[转载]FRED运用：Arizona眼睛模型 [复制链接]

简介 !Jl0Eu  
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。 Fg_s'G,`  
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模型 a@ }r[0O  
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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。 1:UC\WW  
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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. 5>Yd\(`K  
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光源 15DK\_;  
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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。 CT%m_lN  
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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。 G>>u#>0  
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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。 w1(06A}/
 
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视网膜的散射 _x1[$A,GuB  
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在散射文件中，有一个名为“Retina surface”的72%的反射型朗伯散射，它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射，改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 wD^do  
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注意在视网膜的表面有散射重点采样规格定义，在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳，半角度10度。 e4%*I8 ^e  
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脚本 MYSc*G  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框，如下图所示： Cf=q_\0|W  
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如果“OK”按钮按下，将会核对对话框下面的代码行，如果点击取消则脚本终止。然后输入的参数赋予变量，如果此处是保留为空白，则使用默认值。因此，如果没有值输入并点击“OK”按钮，则脚本是以屈光度为0，光瞳直径为4mm来运行的。 rnv7L^9^A  
余下的脚本计算与屈光度有关的所有参数。 ;VlZd*M?  
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分析 O| 6\g>ew  
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屈光度为4，光瞳直径为4mm，字母F点在视网膜上所成的像。 PeUd  
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脚本代码 {F+M&+``  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. j[J@tM#  
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Dim entity As T_ENTITY xD=qU  
Dim op As T_OPERATION X$|TN+Ub  
Dim mat As T_MODELMATERIAL 0Q- Mxcj  
Dim A As Double OWXye4`*  
Dim pupilDiam As Double 6
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Dim eID As Long <
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Dim parID As Long Ma=6kX]  
Dim count As Integer tGO[A#9a  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ncJFB,4  
Dim tlens As Double, nlens As Double -wRyMY_D  
Dim curv As Double, conic As Double L+~YCat|$U  
Dim ok As Long <r+!hJ[s'  
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Sub Main $,e?X}4  
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    '用户输入对话框 hi3sOK*r;<  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 teOBsFy/I  
        TextBox 220,21,40,21,.TextBox1 'default: 0 gAr`hXO  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 &Ky 
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        OKButton 40,91,90,21 yw*mA1v  
        CancelButton 190,91,90,21 s\Pt,I@Y_  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 2}Z4a\YX  
        TextBox 220,49,40,21,.TextBox2 'default: 4 Y!= k  
    End Dialog UrhM)h?%  
    Dim dlg As UserDialog BU]WN7]D$  
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    ok = Dialog (dlg) /y9J)lx  
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    If ok=0 Then    'cancel button was pressed WE.$at{*h  
        Print "Execution cancelled." .mT#%ex  
        End G_^iR-
  
