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    [技术]Arizona眼睛模型 [复制链接]

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    离线infotek
     
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    只看楼主 倒序阅读 楼主  发表于: 2021-10-22
    简介 }2X"  
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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。 BY&+fK ae  
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    模型 >U2[]fu  
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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。 QE b ^'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. B0&W wa:  
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    光源 XXe?@w2{  
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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。 fz hCV  
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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。 !-OPzfHrI  
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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。 |oL}c!0vs  
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    图2. 字母F光源的设定方法光 /xu#ZZ?8F_  
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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 pod=|(c  
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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。 p3N/"t&>  
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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。 js~?y|e8k  
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    图5. 视网膜重点采样规格设定
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    脚本 -#e3aXe  
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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: 82z\^a  
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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。 ^@"EI|fsP  
    余下的脚本计算与屈光度有关的所有参数。 :zW I"  
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    分析 <x^Ab#K"  
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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。 J2ryYdo>  
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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 zlw+=NX  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. `ecIy_O3P&  
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    Dim entity As T_ENTITY ZYi."^l  
    Dim op As T_OPERATION tE~OWjL  
    Dim mat As T_MODELMATERIAL W'B=H1  
    Dim A As Double p#yq'kY  
    Dim pupilDiam As Double sFvu@Wm'7W  
    Dim eID As Long PU"C('AP  
    Dim parID As Long R;6$lO8C&  
    Dim count As Integer 5Q9nJC{'NN  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double KTQy pv  
    Dim tlens As Double, nlens As Double 8H%-/2NW  
    Dim curv As Double, conic As Double h !yu. v  
    Dim ok As Long dE`a1H%  
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    Sub Main nNN~Z'bG  
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        '用户输入对话框 A$H;2T5N  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 b#17N2xkT  
            TextBox 220,21,40,21,.TextBox1 'default: 0 !sJ*0  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 z;#DX15Rj  
            OKButton 40,91,90,21 ++HHUM  
            CancelButton 190,91,90,21 sghQ!ux  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 sb]{05:  
            TextBox 220,49,40,21,.TextBox2 'default: 4 $CXMeY{tOo  
        End Dialog qt.G_fOz  
        Dim dlg As UserDialog \$iU#Z  
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        ok = Dialog (dlg) s.zfiJ  
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        If ok=0 Then    'cancel button was pressed hhqSfafUX  
            Print "Execution cancelled." EGY'a*]cU  
            End ~$bkWb*RJ  
        End If 24}?GO  
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        'Assign accommodation and pupil diameter & use defaults if field left empty |\ZsoA  
        If dlg.TextBox1 = "" Then I|`/#BYbW  
            A = 0           'Default accommodation -Tzp;o  
        Else Ji#"PE/Pt  
            A = CDbl(dlg.TextBox1) "L(4 EcO@  
        End If } ^}fx [  
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        If dlg.TextBox2 = "" Then e1EFZ,EcaO  
            pupilDiam = 4   'Default pupil diameter {1<XOp#b  
        Else CSA.6uIT  
            pupilDiam = CDbl(dlg.TextBox2) 5*q!:$ W  
        End If 5)T=^"IHXi  
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        Print " " +# 38  
        Print "Accommodation = " & A & " Diopters" o~_wx  
        Print "Pupil Diameter = " & pupilDiam & " mm" cEP!DUo  
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        ' Calculate new parameters with accommodation 0L ^WTq  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness {hXIP`  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens 9(\eL9^  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens "<#-#j  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens  |>Q ] q  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens R>r@I_  
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        tlens = 3.767 + 0.04*A                  'Lens thickness qHGwD20 ~  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction !vaS fL*]  
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        'Adjust parameters to account for accommodation \NiW(!Z}  
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        '************************************************************************* $,mljJSQv  
        'Aqueous thickness (Position of Lens) zK Y 9 'y  
        '************************************************************************* #[Z1W8e  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) eaG_)y  
        GetCustomElement eID, entity ke+3J\;>  
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        parID = FindFullName( "Geometry.Arizona Eye" ) U #u=9%'  
