[技术]Arizona眼睛模型 [复制链接]

简介 />uE)R$  
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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。 >"z`))9  
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模型 D( y c  
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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。 yr*~?\  
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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. A<(Fn_&W  
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光源 y5?kv-"c  
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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。 |oQhtk8.  
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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。 di]CYLf  
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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。 <e wcWr  
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视网膜的散射 :H]MMe  
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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。 x]608I T  
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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。 &o&}5Aba9  
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脚本 ) bd`U  
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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： 9niffq)h  
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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。 e5w0}/yW/  
余下的脚本计算与屈光度有关的所有参数。 .$+,Y4q~(  
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分析 ~|oB|>  
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屈光度为4，光瞳直径为4mm，字母F点在视网膜上所成的像。 5!57<n  
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脚本代码 hn$jI5*`  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. #8%~u+"N  
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Dim entity As T_ENTITY L9l]0C37e  
Dim op As T_OPERATION Wi*HLP!lNC  
Dim mat As T_MODELMATERIAL 2Y;iqR  
Dim A As Double rT
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Dim pupilDiam As Double D+h`Z]"|  
Dim eID As Long R#ya9GN{  
Dim parID As Long
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Dim count As Integer bOr6"nn  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double @y|JIBBRc  
Dim tlens As Double, nlens As Double ?9~|K/`l  
Dim curv As Double, conic As Double ir_X65l/2  
Dim ok As Long Xa$
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Sub Main D6'-c#  
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    '用户输入对话框 g&/r =U  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 )-i(%;,*e  
        TextBox 220,21,40,21,.TextBox1 'default: 0 , lBHA+@  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 y)7;"3Q<  
        OKButton 40,91,90,21 ciN*gwI)  
        CancelButton 190,91,90,21 QD 0p  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 R1/mzPG  
        TextBox 220,49,40,21,.TextBox2 'default: 4 !A+jX7Nb  
    End Dialog NH,4>mV$!  
    Dim dlg As UserDialog C-(O*hK  
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    ok = Dialog (dlg) h
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    If ok=0 Then    'cancel button was pressed uTmT'u:}  
        Print "Execution cancelled." h~#.s*0.F  
        End :|=Xh"l"  
    End If *{=q:E$  
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    'Assign accommodation and pupil diameter & use defaults if field left empty }jL4F$wC  
    If dlg.TextBox1 = "" Then wNl "y  
        A = 0           'Default accommodation TEbE-h0)]  
    Else g7K<"Z {M  
        A = CDbl(dlg.TextBox1) D Z=OZ.v  
    End If l YjPrA]TC  
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    If dlg.TextBox2 = "" Then %vU
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        pupilDiam = 4   'Default pupil diameter 92^Dn`g  
    Else *C(q{|f  
        pupilDiam = CDbl(dlg.TextBox2) %z["TVH  
    End If :Lq=)'d;6  
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    Print " " ,"T[#A~  
    Print "Accommodation = " & A & " Diopters" / KKA/  
    Print "Pupil Diameter = " & pupilDiam & " mm" C+-sf  
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    ' Calculate new parameters with accommodation =fI0q7]ndz  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness rmdG"s  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens O9:J ^g  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens z_:r&UP`"  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ,.,Y{CP  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens {G _|gs
 
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    tlens = 3.767 + 0.04*A                  'Lens thickness \6,Z<.I  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction t\lx*_lr  
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    'Adjust parameters to account for accommodation kk/vgte-)e  
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    '************************************************************************* {ALOs^_-  
    'Aqueous thickness (Position of Lens) |bjLmGb  
    '************************************************************************* w%f51Ex  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) oX[I4i%G  
    GetCustomElement eID, entity #M8>
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    parID = FindFullName( "Geometry.Arizona Eye" ) l78:.  
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    ' Delete any shift(s) in z Jry643K>:;  
    count = 0 9S)A6]  
    While GetOperationCount(eID)>count _2Fa.gi  
        GetOperation eID, count, op 90+Hv:wF  
        If op.Type="ShiftZ" Then %l)~C%T  
            DeleteOperation eID,count ^Kh>La:>O  
            count=count-1 Ji:0J},m  
        End If  SwmX_F#_  
        count=count+1 aB4L$M8x  
    Wend Py#iC#g~  
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    'Set new shift in H3qL&xL  
    op.Type = "ShiftZ" iTeFy-Ct  
    op.val1 = taq x:IY6 l  
    op.parent = parID ZQrgYeQl"  
    AddOperation eID, op ?a-}1A{  
    Print "Set aqueous humor thickness = " & taq-0.55 +4Lj}8,  
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    '************************************************************************* s&qr2'F+z  
    'Radius and conic constant of anterior lens ,5Tw
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    '************************************************************************* }ilX 2s?>  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) r#K"d  
    GetConic eID, entity, curv, conic {X>U`0P  
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    SetConic eID, entity, 1/Rant, CCant .@]M'S^1  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant c)=UX_S!  
