[技术]Arizona眼睛模型 [复制链接]

简介 m]e0X*Kg  
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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。 du8!3I  
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模型 > `0| 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。 p>!1S  
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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. _
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光源 <w;D$l}u  
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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。 .^BWR  
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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。 s^obJl3
 
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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。 E=A/4p6\$  
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视网膜的散射 |%n|[LP'  
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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。 3HXh6( e  
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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。 oJhEHx[f  
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脚本 )x y9X0  
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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： 4
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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~Tw?z-|  
余下的脚本计算与屈光度有关的所有参数。 L!`*R)
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分析 RJQ/y3  
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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。 R65;oJh  
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脚本代码 cKaL K#~  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. &pa)Ee>  
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Dim entity As T_ENTITY f:)]FHPB1  
Dim op As T_OPERATION F^4*|g  
Dim mat As T_MODELMATERIAL 9?EY.}~  
Dim A As Double |j\eBCnH3  
Dim pupilDiam As Double =f/avGX  
Dim eID As Long 0]f?Dx/8  
Dim parID As Long \UVT_=Y  
Dim count As Integer <h)deB+}  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double LX&=uv%-^  
Dim tlens As Double, nlens As Double qg/Y;tGSx  
Dim curv As Double, conic As Double gEX:S(1QP  
Dim ok As Long 37GHt9l  
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Sub Main HJ2O@e  
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    '用户输入对话框 _p3WE9T  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1  ."$=
  
        TextBox 220,21,40,21,.TextBox1 'default: 0 T1Ln)CS?9  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 DR#3njjEC  
        OKButton 40,91,90,21 sIP6GWK$  
        CancelButton 190,91,90,21 C={sE*&dYX  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Ip1QVND  
        TextBox 220,49,40,21,.TextBox2 'default: 4 Xmw2$MCB  
    End Dialog l%vhV&  
    Dim dlg As UserDialog n=<q3}1Jej  
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    ok = Dialog (dlg) G>?x-!9qcH  
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    If ok=0 Then    'cancel button was pressed 476M` gA  
        Print "Execution cancelled." SV$ASs  
        End t/4/G']W  
    End If GL
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    'Assign accommodation and pupil diameter & use defaults if field left empty k;9#4^4(  
    If dlg.TextBox1 = "" Then CVn;RF6  
        A = 0           'Default accommodation JJ= ~o@|c  
    Else #dXZA>b9  
        A = CDbl(dlg.TextBox1) `pn-fk  
    End If '8iv?D5M  
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    If dlg.TextBox2 = "" Then l-JKcsM  
        pupilDiam = 4   'Default pupil diameter V3.vE,  
    Else W"DxIy  
        pupilDiam = CDbl(dlg.TextBox2) oD|+X/FK  
    End If m''iE  
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    Print " " 
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    Print "Accommodation = " & A & " Diopters" \p_8YC  
    Print "Pupil Diameter = " & pupilDiam & " mm" ~=aI2(b  
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    ' Calculate new parameters with accommodation s2 t-T0;  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness YV>VA<
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 9fk\Ay1P  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens .,(uoK{  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens `XRb:d^  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens uc{Qhw!;:  
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    tlens = 3.767 + 0.04*A                  'Lens thickness [~&:`I1  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 7{6cLYl  
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    'Adjust parameters to account for accommodation :7AauoI  
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    '************************************************************************* B[k+#YYY  
    'Aqueous thickness (Position of Lens) &bRxy`ZH  
    '************************************************************************* }<x!95  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) T[2f6[#[_  
    GetCustomElement eID, entity -p]`(S%  
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    parID = FindFullName( "Geometry.Arizona Eye" ) gx{~5&1  
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    ' Delete any shift(s) in z lyc{Z%!3  
    count = 0 r z>zdj5}  
    While GetOperationCount(eID)>count DqC}f#  
        GetOperation eID, count, op ?5+KHG*)  
        If op.Type="ShiftZ" Then
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            DeleteOperation eID,count =M km:'1r  
            count=count-1 ]9l%  
        End If "Z1&z-   
        count=count+1
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    Wend M%dl?9pbq  
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    'Set new shift in 2$/gg"g+  
    op.Type = "ShiftZ" h,RUL  
    op.val1 = taq (YWc%f4  
    op.parent = parID X +
  
