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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。 kC0!`$<2f)  
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模型 M<)2  
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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。 8z CAy@u  
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. w(j9[  
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光源 agYK aM1N  
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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。 yjq )}y,tF  
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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。 4.'EEuRw\}  
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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。 ,&=`T 7i  
图2. 字母F光源的设定方法光 bwJi[xF  
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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 )9r%% #  
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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。 h+UscdU l  
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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。 zq.&Mw?  
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图5. 视网膜重点采样规格设定
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脚本 aA`q!s.%A  
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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: Y14R"*t~  
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。 nY9qYFw  
余下的脚本计算与屈光度有关的所有参数。 :dN35Y]a  
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分析 j/D)UWkR  
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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。 ^Nw]'e3  
图7. 字母F在视网膜上颜色分析
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脚本代码 rR@n> Xx  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. @/~k8M/  
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Dim entity As T_ENTITY i\;&CzC:  
Dim op As T_OPERATION `^L<db^A  
Dim mat As T_MODELMATERIAL 6 ]PM!6  
Dim A As Double 3:joSQa  
Dim pupilDiam As Double {(}w4.!  
Dim eID As Long MLBg_<  
Dim parID As Long mN{ajf)@  
Dim count As Integer _qt;{,t  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double `B\KS*Gya#  
Dim tlens As Double, nlens As Double = 6<w'>  
Dim curv As Double, conic As Double T[h}A"yK;  
Dim ok As Long R}wwC[{  
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Sub Main k;fnC+Y$s  
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    '用户输入对话框 O3C)N I\i  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 j+13H+dN  
        TextBox 220,21,40,21,.TextBox1 'default: 0 }8V;s-1  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 I "Q9W|J_&  
        OKButton 40,91,90,21 *T>#zR{  
        CancelButton 190,91,90,21 {`K]sa7`  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Gp ^ owr  
        TextBox 220,49,40,21,.TextBox2 'default: 4 /[|}rqX(  
    End Dialog }`9fZK{. @  
    Dim dlg As UserDialog ;%rs{XO9  
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    ok = Dialog (dlg) ZU| V+yT  
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    If ok=0 Then    'cancel button was pressed 1!;"bHpk  
        Print "Execution cancelled." R5NRCI  
        End C*{15!d:G  
    End If +%e%UF@  
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    'Assign accommodation and pupil diameter & use defaults if field left empty _yxe2[TD  
    If dlg.TextBox1 = "" Then n^JUZ8  
        A = 0           'Default accommodation 0l(E!d8&'  
    Else ]m/@wW9  
        A = CDbl(dlg.TextBox1) \2gvp6  
    End If G {pP}  
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    If dlg.TextBox2 = "" Then ZM-/n>  
        pupilDiam = 4   'Default pupil diameter [al(>Wr9  
    Else =0s`4Y"+  
        pupilDiam = CDbl(dlg.TextBox2) %qNj{<&  
    End If F;?TR[4!k  
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    Print " " 2[8fFo>  
    Print "Accommodation = " & A & " Diopters" ,<;l"v(  
    Print "Pupil Diameter = " & pupilDiam & " mm"  +eDN,iv  
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    ' Calculate new parameters with accommodation {hs2?#p  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Ypn%[sSOp  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens >%n8W>^^4  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens u:AfHZ  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens [Q7->Wo|S:  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens Eo7 _v  
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    tlens = 3.767 + 0.04*A                  'Lens thickness r6 oX6.c  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Q QsVIHA  
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    'Adjust parameters to account for accommodation nJldz;  
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    '************************************************************************* .^[fG59  
    'Aqueous thickness (Position of Lens) Pg*?[^*  
    '************************************************************************* a2c x  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) nu469  
    GetCustomElement eID, entity XI%RneuDr:  
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    parID = FindFullName( "Geometry.Arizona Eye" ) m{:"1]  
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    ' Delete any shift(s) in z ~4MtDf  
    count = 0 (B>yaM#5  
    While GetOperationCount(eID)>count dl*_ m3T  
        GetOperation eID, count, op ]/aRc=Gn  
        If op.Type="ShiftZ" Then VL_)]LR*)  
            DeleteOperation eID,count e/]O<,*  
