecutive patients diagnosed as DME. The condition of the posterior wall of the posterior precortical vitreous pocket (PPVP) was classified into 4 groups based on 12-mm horizontal and vertical scans through the macula using SS-OCT. Classifications were: Group 1, no posterior vitreous detachments (PVDs); Group 2, perifoveal PVD; Group 3, macular PVD; and Group 4, complete PVD. DME types, which included cystoid macular edema (CME) and serous retinal detachment (SRD), were also investigated in each group. The control group consisted of 46 eyes of 39 diabetic patients without DME as shown by OCT. Result: The number of eyes diagnosed as DME for each of the groups was 18, 35, 6 and 22, respectively. OCT images revealed there were 35 (43%) out of 81 eyes with perifoveal PVD, that was accompanied by CME (94%) with or without SRD, which was statistically significant as compared with the other groups (P=0.0005). In Group 2, there were 21 (60%) out of 35 eyes with proliferative diabetic retinopathy (PDR), with this ratio significantly higher when compared to the other groups (P=0.034). Conclusion: A significant correlation exists between CME associated with DME and perifoveal PVD.

Choroidal thickness in geographic atrophy secondary to age-related macular degeneration.

To analyze choroidal thickness (CT) in eyes with geographic atrophy (GA) secondary to age-related macular degeneration (AMD). A total of 72 eyes of 72 patients (mean age, 75.97 ± 7.09 years) with GA and 37 eyes of 37 healthy controls (73.89 ± 6.19 years) were examined by confocal scanning laser ophthalmoscopy and enhanced depth imaging (EDI) spectral-domain optical coherence tomography. Choroidal thickness was measured at 25 defined points in horizontal and vertical scans. Geographic atrophy size was determined in fundus autofluorescence (FAF) images and GA subtypes were classified based on abnormal FAF in the perilesional zone. In GA, subfoveal CT (fCT) was significantly thinner compared to controls (173.03 ± 90.22 vs. 253.95 ± 69.19 μm, P < 0.001). Analysis of averaged measurements of all 25 points obtained per patient (mCT) revealed similar results (162.07 ± 76.26 vs. 228.00 ± 66.24 μm, P < 0.001). Spatial differences in CT between both groups were largest superior to the fovea. Addressing "diffuse-trickling" (n = 15) and "non-diffuse-trickling" (n = 57) GA independently, fCT was 114.67 ± 43.32 and 188.39 ± 93.26 μm, respectively (P = 0.002), with both groups being significantly thinner than controls (P < 0.001 for "diffuse-trickling" and P < 0.001 for "?non-diffuse-trickling"). Similar results were obtained for mCT, which was 110.21 ± 29.66 μm in "diffuse-trickling," 175.72 ± 79.02 μm in "?non-diffuse-trickling" and 228.00 ± 66.24 μm in controls. Differences were significant with P = 0.002 between both GA groups and P ≤ 0.001 toward controls for each GA group. The results indicate that the choroid in eyes with GA is thinner compared to normal eyes of similar age. Hereby, the extent of thinning is most pronounced in a specific subtype of GA identified by FAF imaging ("diffuse trickling"). Such GA subtype-related differences in choroidal thickness may reflect heterogeneity in the pathogenesis of disease. (ClinicalTrials.gov number, NCT02051998.).

Adaptive optics imaging of healthy and abnormal regions of retinal nerve fiber bundles of patients with glaucoma.

