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xunjigd 2016-02-24 12:53

FRED运用：Arizona眼睛模型

简介 sfpZc7  
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。 S 8kCp;  
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模型 +KF^Z$I  
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模型的定义如表1种所示，由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度（A）来决定。 pd:WEI ,  
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Table 1. AZ眼睛模型的定义
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在FRED中使用0屈光度来创建的，光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. @D]5civm_  
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光源 us1Hu)  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 _?-E7:Sw  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处，并增加了pre-propagation distance= -8。尽管光线在光瞳处创建，规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射，而不是在光瞳处入射。 3$jT*OyG#  
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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。 xzdf^Ce  
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图2. 字母F光源的设定方法光 l3{-z4mw  
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图3. 字母F在视网膜上位置点列图
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视网膜的散射 '3R`lv   
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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。 `Syl:rU~y@  
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图4. 视网膜朗伯散射设定
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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。 g1;:KzVv  
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图5. 视网膜重点采样规格设定
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脚本 Ja|5 @  
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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：  03L]  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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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。 ({ +!`}GY  
余下的脚本计算与屈光度有关的所有参数。 `:ArT}F  
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分析 TCMCK_SQL  
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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。 l94b^W}1)W  
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图7. 字母F在视网膜上颜色分析
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脚本代码 pD8+ 4;A  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. H/"-Z;0{  
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Dim entity As T_ENTITY G ?9"Y%  
Dim op As T_OPERATION &r[`>B{tP  
Dim mat As T_MODELMATERIAL 99]R$eT8  
Dim A As Double 'g">LQ~a+  
Dim pupilDiam As Double d}OTO10  
Dim eID As Long 2\R'@L*  
Dim parID As Long > ;jZa  
Dim count As Integer 2my_;!6T[  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double gx-2v|pZ  
Dim tlens As Double, nlens As Double Vk` h2BV  
Dim curv As Double, conic As Double 9,c(y sv"  
Dim ok As Long O 5!7'RZ  
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Sub Main \0A3]l  
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    '用户输入对话框 -Sq z5lo  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ?)/#+[xa  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ;Y)w@bNt@  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 BfXgh'Z~  
        OKButton 40,91,90,21 l(yZO$  
        CancelButton 190,91,90,21 r^2p*nr}  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 yyR0]NzYUD  
        TextBox 220,49,40,21,.TextBox2 'default: 4 oph}5Krd)  
    End Dialog WEAT01  
    Dim dlg As UserDialog !zBhbmlKt  
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    ok = Dialog (dlg) 87=&^.~`  
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    If ok=0 Then    'cancel button was pressed E!;SL|lj.  
        Print "Execution cancelled." )z>|4@,  
        End 3W V"U  
    End If GL&y@6  
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    'Assign accommodation and pupil diameter & use defaults if field left empty 3N 8t`N  
    If dlg.TextBox1 = "" Then L]yS[UN$  
        A = 0           'Default accommodation _,kj:R.  
    Else N>Xo_-QCY  
        A = CDbl(dlg.TextBox1) G3t xj  
    End If XWn VgY s  
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    If dlg.TextBox2 = "" Then I) rCd/  
        pupilDiam = 4   'Default pupil diameter =NpYFKmMhV  
    Else hC:n5]K  
        pupilDiam = CDbl(dlg.TextBox2) T=<@]$?  
    End If \1d (9jR  
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    Print " " AJt+p&I[J  
    Print "Accommodation = " & A & " Diopters" 1f%1*L0>@  
    Print "Pupil Diameter = " & pupilDiam & " mm" [2>yYr s_=  
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    ' Calculate new parameters with accommodation -N6f1>}pE  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness >/{@C  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens [v7F1@6b  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ]E7F /O/.  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens +ndaLhj'  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens !]42^?GH  
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    tlens = 3.767 + 0.04*A                  'Lens thickness P|^f0Rw3.  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 2$9odD<r  
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    'Adjust parameters to account for accommodation ^"2i   
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    '************************************************************************* ,%6P0#-  
    'Aqueous thickness (Position of Lens) |<HPn4 ,X  
    '************************************************************************* tG:25T0  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) u&^b~# T  
    GetCustomElement eID, entity oOnop-z7  
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    parID = FindFullName( "Geometry.Arizona Eye" ) F7 5#*  
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    ' Delete any shift(s) in z z[LNf.)}  
    count = 0 >/g#lS 5  
    While GetOperationCount(eID)>count `V=N*hv`  
        GetOperation eID, count, op Ld\R:{M"  
        If op.Type="ShiftZ" Then [\'%?BH(^  
            DeleteOperation eID,count I+BHstF5um  
            count=count-1 eds o2  
        End If O80<Z#%j`  
        count=count+1 ^b/ Z)3  
    Wend g~Z vA(`  
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    'Set new shift in o#;b  
    op.Type = "ShiftZ" |^0XYBxQ  
    op.val1 = taq 5k!g%sZ  
    op.parent = parID 1uG"f<TsR  
    AddOperation eID, op ,qA(\[  
    Print "Set aqueous humor thickness = " & taq-0.55 u&1q [0y  
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    '************************************************************************* qUh2hz:  
    'Radius and conic constant of anterior lens 3%l*N&gsg:  
    '************************************************************************* hwu]Er.gn  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 3Iua*#<m,  
    GetConic eID, entity, curv, conic d^ Inb!%w  
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    SetConic eID, entity, 1/Rant, CCant N6>(;ugJ1-  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 5G::wuxk  
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    '************************************************************************* #J@[Wd  
    'Radius and conic constant of posterior lens RzxNbeki[W  
    '*************************************************************************  RwKdxK+;  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) %+f>2U4I  
    GetConic eID, entity, curv, conic ]*v dSr-J  
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    SetConic eID, entity, 1/Rpost, CCpost J3,fk)  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Qr1"Tk7s  
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    '************************************************************************* .}^g!jm~h  
    'Lens thickness (Position of posterior lens surface) *$yR*}A  
    '************************************************************************* 1s%#$ 7  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Hcl(3> Jn2  
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    ' Delete any z-shift(s) A$<.a'&T!  
