[转载]FRED运用：Arizona眼睛模型 [复制链接]

简介 sXFZWj}\  
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。 o66}yJzmD  
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模型 k8zI(5.>
 
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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。 oEpFuWp%A  
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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.
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光源 & 1f+,  
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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。 scV5PUq  
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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。 7b+6%fV  
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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。 G' 1'/  
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视网膜的散射 &UFZS94@r  
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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。 !5!<C,U  
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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。 !8b^,  
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脚本 vP,n(reM  
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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： -G=]=f/'  

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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。 2Khv>#l  
余下的脚本计算与屈光度有关的所有参数。 (;,sc$H]  
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分析 #0<XNLM  
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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。 K)P%;X  
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脚本代码 [-x7_=E#  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. Z30A{6}  
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Dim entity As T_ENTITY E(|>Ddv B&  
Dim op As T_OPERATION t`QENXA}  
Dim mat As T_MODELMATERIAL TsZ@  
Dim A As Double >R=|Wo`Ri  
Dim pupilDiam As Double 3gf1ownC  
Dim eID As Long M3Kfd  
Dim parID As Long j+YJbL v  
Dim count As Integer e';_Y>WQy  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double aQ~s`^D  
Dim tlens As Double, nlens As Double !!ya  
Dim curv As Double, conic As Double Q@HV- (A  
Dim ok As Long !&\INl-Z  
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Sub Main 1 {)Q[#l  
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    '用户输入对话框 ?%kV?eu'  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 mVmGg,  
        TextBox 220,21,40,21,.TextBox1 'default: 0 i?;Kq~,  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 3M=  
        OKButton 40,91,90,21 ET >](l9  
        CancelButton 190,91,90,21 |&jXp%4T  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1  C.QO#b  
        TextBox 220,49,40,21,.TextBox2 'default: 4 9ll~~zF99|  
    End Dialog 5(8@%6>ruj  
    Dim dlg As UserDialog D#z:()VT(  
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    ok = Dialog (dlg) 3mni>*q7d  
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    If ok=0 Then    'cancel button was pressed =qIyqbXz  
        Print "Execution cancelled." Q7A MRrN  
        End ;=UsAB]  
    End If u-C)v*#L  
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    'Assign accommodation and pupil diameter & use defaults if field left empty -{+}@?  
    If dlg.TextBox1 = "" Then V1JIht>Opo  
        A = 0           'Default accommodation L
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    Else bu"!jHPB  
        A = CDbl(dlg.TextBox1) &VcV$8k  
    End If FCn_^l)EA  
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    If dlg.TextBox2 = "" Then yCX?!E;La  
        pupilDiam = 4   'Default pupil diameter 3D(0=$W  
    Else VD\=`r)nT  
        pupilDiam = CDbl(dlg.TextBox2) A+)`ZTuO  
    End If zv"Z DRW  
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    Print " " E+JqWR5  
    Print "Accommodation = " & A & " Diopters" ?pZOeqqu$  
    Print "Pupil Diameter = " & pupilDiam & " mm" <"|,"hA  
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    ' Calculate new parameters with accommodation &8 x-o,  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness K96<M);:g  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens WeiFmar  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens n.G!43@*N  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ^v`\x5"Vp  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens uRr o?m<  
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    tlens = 3.767 + 0.04*A                  'Lens thickness *`RkTcG  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction j,dR,Nd  
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    'Adjust parameters to account for accommodation {jX2}  
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    '************************************************************************* )%@J=&G8TT  
    'Aqueous thickness (Position of Lens) >&5DsV.B  
    '************************************************************************* NPe%F+X  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) EJNU761  
    GetCustomElement eID, entity :zF,A,)  
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    parID = FindFullName( "Geometry.Arizona Eye" ) -pXSSa;O9  
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    ' Delete any shift(s) in z ;x@~A^<el  
    count = 0 8q}q{8  
    While GetOperationCount(eID)>count xjj6WED  
        GetOperation eID, count, op eM?I$ePTN  
        If op.Type="ShiftZ" Then -I,$_  
            DeleteOperation eID,count 'u |c  
            count=count-1 VZmLS 4E  
        End If <T|3`#o0  
        count=count+1 Q|?L*Pq2I  
    Wend U0N 60  
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    'Set new shift in X=fYWj[H,  
    op.Type = "ShiftZ" 8i#2d1O  
    op.val1 = taq !\.pq 2  
    op.parent = parID *]/zc1Q4M  
    AddOperation eID, op CD( :jM?  
    Print "Set aqueous humor thickness = " & taq-0.55 V7fq4O^:  
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    '************************************************************************* i
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    'Radius and conic constant of anterior lens XXcl{1Kp!@  
    '************************************************************************* ++Ts  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ;dZZ;#k%  
    GetConic eID, entity, curv, conic hVAn>_(  
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    SetConic eID, entity, 1/Rant, CCant ;m{1_1  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant O$j7i:G'5  
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    '************************************************************************* jrr*!^4|  
    'Radius and conic constant of posterior lens &n}f?  
    '************************************************************************* /quc}"__  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) J^5So  
    GetConic eID, entity, curv, conic <?}-$  
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    SetConic eID, entity, 1/Rpost, CCpost dx{bB%?Y\=  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost sF?TmBQ*  
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    '************************************************************************* @oY~..d`
 