To better understand the nature of glaucomatous damage of the macula, especially the structural changes seen between relatively healthy and clearly abnormal (AB) retinal regions, using an adaptive optics scanning light ophthalmoscope (AO-SLO). Adaptive optics SLO images and optical coherence tomography (OCT) vertical line scans were obtained on one eye of seven glaucoma patients, with relatively deep local arcuate defects on the 10-2 visual field test in one (six eyes) or both hemifields (one eye). Based on the OCT images, the retinal nerve fiber (RNF) layer was divided into two regions: (1) within normal limits (WNL), relative RNF layer thickness within mean control values ±2 SD; and (2) AB, relative thickness less than -2 SD value. As seen on AO-SLO, the pattern of AB RNF bundles near the border of the WNL and AB regions differed across eyes. There were normal-appearing bundles in the WNL region of all eyes and AB-appearing bundles near the border with the AB region. This region with AB bundles ranged in extent from a few bundles to the entire AB region in the case of one eye. All other eyes had a large AB region without bundles. However, in two of these eyes, a few bundles were seen within this region of otherwise missing bundles. The AO-SLO images revealed details of glaucomatous damage that are difficult, if not impossible, to see with current OCT technology. Adaptive optics SLO may prove useful in following progression in clinical trials, or in disease management, if AO-SLO becomes widely available and easy to use.

Robust Feature Extraction Technique for License Plate Characters Recognition

ABSTRACTThis paper presents two novel geometrical feature extraction techniques for license plate (LP) characters recognition, written in English alphabets and numerals. A robust character recognition technique has to recognize different format, broken, and distorted characters by extracting invariant and discriminative character features. In this paper, we have extracted two types of geometrical features and a statistical crossing count feature with the help of horizontal, vertical, right diagonal, and left diagonal scan lines and centroid of the character to be recognized. For character recognition, we have used edit distance metric. The proposed technique can be enhanced to recognize any language scripts and is tested for Indian scripts. The proposed LP characters recognition technique is evaluated using 741 images of media-lab benchmark database, 49 images of Israeli vehicle LPs, and 110 images of proprietary Indian vehicle LPs having different environmental conditions and plate variations. The proposed technique achieved success rate of 98.8% for LP characters recognition which outperforms many LP character recognition techniques in the literature.

Raman light scattering on ultra-thin films of LaNiO3 under compressive strain

In order to investigate the lattice dynamics of very thin films, we have carried out a series of depth-resolved Raman scattering measurements. Combining the narrow depth-of-field of confocal Raman spectroscopy with vertical scans of the sample, we have obtained high quality phonon spectra of fully strained LaNiO3 films with thickness as low as 4 pseudocubic unit cells. With increasing film thickness a large softening of a LaNiO3Eg-bending mode is observed, indicating the relaxation of biaxial compressive strain imposed by the LaAlO3 substrate.

A new spatially scanning 2.7 µm laser hygrometer and new small-scale wind tunnel for direct analysis of the H2O boundary layer structure at single plant leaves

A new spatially scanning TDLAS in situ hygrometer based on a 2.7-µm DFB diode laser was constructed and used to analyse the water vapour concentration boundary layer structure at the surface of a single plant leaf. Using an absorption length of only 5.4 cm, the TDLAS hygrometer permits a H2O vapour concentration resolution of 31 ppmv. This corresponds to a normalized precision of 1.7 ppm m. In order to preserve and control the H2O boundary layer on an individual leaf and to study the boundary layer dependence on the wind speed to which the leaf might be exposed in nature, we also constructed a new, application specific, small-scale, wind tunnel for individual plant leaves. The rectangular, closed-loop tunnel has overall dimensions of 1.2 × 0.6 m and a measurement chamber dimension of 40 × 54 mm (H × W). It allows to generate a laminar flow with a precisely controlled wind speed at the plant leaf surface. Combining honeycombs and a miniaturized compression orifice, we could generate and control stable wind speeds from 0.1 to 0.9 m/s, and a highly laminar and homogeneous flow with an excellent relative spatial homogeneity of 0.969 ± 0.03. Combining the spectrometer and the wind tunnel, we analysed (for the first time) non-invasively the wind speed-dependent vertical structure of the H2O vapour distribution within the boundary layer of a single plant leaf. Using our time-lag-free data acquisition procedure for phase locked signal averaging, we achieved a temporal resolution of 0.2 s for an individual spatial point, while a complete vertical spatial scan at a spatial resolution of 0.18 mm took 77 s. The boundary layer thickness was found to decrease from 6.7 to 3.6 mm at increasing wind speeds of 0.1–0.9 m/s. According to our knowledge, this is the first experimental quantification of wind speed-dependent H2O vapour boundary layer concentration profiles of single plant leaves.

