[转载]FRED运用：Arizona眼睛模型 [复制链接]

简介 iHBetkAu  
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。 _3~/Z{z8  
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模型 K2|2Ks_CS  
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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。 1cq"H/N  
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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. 3b{ 7Z 2  
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光源 ,Pi!%an w  
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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。 &rs
  
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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。 O2{~Q{p  
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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。 03
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视网膜的散射 +}VaQ8ti4  
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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。 JkShtLEr  
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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。 ^/~ZP?%]  
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脚本 @>fsg-|  
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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： I1pnF61U  
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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。 jj&mRF0gCb  
余下的脚本计算与屈光度有关的所有参数。 %*zV&H   
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分析 J@o_-\@  
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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。 a<0q%Ax  
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脚本代码 (%c&Km7K  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 3$?nzKTW\  
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Dim entity As T_ENTITY 4.Q[Tu  
Dim op As T_OPERATION 2TG2<wqvE  
Dim mat As T_MODELMATERIAL Q<NQ9lX  
Dim A As Double 2D(sA  
Dim pupilDiam As Double \2!.  
Dim eID As Long rK3KxG  
Dim parID As Long  &
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Dim count As Integer ^q_wtuQ  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double $EHFf$M  
Dim tlens As Double, nlens As Double k.7!)jL7  
Dim curv As Double, conic As Double ,RDWx  
Dim ok As Long :f:&B8  
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Sub Main kL8E#  
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    '用户输入对话框 fN@ZJ~F%j  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 %y\5L#T!>  
        TextBox 220,21,40,21,.TextBox1 'default: 0 Tay$::V  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 !vSq?!y6*P  
        OKButton 40,91,90,21 </Y(4Xwf=  
        CancelButton 190,91,90,21 dGj0;3FI%  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 N p*T[J  
        TextBox 220,49,40,21,.TextBox2 'default: 4 7x77s  
    End Dialog oOc-1C y  
    Dim dlg As UserDialog S(U9Dlyarg  
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    ok = Dialog (dlg) u Fw1%  
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    If ok=0 Then    'cancel button was pressed `#w#!@s#@  
        Print "Execution cancelled." qou\4YZ  
        End r7].48D  
    End If {chZ&8)f  
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    'Assign accommodation and pupil diameter & use defaults if field left empty -9.lFuI  
    If dlg.TextBox1 = "" Then [3qH?2&  
        A = 0           'Default accommodation w&T\8k=  
    Else fVgN8b|&'  
        A = CDbl(dlg.TextBox1) 4X*U~}  
    End If _&\'Va$  
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    If dlg.TextBox2 = "" Then %o4v} mzV  
        pupilDiam = 4   'Default pupil diameter - AgD  
    Else lwgwdB  
        pupilDiam = CDbl(dlg.TextBox2) &*'^
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    End If GDC@s<[k  
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    Print " " &4KUXn[F  
    Print "Accommodation = " & A & " Diopters" 5@r6'Z  
    Print "Pupil Diameter = " & pupilDiam & " mm" %*!6R:gAp  
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    ' Calculate new parameters with accommodation mjg@c|rTG  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 7gV9
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ~GX ]K H  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 0Fon`3(^\  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens sRZ<c  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens p&V64L:V  
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    tlens = 3.767 + 0.04*A                  'Lens thickness l3ogMRq@  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction
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    'Adjust parameters to account for accommodation $V`1<>4  
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    '************************************************************************* 'Ca;gi !U  
    'Aqueous thickness (Position of Lens) \+sa[
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    '*************************************************************************
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    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) KWjhkRK4]  
    GetCustomElement eID, entity ^yc8is'`  
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    parID = FindFullName( "Geometry.Arizona Eye" ) !',%kvJI  
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    ' Delete any shift(s) in z D6?h 6`J  
    count = 0 Q<D_QJ  
    While GetOperationCount(eID)>count gt.F[q3  
        GetOperation eID, count, op tF-l=ph}`  
        If op.Type="ShiftZ" Then f1'X<VA  
            DeleteOperation eID,count Yl'8" \HF  
            count=count-1
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        End If KFO K%vbM  
        count=count+1 +2eri_p  
    Wend #prYZcHv:_  
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    'Set new shift in /Ta-3Eh!  
    op.Type = "ShiftZ" r_Ou\|jU  
    op.val1 = taq u1UCe  
    op.parent = parID `p* 43nV  
    AddOperation eID, op (2Lmu[  
    Print "Set aqueous humor thickness = " & taq-0.55 2BF455e   
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    '************************************************************************* g)$KN,gGuO  
    'Radius and conic constant of anterior lens | Z7j s"  
    '************************************************************************* V0 Z8VqV  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) <+ [N*  
    GetConic eID, entity, curv, conic (gVN<Es  
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    SetConic eID, entity, 1/Rant, CCant d*6/1vyjT  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant _e>N3fT  
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    '************************************************************************* [tt{wl"E  
    'Radius and conic constant of posterior lens DH
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    '************************************************************************* 3`{ vx  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Gukvd6-g9b  
    GetConic eID, entity, curv, conic Hu6Qr  
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    SetConic eID, entity, 1/Rpost, CCpost pnp8`\cIH  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost jwLZC  
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    '************************************************************************* svxjad@l/  
    'Lens thickness (Position of posterior lens surface) z<fd!g+^  
    '************************************************************************* I;wxgWOP  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) E.Th}+
  
