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Annual International Conference of the... Jul 2019The fundus observation by ophthalmoscope is a non-invasive approach for diagnosis of various retinal diseases. The vein and artery pulsation are usually clearly apparent...
The fundus observation by ophthalmoscope is a non-invasive approach for diagnosis of various retinal diseases. The vein and artery pulsation are usually clearly apparent on fundus and might be also important for medical practice. Thus our method focuses on these changes and analyzes the time delay between the pulsation signal detected in the vein and the artery region. Data acquired by an experimental video-ophthalmoscope from five subjects with no eye diseases are analyzed. The analysis is based on the selection of artery and vein regions of interest and computation of averaged brightness within these regions for each frame. These extracted signals are filtered, interpolated and the trend is eliminated. Finally, the delays between artery and vein pulsation signals are determined using phase spectra. The measured delays are in the range of 15 to 95 ms, which is comparable with other published results.
Topics: Fundus Oculi; Humans; Ophthalmoscopes; Retina; Retinal Artery; Retinal Vein; Time
PubMed: 31946916
DOI: 10.1109/EMBC.2019.8856306 -
Translational Vision Science &... Jul 2020Adaptive optics scanning laser ophthalmoscope (AOSLO) capillary perfusion images can possess large variations in contrast, intensity, and background signal, thereby...
PURPOSE
Adaptive optics scanning laser ophthalmoscope (AOSLO) capillary perfusion images can possess large variations in contrast, intensity, and background signal, thereby limiting the use of global or adaptive thresholding techniques for automatic segmentation. We sought to develop an automated approach to segment perfused capillaries in AOSLO images.
METHODS
12,979 image patches were extracted from manually segmented AOSLO montages from 14 eyes and used to train a convolutional neural network (CNN) that classified pixels as capillaries, large vessels, background, or image canvas. 1764 patches were extracted from AOSLO montages of four separate subjects, and were segmented manually by two raters (ground truth) and automatically by the CNN, an Otsu's approach, and a Frangi approach. A modified Dice coefficient was created to account for slight spatial differences between the same manually and CNN-segmented capillaries.
RESULTS
CNN capillary segmentation had an accuracy (0.94), a Dice coefficient (0.67), and a modified Dice coefficient (0.90) that were significantly higher than other automated approaches ( < 0.05). There were no significant differences in capillary density and mean segment length between manual ground-truth and CNN segmentations ( > 0.05).
CONCLUSIONS
Close agreement between the CNN and manual segmentations enables robust and objective quantification of perfused capillary metrics. The developed CNN is time and computationally efficient, and distinguishes capillaries from areas containing diffuse background signal and larger underlying vessels.
TRANSLATIONAL RELEVANCE
This automatic segmentation algorithm greatly increases the efficiency of quantifying AOSLO capillary perfusion images.
Topics: Capillaries; Humans; Lasers; Neural Networks, Computer; Ophthalmoscopes; Perfusion
PubMed: 32855847
DOI: 10.1167/tvst.9.2.43 -
Indian Journal of Ophthalmology Jul 2019
Topics: Adult; Choroid; Equipment Design; Eye Diseases; Female; Humans; Male; Middle Aged; Ophthalmoscopes; Smartphone; Young Adult
PubMed: 31238488
DOI: 10.4103/ijo.IJO_90_19 -
Optometry and Vision Science : Official... Apr 2010Adaptive optics (AO) describes a set of tools to correct or control aberrations in any optical system. In the eye, AO allows for precise control of the ocular... (Review)
Review
Adaptive optics (AO) describes a set of tools to correct or control aberrations in any optical system. In the eye, AO allows for precise control of the ocular aberrations. If used to correct aberrations over a large pupil, for example, cellular level resolution in retinal images can be achieved. AO systems have been demonstrated for advanced ophthalmoscopy as well as for testing and/or improving vision. In fact, AO can be integrated to any ophthalmic instrument where the optics of the eye is involved, with a scope of applications ranging from phoropters to optical coherence tomography systems. In this article, I discuss the applications and advantages of using AO in a specific system, the AO scanning laser ophthalmoscope. Since the Borish award was, in part, awarded to me because of this effort, I felt it appropriate to select this as the topic for this article. Furthermore, users of AO scanning laser ophthalmoscope continue to appreciate the benefits of the technology, some of which were not anticipated at the time of development, and so it is time to revisit this topic and summarize them in a single article.
