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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 7VskZbj\  
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人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 ?2R!n" m-d  
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模型 !E|R3e X_  
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模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 hL&7D @  
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Table 1. AZ眼睛模型的定义
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在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. !? H:?  
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光源 'n^?DPvD  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 :hcOceNz  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 4E_u.tJ  
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在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 }@/Ox  
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图2. 字母F光源的设定方法光 K4H27SH  
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图3. 字母F在视网膜上位置点列图
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视网膜的散射 -m[ tYp,q  
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在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 +t&+f7  
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图4. 视网膜朗伯散射设定
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注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 )2 q r^)  
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图5. 视网膜重点采样规格设定
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脚本 P.g./8N`z  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: <%W&xk  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 Nf2lw]-G4  
余下的脚本计算与屈光度有关的所有参数。 2yD ?f8P4  
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分析 N})vrB;1  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ~p:hqi1+<+  
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图7. 字母F在视网膜上颜色分析
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脚本代码 S6C DK:  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 9b&;4Yq!f  
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Dim entity As T_ENTITY gNZ"Kr o6  
Dim op As T_OPERATION O'xp"e,  
Dim mat As T_MODELMATERIAL "vkM*HP  
Dim A As Double I2NMn5>  
Dim pupilDiam As Double 0LP0q9S:9  
Dim eID As Long ??|,wIRz  
Dim parID As Long ?5;wPDsK  
Dim count As Integer QNv5CQ&  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double \d:Uq5d)0  
Dim tlens As Double, nlens As Double j~=<O<P  
Dim curv As Double, conic As Double V\Y, 4&bI  
Dim ok As Long [9}<N2,9z  
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Sub Main k8SY=HP  
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    '用户输入对话框 &oJ[ *pQ  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 |oX9SUl  
        TextBox 220,21,40,21,.TextBox1 'default: 0 qI tbY%  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 n$h+_xN  
        OKButton 40,91,90,21 EFu$>Z4  
        CancelButton 190,91,90,21 /xr75|-8  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 P1]F0fR  
        TextBox 220,49,40,21,.TextBox2 'default: 4 7fd,I%v  
    End Dialog hYA1N&yz@  
    Dim dlg As UserDialog cg_tJ^vrY  
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    ok = Dialog (dlg) X'%BS  
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    If ok=0 Then    'cancel button was pressed u@+^lRGFh  
        Print "Execution cancelled." }dqOE-"I"n  
        End U+(qfa5(  
    End If *IF ~ab2  
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    'Assign accommodation and pupil diameter & use defaults if field left empty 4(Y-TFaf  
    If dlg.TextBox1 = "" Then Ra^c5hP:.E  
        A = 0           'Default accommodation xk,1 D  
    Else CG J_k?h  
        A = CDbl(dlg.TextBox1) ' ~z`kah  
    End If =+<DNW@%  
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    If dlg.TextBox2 = "" Then x #|t#N%  
        pupilDiam = 4   'Default pupil diameter RaymSh  
    Else ,wHlU-%  
        pupilDiam = CDbl(dlg.TextBox2) us<dw@P7{  
    End If =NPo<^Lae  
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    Print " " @)z?i  
    Print "Accommodation = " & A & " Diopters" b `cH.v  
    Print "Pupil Diameter = " & pupilDiam & " mm" |y?W#xb  
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    ' Calculate new parameters with accommodation mVK^gJ3  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness z_y@4B6>}  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens q^QLNKOH"  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens O31.\ZR2  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens C [8='i26  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens /de~+I5AB~  
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    tlens = 3.767 + 0.04*A                  'Lens thickness ^5FwYXAxi  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction <c [X^8   
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    'Adjust parameters to account for accommodation )G#O#Yy  
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    '************************************************************************* G?:5L0g  
    'Aqueous thickness (Position of Lens) Xupwh5G2  
    '************************************************************************* _w%{yF6   
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) "`[4(j  
    GetCustomElement eID, entity _sCzee&uQ  
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    parID = FindFullName( "Geometry.Arizona Eye" ) 8`WaUB%  
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    ' Delete any shift(s) in z UGA` `;f  
    count = 0 #!4 HSBf  
    While GetOperationCount(eID)>count QKt{XB6Y  
        GetOperation eID, count, op v0pev;C  
        If op.Type="ShiftZ" Then U {9yfy  
            DeleteOperation eID,count jF{\=&fU  
            count=count-1 eTY(~J#'  
        End If !Bhs8eGr3  
        count=count+1 TO] cZZ<  
    Wend A_5M\iN\  
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    'Set new shift in  .V l  
    op.Type = "ShiftZ" TM,Fab &  
    op.val1 = taq ;7mE%1X  
    op.parent = parID =UZQ` {  
    AddOperation eID, op ]%h|ox0  
    Print "Set aqueous humor thickness = " & taq-0.55 X`k#/~+0  
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    '************************************************************************* K|rG&#1J  
    'Radius and conic constant of anterior lens a0&R! E;  
    '************************************************************************* l-6W]\v Z  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) XhJYsq]]J  
    GetConic eID, entity, curv, conic 5VE9DTE  
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    SetConic eID, entity, 1/Rant, CCant 2nB{oF-Z  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 6" GHVFB  
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    '************************************************************************* }h9f(ZyJn  
    'Radius and conic constant of posterior lens #pWeMt'  
    '************************************************************************* S&Sa~Oq<o  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) p+xjYU4^C  
    GetConic eID, entity, curv, conic  Y?IXV*J  
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    SetConic eID, entity, 1/Rpost, CCpost o[ 4e_ @E  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost o/I`L  
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    '************************************************************************* V7,;N@FL  
    'Lens thickness (Position of posterior lens surface) |OO2>(Fj  
    '************************************************************************* h@D!/PS  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Hni?r!8r  
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    ' Delete any z-shift(s) (L !#2Jy  
    count = 0 bA(-7l?  
