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infotek 2022-02-25 09:52

Arizona眼睛模型

简介 slPLc  
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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。 $K-od3h4=  
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模型 0{0A,;b  
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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。 7R4xJ H  
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. Y#[Wv1hi  
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光源 iRwlK5(&  
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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。 8AX+s\N  
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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。 dF (m!P/R  
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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。 f*uD9l%/  
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图2. 字母F光源的设定方法光 c+_F}2)  
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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 qYi<GI*|@  
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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。 B^{87YR  
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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。 T d6Gu"  
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图5. 视网膜重点采样规格设定
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脚本 !uno!wUIYd  
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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: J&<uP)<  
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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。 8N58w)%7`  
余下的脚本计算与屈光度有关的所有参数。 K9BoIHo  
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分析 Nvef+L,v  
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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。 t G{?  
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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 ' YONRha  
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  1. Option Explicit     'Remove this to enable non-dimensioned variables to be used. lQ}e"#<  
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    Dim entity As T_ENTITY /G>reG,G  
    Dim op As T_OPERATION ,;_D~7L  
    Dim mat As T_MODELMATERIAL ~6hG"t]:  
    Dim A As Double H$ sNp\[{  
    Dim pupilDiam As Double )kE(%q:*P$  
    Dim eID As Long bnWKfz5  
    Dim parID As Long i"rrM1/r  
    Dim count As Integer ,0~/ Cn  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double $B iG7,[#  
    Dim tlens As Double, nlens As Double C~5-E{i  
    Dim curv As Double, conic As Double `tCOe  
    Dim ok As Long M?UlC   
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    Sub Main Kk^tQwj/QE  
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        '用户输入对话框 _n3Jf<Y  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 N1V qK  
            TextBox 220,21,40,21,.TextBox1 'default: 0 ;5*)kX  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 Wu 71q=  
            OKButton 40,91,90,21 :*2+t-  
            CancelButton 190,91,90,21 + njE  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 V zx%N.  
            TextBox 220,49,40,21,.TextBox2 'default: 4 ,]N!I%SI  
        End Dialog qdn\8Pn  
        Dim dlg As UserDialog 6g ,U+~  
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        ok = Dialog (dlg) 5T[9|zJs  
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        If ok=0 Then    'cancel button was pressed C/P,W>8  
            Print "Execution cancelled." -S=Zsr\  
            End ^"w.v' sL  
        End If HY]vaA`  
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        'Assign accommodation and pupil diameter & use defaults if field left empty 7p?6j)rj  
        If dlg.TextBox1 = "" Then @"}dbW<DV  
            A = 0           'Default accommodation J! 4l-.-  
        Else f77uqv(Y  
            A = CDbl(dlg.TextBox1) ,i2%FW  
        End If B;8YX>r  
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        If dlg.TextBox2 = "" Then .P=uR8  
            pupilDiam = 4   'Default pupil diameter JlsRP  
        Else *JG?^G"l  
            pupilDiam = CDbl(dlg.TextBox2) S.+)">buH  
        End If i3.8m=>  
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        Print " " _"Q +G@@  
        Print "Accommodation = " & A & " Diopters" E<3hy  
        Print "Pupil Diameter = " & pupilDiam & " mm" q{UP_6O F  
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        ' Calculate new parameters with accommodation Y2Mti- \  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness r'hr 'wZ  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens W%09.bF  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens u[U~`*i*rA  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens KQ/v](7 7  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens Z*kGWL  
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        tlens = 3.767 + 0.04*A                  'Lens thickness [;VNuF  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 2 G_*Pqc  
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        'Adjust parameters to account for accommodation 3V`K^X3  
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        '************************************************************************* jh]wHG  
        'Aqueous thickness (Position of Lens) $*%Ml+H-  
        '************************************************************************* .i/]1X*;r^  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ~}4o=O(  
        GetCustomElement eID, entity uw+v]y  
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        parID = FindFullName( "Geometry.Arizona Eye" ) }i/&m&VU  
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        ' Delete any shift(s) in z #hd<5+$U}l  
        count = 0 AEi@t0By  
        While GetOperationCount(eID)>count 'N5qX>Ob  
            GetOperation eID, count, op q4 'x'8  
            If op.Type="ShiftZ" Then xP'IyABx  
                DeleteOperation eID,count <_ */  
                count=count-1 )QTk5zt  
            End If nl5K1!1  
            count=count+1 %>i7A?L  
        Wend iTD}gC  
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        'Set new shift in c0<Y017sG  
        op.Type = "ShiftZ" $t 1]w]}d  
        op.val1 = taq 6kT l(+  
        op.parent = parID #X"\:yN  
        AddOperation eID, op |i?AtOt@f  
        Print "Set aqueous humor thickness = " & taq-0.55 $Miii`VS9  
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        '************************************************************************* X@9_ukdpu  
        'Radius and conic constant of anterior lens 'A !Dg  
        '************************************************************************* =Mn! [  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 30>TxL=&  
        GetConic eID, entity, curv, conic I2j;9Qcz  
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        SetConic eID, entity, 1/Rant, CCant 4,s: G.g  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant )\^o<x2S  
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        '************************************************************************* RO wbzA)]r  
        'Radius and conic constant of posterior lens lbg6n:@  
        '************************************************************************* UUb!2sO  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ; tvB{s_  
        GetConic eID, entity, curv, conic (G PJ=r  
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        SetConic eID, entity, 1/Rpost, CCpost z8Dn<h  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost (P`{0^O"}  
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        '************************************************************************* jI;bVG  
        'Lens thickness (Position of posterior lens surface) |,sUD/rt  
        '************************************************************************* Y[s  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 5\=9&{WjND  
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        ' Delete any z-shift(s)  N%r}0  
        count = 0 lBG* P>;  
        While GetOperationCount(eID)>count aGpRdF1;!  
