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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 5zt5]zl'  
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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。 Z3iX^  
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    模型 =[Tf9u QY  
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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。 11JO[  
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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. {1GIiP-U  
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    光源 ?=?9a  
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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。 );^{;fLy%  
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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。 ' @j8tK  
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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。 _\FA}d@N  
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    图2. 字母F光源的设定方法光 6EG`0h6  
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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 GZ"J6/0-|  
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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。 PPNZ(j   
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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。 5LxzET"P  
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    图5. 视网膜重点采样规格设定
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    脚本 4_?*@L1  
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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: _l.kbfp@  
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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。 -"3<Ll  
    余下的脚本计算与屈光度有关的所有参数。 *AN2&>Y  
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    分析 )`]} D[j  
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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。 Nc:>]  
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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 uEkUK|  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. E&RK My)  
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    Dim entity As T_ENTITY m/W)IG>  
    Dim op As T_OPERATION 4*9:  
    Dim mat As T_MODELMATERIAL u-E*_% y  
    Dim A As Double b 7bbrR8  
    Dim pupilDiam As Double NFcMh+qnK  
    Dim eID As Long Flzl,3rW4  
    Dim parID As Long w`J s "_\  
    Dim count As Integer ~*h` ?A0  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double d.uJ}=|  
    Dim tlens As Double, nlens As Double c~+l|r=u?  
    Dim curv As Double, conic As Double $ OMGo`z  
    Dim ok As Long gb_k^wg~1'  
    N!F ;!  
    Sub Main X+T +y>e a  
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        '用户输入对话框 G>0S( M)  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 E6d0YgfD  
            TextBox 220,21,40,21,.TextBox1 'default: 0 \[w82%U  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 y2eeE CS]  
            OKButton 40,91,90,21 -?WhJ.U  
            CancelButton 190,91,90,21 #b4Pn`[   
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 nAJ<@a  
            TextBox 220,49,40,21,.TextBox2 'default: 4 =<,AzuV  
        End Dialog fu95-)M  
        Dim dlg As UserDialog e'uI~%$NJL  
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        ok = Dialog (dlg) M[R\URu8  
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        If ok=0 Then    'cancel button was pressed :jq   
            Print "Execution cancelled." 9RoN,e8!  
            End g2WDa'{L  
        End If D-BWgK  
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        'Assign accommodation and pupil diameter & use defaults if field left empty ,#42ebGHR  
        If dlg.TextBox1 = "" Then c91rc>  
            A = 0           'Default accommodation 9+\3E4K  
        Else ;Qc_Tf=,  
            A = CDbl(dlg.TextBox1) Q1Sf7)  
        End If zl j%v/9  
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        If dlg.TextBox2 = "" Then }pa@qZXh  
            pupilDiam = 4   'Default pupil diameter /CAi%UH,F  
        Else MNKB4C8 >  
            pupilDiam = CDbl(dlg.TextBox2) MKYXYR  
        End If "1H?1"w~  
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        Print " " iQ9jt  
        Print "Accommodation = " & A & " Diopters" Q2)z1'Wv  
        Print "Pupil Diameter = " & pupilDiam & " mm" d aIt `}s  
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        ' Calculate new parameters with accommodation mzz77i  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness AoEG%nT  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens <[2]p\rj  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens zM^ux!T=  
    )} y1  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens H1'`* }V  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens eGS1% [  
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        tlens = 3.767 + 0.04*A                  'Lens thickness a(Bo.T<2@  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Pgs^#(^>  
    tdn[]|=  
        'Adjust parameters to account for accommodation =!'gV:M  
    2bS)|#v<_t  
        '************************************************************************* \$2E  
        'Aqueous thickness (Position of Lens) G l=dL<F  
        '************************************************************************* SB1\SNB  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) z6 v RTY  
        GetCustomElement eID, entity iO;q]  
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        parID = FindFullName( "Geometry.Arizona Eye" ) N?H;fK4v  
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        ' Delete any shift(s) in z rHu  #  
        count = 0 iq '3.-xYr  
        While GetOperationCount(eID)>count `5;O|qRq  
            GetOperation eID, count, op sAIL+O  
            If op.Type="ShiftZ" Then SnRTC<DDh  
                DeleteOperation eID,count q79)nhC F  
                count=count-1 &_ Ewu@4  
            End If n`T 4aDm  
            count=count+1 W xyQA:3s  
        Wend 7'_zJI^  
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        'Set new shift in wxARD3%  
        op.Type = "ShiftZ" $WvI%r  
        op.val1 = taq 5@"&%8oeq0  
        op.parent = parID L=Q- r[  
        AddOperation eID, op ,8g~,tMr+  
        Print "Set aqueous humor thickness = " & taq-0.55 y@J]busU  
    _cx}e!BK#  
        '************************************************************************* Xi_>hL+R(  
        'Radius and conic constant of anterior lens W{l+_a{/9  
        '************************************************************************* ;8;nY6Ie  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) W|3XD-v@  
        GetConic eID, entity, curv, conic *A`hKx  
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        SetConic eID, entity, 1/Rant, CCant HH3WZ^0>  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 2i#wJ8vrF  
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        '************************************************************************* t<9oEjk["  
        'Radius and conic constant of posterior lens b&A+`d  
        '************************************************************************* AZxx%6  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 0ANqEQX  
        GetConic eID, entity, curv, conic q[Hx y  
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        SetConic eID, entity, 1/Rpost, CCpost ZVJbpn<lo)  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost "?V4Tl~uu  
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        '************************************************************************* {IJV(%E   
        'Lens thickness (Position of posterior lens surface) 7rc^-!k  
        '************************************************************************* )h,+>U@  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ;Aiuy{<  
    1agyT  
        ' Delete any z-shift(s) Q <EFd   
        count = 0 8HdmG{7.  
