[技术]Arizona眼睛模型 [复制链接]

简介 /j3oHi$  
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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。 F \}
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模型 a$;+-Y  
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模型的定义如表1种所示，由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度（A）来决定。 t*Lo;]P  
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在FRED中使用0屈光度来创建的，光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. x1A^QIuxO  
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光源 ]1D>3  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 S7N54X2JwL  
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处，并增加了pre-propagation distance= -8。尽管光线在光瞳处创建，规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射，而不是在光瞳处入射。 Td8'z'  
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在往下看是内置的脚本用来修改屈光度，使其为4（250mm），光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 xB9^DURr\  
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视网膜的散射 qJISB7F[%O  
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在散射文件中，有一个名为“Retina surface”的72%的反射型朗伯散射，它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射，改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 h"ZF,g;a  
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注意在视网膜的表面有散射重点采样规格定义，在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳，半角度10度。 `bt]v$  
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脚本 _#N~$  
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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：  hA/FK  
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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。 Zsf<)Vx  
余下的脚本计算与屈光度有关的所有参数。 ugMJ}IGq  
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分析 CR, Y%0vQ  
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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。 _Zb_9&  
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脚本代码 %\5y6  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. z|pH>R?:  
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Dim entity As T_ENTITY
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Dim op As T_OPERATION ~r>WnI:vg  
Dim mat As T_MODELMATERIAL (<8T*Xo  
Dim A As Double ?w<x_Lo  
Dim pupilDiam As Double -B`;Sx  
Dim eID As Long HjV^6oP  
Dim parID As Long >n` OLHg;  
Dim count As Integer NWoZDsu  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double B /Dj2  
Dim tlens As Double, nlens As Double Qt@~y'O  
Dim curv As Double, conic As Double qTffh{q V  
Dim ok As Long l(&CO<4q?  
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Sub Main .h7b 4J  
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    '用户输入对话框 @br%:Nt  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 y`(z_5ClT  
        TextBox 220,21,40,21,.TextBox1 'default: 0 u2Rmp4]  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 mZq*o<kTA  
        OKButton 40,91,90,21 4@8i,q>  
        CancelButton 190,91,90,21 Ylo@  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 OgOu$.  
        TextBox 220,49,40,21,.TextBox2 'default: 4 nS4~1a  
    End Dialog 3QXGbu}:h!  
    Dim dlg As UserDialog 59EAqz[:  
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    ok = Dialog (dlg) '{7A1yJnY%  
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    If ok=0 Then    'cancel button was pressed uO":\<1#  
        Print "Execution cancelled." ]v9<^!  
        End Zr$PSp}  
    End If "bw4{pa+  
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    'Assign accommodation and pupil diameter & use defaults if field left empty "%}PVO!  
    If dlg.TextBox1 = "" Then k+s<;{  
        A = 0           'Default accommodation f$H"|Mbe  
    Else <-lz_  
        A = CDbl(dlg.TextBox1) b!`:|!7r'  
    End If 'z!I#Y!Y  
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    If dlg.TextBox2 = "" Then Kvk;D ]$  
        pupilDiam = 4   'Default pupil diameter Ebq5P$  
    Else ^ro?.,c T  
        pupilDiam = CDbl(dlg.TextBox2) jMw;`yh  
    End If w5&UG/z%l  
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    Print " " my04>6j0  
    Print "Accommodation = " & A & " Diopters" YemOP9  
    Print "Pupil Diameter = " & pupilDiam & " mm" J@R+t6$3O  
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    ' Calculate new parameters with accommodation z:fd'NC  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness >i=O =w  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens NghQ#c  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens @AyC0}  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ?j $z[_K  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens @c{Z?>dUc#  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 9VP|a-  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction }"3L>%Q5  
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    'Adjust parameters to account for accommodation %n-LDn  
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    '************************************************************************* 778L[wYe  
    'Aqueous thickness (Position of Lens) t[^}/ S  
    '************************************************************************* l+T\DZ  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) k:d'aP3  
    GetCustomElement eID, entity v3hNvcMpf  
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    parID = FindFullName( "Geometry.Arizona Eye" ) fEgZ/p!g  
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    ' Delete any shift(s) in z xXHz)w  
    count = 0 al"1T-  
    While GetOperationCount(eID)>count
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        GetOperation eID, count, op q Rt
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        If op.Type="ShiftZ" Then WQ6E8t)  
            DeleteOperation eID,count 6?hv,^  
            count=count-1 QtX ->6P>  
        End If ;GvyL>|-~  
        count=count+1 hz )L+  
    Wend (6.0gB$aTu  
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    'Set new shift in IG#=}q
  
    op.Type = "ShiftZ"  -EITz  
    op.val1 = taq qk:F6kL\`  
    op.parent = parID O>'o;0  
    AddOperation eID, op Q_@ Z.{  
    Print "Set aqueous humor thickness = " & taq-0.55 \DfvNeF  
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    '************************************************************************* M/B_-8B_D  
    'Radius and conic constant of anterior lens Y6g[y\*t  
    '************************************************************************* yqB{QFXO  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) m2N ?Fg  
    GetConic eID, entity, curv, conic 46$u}"E  

