scholarly journals Reconstructing the Optical Parameters of a Layered Medium with Optical Coherence Elastography

Author(s):  
Peter Elbau ◽  
Leonidas Mindrinos ◽  
Leopold Veselka
2021 ◽  
Vol 14 (3) ◽  
pp. 46-53
Author(s):  
E. P. Tarutta ◽  
R. R. Khubieva ◽  
G. A. Markosyan

Purpose: to assess the thickness of the central region of the retina and choroid, the layer of nerve fibers in the macular and peripapillary regions, the density of the superficial and deep plexus of the retina and the choroid in congenital and acquired myopia and see how they are related with the refraction and axial length of the eye.Material and methods. 33 patients aged 6 to 16 (averagely, 12.07 ± 3.09 years) were divided into 3 groups: 1) with congenital myopia (23 eyes), 2) with acquired myopia (9 eyes), and 3) the control group with emmetropia (20 eyes). Chorioretinal and hemodynamic parameters were determined using an RS-3000 Advance 2 spectral optical coherence tomograph (Nidek, Japan). Correlation analysis was performed using Pearson’s linear correlation coefficient (r).Results. Structural changes in the sensory and vascular membranes of the eye were revealed in both myopic groups as compared to the control group. Of the two clinical groups, more severe structural disorders were found in congenital myopia. Hemodynamic parameters revealed abnormalities in the deep retinal layers, as well as in the choriocapillary layer. The comparative analysis showed that morphological changes in the posterior pole have a stronger correlation with anatomical parameters as compared to optical ones.Conclusion. Optical coherence tomography is an informative method of differential diagnosis, monitoring, and prognostication of changes in the posterior pole in myopia.


2013 ◽  
Vol 333-335 ◽  
pp. 135-139
Author(s):  
Hai Ye ◽  
Ying Jun Gao

In order to measure the optical parameters of biological tissue accurately and non-invasive, the measurement system based on optical coherence tomography was analyzed and designed from two aspects of hardware and software. The refractive index was calibrated by standard refractive index solutions, experiments were preformed to obtain refractive index of tissue samples and scattering coefficient of IntralipidTMsolution with different concentrations. Results show that the experimental values of refractive index agree with the standard values roughly and scattering coefficient linear relate with concentration in IntralipidTMsolution. The measurement system designed in our experiment is accurate and reliable, simple and feasible.


2009 ◽  
Vol 17 (20) ◽  
pp. 17426 ◽  
Author(s):  
Arata Miyazawa ◽  
Masahiro Yamanari ◽  
Shuichi Makita ◽  
Masahiro Miura ◽  
Keisuke Kawana ◽  
...  

2010 ◽  
Author(s):  
Arata Miyazawa ◽  
Masahiro Yamanari ◽  
Shuichi Makita ◽  
Masahiro Miura ◽  
Keisuke Kawana ◽  
...  

Author(s):  
R. Hegerl ◽  
A. Feltynowski ◽  
B. Grill

Till now correlation functions have been used in electron microscopy for two purposes: a) to find the common origin of two micrographs representing the same object, b) to check the optical parameters e. g. the focus. There is a third possibility of application, if all optical parameters are constant during a series of exposures. In this case all differences between the micrographs can only be caused by different noise distributions and by modifications of the object induced by radiation.Because of the electron noise, a discrete bright field image can be considered as a stochastic series Pm,where i denotes the number of the image and m (m = 1,.., M) the image element. Assuming a stable object, the expectation value of Pm would be Ηm for all images. The electron noise can be introduced by addition of stationary, mutual independent random variables nm with zero expectation and the variance. It is possible to treat the modifications of the object as a noise, too.


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