scholarly journals Versatile Multi-Detector Scheme for Adaptive Optics Scanning Laser Ophthalmoscopy

2018 ◽  
Author(s):  
Sanam Mozaffari ◽  
Volker Jaedicke ◽  
Francesco Larocca ◽  
Pavan Tiruveedhula ◽  
Austin Roorda
Keyword(s):  
Adaptive Optics ◽  
Signal To Noise Ratio ◽  
Scattered Light ◽  
Scanning Laser ◽  
Retinal Vasculature ◽  
Single Element ◽  
Scanning Laser Ophthalmoscopy ◽  
Signal To Noise ◽  
Detection Scheme ◽  
Multiple Detectors

AbstractAdaptive Optics Scanning Laser Ophthalmoscopy (AOSLO) is a powerful tool for imaging the retina at high spatial and temporal resolution. In this paper, we present a multi-detector scheme for AOSLO which has two main configurations: pixel reassignment and offset aperture imaging. In this detection scheme, the single element detector of the standard AOSLO is replaced by a fiber bundle which couples the detected light into multiple detectors. The pixel reassignment configuration allows for more light throughput while maintaining optimal confocal resolution. The increase in signal-to-noise ratio (SNR) from this configuration can improve the accuracy of motion registration techniques. The offset aperture imaging configuration enhances the detection of multiply scattered light, which improves the contrast of retinal vasculature and inner retinal layers similar to methods such as nonconfocal split-detector imaging and multi-offset aperture imaging.

scholarly journals Characterization of In Vivo Retinal Lesions of Diabetic Retinopathy Using Adaptive Optics Scanning Laser Ophthalmoscopy

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Sonja G. Karst ◽  
Jan Lammer ◽  
Salma H. Radwan ◽  
Hanna Kwak ◽  
Paolo S. Silva ◽  
...  
Keyword(s):  
Diabetic Retinopathy ◽  
Adaptive Optics ◽  
Scattered Light ◽  
Disease Onset ◽  
Morphological Characteristics ◽  
Response To Therapy ◽  
Vascular Lesions ◽  
Scanning Laser ◽  
Scanning Laser Ophthalmoscopy

Purpose. To characterize hallmark diabetic retinopathy (DR) lesions utilizing adaptive optics scanning laser ophthalmoscopy (AOSLO) and to compare AOSLO findings with those on standard imaging techniques. Methods. Cross-sectional study including 35 eyes of 34 study participants. AOSLO confocal and multiply scattered light (MSL) imaging were performed in eyes with DR. Color fundus photographs (CF), infrared images of the macula (Spectralis, Heidelberg), and Spectralis spectral domain optical coherence tomography SDOCT B-scans of each lesion were obtained and registered to corresponding AOSLO images. Main Outcome Measures. Individual lesion characterization by AOSLO imaging. AOSLO appearance was compared with CF and SDOCT imaging. Results. Characterized lesions encompassed 52 microaneurysms (MA), 20 intraretinal microvascular abnormalities (IRMA), 7 neovascularization (NV), 11 hard exudates (HE), 5 dot/blot hemorrhages (HEM), 4 cotton wool spots (CWS), and 14 intraretinal cysts. AOSLO allowed assessment of perfusion in vascular lesions and enabled the identification of vascular lesions that could not be visualized on CF or SDOCT. Conclusions. AOSLO imaging provides detailed, noninvasive in vivo visualization of DR lesions enhancing the assessment of morphological characteristics. These unique AOSLO attributes may enable new insights into the pathological changes of DR in response to disease onset, development, regression, and response to therapy.

MEMS-based adaptive optics scanning laser ophthalmoscopy

2006 ◽  
Vol 31 (9) ◽  
pp. 1268 ◽  
Author(s):  
Yuhua Zhang ◽  
Siddharth Poonja ◽  
Austin Roorda
Keyword(s):  
Adaptive Optics ◽  
Scanning Laser ◽  
Scanning Laser Ophthalmoscopy

scholarly journals Photometric Characteristics of Data from the Hubble Space Telescope Goddard-High Resolution Spectrograph

1988 ◽  
Vol 132 ◽  
pp. 35-38
Author(s):  
Dennis C. Ebbets ◽  
Sara R. Heap ◽  
Don J. Lindler
Keyword(s):  
Exposure Time ◽  
Hubble Space Telescope ◽  
Signal To Noise Ratio ◽  
Scattered Light ◽  
Signal To Noise ◽  
Space Telescope ◽  
Additional Noise ◽  
Reduction Strategies ◽  
Noise Ratio

The G-HRS is one of four axial scientific instruments which will fly aboard the Hubble Space Telescope (ref 1,2). It will produce spectroscopic observations in the 1050 A ≤ λ ≤ 3300 A region with greater spectral, spatial and temporal resolution than has been possible with previous space-based instruments. Five first order diffraction gratings and one Echelle provide three modes of spectroscopic operation with resolving powers of R = λ/ΔΔ = 2000, 20000 and 90000. Two magnetically focused, pulse-counting digicon detectors, which differ only in the nature of their photocathodes, produce data whose photometric quality is usually determined by statistical noise in the signal (ref 3). Under ideal circumstances the signal to noise ratio increases as the square root of the exposure time. For some observations detector dark count, instrumental scattered light or granularity in the pixel to pixel sensitivity will cause additional noise. The signal to noise ratio of the net spectrum will then depend on several parameters, and will increase more slowly with exposure time. We have analyzed data from the ground based calibration programs, and have developed a theoretical model of the HRS performance (ref 4). Our results allow observing and data reduction strategies to be optimized when factors other than photon statistics influence the photometric quality of the data.

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