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infotek 2022-02-25 09:52

Arizona眼睛模型

简介 .vIRz-S  
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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。 _W,?_"[R=  
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模型 CPY|rV  
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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。 ]n'.}"8Kn  
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. >>;He7  
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光源 N ;n55N  
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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[fg!vig#7  
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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。 /nt%VLms %  
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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。 /R( .7N  
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图2. 字母F光源的设定方法光 w2`JFxQ^x  
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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 )sK _k U{\  
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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。 /CbM-jf  
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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。 JxRn)D  
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图5. 视网膜重点采样规格设定
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脚本 cz$*6P<9J  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: _gCi@uXS3  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 )Oj{x0{\Q  
余下的脚本计算与屈光度有关的所有参数。 'm/`= QX  
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分析 1ZWr@,\L  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 P4s,N|bs`  
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图7. 字母F在视网膜上颜色分析
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脚本代码 r#6djs1  
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  1. Option Explicit     'Remove this to enable non-dimensioned variables to be used. cNl$ vP83z  
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    Dim entity As T_ENTITY y"w`yl{_  
    Dim op As T_OPERATION  '^,|8A2  
    Dim mat As T_MODELMATERIAL -TNb=2en(  
    Dim A As Double =~k#<q1^  
    Dim pupilDiam As Double l<s6Uu"  
    Dim eID As Long KFM)*Icg\8  
    Dim parID As Long j3/K;U/SGJ  
    Dim count As Integer Qf}}/k|)k  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double g6.Tx]?b$  
    Dim tlens As Double, nlens As Double nYnv.5  
    Dim curv As Double, conic As Double zf[KZ\6H   
    Dim ok As Long m=^ihQ  
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    Sub Main *k;%H'2g{}  
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        '用户输入对话框 YH0utc  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Tpp?(lT7r  
            TextBox 220,21,40,21,.TextBox1 'default: 0 Mqmy*m[U  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 'L veCi_  
            OKButton 40,91,90,21 9XN/ w p  
            CancelButton 190,91,90,21 \U HI%1^  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 QG;V\2T2[  
            TextBox 220,49,40,21,.TextBox2 'default: 4 5oOFl  
        End Dialog c7 O$< F  
        Dim dlg As UserDialog |6Qn/N$+f  
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        ok = Dialog (dlg) qW9~S0sl  
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        If ok=0 Then    'cancel button was pressed 7)l+h Z  
            Print "Execution cancelled." >s>{+6e  
            End 2U'Vq  
        End If 5uL!Ae  
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        'Assign accommodation and pupil diameter & use defaults if field left empty *|3G"B{w6  
        If dlg.TextBox1 = "" Then GFYHt!&[\  
            A = 0           'Default accommodation U^9#uK6GM  
        Else h`V#)Q  
            A = CDbl(dlg.TextBox1) I?Q[ZH:M  
        End If e!1am%aE  
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        If dlg.TextBox2 = "" Then 70T{tB  
            pupilDiam = 4   'Default pupil diameter k'-5&Q  
        Else m4'x>Z  
            pupilDiam = CDbl(dlg.TextBox2) }x?2txuu  
        End If .=/TT|eMS  
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        Print " " [Qn$i/ ` J  
        Print "Accommodation = " & A & " Diopters" Ydh+iLjhx  
        Print "Pupil Diameter = " & pupilDiam & " mm" ECLQqjB  
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        ' Calculate new parameters with accommodation 3KN})*1  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness vQ1#Zg y  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens p JM&R<i:  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens !)LVZfQ0  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens a>BPK"K2  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 0yBiio  
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        tlens = 3.767 + 0.04*A                  'Lens thickness @ wx  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Zo T8  
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        'Adjust parameters to account for accommodation TX$4x~:  
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        '************************************************************************* >\ x!a:}  
        'Aqueous thickness (Position of Lens) Xx e07J~  
        '************************************************************************* R9)"%SO<y  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) m53~Ysq<  
        GetCustomElement eID, entity zF#:Uc`C5U  
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        parID = FindFullName( "Geometry.Arizona Eye" ) 0{ !+N6MiR  
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        ' Delete any shift(s) in z .[C@p`DZ  
        count = 0 y5`$Aa4~  
        While GetOperationCount(eID)>count )5/,B-+O"  
            GetOperation eID, count, op ,HtX D~N  
            If op.Type="ShiftZ" Then xpB* > zb  
                DeleteOperation eID,count 4s7&*dJ  
                count=count-1 7~m[:Eg6[s  
            End If tu5T^"B qO  
            count=count+1 {P!1VYs5  
        Wend u E<1PgW  
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        'Set new shift in c, FZ{O@  
        op.Type = "ShiftZ" V[ 'lB.&t  
        op.val1 = taq Y [%<s/  
        op.parent = parID =a!_H=+4  
        AddOperation eID, op nIf~ds&TT  
        Print "Set aqueous humor thickness = " & taq-0.55 w>TTu: 7  
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        '************************************************************************* 9|qzFmE#  
        'Radius and conic constant of anterior lens B2l5}"{ `  
        '************************************************************************* }}gtz-w  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) hK 1 H'~c  
        GetConic eID, entity, curv, conic HJt@m &H|  
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        SetConic eID, entity, 1/Rant, CCant [K""6D  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant vX<^x2~9(  
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        '************************************************************************* Y4 {/P1F  
        'Radius and conic constant of posterior lens <N,:w`g#  
        '************************************************************************* +D d !  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) HJjx!7h  
        GetConic eID, entity, curv, conic c)4L3W-x=  
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        SetConic eID, entity, 1/Rpost, CCpost H_FT%`iM  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost $nr=4'y Z  
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        '************************************************************************* <7_s'UAL!  