Sensor fusion of cameras and a laser for city-scale 3D reconstruction.

This paper presents a sensor fusion system of cameras and a 2D laser sensor for large-scale 3D reconstruction. The proposed system is designed to capture data on a fast-moving ground vehicle. The system consists of six cameras and one 2D laser sensor, and they are synchronized by a hardware trigger. Reconstruction of 3D structures is done by estimating frame-by-frame motion and accumulating vertical laser scans, as in previous works. However, our approach does not assume near 2D motion, but estimates free motion (including absolute scale) in 3D space using both laser data and image features. In order to avoid the degeneration associated with typical three-point algorithms, we present a new algorithm that selects 3D points from two frames captured by multiple cameras. The problem of error accumulation is solved by loop closing, not by GPS. The experimental results show that the estimated path is successfully overlaid on the satellite images, such that the reconstruction result is very accurate.

Differential diagnosis of macular edema of different pathophysiologic origins by spectral domain optical coherence tomography.

To develop a classification approach based solely on spectral domain optical coherence tomography to differentiate macular edema (ME) of different disease entities and to determine underlying pathology. A cross-sectional study including 153 participants: 27 with Irvine-Gass, 31 with uveitic ME, 24 with ME after branch retinal vein occlusion, 13 with central retinal vein occlusion, 44 with diabetic ME, and 14 controls. Spectral domain optical coherence tomography was graded according to a standardized reading protocol. Grading characteristics were: ME pattern in the central line (horizontal/vertical) and in volume scans, distribution of cysts in Early Treatment Diabetic Retinopathy Study grid, morphologic features, and quantitative parameters such as individual layer thickness. The parameters in a best-fitting multivariate model were evaluated for reliability to predict the underlying pathology using a leave-one-out crossover-validation analysis. To evaluate clinical reliability, two masked clinicians graded spectral domain optical coherence tomography images according to the assessed parameters. The best-fitting multivariate model revealed that microfoci, ME pattern in vertical line scan, and foveal retinal nerve fiber layer thickness are the best indicators of the underlying pathology of ME. Classification accuracy of this model was 96%, mean cross-validated test classification accuracy was 84% (r² = 0.95, P < 0.0001). Clinical relevance was examined with 2 independent readers, yielding classification accuracies of 86% in both cases. Macular edema demonstrates characteristic patterns, morphologic features, and layer thicknesses dependent on the underlying disease process. Diagnostic recognition of these features may allow clinical and automated disease identification based primarily on spectral domain optical coherence tomography analysis.

Swept-Source Optical Coherence Tomography Features of Choroidal Nevi

To investigate the morphologic characteristics of choroidal nevi using swept-source optical coherence tomography and compare this with enhanced-depth optical coherence tomography. Retrospective observational case series. One choroidal nevus each from 30 eyes of 30 patients was included and received imaging with swept-source OCT (SS-OCT) and enhanced-depth imaging OCT (EDI-OCT). For SS-OCT, a scan acquisition protocol was used involving 12 mm horizontal and vertical scans in the posterior fundus. The main outcome measures were morphologic features of choroidal nevi obtained with SS-OCT imaging. These features were compared to images obtained with EDI-OCT. A 2-tailed Fisher exact test was the statistical method used. SS-OCT allowed for an appreciation of intralesional details: Of the 30 nevi imaged, intralesional vessels were apparent in 30 (100%), intralesional cavities in 6 (20%), intralesional granularity in 14 (47%), abnormal choriocapillaris in 25 (83%), and abnormal choriocapillaris confined to the tumor apex in 17 (58%). Distended bordering vessels were identified in 22 nevi (73%) and were significantly associated with the presence of previous or persistent subretinal fluid. Intrinsic hyperreflectivity with hyporeflective shadowing was significantly (P = .05) more apparent in 14 of 21 melanotic nevi (67%) compared with 2 of 9 amelanotic nevi (22%). Visualization of the complete nevus-scleral interface was significantly (P = .02) more apparent in 7 of 9 amelanotic nevi (78%) compared with 6 of 21 melanotic nevi (29%), and was not significantly related to tumor thickness (measured by ultrasound) or to tumor configuration. Tumor diameter (but not tumor height) was statistically significantly associated with secondary retinal changes (P = .05) and configuration (P = .01). EDI-OCT was equivalent at determining secondary retinal changes (P = .29), the presence of distended bordering vessels (P = 1), visualization of the nevus-scleral interface (P = .6), and hyporeflective gradation at the nevus-scleral interface (P = .33). However, in melanotic lesions, SS-OCT was significantly superior at visualizing intralesional vessels (P = .0002), intralesional granularity (P = .0005), and abnormal choriocapillaris (P = .0001). Imaging of choroidal nevi with SS-OCT enables visualization of intralesional details such as vessels (present in 100% of tumors imaged), cavities, and granularity. For melanotic lesions, SS-OCT is significantly better at depicting certain intralesional characteristics compared to EDI-OCT. Distended bordering vessels were recognized in over two thirds of the nevi imaged and were significantly associated with previous or persistent subretinal fluid.

