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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 T,Fm"U6[(  
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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。 Fq4lXlSB  
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模型 =t HD 4I  
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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。 1Df, a#,y"  
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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. eN4t1 $  
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光源 CMFC"eS e  
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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。 G-ZhGbAI7  
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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。 qNy-o\;XN  
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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。 py=i!vb&Z%  
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图2. 字母F光源的设定方法光 i!tc  
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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 Z|}H^0~7S  
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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。 {x|MA(NO  
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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。 fH; |Rm  
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图5. 视网膜重点采样规格设定
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脚本 ML"_CQlE7  
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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: TX&[;jsj  
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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。 =1eV   
余下的脚本计算与屈光度有关的所有参数。 \;i G{}(  
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分析 4^0\dq  
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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。 0,bt^a  
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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 )eVzSj>MT  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. wE)] ah:  
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Dim entity As T_ENTITY dP?nP(l  
Dim op As T_OPERATION .[#xQ=9`  
Dim mat As T_MODELMATERIAL BEFe~* ~  
Dim A As Double ,nI_8r"M>  
Dim pupilDiam As Double Tq.MubaO  
Dim eID As Long X #&(~1O  
Dim parID As Long C+DG+_%V*S  
Dim count As Integer bOi};/f  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double =CWc`  
Dim tlens As Double, nlens As Double 'W}~)+zK  
Dim curv As Double, conic As Double pHigxeV2  
Dim ok As Long @T9m}+fR  
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Sub Main | pF5`dX  
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    '用户输入对话框 ys:1Z\$P  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ,xm;JXJ  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ]r"31.w(  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 %g!yccD9  
        OKButton 40,91,90,21 |~7+/VvI+  
        CancelButton 190,91,90,21 ?T tQZ  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 t `N ">c"  
        TextBox 220,49,40,21,.TextBox2 'default: 4 b5lk0jA  
    End Dialog SJso'6 g  
    Dim dlg As UserDialog [lmHXf@1C  
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    ok = Dialog (dlg) +8L(pMI4  
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    If ok=0 Then    'cancel button was pressed >lUBt5gU  
        Print "Execution cancelled." =x|##7  
        End )6O\WB|  
    End If 53g8T+`\(  
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    'Assign accommodation and pupil diameter & use defaults if field left empty QC$=Fs5+  
    If dlg.TextBox1 = "" Then ykErt%k<n  
        A = 0           'Default accommodation p.6$w:eV  
    Else _ C7abw-  
        A = CDbl(dlg.TextBox1) 6ON  
    End If ?$>u!V<'  
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    If dlg.TextBox2 = "" Then L7~+x^kw  
        pupilDiam = 4   'Default pupil diameter W}#QKZ)MB  
    Else 4d{"S02h  
        pupilDiam = CDbl(dlg.TextBox2) L8,H9T#e  
    End If B:R7[G;1  
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    Print " " $Uv<LVd(  
    Print "Accommodation = " & A & " Diopters" 4~]8N@Bii  
    Print "Pupil Diameter = " & pupilDiam & " mm" >Hd~Ca>  
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    ' Calculate new parameters with accommodation Im0+`9Jw  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness +X2 i/}  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 2n-Tpay0  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens :IP;Frc MP  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ihpz}g  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 3iwoMrp  
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    tlens = 3.767 + 0.04*A                  'Lens thickness ]yj4~_&O  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction &vJ(P!2f<  
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    'Adjust parameters to account for accommodation Q KcF1?  