Topics: Equipment Design; Humans; Lenses; Ophthalmoscopes; Ophthalmoscopy
PubMed: 20160657
DOI: 10.1097/OPX.0b013e3181d39479 -
Studies in Health Technology and... 2009We present a training simulator for indirect ophthalmoscopy. An optical tracking system is used to reconstruct the position of a lens mockup and a model of the patient's...
We present a training simulator for indirect ophthalmoscopy. An optical tracking system is used to reconstruct the position of a lens mockup and a model of the patient's face. Refraction and illumination are computed in real-time and displayed on a head-mounted display using augmented reality. A case database completes the training system which allows to practise the examination and to study clinical patterns.
Topics: Computer Simulation; Education, Medical; Equipment Design; Humans; Models, Biological; Ophthalmoscopes; Ophthalmoscopy; User-Computer Interface
PubMed: 19377172
DOI: No ID Found -
International Journal of Pharmaceutics Sep 2021To address the need for noninvasive monitoring of injectable preformed drug delivery implants in the eye, we developed noninvasive methods to monitor such implants in...
Noninvasive monitoring of suprachoroidal, subretinal, and intravitreal implants using confocal scanning laser ophthalmoscope (cSLO) and optical coherence tomography (OCT).
To address the need for noninvasive monitoring of injectable preformed drug delivery implants in the eye, we developed noninvasive methods to monitor such implants in different locations within the eye. Cylindrical polymeric poly(lactide-co-glycolide) or metal implants were injected into isolated bovine eyes at suprachoroidal, subretinal, and intravitreal locations and imaged noninvasively using the cSLO and OCT modes of a Heidelberg Spectralis HRA + OCT instrument after adjusting for the corneal curvature. Length and diameter of implants were obtained using cSLO images for all three locations, and the volume was calculated. Additionally, implant volume for suprachoroidal and subretinal location was estimated by integrating the cross-sectional bleb area over the implant length in multiple OCT images or using the maximum thickness of the implant based on thickness map along with length in cSLO image. Simultaneous cSLO and OCT imaging identified implants in different regions of the eye. Image-based measurements of implant dimensions mostly correlated well with the values prior to injection using blade micrometer. The accuracy (82-112%) and precision (1-19%) for noninvasive measurement of length was better than the diameter (accuracy 69-130%; precision 3-38%) using cSLO image for both types of implants. The accuracy for the measurement of volume of both types of implants from all three intraocular locations was better with cSLO imaging (42-152%) compared to those obtained using OCT cross-sectional bleb area integration (117-556%) or cSLO and thickness map (32-279%) methods. Suprachoroidal, subretinal, and intravitreal implants can be monitored for length, diameter, and volume using cSLO and OCT imaging. Such measurements may be useful in noninvasively monitoring implant degradation and drug release in the eye.
Topics: Animals; Cattle; Cross-Sectional Studies; Lasers; Ophthalmoscopes; Tomography, Optical Coherence
PubMed: 34271155
DOI: 10.1016/j.ijpharm.2021.120887 -
Ophtalmologie : Organe de La Societe... 1990We have used the scanning laser opthalmoscope (SLO) with a personal computer to develop static microperimetry techniques. They allow to see in real-time on a television... (Review)
Review
We have used the scanning laser opthalmoscope (SLO) with a personal computer to develop static microperimetry techniques. They allow to see in real-time on a television monitor the precise retinal localization of the stimulus and fixation. The testing is performed under strict conditions. The size of stimuli can vary between 6 and 30 minarc on a side. 255 different intensity levels are possible with the instrument. We have selected 12 of them, representing a logarithmic scale. Stimulus duration can vary between 50 and 500 ms. Examples of macular pathology including subretinal neovascularization, drusen and macular edema are given.
Topics: Humans; Lasers; Ophthalmoscopes; Visual Field Tests
PubMed: 2250964
DOI: No ID Found -
Bericht Uber Die Zusammenkunft.... 1970
Topics: Germany, West; Methods; Ophthalmoscopes
PubMed: 5537539
DOI: No ID Found -
Nihon Ganka Kiyo Aug 1967
Topics: Contact Lenses; Ophthalmoscopes
PubMed: 5626012
DOI: No ID Found -
The Journal of Physiology Oct 1979
Topics: Ophthalmoscopes; Optics and Photonics
PubMed: 521906
DOI: No ID Found