Vertically scanned laser sheet microscopy.

Laser sheet microscopy is a widely used imaging technique for imaging the three-dimensional distribution of a fluorescence signal in fixed tissue or small organisms. In laser sheet microscopy, the stripe artifacts caused by high absorption or high scattering structures are very common, greatly affecting image quality. To solve this problem, we report here a two-step procedure which consists of continuously acquiring laser sheet images while vertically displacing the sample, and then using the variational stationary noise remover (VSNR) method to further reduce the remaining stripes. Images from a cleared murine colon acquired with a vertical scan are compared with common stitching procedures demonstrating that vertically scanned light sheet microscopy greatly improves the performance of current light sheet microscopy approaches without the need for complex changes to the imaging setup and allows imaging of elongated samples, extending the field of view in the vertical direction.

The Association Between the Foveal Avascular Zone and Retinal Thickness

To investigate the association between the size and shape of the foveal avascular zone and retinal thickness in healthy subjects. In vivo imaging of the foveal microvasculature was performed on 32 subjects by using an adaptive optics scanning laser ophthalmoscope (AOSLO). Motion contrast maps of the AOSLO images were used to generate a montage revealing the foveal capillary network. Foveal avascular zone (FAZ) diameters along the horizontal (FAZH) and vertical (FAZV) meridians were measured on the montages. An asymmetry index (AI) of the FAZ was then computed as the ratio of the FAZH to FAZV. Retinal thickness was investigated by using spectral-domain optical coherence tomography (SDOCT). Inner retinal layer (INLFAZ) thickness and outer nuclear layer (ONLFAZ) thickness were measured at the edges of the FAZ on the horizontal and vertical SDOCT scans on the same eye. The foveal capillary network was readily visualized in all subjects. As expected there was individual variation in the size and shape of the FAZ. Along the horizontal and vertical meridians, the mean±SD (μm) of the FAZ diameter was 607±217 and 574±155, respectively. The INLFAZ thickness was 68±9 and 66±9, and the ONLFAZ thickness was 103±13 and 105±11, respectively. The mean±SD of the AI was 1.03±0.27. The difference between FAZH and FAZV decreases with increasing FAZ area (P=0.004). Mean ONLFAZ was negatively correlated with FAZ effective diameter (P<0.0001). No significant correlation was found between mean INLFAZ and FAZ effective diameter (P=0.16). Despite large individual variations in size and shape of the FAZ, the INLFAZ has a relatively constant thickness at the margins of the FAZ, suggesting the presence of retinal capillaries is needed to sustain an INLFAZ thickness greater than 60 μm. A smaller FAZ area is associated with a vertically elongated FAZ.