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    '************************************************************************* eMpEFY  
    'Aqueous thickness (Position of Lens) cpr{b8Xb8&  
    '************************************************************************* ,J`lr U0  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) qH {8n`  
    GetCustomElement eID, entity ~vjr;a(B  
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    parID = FindFullName( "Geometry.Arizona Eye" ) `a/PIc"  
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    ' Delete any shift(s) in z }Uqa8&  
    count = 0 MQbNWUi  
    While GetOperationCount(eID)>count Pi"tQyw39$  
        GetOperation eID, count, op Eezlx9b  
        If op.Type="ShiftZ" Then }LHT#{+ x  
            DeleteOperation eID,count C>k;MvqO  
            count=count-1 <x>k3bD  
        End If N18diP[C  
        count=count+1 2RSHB o  
    Wend 3-_U-:2"  
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    'Set new shift in yuy+}]uB@  
    op.Type = "ShiftZ" \^;|S  
    op.val1 = taq cc2oFn  
    op.parent = parID ?-.Ep0/  
    AddOperation eID, op cciAMQhA  
    Print "Set aqueous humor thickness = " & taq-0.55 C9z~)aL}7  
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    '************************************************************************* -UD~>s  
    'Radius and conic constant of anterior lens M|Lw`?T  
    '************************************************************************* 28UL  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) g qJEJ~  
    GetConic eID, entity, curv, conic Fy(nu-W  
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    SetConic eID, entity, 1/Rant, CCant iuU3*yyn  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant hklO:,`  
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    '************************************************************************* jt10gVC  
    'Radius and conic constant of posterior lens MLv.v&@S  
    '************************************************************************* b0z{"  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) )o'U0rAx|a  
    GetConic eID, entity, curv, conic thZ@Br O#  
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    SetConic eID, entity, 1/Rpost, CCpost -Y jv&5  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost h2/1S{/n]  
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    '************************************************************************* yK>0[6l  
    'Lens thickness (Position of posterior lens surface) RwE*0 T  
    '************************************************************************* 1R+ )T'in  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) \Zz= 4 j  
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    ' Delete any z-shift(s) Zh~Lm  
    count = 0 lJ>QTZH!wW  
    While GetOperationCount(eID)>count &"j).Ogm4  
        GetOperation eID, count, op Uc4 L|:  
        If op.Type="ShiftZ" Then @<w9fzi  
            DeleteOperation eID,count Mp=kZs/  
            count=count-1 2Fp]S a  
        End If @|UIV  
        count=count+1 Q3'B$,3O^  
    Wend _]~ht H  
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    'Set new z-shift z:Zn.e*$b  
    op.Type = "ShiftZ" hZ\W ?r  
    op.val1 = tlens #NQz&4W  
    op.parent = parID .L(j@I t  
    AddOperation eID, op {@K2WB  
    Print "Set lens thickness = " & tlens HfeflGme*  
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    '************************************************************************* FnQ_=b  
    'Lens index of refraction f$S QhK5`  
    '************************************************************************* ?D^,K`wY=B  
    eID = FindMaterial( "Lens" ) [sY1|eX   
    GetModelMaterial eID, mat =*>4Gh i  
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    mat.Nd = nlens +D-+}&oW  
    SetModelMaterial eID, mat xd BZ^Q  
    Print "Set lens index of refraction = " & nlens [?f.0q  
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    '************************************************************************* 0*:hm%g  
    'Pupil diameter (7jB_ p%  
    '************************************************************************* (R*jt,x  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) kcz#8K]~  
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    'Adjust pupil diameter (trimming volume inner hole) $Ex 9  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" y>cmKE  
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    ' Adjust pupil location to just in front of the lens Gx*0$4xJ3  
    parID = FindFullName( "Geometry.Arizona Eye" ) 8 W<)c  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) .5CELtR  
    count = 0 _} 9R}  
    While GetOperationCount(eID)>count \/4%[Q2QDm  
        GetOperation eID, count, op ,JBw$ C  
        If op.Type="ShiftZ" Then oY6|h3T=Q$  
            DeleteOperation eID,count E+c3KqM  
            count=count-1 |tJ%:`DGw  
        End If  nIDsCu=A  
        count=count+1 n]fbV/ x  
    Wend |>}0? '/]  
    op.Type = "ShiftZ" ?*mbce[  
    op.val1 = taq-0.01 ~S_IU">E  
    op.parent = parID ST8/ ;S#c  
    AddOperation eID, op P$ dgO  
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    Print "Set pupil diameter = " & pupilDiam <^'+ ]?  
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    'Update AZ Eye subassembly Description g!Yh=kA'N  
    eID = FindFullName( "Geometry.Arizona Eye" ) wfTv<WG,.E  
    GetEntity eID, entity hYv 6-5_  
    entity.Description = "Accommodation = " & A & "D" Aag)c~D  
    SetEntity eID, entity jv=f@:[`I  
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    Update Tocdh.H|  
    Print "DONE!" 7>@/*S{X  
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End Sub <07W&`Dw  
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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: !=:MG#p  
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Accommodation = 4 Diopters 2/4x]i H*  
Pupil Diameter = 4 mm g+r{>x  
Set aqueous humor thickness = 2.81 u2O^3r G-  
Set anterior lens radius = 10.4 and conic constant = -2.375869 3v>,c>b([  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 >upUY(3&  
Set lens thickness = 3.927 j~f 7WJ  
Set lens index of refraction = 1.42672 |b~g^4  
Set pupil diameter = 4 m:Cx~  
DONE! rkc%S5we  
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