            GetOperation eID, count, op >j`*-(`2fa  
            If op.Type="ShiftZ" Then  QV .A.DK  
                DeleteOperation eID,count ~iwEhF   
                count=count-1 'R]Z9h  
            End If RX2= iO"  
            count=count+1 y\0^c5}  
        Wend |!!E5osXq  
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        'Set new z-shift z%Z}vWn  
        op.Type = "ShiftZ" 3:Z(tM&-O  
        op.val1 = tlens lf|^^2'*2<  
        op.parent = parID ['R=@.  
        AddOperation eID, op J1R%w{  
        Print "Set lens thickness = " & tlens =r-Wy.a@  
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        '************************************************************************* ,s)~Y p?<  
        'Lens index of refraction 2OT6*+D  
        '************************************************************************* VsZ_So;  
        eID = FindMaterial( "Lens" ) &PgdCijGq;  
        GetModelMaterial eID, mat f "&q~V4?  
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        mat.Nd = nlens \~?s= LT  
        SetModelMaterial eID, mat *(>$4$9n  
        Print "Set lens index of refraction = " & nlens /pk; E$qv  
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        '************************************************************************* "5y^s!/  
        'Pupil diameter Bp/8 >E O`  
        '************************************************************************* \FKIEg+(2  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Y 4714  
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        'Adjust pupil diameter (trimming volume inner hole) bs`/k&'  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" %@xYg{  
    ?x[>g!r  
        ' Adjust pupil location to just in front of the lens xK y<o  
        parID = FindFullName( "Geometry.Arizona Eye" ) [KE4wz+s{  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) jU#%@d6!#  
        count = 0 ` q@~78`  
        While GetOperationCount(eID)>count \)#3S $L~  
            GetOperation eID, count, op HkV/+ {;S~  
            If op.Type="ShiftZ" Then +nZG!nP  
                DeleteOperation eID,count R|M:6]}   
                count=count-1 (qG$u&  
            End If .XE]vo  
            count=count+1 (,TO|  
        Wend nx +& {hn(  
        op.Type = "ShiftZ" '9[_ w$~(  
        op.val1 = taq-0.01 (\I =v".  
        op.parent = parID &%bX&;ECzf  
        AddOperation eID, op e=R} 4`  
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        Print "Set pupil diameter = " & pupilDiam .iS]aJJ  
    <'B^z0I,  
        'Update AZ Eye subassembly Description Sh*P^i.]+  
        eID = FindFullName( "Geometry.Arizona Eye" ) <|_Ey)1 6  
        GetEntity eID, entity A^Zs?<C-  
        entity.Description = "Accommodation = " & A & "D" \mDm *UuG  
        SetEntity eID, entity avz 4 &  
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        Update <?g{Rn  
        Print "DONE!" GkC88l9z  
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    End Sub C;ye%&g>  
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    如果屈光度是4,光瞳直径是4,则会输出如下数据: ={Hbx> p  
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    Accommodation = 4 Diopters *,pqpD>  
    Pupil Diameter = 4 mm t(yv   
    Set aqueous humor thickness = 2.81 [~o3S$C&7  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 xle29:?l  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 ?`XKaD! f  
    Set lens thickness = 3.927 Cnr48ukq  
    Set lens index of refraction = 1.42672 `otQ'e~+t  
    Set pupil diameter = 4 RW)C<g  
    DONE!
silence唯爱 2022-02-25 13:53
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