        'Lens thickness (Position of posterior lens surface) ~' w]%rh!  
        '************************************************************************* KtD XB>  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) #MUY!  
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        ' Delete any z-shift(s) Nj=0bg"Qg5  
        count = 0 U<I]_]  
        While GetOperationCount(eID)>count W:JR\KKU  
            GetOperation eID, count, op !nL>Ly  
            If op.Type="ShiftZ" Then 1'f&  
                DeleteOperation eID,count Q PrP3DK  
                count=count-1 TGHyBPJb  
            End If W<>R;~)  
            count=count+1 2B b,ZC*  
        Wend A$70!5*  
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        'Set new z-shift ~- eB  
        op.Type = "ShiftZ" %\T#Ik~3  
        op.val1 = tlens OM?FpRVU8  
        op.parent = parID ko ~D;M:  
        AddOperation eID, op /<1zzeHRSD  
        Print "Set lens thickness = " & tlens _o? I=UN2:  
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        '************************************************************************* xM=?ES  
        'Lens index of refraction ,0f^>3&n>e  
        '************************************************************************* h?p!uQ  
        eID = FindMaterial( "Lens" ) !GnwE  
        GetModelMaterial eID, mat r6vI6|1  
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        mat.Nd = nlens ?-JW2 E"uT  
        SetModelMaterial eID, mat Qt>Bvu Q  
        Print "Set lens index of refraction = " & nlens ;:/C.%d  
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        '************************************************************************* y+h/jEbM</  
        'Pupil diameter %OOy90b2  
        '************************************************************************* T%4yPmY  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 5E^P2Mlc  
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        'Adjust pupil diameter (trimming volume inner hole) X@za4d  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 49= K]X  
    N?IdaVLj  
        ' Adjust pupil location to just in front of the lens YmD~&J  
        parID = FindFullName( "Geometry.Arizona Eye" ) ySHpN>U  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Zn:]?%afdO  
        count = 0 e5(c,,/  
        While GetOperationCount(eID)>count .|@2Uf  
            GetOperation eID, count, op @H}{?-XyA  
            If op.Type="ShiftZ" Then }U?:al/m  
                DeleteOperation eID,count Wr`<bLq1vs  
                count=count-1 NjKC{L5S:  
            End If F`>qg2wO  
            count=count+1 9M-W 1prb  
        Wend 0-p %.}GE  
        op.Type = "ShiftZ" q8MyEoc:n  
        op.val1 = taq-0.01 `>=@Kc  
        op.parent = parID r,q.RWuII  
        AddOperation eID, op #vc!SI  
    H(kxRPH4@]  
        Print "Set pupil diameter = " & pupilDiam lQxEiDIL  
    &5*t*tI  
        'Update AZ Eye subassembly Description >7z(?nQYT^  
        eID = FindFullName( "Geometry.Arizona Eye" ) }\1V%c  
        GetEntity eID, entity nfh<3v|kvR  
        entity.Description = "Accommodation = " & A & "D" N{<5)L~Y  
        SetEntity eID, entity $."F z x  
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        Update AoY!f'Z  
        Print "DONE!" }!"Cvu  
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    End Sub (:R5"|]@<x  
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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: #mD_<@@  
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    Accommodation = 4 Diopters 7Kpv fyL{  
    Pupil Diameter = 4 mm %S^:5#9  
    Set aqueous humor thickness = 2.81 qDgy7kkQ  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 T8^l}Y B  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 [E/. r{S  
    Set lens thickness = 3.927 ?v`24p3PC  
    Set lens index of refraction = 1.42672 kx;7/fH  
    Set pupil diameter = 4 1GPBqF  
    DONE!
silence唯爱 2022-02-25 13:53
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