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    '************************************************************************* dLTA21b#  
    'Radius and conic constant of posterior lens G3t 4$3|  
    '************************************************************************* @7<m.?A!  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) g].hL  
    GetConic eID, entity, curv, conic AkRZUj\  
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    SetConic eID, entity, 1/Rpost, CCpost wenJ(0L|  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost .[#bOp*  
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    '************************************************************************* ^o*$+DbC  
    'Lens thickness (Position of posterior lens surface) 64qQ:D7C  
    '************************************************************************* 4WV)&50  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) hTbot^/  
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    ' Delete any z-shift(s) oM#S
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    count = 0 gedk  
    While GetOperationCount(eID)>count E|Z7art  
        GetOperation eID, count, op [u2)kH$  
        If op.Type="ShiftZ" Then },
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            DeleteOperation eID,count }\/f~?tEh  
            count=count-1 *npe]cC  
        End If 7%4@*  
        count=count+1 /I&b5Vp  
    Wend r#[YBaCZJ  
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    'Set new z-shift +,
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    op.Type = "ShiftZ" }~28UXb23  
    op.val1 = tlens >#\&%0OZw  
    op.parent = parID Af"vSL  
    AddOperation eID, op kpN'H_ .  
    Print "Set lens thickness = " & tlens ;i><03  
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    '************************************************************************* ba  
    'Lens index of refraction VCvqiHn  
    '************************************************************************* n`hes_{,g  
    eID = FindMaterial( "Lens" ) (_lc< Bj  
    GetModelMaterial eID, mat kY6))9 O  
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    mat.Nd = nlens =`]yq;(C7j  
    SetModelMaterial eID, mat $wn"+wX  
    Print "Set lens index of refraction = " & nlens Zb7:qe<UN  
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    '************************************************************************* D:HeP:.I  
    'Pupil diameter 'HV}Tr  
    '************************************************************************* 1xo<V5  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) _9Ig`?<>I  
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    'Adjust pupil diameter (trimming volume inner hole) Yg#)@L  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" U)p P^:|  
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    ' Adjust pupil location to just in front of the lens I -obfyije  
    parID = FindFullName( "Geometry.Arizona Eye" ) E 2DTE  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) -3r&O:  
    count = 0 +:d))r=n  
    While GetOperationCount(eID)>count ;
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        GetOperation eID, count, op !m1pL0  
        If op.Type="ShiftZ" Then 4>^ %_Xj[  
            DeleteOperation eID,count @]HV:7<q  
            count=count-1 ";
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        End If viBf".  
        count=count+1 *R>I%?]V3  
    Wend qD4e] 5  
    op.Type = "ShiftZ" 8X]j;Rb  
    op.val1 = taq-0.01 I=^%l7  
    op.parent = parID f(?`PD[  
    AddOperation eID, op GKPqBi[rO  
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    Print "Set pupil diameter = " & pupilDiam ,9"</\]`  
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    'Update AZ Eye subassembly Description DRVvW6s  
    eID = FindFullName( "Geometry.Arizona Eye" ) ,Ql3RO,  
    GetEntity eID, entity Y
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    entity.Description = "Accommodation = " & A & "D" eeb8v:4  
    SetEntity eID, entity *(d^k;  
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    Update m=fmf(  
    Print "DONE!" S-yd-MtQp  
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End Sub $YaL3n  
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如果屈光度是4，光瞳直径是4，则会输出如下数据： ASy7")5  
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Accommodation = 4 Diopters m$hSL4N  
Pupil Diameter = 4 mm M7,|+W/RK  
Set aqueous humor thickness = 2.81 1xq1te)  
Set anterior lens radius = 10.4 and conic constant = -2.375869 ZLKS4  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 wQnr*kyza  
Set lens thickness = 3.927 =4JVUu~Z  
Set lens index of refraction = 1.42672 ?67j+)  
Set pupil diameter = 4 %v~j10e  
DONE! a/^YgrC\T