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        ' Delete any shift(s) in z P0Q]Ds|  
        count = 0 ,n}h_ct  
        While GetOperationCount(eID)>count (O&R-5m  
            GetOperation eID, count, op 4TP AD)C  
            If op.Type="ShiftZ" Then rx$B(z(c  
                DeleteOperation eID,count B7*^rbI:X  
                count=count-1 5i<E AKL  
            End If ![>j`i  
            count=count+1 Q^B !^_M  
        Wend _gLj(<^9  
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        'Set new shift in prdlV)LTpY  
        op.Type = "ShiftZ" VssD  
        op.val1 = taq *ommU(r8  
        op.parent = parID P 2j"L#%  
        AddOperation eID, op dR^7d _!  
        Print "Set aqueous humor thickness = " & taq-0.55 \\Z{[{OZ  
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        '************************************************************************* PsV1btq]  
        'Radius and conic constant of anterior lens 5>S<9A|Q  
        '************************************************************************* !U 6 x_  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Y`U[Y Hx  
        GetConic eID, entity, curv, conic >" z$p@7  
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        SetConic eID, entity, 1/Rant, CCant ^L,Uz:[J  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant vi4lmkyh^  
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        '************************************************************************* S260h,(,  
        'Radius and conic constant of posterior lens 5Nt40)E}sN  
        '************************************************************************* 68!W~%?pR  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 0- =PP@W  
        GetConic eID, entity, curv, conic ?k}"g$JFn  
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        SetConic eID, entity, 1/Rpost, CCpost wqZ*$M   
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost e2}5< 7  
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        '************************************************************************* |})7\o  
        'Lens thickness (Position of posterior lens surface) HRG2sv T4t  
        '************************************************************************* >k)zd-  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) /}ADV2sF  
    Jn+k$'6 %#  
        ' Delete any z-shift(s) >$g+Gx\v4  
        count = 0 /Cl=;^)  
        While GetOperationCount(eID)>count ag7(nn0!  
            GetOperation eID, count, op &|LP>'H;  
            If op.Type="ShiftZ" Then 0wA?.~ L  
                DeleteOperation eID,count )[Bl3+'  
                count=count-1 x =7qC#+)  
            End If <* vWcCS1  
            count=count+1 *oW^P~m/  
        Wend #cF ?a5  
    iVQ)hs W/  
        'Set new z-shift G'dN_6ho3  
        op.Type = "ShiftZ" s^QXCmb$8  
        op.val1 = tlens s4&JBm(33N  
        op.parent = parID 1p DL()t  
        AddOperation eID, op :mI[fQ  
        Print "Set lens thickness = " & tlens Xh[02iL-  
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        '************************************************************************* jx?"m=`s:  
        'Lens index of refraction NmH:/xU?^  
        '************************************************************************* Wb;x eG  
        eID = FindMaterial( "Lens" ) ]6*+i $  
        GetModelMaterial eID, mat Yqz B="  
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        mat.Nd = nlens ,iy;L_N  
        SetModelMaterial eID, mat FL/395 <:  
        Print "Set lens index of refraction = " & nlens 1%^d <%,]  
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        '************************************************************************* PAcbC| y  
        'Pupil diameter 4_i6q u(4  
        '************************************************************************* zNo(|;19  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ]CnqPLqL  
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        'Adjust pupil diameter (trimming volume inner hole) ,RYahu  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Bt?.8H6Y  
    Y;B#_}yF  
        ' Adjust pupil location to just in front of the lens fN-y8  
        parID = FindFullName( "Geometry.Arizona Eye" ) q]}1/JZS  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Qt VZ)777  
        count = 0 W4ygJL7 6  
        While GetOperationCount(eID)>count UomO^P  
            GetOperation eID, count, op gT=RJB  
            If op.Type="ShiftZ" Then L>PPAI  
                DeleteOperation eID,count ~=#jr0IZ  
                count=count-1 3v:c".O2O  
            End If n#fc=L1U  
            count=count+1 mz<wYV*  
        Wend }w%W A&"W  
        op.Type = "ShiftZ" E{#Y=  
        op.val1 = taq-0.01 (F.vVldBy  
        op.parent = parID B*,Qw_3dG  
        AddOperation eID, op #ozQF~  
    [-pB}1Dxb  
        Print "Set pupil diameter = " & pupilDiam ;<~lzfs  
    8ba*:sb  
        'Update AZ Eye subassembly Description !arTR.b\  
        eID = FindFullName( "Geometry.Arizona Eye" ) ;=ci7IT'  
        GetEntity eID, entity rjJ-ZRs\  
        entity.Description = "Accommodation = " & A & "D" +P//p$pE  
        SetEntity eID, entity e|~s'{3  
    /EXub U73  
        Update 1$^=M[v  
        Print "DONE!" M,f|.p{,Y  
         %J 'RO  
    End Sub $S(q;Y  
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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: VJ'bS9/T  
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    Accommodation = 4 Diopters Pp9nilb_(  
    Pupil Diameter = 4 mm Pqc +pE  
    Set aqueous humor thickness = 2.81 |vLlEN/S  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 Wt8=j1>  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 iI.d8}A  
    Set lens thickness = 3.927 G._E9  
    Set lens index of refraction = 1.42672 ^1 P@BRh  
    Set pupil diameter = 4 s/=.a2\  
    DONE! MG G c  
     
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