[技术]Arizona眼睛模型 [复制链接]

简介 JIeKp7;^  
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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。 /]pBcb|<  
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模型 rl#[HbPM  
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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。 Ln~Z_!  
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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. v]`}T/n  
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光源 Vn:BasS%  
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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。 'FVh/};Y.D  
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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。 R4xoc;b  
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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。 2L=+z1%I  
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视网膜的散射 ']'H8Y-M  
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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。 |$$gj[+^  
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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。 p#-;u1-B  
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脚本 Gp}:U>V)  
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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： xR9<I:^&  
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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。 BU\P5uB!V  
余下的脚本计算与屈光度有关的所有参数。 - v\n0Jt  
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分析 R-lB.9e#M  
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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。 1J(` kQ)c  
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脚本代码 Gz>M Y4+G  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. `RRC8]l  
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Dim entity As T_ENTITY ROWb:tX}  
Dim op As T_OPERATION v0~'`*|&  
Dim mat As T_MODELMATERIAL
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Dim A As Double RR*eq.;  
Dim pupilDiam As Double jzRfD3_s  
Dim eID As Long r9),F.6,  
Dim parID As Long |AY`OVgcKD  
Dim count As Integer /h)_Q;35S;  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double W(5et5DN,  
Dim tlens As Double, nlens As Double Eb9 eEa<W  
Dim curv As Double, conic As Double BhO*Pfs  
Dim ok As Long ,4RmT\%T  
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Sub Main ;<aT|4  

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    '用户输入对话框 D..dGh.MY  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 _$wXHONt  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ?Cg",k'  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 jm|x=s3}h  
        OKButton 40,91,90,21 b^SQCX+P  
        CancelButton 190,91,90,21 @P
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        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 pS1f y]  
        TextBox 220,49,40,21,.TextBox2 'default: 4 6 WD(  
    End Dialog 7~gIOu  
    Dim dlg As UserDialog zv1#PfO@)  
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    ok = Dialog (dlg) KW3Dr`A  
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    If ok=0 Then    'cancel button was pressed }8H_^G8  
        Print "Execution cancelled." 9VEx0mkdd  
        End ;oej~  
    End If \O*8%  
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    'Assign accommodation and pupil diameter & use defaults if field left empty D)XV{Wit  
    If dlg.TextBox1 = "" Then h($XR+!#  
        A = 0           'Default accommodation .7h:/d Y:  
    Else 4Nz@s^9  
        A = CDbl(dlg.TextBox1) ;zMZ+GZ?;+  
    End If @ m' zm:  
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    If dlg.TextBox2 = "" Then *.4VO+^  
        pupilDiam = 4   'Default pupil diameter ,Z2fVz~9  
    Else k<bA\5K  
        pupilDiam = CDbl(dlg.TextBox2) <{t*yMr   
    End If **oaR  
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    Print " " mes/gqrJ1I  
    Print "Accommodation = " & A & " Diopters" |OgtAI9  
    Print "Pupil Diameter = " & pupilDiam & " mm" KdBE[A-1^M  
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    ' Calculate new parameters with accommodation scXY~l]I*  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 2J>v4EWC  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 1 P0)La#  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens hI+mx  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ,Pq@{i#  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens !>n^ ;u  