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    ' Delete any z-shift(s) `5Z'8^  
    count = 0 *3={s"a.(  
    While GetOperationCount(eID)>count EJ<L,QH3  
        GetOperation eID, count, op "m6G;cv  
        If op.Type="ShiftZ" Then wVI_SQ<8V  
            DeleteOperation eID,count F{Yr8(UHA  
            count=count-1 <Dgf'GrJ  
        End If ZQ`4'|"  
        count=count+1 z(.,BB[  
    Wend : 4-pnn  
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    'Set new z-shift toD!RE  
    op.Type = "ShiftZ" ~}ifwm'7 a  
    op.val1 = tlens PcZ<JJ16F$  
    op.parent = parID {%k[Z9*tO  
    AddOperation eID, op \/S
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    Print "Set lens thickness = " & tlens Yuf+d-%  
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    '************************************************************************* $>_`
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    'Lens index of refraction _ Dz*%  
    '************************************************************************* CXz9bhn<4  
    eID = FindMaterial( "Lens" ) seAEv0YWz  
    GetModelMaterial eID, mat ) d'H&c3  
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    mat.Nd = nlens />:$"+gKo  
    SetModelMaterial eID, mat 4)}>dxv  
    Print "Set lens index of refraction = " & nlens Z]2z*XD  
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    '************************************************************************* G[>CBh5  
    'Pupil diameter L$!2<eK  
    '************************************************************************* Jc5YGj7  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) =
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    'Adjust pupil diameter (trimming volume inner hole) e~># M$  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" _^RN$4.R>  
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    ' Adjust pupil location to just in front of the lens x@O)QaBN!  
    parID = FindFullName( "Geometry.Arizona Eye" ) !~7lY]_U  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) #7:ah  
    count = 0 z$g__q-  
    While GetOperationCount(eID)>count k+i0@G'C(  
        GetOperation eID, count, op A4d3hF~l`  
        If op.Type="ShiftZ" Then Dh#5-Kf%  
            DeleteOperation eID,count ei1
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            count=count-1 4~oRcO8!Y  
        End If %Rr_fSoV  
        count=count+1 TL$w~dY  
    Wend YFj#{C.  
    op.Type = "ShiftZ" N(J#<;!yb  
    op.val1 = taq-0.01 [;-;{ *{G  
    op.parent = parID

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    AddOperation eID, op I`g&>  
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    Print "Set pupil diameter = " & pupilDiam Abmi=]\bx  
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    'Update AZ Eye subassembly Description -<T>paE9  
    eID = FindFullName( "Geometry.Arizona Eye" ) #\xy,C'Y  
    GetEntity eID, entity %g>k0~TRf#  
    entity.Description = "Accommodation = " & A & "D" |KPNl\%ID  
    SetEntity eID, entity #-"C_~-MH  
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    Update aDLlL?r3  
    Print "DONE!" ,PKUgL}w  
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End Sub 6y?uH;SL  
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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： E2.!|u2  
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Accommodation = 4 Diopters &g*1
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Pupil Diameter = 4 mm mB bGj3u;  
Set aqueous humor thickness = 2.81 J=O_nup6C  
Set anterior lens radius = 10.4 and conic constant = -2.375869 G$/Qcr6W<  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 mmNn,>AO!  
Set lens thickness = 3.927 I
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Set lens index of refraction = 1.42672 Pum&\.l  
Set pupil diameter = 4 Ts=TaRwWf  
DONE! fp3`O9+em  
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