[技术]Arizona眼睛模型 [复制链接]

简介 |]w0ytL>(2  
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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。 a39Kl_\  
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模型 ppP7jiGo  
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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。 `9SuDuw;s  
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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. nJ<h}*[  
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光源 |f#~#Y2v  
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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。 VQI  
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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。 TL lR"L5  
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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。 c&vY0/ [  
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视网膜的散射 R]L|&{  
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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。 $$_aHkI j  
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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。 ]U.1z  
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脚本 D^V0kC p!F  
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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： Y).5(t7zaR  
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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。 ^o^[p %  
余下的脚本计算与屈光度有关的所有参数。 OCIWQ/ P  
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分析 huVw+vAA  
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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。 6B>1"h%Wf  
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脚本代码 (T+fO}0  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. e%.Xya#\  
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Dim entity As T_ENTITY [gI;;GW  
Dim op As T_OPERATION ?`T< sk8c  
Dim mat As T_MODELMATERIAL `D)ay  
Dim A As Double itV
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Dim pupilDiam As Double CZaUrr  
Dim eID As Long (s`oJLW>  
Dim parID As Long Teq1VK3Hr  
Dim count As Integer 5MUM{(C  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double <Th)&  
Dim tlens As Double, nlens As Double n-iy;L^b  
Dim curv As Double, conic As Double k+Ew+j1_  
Dim ok As Long
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Sub Main 1 ?X(q  
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    '用户输入对话框 ::bK{yZm  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Hjl{M>z  
        TextBox 220,21,40,21,.TextBox1 'default: 0 1HOYp*{#wP  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 X]up5tk~  
        OKButton 40,91,90,21 [4Tiukk(  
        CancelButton 190,91,90,21 sbnNk(XINQ  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 f%r0K6p  
        TextBox 220,49,40,21,.TextBox2 'default: 4 ACQbw)tiv}  
    End Dialog ND);7  
    Dim dlg As UserDialog i"|="O0v5  
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    ok = Dialog (dlg) zdY+?s)p  
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    If ok=0 Then    'cancel button was pressed $r0~&$T&  
        Print "Execution cancelled." N$u;Q(^  
        End 0V{a{>+  
    End If Y4E
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    'Assign accommodation and pupil diameter & use defaults if field left empty ma4Pmk  
    If dlg.TextBox1 = "" Then rHhn)m  
        A = 0           'Default accommodation -"*UICd  
    Else />1Ndj  
        A = CDbl(dlg.TextBox1) /JaCbT?*T  
    End If
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    If dlg.TextBox2 = "" Then }~gBnq_DDU  
        pupilDiam = 4   'Default pupil diameter L0ZgxG3:g  
    Else ~~J xw ]  
        pupilDiam = CDbl(dlg.TextBox2) rKZ1 c,y  
    End If GL4-v[]6I  
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    Print " " T(UdV]~]"  
    Print "Accommodation = " & A & " Diopters" z=ItKoM*<  
    Print "Pupil Diameter = " & pupilDiam & " mm" yO@KjCv"  
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    ' Calculate new parameters with accommodation pUs:r0B  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness (#zSVtZ  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens IYtM'!u  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens WxNPAJ6YH  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens %EC{O@EAk  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens >:5^4/fo*  
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    tlens = 3.767 + 0.04*A                  'Lens thickness ]-  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 8<cD+Jtj  
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    'Adjust parameters to account for accommodation x9fNIuAQ  
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    '************************************************************************* UclQo~3  
    'Aqueous thickness (Position of Lens) NZUQ R`5  
    '************************************************************************* 6U{&`8C  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) X^L)5n+$X  
    GetCustomElement eID, entity fC!]MhA"i  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ,`<w#  
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    ' Delete any shift(s) in z JE~ci#|!  
    count = 0 uFd.2,XNP  
    While GetOperationCount(eID)>count [Xy^M3
  