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    tlens = 3.767 + 0.04*A                  'Lens thickness @X$~{Vp__  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Hp#IOsP~  
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    'Adjust parameters to account for accommodation i4Ps#R_wx  
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    '************************************************************************* uR;m<wPH,f  
    'Aqueous thickness (Position of Lens) ji8)/  
    '************************************************************************* }K rQPg  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Wu{cE;t  
    GetCustomElement eID, entity (IE\}QcK  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ^]{)gk8P~2  
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    ' Delete any shift(s) in z \&KfIh8  
    count = 0 bhqV2y*'  
    While GetOperationCount(eID)>count \$Jz26 -n  
        GetOperation eID, count, op 2^V/>|W>w  
        If op.Type="ShiftZ" Then pA~eGar_J  
            DeleteOperation eID,count O/N Ed)H!  
            count=count-1 |qp^4vq.p  
        End If .%\lYk]  
        count=count+1 =!V
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    Wend E1"H(m&6  
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    'Set new shift in F\)?Ntj)>@  
    op.Type = "ShiftZ" $G,#nh2 oD  
    op.val1 = taq nQHQVcDs8  
    op.parent = parID ?Dr_WFNjO  
    AddOperation eID, op 8|U-{"!O?  
    Print "Set aqueous humor thickness = " & taq-0.55 /x2MW5H  
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    '************************************************************************* @hz~9AII9  
    'Radius and conic constant of anterior lens [f8mh88r  
    '************************************************************************* 3-%F)@n  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Qf$3!O}G  
    GetConic eID, entity, curv, conic '1f:8  
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    SetConic eID, entity, 1/Rant, CCant I<&(Dg|XQ  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ,cF $_7M  
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    '************************************************************************* 6u6,9VG,  
    'Radius and conic constant of posterior lens 2Nau]y]=  
    '************************************************************************* '^6jRI,  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) H[;\[3  
    GetConic eID, entity, curv, conic =KCAHNr4?  
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    SetConic eID, entity, 1/Rpost, CCpost Jh6 z5xUV  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost }Q<cE$c  
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    '************************************************************************* =Felo8+   
    'Lens thickness (Position of posterior lens surface) bS2)L4MQY  
    '************************************************************************* ej^pFo  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) (&=gM  
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    ' Delete any z-shift(s)
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    count = 0 Y \oz9tf8  
    While GetOperationCount(eID)>count Q=}U  
        GetOperation eID, count, op wV&UB@  
        If op.Type="ShiftZ" Then `yXJaTbo  
            DeleteOperation eID,count vf&Sk
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            count=count-1 Mu>WS)1lS  
        End If l`M7a9*U  
        count=count+1 j3kcNb  
    Wend \ld{Z;e  
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    'Set new z-shift 7c7:B2Lq  
    op.Type = "ShiftZ" V]fsjpvlmr  
    op.val1 = tlens Ug=)_~  
    op.parent = parID u@ psVt   
    AddOperation eID, op +kdZfv>  
    Print "Set lens thickness = " & tlens Q9C;_Up  
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    '************************************************************************* S@WzvM  
    'Lens index of refraction YS|Ve*t(L=  
    '************************************************************************* q<2b,w==  
    eID = FindMaterial( "Lens" ) tXu_o6]  
    GetModelMaterial eID, mat rF>7 >wq  
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    mat.Nd = nlens B?|url6h  
    SetModelMaterial eID, mat Pm}
 
    Print "Set lens index of refraction = " & nlens *(pmFEc
 
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    '************************************************************************* 8`?vWJS  
    'Pupil diameter _1sjsGp>  
    '************************************************************************* ~UhTy~jya  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 2uajK..b  
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    'Adjust pupil diameter (trimming volume inner hole) q,
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" =4H"&Eu{  
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    ' Adjust pupil location to just in front of the lens YlP8fxS  
    parID = FindFullName( "Geometry.Arizona Eye" ) =u,8(:R]s  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) k#Bq8d  
    count = 0 +_E\Omcw  
    While GetOperationCount(eID)>count wFHbz9|@I  
        GetOperation eID, count, op q/N1q&  
        If op.Type="ShiftZ" Then JF%_8Ye5  
            DeleteOperation eID,count hCX_^%  
            count=count-1 A['0~tOP  
        End If }1)tALA  
        count=count+1 DGY?4r7>y  
    Wend c&rS7%  
    op.Type = "ShiftZ" lMN3;}K  
    op.val1 = taq-0.01 I_\#(  
    op.parent = parID ]=EYju@  
    AddOperation eID, op =SEgv;#KZ~  
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    Print "Set pupil diameter = " & pupilDiam 2xEG s Q  
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    'Update AZ Eye subassembly Description k9|8@3(h  
    eID = FindFullName( "Geometry.Arizona Eye" ) =,4iMENm!  
    GetEntity eID, entity =Co[pt  
    entity.Description = "Accommodation = " & A & "D" ?-HLP%C('  
    SetEntity eID, entity m+7/ebj{A  
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    Update
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    Print "DONE!" %Uz 5Ve  
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End Sub =bwuLno>  
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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： $afE= qC*  
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Accommodation = 4 Diopters l)^sE)  
Pupil Diameter = 4 mm 9BA*e-[  
Set aqueous humor thickness = 2.81 1m5=N
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Set anterior lens radius = 10.4 and conic constant = -2.375869 c%bGVRhE  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 MMYV8;c  
Set lens thickness = 3.927 9jC>OZ0s  
Set lens index of refraction = 1.42672 ee+*&CT)  
Set pupil diameter = 4 ER ^#J**  
DONE! A3Lfh6O