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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 (~%NRH<\  
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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。 Yku6\/^  
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模型 nGe4IY\-w  
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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。 lVQE}gd%m  
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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. Ws7fWK;  
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光源 qJ(uak  
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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。 H8I)D& cw  
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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。 !yPy@eP~  
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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。 _B#x{ii  
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图2. 字母F光源的设定方法光 tM;cvc`/  
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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 k}F7Jw#.  
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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。 C3Q #[  
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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。 rh1PpsSc  
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图5. 视网膜重点采样规格设定
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脚本 =DfI^$Lr:  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: y>x"/jzF#  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。  q/ Y4/  
余下的脚本计算与屈光度有关的所有参数。 gk6R#  
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分析 nvf5a-C+q  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 s7sd(f]=  
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图7. 字母F在视网膜上颜色分析
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脚本代码 F?R6zvive  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 9ybR+dGm+  
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Dim entity As T_ENTITY hWbu Z%  
Dim op As T_OPERATION :t!J 9  
Dim mat As T_MODELMATERIAL B=K<k+{6"  
Dim A As Double ;"Qq/ knVL  
Dim pupilDiam As Double ~y"R{-%uS  
Dim eID As Long z+;$cfN  
Dim parID As Long KTT!P 4  
Dim count As Integer 0@b<?Ms9  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 4cSs=|m?+  
Dim tlens As Double, nlens As Double F/lL1nTdK  
Dim curv As Double, conic As Double ]}].A q  
Dim ok As Long }NwmZ w>_  
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Sub Main ty~Sf-Pri  
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    '用户输入对话框 sj&(O@~R  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 @w==*.x  
        TextBox 220,21,40,21,.TextBox1 'default: 0 !p+rU?  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ef{Hj[8  
        OKButton 40,91,90,21 6x(b/`VW  
        CancelButton 190,91,90,21 > `eo0  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 =/|GWQ j  
        TextBox 220,49,40,21,.TextBox2 'default: 4 \R@}X cqZ  
    End Dialog ,B/TqPP  
    Dim dlg As UserDialog ~I> |f  
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    ok = Dialog (dlg) 6Zw$F3 <  
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    If ok=0 Then    'cancel button was pressed W%ix|R^2]  
        Print "Execution cancelled." HI D6h!  
        End >BO!jv!a  
    End If A ;`[va  
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    'Assign accommodation and pupil diameter & use defaults if field left empty |AvsT{2  
    If dlg.TextBox1 = "" Then  !vl1#@  
        A = 0           'Default accommodation `{"V(YMEV  
    Else >^9j>< Z  
        A = CDbl(dlg.TextBox1) 5?>Q[a.Ne  
    End If d:&cq8^  
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    If dlg.TextBox2 = "" Then N/{=j  
        pupilDiam = 4   'Default pupil diameter (0 t{  
    Else ?P7QAolrr  
        pupilDiam = CDbl(dlg.TextBox2) 8sDw:wTC  
    End If kH0kf-4\  
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    Print " " J^` pE^S  
    Print "Accommodation = " & A & " Diopters" Gv)*[7  
    Print "Pupil Diameter = " & pupilDiam & " mm" 0[ n;ZL~  
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    ' Calculate new parameters with accommodation mp(:D&M  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness t x1TtWo  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ri"=)]  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens L-|7 &  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens !h1|B7N  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 25xt*30M  
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    tlens = 3.767 + 0.04*A                  'Lens thickness aFrZ ;_  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 9J49s1  
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    'Adjust parameters to account for accommodation [F *hjGLc}  
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    '************************************************************************* uZ1G,9  
    'Aqueous thickness (Position of Lens) R^ I4_ZA  
    '************************************************************************* I%{D5.du  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) IU}g[O Cu  
    GetCustomElement eID, entity $I4J Kh  
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    parID = FindFullName( "Geometry.Arizona Eye" ) :VRQd}$Pi  
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    ' Delete any shift(s) in z v'y<}U  
    count = 0 ir )~T0  
    While GetOperationCount(eID)>count y7R{6W_U>  
        GetOperation eID, count, op n)]u|qq  
        If op.Type="ShiftZ" Then G"<} s mB  
            DeleteOperation eID,count U3>ES"N  
            count=count-1 .YS48 c  
        End If _32 o7}!x  
        count=count+1 \xZ6+xZd1  
    Wend bb`DyUy ^+  
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    'Set new shift in g31\7\)Ir  
    op.Type = "ShiftZ" c30 kb  
    op.val1 = taq +r =p ,leb  
    op.parent = parID N*hx;k9  
    AddOperation eID, op [ 3SbWwg  
    Print "Set aqueous humor thickness = " & taq-0.55 #5IfF~* i  
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    '************************************************************************* ,n{ |d33  
    'Radius and conic constant of anterior lens Q;p% VQ  
    '************************************************************************* \"=@uqar2  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 1,G f;mcQ  
    GetConic eID, entity, curv, conic UbwD2>  
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    SetConic eID, entity, 1/Rant, CCant /{X2:g{  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant QW@`4W0F  
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    '************************************************************************* qc^qCGy!z  
    'Radius and conic constant of posterior lens ivl_=  
    '************************************************************************* 0(!=N 1l  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) u#34mg..  