            count=count-1 WX%h4)z*  
        End If Eonq'Re$  
        count=count+1 wq:b j=j  
    Wend rt5oRf:wY  
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    'Set new shift in F9m2C'U  
    op.Type = "ShiftZ" [<en1  
    op.val1 = taq _9Dn \=g  
    op.parent = parID Ek"YM[  
    AddOperation eID, op ~=`f]IL  
    Print "Set aqueous humor thickness = " & taq-0.55 =gMaaGg p,  
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    '************************************************************************* cwH,l$  
    'Radius and conic constant of anterior lens FX7Cjo#=R  
    '************************************************************************* 'sm[CNzS  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) %-@'CNP  
    GetConic eID, entity, curv, conic ax-=n(   
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    SetConic eID, entity, 1/Rant, CCant +L`V[;  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant SjZd0H0  
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    '************************************************************************* bh=\  
    'Radius and conic constant of posterior lens (A7T}znG  
    '************************************************************************* a6;gBoV  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ]}nu9z<  
    GetConic eID, entity, curv, conic L/qZ ;{  
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    SetConic eID, entity, 1/Rpost, CCpost r:fwrC  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Nb gp_:{  
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    '************************************************************************* 2"T8^r|U  
    'Lens thickness (Position of posterior lens surface) S9OxI$6Y  
    '************************************************************************* 3M}AxE u  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) /'-:=0a  
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    ' Delete any z-shift(s) 1k!D0f3qb  
    count = 0 y\[L?Rmd  
    While GetOperationCount(eID)>count mcvDxjk,h  
        GetOperation eID, count, op NY~ dM\  
        If op.Type="ShiftZ" Then ! a86iHU  
            DeleteOperation eID,count l9]o\JFXk  
            count=count-1 YH6snC$u  
        End If aF D="Zh  
        count=count+1 a^@+%?X  
    Wend c eqFQ  
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    'Set new z-shift  =Ov9Kf  
    op.Type = "ShiftZ" ^it4z gx@  
    op.val1 = tlens 'g. :MQ8  
    op.parent = parID Bfbl#ZkyL  
    AddOperation eID, op g;$E1U=R-E  
    Print "Set lens thickness = " & tlens q A.+U:I8  
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    '************************************************************************* )URwIe{  
    'Lens index of refraction i:g{{Uuv  
    '************************************************************************* 1UC2zM"  
    eID = FindMaterial( "Lens" ) C#Y,r)l  
    GetModelMaterial eID, mat D[V`^CTu  
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    mat.Nd = nlens <inl{CX/  
    SetModelMaterial eID, mat LOe4c0C6Ca  
    Print "Set lens index of refraction = " & nlens :RPVT,O}  
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    '************************************************************************* $Xf~# uH  
    'Pupil diameter N[>:@h  
    '************************************************************************* ggMUdlU  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) i"/r)>"b  
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    'Adjust pupil diameter (trimming volume inner hole) AD(xaQ&T  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" fH&zR#T7U4  
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    ' Adjust pupil location to just in front of the lens S45'j(S=  
    parID = FindFullName( "Geometry.Arizona Eye" ) /({P1ti:C  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) sbzeY 1  
    count = 0 JW-|<CJ  
    While GetOperationCount(eID)>count #&k8TY  
        GetOperation eID, count, op ?b5H 2 W  
        If op.Type="ShiftZ" Then FWIih5 3`  
            DeleteOperation eID,count /=bSt  
            count=count-1 AYt*'Zeg!s  
        End If O(odNQy~  
        count=count+1 " l.!Ed  
    Wend /GyEVCc  
    op.Type = "ShiftZ" .6LS+[  
    op.val1 = taq-0.01 ^mAJ[^%  
    op.parent = parID )q^(T1  
    AddOperation eID, op STw oYn  
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    Print "Set pupil diameter = " & pupilDiam 1p~5h(jI  
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    'Update AZ Eye subassembly Description jBS'g{y-!  
    eID = FindFullName( "Geometry.Arizona Eye" ) <H!O:Mf_p  
    GetEntity eID, entity f:S}h-AL&  
    entity.Description = "Accommodation = " & A & "D" 1PmX." a  
    SetEntity eID, entity ;>5,  
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    Update gbJG`zC>U  
    Print "DONE!" Y!F!@`%G  
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End Sub 'g2vX&=$A  
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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: L(;.n>/  
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Accommodation = 4 Diopters X`D+jiQ(f  
Pupil Diameter = 4 mm (NPxab8e*  
Set aqueous humor thickness = 2.81 !KAsvF,j  
Set anterior lens radius = 10.4 and conic constant = -2.375869 3Mur*tj#  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 G#|Hu;C6"  
Set lens thickness = 3.927 RU7!U mf  
Set lens index of refraction = 1.42672 J,9%%S8/C  
Set pupil diameter = 4 vsc&Ju%k  
DONE!
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