Optical system of human eye model

2010 ◽  
Author(s):  
Vladislav V. Druzhin ◽  
Alexey P. Tsapenko
Keyword(s):  
2014 ◽  
Vol 12 (11) ◽  
pp. 113301-113303 ◽  
Author(s):  
Meimei Kong Meimei Kong ◽  
Zhen Li Zhen Li
Keyword(s):  

2012 ◽  
Vol 17 (7) ◽  
pp. 0750091 ◽  
Author(s):  
Yi-Chun Chen ◽  
Chong-Jhih Jiang ◽  
Tsung-Hsun Yang ◽  
Ching-Cherng Sun

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Teerapot Wessapan ◽  
Phadungsak Rattanadecho

Human eye is one of the most sensitive parts of the entire human body when exposed to electromagnetic fields. These electromagnetic fields interact with the human eye and may lead to cause a variety of ocular effects from high intensity radiation. However, the resulting thermo-physiologic response of the human eye to electromagnetic fields is not well understood. In order to gain insight into the phenomena occurring within the human eye with temperature distribution induced by electromagnetic fields, a detailed knowledge of absorbed power distribution as well as temperature distribution is necessary. This study presents a numerical analysis of specific absorption rate (SAR) and heat transfer in the heterogeneous human eye model exposed to electromagnetic fields. In the heterogeneous human eye model, the effect of power density on specific absorption rate and temperature distribution within the human eye is systematically investigated. In particular, the results calculated from a developed heat transfer model, considered natural convection and porous media theory, are compared with the results obtained from a conventional heat transfer model (based on conduction heat transfer). In all cases, the temperatures obtained from the developed heat transfer model have a lower temperature gradient than that of the conventional heat transfer model. The specific absorption rate and the temperature distribution in various parts of the human eye during exposure to electromagnetic fields at 900 MHz, obtained by numerical solution of electromagnetic wave propagation and heat transfer equation, are also presented. The results show that the developed heat transfer model, which is the more accurate way to determine the temperature increase in the human eye due to electromagnetic energy absorption from electromagnetic field exposure.


Author(s):  
Nataly Yu. Ilyasova ◽  
◽  
Dmitriy A. Abulkhanov ◽  
Alexander V. Kupriyanov ◽  
Alexey V. Karsakov ◽  
...  

2008 ◽  
Vol 75 (3) ◽  
pp. 172 ◽  
Author(s):  
A. V. Dubinin ◽  
T. Yu. Cherezova ◽  
A. I. Belyakov ◽  
A. V. Kudryashov
Keyword(s):  

2021 ◽  
pp. 143-146
Author(s):  
Stephen R. Wilk

A conundrum—you can estimate the focal length of a positive lens by using it to project the image of a distant scene onto the wall in a darkened room. But if you try to do it by placing the lens, a focal length away from an illuminated object and looking for the point where to produces a lens-filling collimated beam, you don’t get the correct length. When you’re figuring out the behavior of images in an optical system meant to be viewed with the human eye, don’t forget to include the optics of the eye itself.


2017 ◽  
Vol 17 (02) ◽  
pp. 1750038 ◽  
Author(s):  
PEISHAN DAI ◽  
YALI ZHAO ◽  
HANWEI SHENG ◽  
LING LI ◽  
JING WU ◽  
...  

Elevated intraocular pressure (IOP) may be the primary risk factor to the development of glaucoma. Finite element (FE) modeling is commonly considered as an effective method to quantitatively analyze pathogenesis of glaucoma. Recent researches focus on establishing partial human eye models. A refined global human eye model was developed using ANSYS software to investigate the correlation between IOP elevation and biomechanical responses. First, the pressure transferring process according to IOP elevation in the whole eye was analyzed to simulate the effects of IOP elevation on glaucoma. Then, the biomechanical responses of the anterior eye segment under various pressure differences between the anterior and posterior chambers (AC and PC) were analyzed to simulate posterior nonadhesion of iris and posterior synechia. This global eye model not only simulated the responses of elevated IOP on ocular structures, but also revealed the process of pressure transferring among each tissue from the anterior eye segment to the optic nerve head (ONH) region. The local mechanical characteristics of the ocular structures obtained from the global model agreed with previous findings. This global model may shed light on the studies of multifactorial glaucoma.


2020 ◽  
Vol 82 (5) ◽  
pp. 341-343
Author(s):  
Kwok-chi Lau

A physical eye model made of a water balloon and a convex lens is described. It can be used to model how an image is formed in the eye as well as shortsightedness and farsightedness. The model is unique in featuring a fluid-filled “eyeball” with “intraocular pressure,” making it a useful tool for teaching about accommodation and glaucoma. Instructional ideas for the model are suggested.


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