[技术]Arizona眼睛模型 [复制链接]

简介 R! n7g8I%  
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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。 ~N/a\%`  
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模型 k'*vG6!  
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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。 ?~IdPSY  
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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. &E
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光源 +]( #!}oH  
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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。 <$pv;]n  
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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。 o~W,VhCP
 
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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。 k ]T  
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视网膜的散射 WMW=RgiW\  
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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。 ^7*7^<  
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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。 @Kn@j D;  
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脚本 y"s
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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： +V9xKhR;x  
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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。 .)Pul|)d  
余下的脚本计算与屈光度有关的所有参数。 #,#:{&H  
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分析 @HSK[[?  
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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。 -'L~Y~'.  
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脚本代码 ].5q,A]  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. aG]^8`~>'  
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Dim entity As T_ENTITY C"mWO Y2]  
Dim op As T_OPERATION >M!LC  
Dim mat As T_MODELMATERIAL '-J<ib t  
Dim A As Double ~IWdFUKk  
Dim pupilDiam As Double C@Go]*c  
Dim eID As Long ~iQBgd@D^  
Dim parID As Long AL^tUcl  
Dim count As Integer F u^j- Io  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double T9!NuKfur  
Dim tlens As Double, nlens As Double E/wxX#]\  
Dim curv As Double, conic As Double hW/Ve'x[  
Dim ok As Long dFhyT.Y?  
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Sub Main -^(KGu&L&u  
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    '用户输入对话框 *}';q`u}  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1
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        TextBox 220,21,40,21,.TextBox1 'default: 0 O"df5x9@  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 @iXBy:@  
        OKButton 40,91,90,21 vdQ#CG$/  
        CancelButton 190,91,90,21 >SLmlK  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 QtXiUx^ k<  
        TextBox 220,49,40,21,.TextBox2 'default: 4 &Td)2Wt  
    End Dialog sf[|8}(  
    Dim dlg As UserDialog )8eb(!}7  
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    ok = Dialog (dlg) j;V\~[I^u  
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    If ok=0 Then    'cancel button was pressed rIYO(}Fl  
        Print "Execution cancelled." :dRC$?f4  
        End 9wGsHf8]  
    End If oWLP|c~Ap  
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    'Assign accommodation and pupil diameter & use defaults if field left empty V9qA'k  
    If dlg.TextBox1 = "" Then QT73=>^B  
        A = 0           'Default accommodation j (Q#NFT7  
    Else .taP2^2Z  
        A = CDbl(dlg.TextBox1)
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    End If _j3rs97@|  
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    If dlg.TextBox2 = "" Then _KkaseR  
        pupilDiam = 4   'Default pupil diameter jb,a>9]p  
    Else p~=z)7%e'  
        pupilDiam = CDbl(dlg.TextBox2) E8"&gblg  
    End If
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    Print " " 8 l)K3;q_  
    Print "Accommodation = " & A & " Diopters" V_D wHq2  
    Print "Pupil Diameter = " & pupilDiam & " mm"
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    ' Calculate new parameters with accommodation `w`N5 !  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness +!px+*)bW  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens mAGD qz>f  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens X=Ar"Dx}}s  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 5mpql[v3P  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens DEhR\
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    tlens = 3.767 + 0.04*A                  'Lens thickness UR=s=G|  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction W94u7a  
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    'Adjust parameters to account for accommodation K@%T5M4j  
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    '************************************************************************* &qSf ~7/  
    'Aqueous thickness (Position of Lens) mwsBj)  
    '************************************************************************* RMpiwO^  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) AB,(%JT/2{  
    GetCustomElement eID, entity ub9[!}r't  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ,Nhv#U<$  
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    ' Delete any shift(s) in z 5 -|7I7(G$  
    count = 0 htL1aQ.  
    While GetOperationCount(eID)>count `8O Bw  
        GetOperation eID, count, op N%Y!{k5T7  
        If op.Type="ShiftZ" Then !\d~9H%`B  
            DeleteOperation eID,count ,30lu a  
            count=count-1 :E|Jqi\  
        End If islHtX V
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        count=count+1 >R6mI  
    Wend bXc*d9]  
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    'Set new shift in a?GXVQ  
    op.Type = "ShiftZ" =-/'$7R,  
    op.val1 = taq cC/32SmY4  
    op.parent = parID l
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    AddOperation eID, op J(!=Dno  
    Print "Set aqueous humor thickness = " & taq-0.55 a3w6&e`  
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    '************************************************************************* oMLs22Do?  