        GetOperation eID, count, op M,0@@:  
        If op.Type="ShiftZ" Then VUfV=&D-*g  
            DeleteOperation eID,count Qg dHIMY  
            count=count-1 l=jfgsj
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        End If %m\dNUz4g  
        count=count+1 \Qp #utC0s  
    Wend l.tNq$3pS  
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    'Set new shift in g.CUo:c  
    op.Type = "ShiftZ" !E\xn^  
    op.val1 = taq C^uH]WO  
    op.parent = parID :5/P{Co(  
    AddOperation eID, op rh;@|/<l  
    Print "Set aqueous humor thickness = " & taq-0.55 |T53m;D  
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    '************************************************************************* 8FY.u{93  
    'Radius and conic constant of anterior lens }Qj
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    '************************************************************************* I+ZK \?Rs  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ~WS;)Q0|  
    GetConic eID, entity, curv, conic 3q*y~5&I  
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    SetConic eID, entity, 1/Rant, CCant + V:P-D  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant v634{:'e  
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    '************************************************************************* EC6&#)g;CO  
    'Radius and conic constant of posterior lens >UTAk  
    '************************************************************************* } $:uN  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) !f~ =p
 
    GetConic eID, entity, curv, conic ]lj,GD)c  
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    SetConic eID, entity, 1/Rpost, CCpost e/@tU'$  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost xFZA18  
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    '************************************************************************* hdB.u^!  
    'Lens thickness (Position of posterior lens surface) 8nOMyNpy~M  
    '************************************************************************* = ;sEi:HC  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) >h3r\r\n3  
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    ' Delete any z-shift(s) \I r&&%  
    count = 0 m&)5QX  
    While GetOperationCount(eID)>count Pkx*1.uo  
        GetOperation eID, count, op 7I~Ww{  
        If op.Type="ShiftZ" Then t7|uZHKK  
            DeleteOperation eID,count _D9`L&X}  
            count=count-1 MB423{
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        End If 2UYtFWB9o  
        count=count+1 x\ieWF1  
    Wend 2ye^mJ17  
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    'Set new z-shift D3#/*Ky  
    op.Type = "ShiftZ" 8y;W+I(71  
    op.val1 = tlens l"%|VWZ{iq  
    op.parent = parID 4&r+K`C0  
    AddOperation eID, op Kg0Vbzvb  
    Print "Set lens thickness = " & tlens ]^,<Ez  
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    '************************************************************************* b-e3i;T!}~  
    'Lens index of refraction G)28#aH  
    '************************************************************************* _RG!lmJV  
    eID = FindMaterial( "Lens" ) +5pK[%k  
    GetModelMaterial eID, mat (fON\)l  
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    mat.Nd = nlens xEBiBskd  
    SetModelMaterial eID, mat k)D:lpxv  
    Print "Set lens index of refraction = " & nlens O_8ERxj g]  
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    '************************************************************************* %MyA;{-F6  
    'Pupil diameter 3nt&Sf  
    '************************************************************************* r(`;CY]@  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) .uzg2Kd_  
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    'Adjust pupil diameter (trimming volume inner hole) &0*l=!:G^  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" KE\p|Xi  
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    ' Adjust pupil location to just in front of the lens V6l*!R  
    parID = FindFullName( "Geometry.Arizona Eye" ) g]|K@sm  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ZbTU1Y/'   
    count = 0 a~YFJAkg9  
    While GetOperationCount(eID)>count O/\L0\T  
        GetOperation eID, count, op fII;t-(x  
        If op.Type="ShiftZ" Then d=%:rLm$  
            DeleteOperation eID,count /sY(/ JE  
            count=count-1 Q+|8|V}w  
        End If eUvIO+av  
        count=count+1 <VV./W8e9  
    Wend Q!/<=95E  
    op.Type = "ShiftZ" U,"lOG'  
    op.val1 = taq-0.01 %zE_Q  
    op.parent = parID <{@?c  
    AddOperation eID, op 8cn)ox|J[  
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    Print "Set pupil diameter = " & pupilDiam `Z]Tp1U  
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    'Update AZ Eye subassembly Description ,j wU\xo`C  
    eID = FindFullName( "Geometry.Arizona Eye" ) {<~0nLyJS  
    GetEntity eID, entity 0S@O]k)  
    entity.Description = "Accommodation = " & A & "D" J{' u  
    SetEntity eID, entity U#G[#sd> K  
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    Update V%k[S|f3  
    Print "DONE!" dDN#>|  
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End Sub 'U]= T<
 
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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： X}'3N'cbkU  
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Accommodation = 4 Diopters a9z|ef  
Pupil Diameter = 4 mm h.c<A{[I6c  
Set aqueous humor thickness = 2.81 ]kLs2? \  
Set anterior lens radius = 10.4 and conic constant = -2.375869 quc?]rb  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 k$kq|  
Set lens thickness = 3.927 2%0zPflT  
Set lens index of refraction = 1.42672 q@;WXHO0  
Set pupil diameter = 4 Z!=/[,b  
DONE! 8r/]Q