    AddOperation eID, op Gxt<kz  
    Print "Set aqueous humor thickness = " & taq-0.55 R S_lQ{'  
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    '************************************************************************* 38.J:?Q  
    'Radius and conic constant of anterior lens fbbl92p  
    '************************************************************************* 7&S|y]$~  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ?@ye*%w_  
    GetConic eID, entity, curv, conic -JW6@L@  
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    SetConic eID, entity, 1/Rant, CCant It:QXLi;  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant *'S%gR=Aa+  
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    '************************************************************************* j`&i4K:  
    'Radius and conic constant of posterior lens h],%va[  
    '************************************************************************* WT? U~.U  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 1H@rNam&  
    GetConic eID, entity, curv, conic 4I[FE;^  
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    SetConic eID, entity, 1/Rpost, CCpost 8QgL7  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost |@9I5Eg)iE  
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    '************************************************************************* (6y3"cbe  
    'Lens thickness (Position of posterior lens surface) zNTu j p  
    '************************************************************************* FH5bC6  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) [";5s&)q  
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    ' Delete any z-shift(s) D{d$L9.  
    count = 0 ~oR&
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    While GetOperationCount(eID)>count ')cgx9   
        GetOperation eID, count, op 7CN[Z9Y^}  
        If op.Type="ShiftZ" Then }4ju2K  
            DeleteOperation eID,count 6&Ir0K/  
            count=count-1 V.[#$ip6:  
        End If P+|8MT0  
        count=count+1 %YAiSSsV  
    Wend NjyIwo0  
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    'Set new z-shift hd BC ^n  
    op.Type = "ShiftZ" aw~EK0yU   
    op.val1 = tlens :pu{3-n.  
    op.parent = parID ;l4\^E1  
    AddOperation eID, op
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    Print "Set lens thickness = " & tlens
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    '************************************************************************* #C7j|9Ew1]  
    'Lens index of refraction 0e](N`  
    '************************************************************************* [$Bb'],k  
    eID = FindMaterial( "Lens" ) >RnMzH/9  
    GetModelMaterial eID, mat \)]2Uh|  
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    mat.Nd = nlens `5&V}"lB  
    SetModelMaterial eID, mat 9(.9l\h  
    Print "Set lens index of refraction = " & nlens ! HC<aWb  
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    '************************************************************************* 9o'6es..@Z  
    'Pupil diameter ,#O8:s  
    '************************************************************************* MW>28  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" )
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    'Adjust pupil diameter (trimming volume inner hole) eV%bJkt.  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" p>
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    ' Adjust pupil location to just in front of the lens e;[8GE.   
    parID = FindFullName( "Geometry.Arizona Eye" ) 3) 0~:  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) jdf@lb=5l  
    count = 0 ]*U')  
    While GetOperationCount(eID)>count %.U{):lNx  
        GetOperation eID, count, op m3-J0D<  
        If op.Type="ShiftZ" Then ^eRT8I  
            DeleteOperation eID,count ,RO(k4  
            count=count-1 XOU$3+8q5  
        End If ='>UKy[=  
        count=count+1 ;qK6."b`;  
    Wend fMaNv6(  
    op.Type = "ShiftZ" ,quTMtk~  
    op.val1 = taq-0.01 !17Z\Ltqyj  
    op.parent = parID kR(=VM JU  
    AddOperation eID, op Zw{tuO7}K  
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    Print "Set pupil diameter = " & pupilDiam 1iDo$]TEK  
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    'Update AZ Eye subassembly Description n82Q.M-H  
    eID = FindFullName( "Geometry.Arizona Eye" ) J,Ap9HJt  
    GetEntity eID, entity LL [>Uu?Y  
    entity.Description = "Accommodation = " & A & "D" VC7F#a*V  
    SetEntity eID, entity J@iN':l-  
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    Update R*m"'|U  
    Print "DONE!" qQvb;jO  
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End Sub ?!oa15  
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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： ulM&kw.4i  
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Accommodation = 4 Diopters %Ege^4PE  
Pupil Diameter = 4 mm |hoZ:  
Set aqueous humor thickness = 2.81 :5J6rj;_  
Set anterior lens radius = 10.4 and conic constant = -2.375869 eov-"SJ
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Set posterior lens radius = -4.424557 and conic constant = -3.081019 NkI:
  
Set lens thickness = 3.927 ): C4}&l  
Set lens index of refraction = 1.42672 yRkMR$5&  
Set pupil diameter = 4 0g-ESf``{n  
DONE! ^ni_%`Ag