    GetConic eID, entity, curv, conic bcprhb  
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    SetConic eID, entity, 1/Rpost, CCpost :j#Fq d[DF  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost <NX6m|DD  
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    '************************************************************************* >_?Waz %  
    'Lens thickness (Position of posterior lens surface) ji|tc9#6  
    '************************************************************************* 3HmJixy  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) K0?:?>*b#  
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    ' Delete any z-shift(s) XFN4m #  
    count = 0 'd 6z^Z6  
    While GetOperationCount(eID)>count )h?Pz1-W1  
        GetOperation eID, count, op Gl>_C@n0h  
        If op.Type="ShiftZ" Then 2l!* o7  
            DeleteOperation eID,count gkDlh{  
            count=count-1 .EoLJHL }  
        End If z@em1W0?Z  
        count=count+1 sv?Lk4_  
    Wend o]*#|4-  
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    'Set new z-shift >) PcK  
    op.Type = "ShiftZ" 8L*P!j9`EY  
    op.val1 = tlens dg]: JU  
    op.parent = parID RBzBR)@5   
    AddOperation eID, op 4!KUPgg  
    Print "Set lens thickness = " & tlens ep2#a#&'  
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    '************************************************************************* ,] ,dOIOwn  
    'Lens index of refraction #!X4\+)  
    '************************************************************************* $>fMu   
    eID = FindMaterial( "Lens" ) :Vf:_;  
    GetModelMaterial eID, mat hzjEO2  
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    mat.Nd = nlens r|tTDKGQ  
    SetModelMaterial eID, mat &*#- %<=1  
    Print "Set lens index of refraction = " & nlens -NyfW+T={  
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    '************************************************************************* wfxg@<WR  
    'Pupil diameter sh%snLw  
    '************************************************************************* ^B|Q&1  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) eD481r  
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    'Adjust pupil diameter (trimming volume inner hole) tb-:9*2j-  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ,!s;o6|*y  
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    ' Adjust pupil location to just in front of the lens gOA  
    parID = FindFullName( "Geometry.Arizona Eye" ) 5 5_#?vw  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) WU -_Y^  
    count = 0 }G#TYF}  
    While GetOperationCount(eID)>count Je#vl4<L  
        GetOperation eID, count, op T.sib&R  
        If op.Type="ShiftZ" Then .*s1d)\:  
            DeleteOperation eID,count b!R\u1b  
            count=count-1 OA_Bz"  
        End If ?m?DAd~ZY  
        count=count+1 ni@N/Z?!pA  
    Wend zMkjdjb  
    op.Type = "ShiftZ" ;U=RV&  
    op.val1 = taq-0.01 #q"^6C 5  
    op.parent = parID <I{)p;u1  
    AddOperation eID, op L/,W  
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    Print "Set pupil diameter = " & pupilDiam m\88Etl@  
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    'Update AZ Eye subassembly Description pk*cc h#  
    eID = FindFullName( "Geometry.Arizona Eye" ) 32r2<QrX  
    GetEntity eID, entity ;L5'3+U  
    entity.Description = "Accommodation = " & A & "D" i%8I (F  
    SetEntity eID, entity ; /3 <  
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    Update s\6kXR  
    Print "DONE!" yu'2  
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End Sub q89#Ftkt  
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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: #4ZDY,>Xi#  
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Accommodation = 4 Diopters ,iXE3TN;W  
Pupil Diameter = 4 mm Ub%al D  
Set aqueous humor thickness = 2.81 G] -$fz  
Set anterior lens radius = 10.4 and conic constant = -2.375869 AS34yM(h  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 uM\(#jZ  
Set lens thickness = 3.927 R$<LEwjSw  
Set lens index of refraction = 1.42672 #-ioLt%  
Set pupil diameter = 4 ZqHh$QBD 9  
DONE! 0Dj<-n{9  
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