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infotek 2023-04-27 08:29

Arizona眼睛模型

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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。 "6IZf>N@#  
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模型 _t"[p_llo  
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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。 (Z @dz  
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. 117lhx].'  
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光源 '/XP4B\(E  
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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。 a_/4^+  
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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。 pam9wfP  
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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。 AH/^v;-  
图2. 字母F光源的设定方法光 LCS.C(n,  
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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 'bLP#TAzf  
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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。 f U=P$s  
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图4. 视网膜朗伯散射设定
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注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 t}I@Rmso  
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图5. 视网膜重点采样规格设定
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脚本 H-&27?s^  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: {T^D&i# o  
图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 ;p~!('{P  
余下的脚本计算与屈光度有关的所有参数。 B*}]'  
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分析 .]KC*2  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 ORP<?SG55u  
图7. 字母F在视网膜上颜色分析
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脚本代码 EUI*:JU-  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. "XV@O jr E  
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Dim entity As T_ENTITY *XWu)>*o  
Dim op As T_OPERATION -Wmb M]Z  
Dim mat As T_MODELMATERIAL re%XaL  
Dim A As Double 5Hj/7~ =  
Dim pupilDiam As Double Xl2g Hh  
Dim eID As Long f^QC4hf0  
Dim parID As Long *re?V9  
Dim count As Integer =$bF[3D  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double #E=8kbD7  
Dim tlens As Double, nlens As Double RuVk>(?WK%  
Dim curv As Double, conic As Double 1Zp/EYWa{  
Dim ok As Long GK,{$SC+=  
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Sub Main Z R=[@Oi  
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    '用户输入对话框 |Fze9kZO  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 _~CJitR3  
        TextBox 220,21,40,21,.TextBox1 'default: 0 9&zR i  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 L.;x=w  
        OKButton 40,91,90,21 ;c]O*\/  
        CancelButton 190,91,90,21 r|ZB3L|7  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 !wd wo0  
        TextBox 220,49,40,21,.TextBox2 'default: 4 p`7d9MV^  
    End Dialog Yz[Rl ^  
    Dim dlg As UserDialog &I)tI^P}  
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    ok = Dialog (dlg) lU=VCuW!  
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    If ok=0 Then    'cancel button was pressed `%#_y67v  
        Print "Execution cancelled." OOIp)=4  
        End Rl0"9D87z  
    End If .j,xh )v"  
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    'Assign accommodation and pupil diameter & use defaults if field left empty X#0yOSR  
    If dlg.TextBox1 = "" Then T>1#SWQ/9  
        A = 0           'Default accommodation *]<=04v]R  
    Else tFn[U#'  
        A = CDbl(dlg.TextBox1) gzVZPvTPE  
    End If  Jn|<G  
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    If dlg.TextBox2 = "" Then rmvrv.$3  
        pupilDiam = 4   'Default pupil diameter ^fd*KM  
    Else E>*b,^J7g  
        pupilDiam = CDbl(dlg.TextBox2) `g(#~0R  
    End If _a"| :kX  
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    Print " " B/lIn' =  
    Print "Accommodation = " & A & " Diopters" xA:;wV  
    Print "Pupil Diameter = " & pupilDiam & " mm" @|ZUyat  
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    ' Calculate new parameters with accommodation ,mCf{V]#  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness V#b*:E.cA  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens T$r/XAs  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens B&59c*K  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens *1b0IQ$g  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ? B|i  
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    tlens = 3.767 + 0.04*A                  'Lens thickness XZ$g~r  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Dvz 6 E  
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    'Adjust parameters to account for accommodation :u=y7[I  
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    '************************************************************************* CP"5E?dcK  
    'Aqueous thickness (Position of Lens) MxGQM>  
    '************************************************************************* PPpaH!(D  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) &l{ctP%q  
    GetCustomElement eID, entity Edh9=sxL  
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    parID = FindFullName( "Geometry.Arizona Eye" ) e>!]_B1ad  
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    ' Delete any shift(s) in z Fgwe`[  
    count = 0 x3 Fn'+  
    While GetOperationCount(eID)>count VOATza`  
        GetOperation eID, count, op ' t(#HBU  
        If op.Type="ShiftZ" Then ;Cx`RF w  
            DeleteOperation eID,count R"t2=3K  
            count=count-1 xK1w->[  
        End If &V &beq4)p  
        count=count+1 5>1c4u`x  
    Wend FRPdfo37  
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    'Set new shift in =.m/ X>  
    op.Type = "ShiftZ" k-s|gC4  
    op.val1 = taq oM#+Z qP  
    op.parent = parID  UiK)m:NU  
    AddOperation eID, op 2"Unk\Y  
    Print "Set aqueous humor thickness = " & taq-0.55 9*n?V;E  
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    '************************************************************************* LG("<CU  
    'Radius and conic constant of anterior lens i}<fg*6@E  
    '************************************************************************* Pa|*Jcr  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ZL!5dT&@W  
    GetConic eID, entity, curv, conic rO1N@kd/  
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    SetConic eID, entity, 1/Rant, CCant vf?m6CMU !  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant rF?QI*`Y(  
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    '************************************************************************* Ve"M8-{oKk  
    'Radius and conic constant of posterior lens R >[G6LOG  
    '************************************************************************* q8e]{sT'!  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) [Q8vS;.  