    While GetOperationCount(eID)>count G`FY[^:  
        GetOperation eID, count, op f9?f!k  
        If op.Type="ShiftZ" Then k\}\>&Zqu  
            DeleteOperation eID,count eq7>-Dmi@  
            count=count-1 >~rytg]f  
        End If  7D\:i1~  
        count=count+1 YiTVy/  
    Wend n~?n+\.&a  
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    'Set new z-shift &&`-A6`p  
    op.Type = "ShiftZ" =g$>]AE  
    op.val1 = tlens t@3y9U$  
    op.parent = parID > ZKHjw  
    AddOperation eID, op  [?moS!  
    Print "Set lens thickness = " & tlens {4HcecT  
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    '************************************************************************* ^,6c9Dxy  
    'Lens index of refraction ;Zw? tU  
    '************************************************************************* P] qL&_  
    eID = FindMaterial( "Lens" ) "D7wtpJ  
    GetModelMaterial eID, mat Y]: Ch (Q  
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    mat.Nd = nlens EOzw&M];r  
    SetModelMaterial eID, mat 6"u"B-cz  
    Print "Set lens index of refraction = " & nlens C0 o  
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    '************************************************************************* L3'$"L.|u  
    'Pupil diameter ?j@(1",=&  
    '************************************************************************* w ;xbQZ|+  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) @ACq:+/Q c  
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    'Adjust pupil diameter (trimming volume inner hole) "aJf W  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" N7mYE  
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    ' Adjust pupil location to just in front of the lens zT ; +akq  
    parID = FindFullName( "Geometry.Arizona Eye" ) -~WDv[ [  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) (Kb_/  
    count = 0 F`RPXY`ux  
    While GetOperationCount(eID)>count #Mrc!pT]xy  
        GetOperation eID, count, op -5d^n\CDK  
        If op.Type="ShiftZ" Then USJk *  
            DeleteOperation eID,count tDn:B$*}W,  
            count=count-1 JbXd9AMh2  
        End If =RjseTS  
        count=count+1 7L$\S[E  
    Wend #-8%g{  
    op.Type = "ShiftZ" QpiA~4  
    op.val1 = taq-0.01 vhKHiw9L  
    op.parent = parID 5LJ0V  
    AddOperation eID, op in#lpDa[  
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    Print "Set pupil diameter = " & pupilDiam J)._&O$  
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    'Update AZ Eye subassembly Description 8\Kpc;zb  
    eID = FindFullName( "Geometry.Arizona Eye" ) Df.eb|[{  
    GetEntity eID, entity 7,"y!\  
    entity.Description = "Accommodation = " & A & "D" ,j e  
    SetEntity eID, entity LW!>_~g-  
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    Update yz^4TqJ  
    Print "DONE!" \/F*JPhy  
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End Sub DAf0bh"  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: (Q}ByX  
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Accommodation = 4 Diopters n<e1=L  
Pupil Diameter = 4 mm ,C0D|q4/!.  
Set aqueous humor thickness = 2.81 fxknfgbg  
Set anterior lens radius = 10.4 and conic constant = -2.375869 Hb3t|<z  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 <HH\VG\H6  
Set lens thickness = 3.927 V)A7q9Bum  
Set lens index of refraction = 1.42672 l- $5CO  
Set pupil diameter = 4 uP$C2glyz  
DONE! !nL>Ly  
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