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    SetConic eID, entity, 1/Rant, CCant JfC.U,7Nc  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant d)dIIzv  
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    '*************************************************************************  5+VdZ'@  
    'Radius and conic constant of posterior lens iRPd=)  
    '************************************************************************* f2yc]I<lr~  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ;qzCoe  
    GetConic eID, entity, curv, conic {;z3$/JB  
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    SetConic eID, entity, 1/Rpost, CCpost } |sP;Rpu  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 0w(<pNA  
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    '************************************************************************* AbfLV942  
    'Lens thickness (Position of posterior lens surface) ^t#]E#  
    '************************************************************************* Hm4lR{A  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) &_!BMzp4  
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    ' Delete any z-shift(s) )zr/9aV  
    count = 0 ( 6r9y3'  
    While GetOperationCount(eID)>count />+JK5  
        GetOperation eID, count, op J }JT%SW  
        If op.Type="ShiftZ" Then M0_K%Z(zaR  
            DeleteOperation eID,count YB)1dzU  
            count=count-1 I ][8[UZ  
        End If [0_Kz"|  
        count=count+1 lt(,/  
    Wend V1j&>-]]9*  
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    'Set new z-shift s31^9a  
    op.Type = "ShiftZ" ~r|.GY  
    op.val1 = tlens rytizbc  
    op.parent = parID V ;>{-p  
    AddOperation eID, op {J|P2a[  
    Print "Set lens thickness = " & tlens 1w\Y._jK  
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    '************************************************************************* WhK?>u  
    'Lens index of refraction 93YD\R+q  
    '************************************************************************* ,[~Ydth  
    eID = FindMaterial( "Lens" ) Fbk<qQH  
    GetModelMaterial eID, mat xcoYo  
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    mat.Nd = nlens RV&2y=eb  
    SetModelMaterial eID, mat vy-{BH  
    Print "Set lens index of refraction = " & nlens W*8D@a0 _  

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    '************************************************************************* J-u,6c  
    'Pupil diameter z*x6V0'yt  
    '************************************************************************* y@hdN=-  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) /mr&Y}7T
 
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    'Adjust pupil diameter (trimming volume inner hole) K$(U>D|  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" `D#l(gZ  
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    ' Adjust pupil location to just in front of the lens Yh"Z@D[d  
    parID = FindFullName( "Geometry.Arizona Eye" ) 9|'bPOKe  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Y&gfe8%5N  
    count = 0 P,wFib^1  
    While GetOperationCount(eID)>count Q~*A`h#  
        GetOperation eID, count, op 7<NX;Fx  
        If op.Type="ShiftZ" Then /$q;-/DnTZ  
            DeleteOperation eID,count w7%N=hL1
 
            count=count-1 .+B!mmp  
        End If 3bPVKsY  
        count=count+1
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    Wend 5B98}N  
    op.Type = "ShiftZ" rj{'X  /  
    op.val1 = taq-0.01 N ~LR  
    op.parent = parID _I'O4s1S  
    AddOperation eID, op kXG+zsT  
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    Print "Set pupil diameter = " & pupilDiam .h*
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    'Update AZ Eye subassembly Description X\$M _b>O  
    eID = FindFullName( "Geometry.Arizona Eye" ) 6tnA
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    GetEntity eID, entity 8
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    entity.Description = "Accommodation = " & A & "D" "@ox=  
    SetEntity eID, entity ^?juY}rZ=|  
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    Update DO%YOv  
    Print "DONE!" P-vA.7  
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End Sub t zV"|s=o  
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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： &0ULj6jj  
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Accommodation = 4 Diopters W C`1;(#G  
Pupil Diameter = 4 mm _l/6Qpf  
Set aqueous humor thickness = 2.81 xt`znNN  
Set anterior lens radius = 10.4 and conic constant = -2.375869 50'6l X(v,  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 5hD
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Set lens thickness = 3.927 1hMk\ -3S  
Set lens index of refraction = 1.42672 r@n%  
Set pupil diameter = 4 7unu-P<C  
DONE! e`_3= kI