    'Radius and conic constant of anterior lens e1JHN  
    '*************************************************************************  "$J5cco  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) N#RC;  
    GetConic eID, entity, curv, conic XRQ1Uh6  
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    SetConic eID, entity, 1/Rant, CCant )6X-m9.X  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant AY<L8  
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    '************************************************************************* ~8(Xn2  
    'Radius and conic constant of posterior lens ,YBO}l  
    '************************************************************************* +HWFoK  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) C{nk,j L  
    GetConic eID, entity, curv, conic dyf>T}Iy  
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    SetConic eID, entity, 1/Rpost, CCpost )eZ}Kt+  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 6)ZaK  
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    '************************************************************************* L aA<`  
    'Lens thickness (Position of posterior lens surface) +_*NY~  
    '************************************************************************* <"`f!k#[  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) fJ _MuAv  
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    ' Delete any z-shift(s) K re*~ "  
    count = 0 SEg{Gso9b  
    While GetOperationCount(eID)>count j1->w8  
        GetOperation eID, count, op -}sMOy`  
        If op.Type="ShiftZ" Then .mqMz
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            DeleteOperation eID,count R1Q,
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            count=count-1 rwW"B  
        End If )G, S7A  
        count=count+1 |T"j7  
    Wend i?@7>Ca  
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    'Set new z-shift A['(@Bz#7~  
    op.Type = "ShiftZ" 9e
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    op.val1 = tlens nSQ]qH&4d  
    op.parent = parID 62.Cq!~  
    AddOperation eID, op lH/"47  
    Print "Set lens thickness = " & tlens JgP%4)]LV  
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    '************************************************************************* 0LzS #J+  
    'Lens index of refraction DoO ;VF  
    '************************************************************************* 1|>vk+;1h  
    eID = FindMaterial( "Lens" ) 76o[qay  
    GetModelMaterial eID, mat ;*F
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    mat.Nd = nlens l?m 3*  
    SetModelMaterial eID, mat z(O*DwY#  
    Print "Set lens index of refraction = " & nlens U+4[w`a}  
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    '************************************************************************* e?07o!7[;  
    'Pupil diameter {|<r7K1<  
    '************************************************************************* [h' 22W  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) %z[=T@  
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    'Adjust pupil diameter (trimming volume inner hole) !H c6$  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" !nsr( 7X2  
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    ' Adjust pupil location to just in front of the lens BonjK#  
    parID = FindFullName( "Geometry.Arizona Eye" ) UL&>]aQ  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) vmfFR  
    count = 0 (M{wkQTO  
    While GetOperationCount(eID)>count }7{(o-  
        GetOperation eID, count, op :nqDX  
        If op.Type="ShiftZ" Then
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            DeleteOperation eID,count =Y!.0)t;*  
            count=count-1 3^q9ll7Op  
        End If .),9a,  
        count=count+1 'h~IbP  
    Wend 8(q8}s$>  
    op.Type = "ShiftZ" V8o, e  
    op.val1 = taq-0.01 QJR},nZ3  
    op.parent = parID eej#14&  
    AddOperation eID, op D?*du#6  
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    Print "Set pupil diameter = " & pupilDiam }lJ|nl`
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    'Update AZ Eye subassembly Description A93(} V7I  
    eID = FindFullName( "Geometry.Arizona Eye" ) <bhJ>  
    GetEntity eID, entity +
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    entity.Description = "Accommodation = " & A & "D" @V Tw>=94  
    SetEntity eID, entity k@n L(2  
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    Update ev/)#i#s{  
    Print "DONE!" UaQW<6
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End Sub $SFreyI;Uf  
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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： F60m]NUM)c  
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Accommodation = 4 Diopters *(/b{
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Pupil Diameter = 4 mm c1*^ \  
Set aqueous humor thickness = 2.81 ?=kH}'igq  
Set anterior lens radius = 10.4 and conic constant = -2.375869 YCzH@94QeV  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 !@ AnwV]  
Set lens thickness = 3.927 9v ,y  
Set lens index of refraction = 1.42672 E J6|y'  
Set pupil diameter = 4 iQCs8hIR  
DONE! f!GFRMM1