    count = 0 9zZr^{lUl  
    While GetOperationCount(eID)>count cFaaLUZk  
        GetOperation eID, count, op Q7*SE%H  
        If op.Type="ShiftZ" Then B{|8#jqY  
            DeleteOperation eID,count u&`XB|~  
            count=count-1 &7<TAo;O  
        End If H#@^R(  
        count=count+1 M%Ji0v38  
    Wend { WIJC ',Y  
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    'Set new z-shift  ;hY S6  
    op.Type = "ShiftZ" m4aB*6<lq  
    op.val1 = tlens ~T9/#-e>BF  
    op.parent = parID >Nvjl~o5  
    AddOperation eID, op J]v%q,"  
    Print "Set lens thickness = " & tlens e^d0zl{  
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    '************************************************************************* Y'yH;M z  
    'Lens index of refraction &f"-d  
    '************************************************************************* { D^{[I  
    eID = FindMaterial( "Lens" ) ^c<ucv6.  
    GetModelMaterial eID, mat |s"nM<ZNZ  
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    mat.Nd = nlens E^QlJ8  
    SetModelMaterial eID, mat D&/kCi=R  
    Print "Set lens index of refraction = " & nlens `!XY]PI+e  
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    '************************************************************************* Du`JaJI  
    'Pupil diameter .uuO>:  
    '************************************************************************* M4zm,>?K  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) d p2F  
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    'Adjust pupil diameter (trimming volume inner hole) >ZPsjQuf"  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" }2<r,  
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    ' Adjust pupil location to just in front of the lens )^ m%i]L _  
    parID = FindFullName( "Geometry.Arizona Eye" ) IOb*GTb  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) xgpi-l  
    count = 0 T,]7ICF#  
    While GetOperationCount(eID)>count (^@ra$.  
        GetOperation eID, count, op 3{""58  
        If op.Type="ShiftZ" Then _9JhL:cY  
            DeleteOperation eID,count X*&[u7No  
            count=count-1 2@9Tfm(=  
        End If 3{ LP?w:@  
        count=count+1 WOQP$D9  
    Wend "$N#p5  
    op.Type = "ShiftZ" :,Pn3xl  
    op.val1 = taq-0.01 >H'4{|  
    op.parent = parID <<(wa j  
    AddOperation eID, op dQ_!)f&w1  
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    Print "Set pupil diameter = " & pupilDiam T? tG~  
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    'Update AZ Eye subassembly Description *"D3E7AO  
    eID = FindFullName( "Geometry.Arizona Eye" ) KHgBo}6  
    GetEntity eID, entity 7]9 a<  
    entity.Description = "Accommodation = " & A & "D" - M[$Zy^  
    SetEntity eID, entity y9_K, g  
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    Update _{r=.W+ w  
    Print "DONE!" VG,u7A*Z#  
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End Sub 'f[T&o&L/  
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如果屈光度是4，光瞳直径是4，则会输出如下数据： #gp,V#T  
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Accommodation = 4 Diopters )^4\,u\@  
Pupil Diameter = 4 mm _C(m<n  
Set aqueous humor thickness = 2.81 XLAN Np%E  
Set anterior lens radius = 10.4 and conic constant = -2.375869 m\$\ 09  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 AI,(z;{P  
Set lens thickness = 3.927 h<Ft_#|o[  
Set lens index of refraction = 1.42672 i|T)p_y(!a  
Set pupil diameter = 4 O>^C4c!  
DONE! QS{1CC9$  
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（文章来源：讯技光电）
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