Retinotoxicity of Hydroxychloroquine: Is It Possible to Demonstrate by Spectral Domain Optical Coherence Tomography Before Development? A Cross Sectional Investigation

Objectives: This study aims to evaluate the alterations of retinal layers in rheumatic patients treated with hydroxychloroquine but without the signs or symptoms of retinopathy by using spectral domain ocular coherence tomography (SD-OCT). Patients and methods: The retinal layers of a total of 402 eyes including 114 patients treated with hydroxychloroquine (for rheumatoid arthritis (n=40), Sjogren’s syndrome (n=47) and connective tissue diseases (n=27) and age-matched 87 healthy controls were evaluated with SD-OCT. The macular cube protocol, optic disc cube protocol and horizontal and vertical HD 5-line raster scan protocol were applied. The measured parameters were compared between hydroxychloroquine users and healthy control group. The results of these parameters were also compared with other disease groups using hydroxychloroquine. The correlation of these parameters with the duration of drug consumption and dose was assessed. Results: All layers of outer fovea, superior and inferior quadrants of retinal nerve fiber layers of hydroxychloroquine users were thinner than nonusers. Connective tissue disease group had longer duration and higher cumulative dose of hydroxychloroquine than other diagnostic groups. This group had thinner mean retinal nerve fiber layers values than the other groups as well. There were significant and negative correlations between cumulative dose of drug and parafoveal region thickness of outer fovea and inferior quadrant of retinal nerve fiber layers. Thickness of parafoveal and perifoveal layers was negatively correlated with the dose of drug per kg of body weight. Conclusion: Our study results show that SD-OCT may be the golden standard technique for the follow-up of antimalarial-induced retinotoxicity in

Study of the scanning lidar on the atmospheric detection

The scanning polarization Mie lidar (SPML) system has been developed and is described. The lidar system has two detection channels to receive the parallel and perpendicular polarization components at the laser wavelength of 532nm, which indicates the nonsphericity of aerosol and cloud particles. It can take the horizontal, vertical and conical scans of the atmosphere with the elevation and azimuth motors. This paper discusses the current capability of the SPML lidar and its results. The observation shows that the SPML lidar can provide the multi-dimensional views of the atmosphere which is impossible to achieve with other ground-based vertically pointing lidars. It is helpful to track and monitor aerosol plumes in urban area, to determinate the planetary boundary layer height and to enhance the measurement of atmosphere in the lower height where the geometrical form factor of lidar system affects.

Comparative difference of the choroidal thickness according to the refractive errors measured by enhanced depth imaging optical coherence tomography

AbstractPurpose To assess the differences of the choroidal thickness(CT) according to the refractive errors using enhanced depth imaging(EDI) optical coherence tomography(OCT).Methods Ninety‐seven eyes in healthy Korean children are categorized into three groups according to the refractive errors: hyperopia(27 eyes), emmetropia(39 eyes), and myopia(31 eyes). They underwent horizontal and vertical EDI OCT scan. The CT was measured at 9 locations: fovea(F) and 1mm &amp; 3mm nasal(N1,N3), temporal(T1,T3), superior(S1,S3) and inferior(I1,I3) area to the fovea. Statistical analysis was performed to evaluate the comparative difference of the CT at each location.Results The overall mean age was 8.2 years and there was no difference in three groups(p=0.320). The foveal CT in hyperopia was 359.41㎛ which was thicker than those in emmetropia(301.97㎛) and myopia(263.94㎛) and CT at the other 8 locations in hyperopia was thicker than in emmtropia and myopia(p&lt;0.05). The CT at S1, T1, N1 and N3 in hyperopia was thicker than those of emmetropia(p&lt;0.05). The CT of hyperopia was thicker than those of myopia except T3 location(p&lt;0.05). The thickest location of three groups was fovea in hyperopia, and T3 in emmetropia and myopia which was 320.79㎛ and 291.74㎛, respectively. The thinnest location was N3 in three groups(220.22㎛ in hyperopia, 163.92㎛ in emmetropia and 151.29㎛ in myopia)Conclusion The CT of hyperopia was thicker in comparison with emmetropia and myopia, especially at nasal area between hyperopia and emmetropia and at all locations except T3 between hyperopia and myopia. The temporal choroid was thicker than the nasal choroid regardless of refractive errors, but the thickest location in hyperopia was the fovea.