        While GetOperationCount(eID)>count Ck2O?Ne  
            GetOperation eID, count, op fQlR;4QX]  
            If op.Type="ShiftZ" Then xA#B1qbw  
                DeleteOperation eID,count BV$lMLD{r  
                count=count-1 m>$+sMZE  
            End If KP[ax2!x  
            count=count+1 ~qLbyzHaB  
        Wend vL{~?vq6  
    vY<(3[pp  
        'Set new z-shift V{@<Z8sW#  
        op.Type = "ShiftZ" Zgt, 'T  
        op.val1 = tlens HQK%Y2S  
        op.parent = parID FD*`$.e3\  
        AddOperation eID, op q/Ba#?sen  
        Print "Set lens thickness = " & tlens Y.3]vno?X  
    ]<A|GY0q1  
        '************************************************************************* z)=D&\HX  
        'Lens index of refraction tX cc#!'4C  
        '************************************************************************* 0K`3BuBs  
        eID = FindMaterial( "Lens" ) bqN({p&  
        GetModelMaterial eID, mat <)n1Z[4  
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        mat.Nd = nlens +,9I3Dq  
        SetModelMaterial eID, mat X3#|9  
        Print "Set lens index of refraction = " & nlens s<H0ka@  
    ,(}7 ST  
        '************************************************************************* YQ g03i  
        'Pupil diameter x"K<@mR5G  
        '************************************************************************* FEw51a+V  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Hu|NS{Ke-  
    2[LT!TT  
        'Adjust pupil diameter (trimming volume inner hole) OljUK,I]  
    OqtQLqN  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" v2G_p |+O  
    *TVr| to  
        ' Adjust pupil location to just in front of the lens 1]aM)},  
        parID = FindFullName( "Geometry.Arizona Eye" ) bv5,Yk  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) D)8&v` L S  
        count = 0 .%<oy"_  
        While GetOperationCount(eID)>count $)vljM<<  
            GetOperation eID, count, op k'&BAC.K,  
            If op.Type="ShiftZ" Then G$}\~dD  
                DeleteOperation eID,count rV)mcfw:Z  
                count=count-1 gpVZZ:~  
            End If mEv<r6qDT  
            count=count+1 9xyj,;P>  
        Wend ZOK2BCoW  
        op.Type = "ShiftZ" 9e^[5D=L  
        op.val1 = taq-0.01 J"yO\Y  
        op.parent = parID iKN~fGRc  
        AddOperation eID, op g+t-<D"L5  
    $IA(QC_]AO  
        Print "Set pupil diameter = " & pupilDiam >y"W(  
    cjHo?m'  
        'Update AZ Eye subassembly Description IkFrzw p  
        eID = FindFullName( "Geometry.Arizona Eye" ) Bab`wfUve  
        GetEntity eID, entity E#v}//  
        entity.Description = "Accommodation = " & A & "D" lPSyFb"  
        SetEntity eID, entity [U]U *x  
    _(5SiK R  
        Update /@X!  
        Print "DONE!" .C$S DhJ~  
         w&hgJ  
    End Sub VUxuX5B3M  
    0#<q]M?hW  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: _?M34&.X  
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    Accommodation = 4 Diopters !'wh hi  
    Pupil Diameter = 4 mm ST5L O#5  
    Set aqueous humor thickness = 2.81 >0Y >T6!  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 C=IT`iom1C  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 u\ro9l  
    Set lens thickness = 3.927 6X~.J4  
    Set lens index of refraction = 1.42672 u n\!K  
    Set pupil diameter = 4 d&4 ve Lu  
    DONE! U<gM gA  
     
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