    End If 9o`7Kc/g  
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    'Assign accommodation and pupil diameter & use defaults if field left empty [<Os~bfOv  
    If dlg.TextBox1 = "" Then NlF0\+h  
        A = 0           'Default accommodation 6@?aVM~  
    Else ksu}+i,a  
        A = CDbl(dlg.TextBox1) Y%fVt|  
    End If fKTDt%  
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    If dlg.TextBox2 = "" Then $h 08Z  
        pupilDiam = 4   'Default pupil diameter xBL$]>  
    Else Tf#2"(!  
        pupilDiam = CDbl(dlg.TextBox2) .|-l+  
    End If c/<Sa|
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    Print " " -Wlp=#9  
    Print "Accommodation = " & A & " Diopters" C(V[wvL  
    Print "Pupil Diameter = " & pupilDiam & " mm" n^iNo  
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    ' Calculate new parameters with accommodation <?LfOSdMs^  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Z;GIlgK9  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens &o
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    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 11)/] ?/j  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens h"%|\o+3  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens VqK%^  
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    tlens = 3.767 + 0.04*A                  'Lens thickness n+{HNr  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction x">W u2  
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    'Adjust parameters to account for accommodation V#'26@@  
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    '************************************************************************* AT B\^;n.  
    'Aqueous thickness (Position of Lens) 9VoDhsKk  
    '************************************************************************* &1
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    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) `fBG~NDw  
    GetCustomElement eID, entity V_&GYXx(J  
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    parID = FindFullName( "Geometry.Arizona Eye" ) 0jxO |N2)  
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    ' Delete any shift(s) in z omM&{ }8g  
    count = 0 W@I 02n2H  
    While GetOperationCount(eID)>count ;^R A!Nj  
        GetOperation eID, count, op vk @%R  
        If op.Type="ShiftZ" Then D JLiZS  
            DeleteOperation eID,count kOs(?=  
            count=count-1 yicO!:bM  
        End If )W&o?VRfO  
        count=count+1 L([E98fo  
    Wend /> ^@ O  
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    'Set new shift in }.0Bl&\UK  
    op.Type = "ShiftZ" .6> hD1'  
    op.val1 = taq C%giv9a  
    op.parent = parID Jy \2I{I'  
    AddOperation eID, op PX;Vo~6  
    Print "Set aqueous humor thickness = " & taq-0.55 tIq>Oojdx  
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    '************************************************************************* )O,wRd>5  
    'Radius and conic constant of anterior lens 3`8dii  
    '************************************************************************* >qR7'QwP  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) S8 :"<B)  
    GetConic eID, entity, curv, conic 86 *;z-G  
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    SetConic eID, entity, 1/Rant, CCant 6}ce1|mkg/  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 7FAIew\r  
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    '************************************************************************* #EJhAJ  
    'Radius and conic constant of posterior lens Ls&+XlrX8  
    '************************************************************************* G+0><,S  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) UQ/qBbn  
    GetConic eID, entity, curv, conic rkkU"l$v  
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    SetConic eID, entity, 1/Rpost, CCpost &~RR&MdZ2  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ~@{w\%(AK]  
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    '************************************************************************* puOC60zI  
    'Lens thickness (Position of posterior lens surface) C)NC&fV  
    '************************************************************************* pgT9hle/  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) O7%2v@j|8  
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    ' Delete any z-shift(s) F8H'^3`b`U  
    count = 0 U#bl=%bF  
    While GetOperationCount(eID)>count l71gf.4g  
        GetOperation eID, count, op 7c-Gm R2  
        If op.Type="ShiftZ" Then +noZ<KFW "  
            DeleteOperation eID,count >
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            count=count-1 *I0Tbc O  
        End If PocYFhWQ`  
        count=count+1 9qK
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    Wend 0n.S,3|  
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    'Set new z-shift
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    op.Type = "ShiftZ" ` @8`qXg  
    op.val1 = tlens EM@;3.IO  
    op.parent = parID '0:i<`qv#g  
    AddOperation eID, op 'B_\TU0 O  
    Print "Set lens thickness = " & tlens 7{f_fkbs  
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    '************************************************************************* 5!Bktgk.  
    'Lens index of refraction n 6{2]&sd  
    '************************************************************************* RsW9:*R  
    eID = FindMaterial( "Lens" ) BYi)j6"  
    GetModelMaterial eID, mat p~2UUmV  
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    mat.Nd = nlens $+cAg>  
    SetModelMaterial eID, mat q]\X~ 9#  
    Print "Set lens index of refraction = " & nlens (DDyK[t+VX  
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    '************************************************************************* e*C6uz9N  
    'Pupil diameter GMW,*if8p  
    '************************************************************************* |9Yi
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    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) /-4$7qd  
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    'Adjust pupil diameter (trimming volume inner hole) e'2Y1h  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" w5KPB5/zu  
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    ' Adjust pupil location to just in front of the lens #`;/KNp 9  
    parID = FindFullName( "Geometry.Arizona Eye" ) R^*K6Ad  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Wkzs<y"  
    count = 0 w8iR|TV  
    While GetOperationCount(eID)>count >O7~h[FN  
        GetOperation eID, count, op 6_gnEve h  
        If op.Type="ShiftZ" Then Vw#{C>  
            DeleteOperation eID,count @ {#mpDX  
            count=count-1 g> S*<  
        End If AW,OHSXh6  
        count=count+1 LO:fJ{ -  
    Wend 6Pn8f  
    op.Type = "ShiftZ" U7iuY~L  
    op.val1 = taq-0.01 ]XA4;7  
    op.parent = parID %UZVb V  
    AddOperation eID, op s '?GH  
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    Print "Set pupil diameter = " & pupilDiam ZH,4oF  
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    'Update AZ Eye subassembly Description FP^{=0  
    eID = FindFullName( "Geometry.Arizona Eye" ) Nt:9MG>1  
    GetEntity eID, entity nkDy!"K  
    entity.Description = "Accommodation = " & A & "D" HKO739&n}  
    SetEntity eID, entity xJZ@DR,#  
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    Update
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    Print "DONE!" O 5Nb  
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End Sub ($nrqAv4  
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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： |=a}iU8  
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Accommodation = 4 Diopters ]i*](UQ  
Pupil Diameter = 4 mm
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Set aqueous humor thickness = 2.81 up'  
Set anterior lens radius = 10.4 and conic constant = -2.375869 =PHIpFIuk  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 ,TJD$^  
Set lens thickness = 3.927 X"fh@.  
Set lens index of refraction = 1.42672 6\jf|:h  
Set pupil diameter = 4 =*vM
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DONE! -fI@])$9J  
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