    'Lens thickness (Position of posterior lens surface) )<;Y-u.UW  
    '************************************************************************* a /l)qB#  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) e
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    ' Delete any z-shift(s) m^f0V2M_  
    count = 0 2%@4]  
    While GetOperationCount(eID)>count ag#S6E^%S  
        GetOperation eID, count, op mD0f<gJ1  
        If op.Type="ShiftZ" Then M!A}NWF  
            DeleteOperation eID,count $i}y8nlQ  
            count=count-1 aS{n8P6vW  
        End If 6YLj^w] %  
        count=count+1 YY((V@|K  
    Wend >:S?Mnv6  
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    'Set new z-shift j4qR(p(vC  
    op.Type = "ShiftZ" ?'Xj g#}<  
    op.val1 = tlens ogtEAv~e7N  
    op.parent = parID U;V7 u/{  
    AddOperation eID, op uK#4(eY=W  
    Print "Set lens thickness = " & tlens ?'#` nx(!  
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    '************************************************************************* HU}7zK2  
    'Lens index of refraction ,p@y] cr  
    '************************************************************************* `*["UER  
    eID = FindMaterial( "Lens" ) UcDS9f_87  
    GetModelMaterial eID, mat z^q0/'  
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    mat.Nd = nlens 6BHXp# #z  
    SetModelMaterial eID, mat vNY{j7l/W  
    Print "Set lens index of refraction = " & nlens bv9]\qC]T<  
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    '************************************************************************* >~sI8czR*  
    'Pupil diameter dulI&_x  
    '************************************************************************* u+e{Mim  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) v ~?qz5:K~  
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    'Adjust pupil diameter (trimming volume inner hole) Oo8VeRZ  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" qQ/^@3tXL  
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    ' Adjust pupil location to just in front of the lens \fr~
  
    parID = FindFullName( "Geometry.Arizona Eye" ) nH'e?>x~e  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ,~$p,ALwN7  
    count = 0 [{,T.;'<j  
    While GetOperationCount(eID)>count L>NL:68yN  
        GetOperation eID, count, op "]x'PI 4J  
        If op.Type="ShiftZ" Then !r8
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            DeleteOperation eID,count FP`b>E qOH  
            count=count-1 7~%?
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        End If G1tY)_-8[  
        count=count+1 T#Z^s~7&I  
    Wend (k)v!O-  
    op.Type = "ShiftZ" 9Cp-qA%t  
    op.val1 = taq-0.01 |?xN\O^#}  
    op.parent = parID <CiSK!  
    AddOperation eID, op o#gWbAG;]b  
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    Print "Set pupil diameter = " & pupilDiam PO^ij2eS  
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    'Update AZ Eye subassembly Description 6=/F$|  
    eID = FindFullName( "Geometry.Arizona Eye" ) V>LwqS~`  
    GetEntity eID, entity 7#a-u<HF"  
    entity.Description = "Accommodation = " & A & "D" \fdv]f  
    SetEntity eID, entity I)[DTCJ~  
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    Update (D&3G;0tK  
    Print "DONE!" )[IC?U:5I  
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End Sub E_wCN&`[  
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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： hEH?[>9  
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Accommodation = 4 Diopters _Y4` xv0/  
Pupil Diameter = 4 mm  A,<E\  
Set aqueous humor thickness = 2.81 P>D)7V9Hh  
Set anterior lens radius = 10.4 and conic constant = -2.375869 Sy_G,+$\  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 U_Ptqqt%  
Set lens thickness = 3.927
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Set lens index of refraction = 1.42672 tw/dD +  
Set pupil diameter = 4 #q$HQ&k  
DONE! hWLA<wdb  
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