    GetConic eID, entity, curv, conic -"N vu  
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    SetConic eID, entity, 1/Rpost, CCpost 1F2(MKOo!  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost BH$hd|KD<  
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    '************************************************************************* !Xq5r8]  
    'Lens thickness (Position of posterior lens surface) _t X1z ^  
    '************************************************************************* NPE 4@c_a@  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) hx~rq `{  
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    ' Delete any z-shift(s) a63Ud<_a7  
    count = 0 Fl==k  
    While GetOperationCount(eID)>count 1)-VlQK p  
        GetOperation eID, count, op O`>u70  
        If op.Type="ShiftZ" Then X4bZ4U*  
            DeleteOperation eID,count QT"o"B  
            count=count-1 V-dub{K  
        End If ZtI@$ An  
        count=count+1 ~!Rf5QA85  
    Wend &D7Mv5i0@  
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    'Set new z-shift cdL0<J b,  
    op.Type = "ShiftZ" ?Bd6<F -G  
    op.val1 = tlens /E Z -  
    op.parent = parID [&p/7  
    AddOperation eID, op %W2 o`W$  
    Print "Set lens thickness = " & tlens BDi+ *8  
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    '************************************************************************* c8o2* C$  
    'Lens index of refraction kxY9[#:<fB  
    '************************************************************************* lp1GK/!s  
    eID = FindMaterial( "Lens" ) 6ZC~q=my  
    GetModelMaterial eID, mat GRgpy  
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    mat.Nd = nlens .7Itbp6=R  
    SetModelMaterial eID, mat t1o_x}z4.  
    Print "Set lens index of refraction = " & nlens V67<Ky>  
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    '************************************************************************* *.-qbwOg  
    'Pupil diameter 3pkx3tp{  
    '************************************************************************* }~ga86:n0  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) %cq8%RT  
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    'Adjust pupil diameter (trimming volume inner hole) `S]DHxS  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Ec!R3+  
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    ' Adjust pupil location to just in front of the lens B,{Q[  
    parID = FindFullName( "Geometry.Arizona Eye" ) F:G Vysy  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ]ex2c{ G  
    count = 0 kE{-h'xADD  
    While GetOperationCount(eID)>count ;.d{$SO  
        GetOperation eID, count, op g+ cH  
        If op.Type="ShiftZ" Then \'P79=AU  
            DeleteOperation eID,count v-}D>)M^W  
            count=count-1 IOH6h=  
        End If aN"dk-eK  
        count=count+1 E vD g{M}  
    Wend YM +4:P2  
    op.Type = "ShiftZ" Z+S1e~~  
    op.val1 = taq-0.01 t[bZg9;  
    op.parent = parID n'<F'1SWv  
    AddOperation eID, op l]geQl:7`r  
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    Print "Set pupil diameter = " & pupilDiam {9h`h08?z  
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    'Update AZ Eye subassembly Description q>dERN&  
    eID = FindFullName( "Geometry.Arizona Eye" ) }H9V$~}@-  
    GetEntity eID, entity I !g+K  
    entity.Description = "Accommodation = " & A & "D" O['5/:-  
    SetEntity eID, entity zWq&HBs  
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    Update RjG=RfB'V  
    Print "DONE!" e\H1IR3  
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End Sub ne'Y{n(8%  
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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: [kPF Jf  
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Accommodation = 4 Diopters s!j vBy  
Pupil Diameter = 4 mm -f%J_`  
Set aqueous humor thickness = 2.81 Vg8c}>7  
Set anterior lens radius = 10.4 and conic constant = -2.375869 N5@l[F7I  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 690;\O '  
Set lens thickness = 3.927 "5$2b>_UE  
Set lens index of refraction = 1.42672 4*_.m9{  
Set pupil diameter = 4 #s|/5[i  
DONE!
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