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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。 \|v`l{  
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模型 f_oq1W)9  
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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。 %_>Tcm=  
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.  ,Qat  
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光源 6 4?Pfir6  
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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。 q5%2WM]6  
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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。 +-U@0&Y3M  
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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。 =D{B}=D\IM  
图2. 字母F光源的设定方法光 l(gJLjTH%  
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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 b9`iZ  
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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。 Gv;;!sZ  
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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。 yE}BfU {.  
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图5. 视网膜重点采样规格设定
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脚本 ?<! nm&~  
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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: u %'y_C3  
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。 !5&%\NSv  
余下的脚本计算与屈光度有关的所有参数。 EA6t36|TX  
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分析 _AprkI_  
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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。 RE 9nU%!  
图7. 字母F在视网膜上颜色分析
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脚本代码 Qo.Uqz.C  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. Lbsr_*4t  
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Dim entity As T_ENTITY BMpF02Y|4  
Dim op As T_OPERATION )%qtE34`  
Dim mat As T_MODELMATERIAL U-eI\Lu  
Dim A As Double 9s(i`RTM  
Dim pupilDiam As Double .1LPlZ  
Dim eID As Long Y87XLvig}  
Dim parID As Long 0vn[a,W<A  
Dim count As Integer MQJ%He"  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double >ukQ, CE~  
Dim tlens As Double, nlens As Double e=7W 7^"_  
Dim curv As Double, conic As Double ' l|R5   
Dim ok As Long =-Nsc1&  
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Sub Main lufeieW  
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    '用户输入对话框 1A^1@^{m'  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 c" +zgP  
        TextBox 220,21,40,21,.TextBox1 'default: 0 E M Q4yK  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 {]`p&@  
        OKButton 40,91,90,21 m6i%DE  
        CancelButton 190,91,90,21 R*bmu  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 H2U:@.o2&  
        TextBox 220,49,40,21,.TextBox2 'default: 4 %'0&ElQ  
    End Dialog qp&4 1  
    Dim dlg As UserDialog P6YQK+  
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    ok = Dialog (dlg) k;Hnu  
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    If ok=0 Then    'cancel button was pressed ,Kw5Ro`I:  
        Print "Execution cancelled." .,M;huRg  
        End Y@%`ZPJ  
    End If K &dT(U  
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    'Assign accommodation and pupil diameter & use defaults if field left empty *ik/p  
    If dlg.TextBox1 = "" Then ,{8v4b-  
        A = 0           'Default accommodation 5un^yRMB-  
    Else c`jDW S  
        A = CDbl(dlg.TextBox1) :u/mTZDi  
    End If b#a@ rh  
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    If dlg.TextBox2 = "" Then `Wn Q   
        pupilDiam = 4   'Default pupil diameter .6m_>Y6  
    Else oH X$k{6  
        pupilDiam = CDbl(dlg.TextBox2) ,E}$[mHyjz  
    End If J +q|$K6  
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    Print " " R ]P;sk5  
    Print "Accommodation = " & A & " Diopters" ]?&FOzN5$P  
    Print "Pupil Diameter = " & pupilDiam & " mm" 6Dst;:  
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    ' Calculate new parameters with accommodation %K1")s  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness !` 26\@1  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ,2,5Odrz  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 9/kXc4  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 1'O0`Me>#  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens  g_q<ze  
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    tlens = 3.767 + 0.04*A                  'Lens thickness $Q/Ya@o  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction h}&b+ 1{X  
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    'Adjust parameters to account for accommodation t&}6;z 3  
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    '************************************************************************* XYfv(y  
    'Aqueous thickness (Position of Lens) 61@EDIYPc  
    '************************************************************************* +S9PML){h  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) &&7r+.Y  
    GetCustomElement eID, entity FS@A8Bb  
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    parID = FindFullName( "Geometry.Arizona Eye" ) [BDGR B7d"  
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    ' Delete any shift(s) in z &leK}je [  
    count = 0 Yc;ec9~  
    While GetOperationCount(eID)>count NXU`wnVJ  
        GetOperation eID, count, op d,9`<1{9  
        If op.Type="ShiftZ" Then >EP(~G3u  
            DeleteOperation eID,count |B^G:7c  
            count=count-1  &`Ck  
        End If HOZRYIQB  
        count=count+1 6rX_-Mm6w  
    Wend Jpj!rXTX*  
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    'Set new shift in n]N96oD  
    op.Type = "ShiftZ" 0LL c 1t>}  
    op.val1 = taq YZE.@Rz  
    op.parent = parID H{(]9{  
    AddOperation eID, op nE|@IGH  
    Print "Set aqueous humor thickness = " & taq-0.55 ^gYD*K!*  
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    '************************************************************************* ?c#$dc"  
    'Radius and conic constant of anterior lens z`U Ukl}T  
    '************************************************************************* Qe$k3!  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Q@QFV~  
    GetConic eID, entity, curv, conic A3{0q>CC  
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    SetConic eID, entity, 1/Rant, CCant Q+$Tt7/  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Y(6Sp'0  
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    '************************************************************************* 23ze/;6%A  
    'Radius and conic constant of posterior lens H0*,8i5I  
    '************************************************************************* ,k0r  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) kB P*K  
    GetConic eID, entity, curv, conic )qU7`0'8  
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    SetConic eID, entity, 1/Rpost, CCpost vqNsZ 8|`  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Y+-xvx :  
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    '************************************************************************* csQfic  
    'Lens thickness (Position of posterior lens surface) LE=k  
    '************************************************************************* %[QV,fD'E  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) XbXA+ey6  
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    ' Delete any z-shift(s) d- E4~)Qy  
    count = 0 L;6.r3bL  
    While GetOperationCount(eID)>count 2eP ;[o  
        GetOperation eID, count, op }5 9U}@xC  
        If op.Type="ShiftZ" Then -yx/7B5@  
            DeleteOperation eID,count \nvAa_,  
            count=count-1 =zg:aTMti  
        End If E~hzh /,34  
        count=count+1 53OJ-m%a  
    Wend }_OM$nzj  
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    'Set new z-shift H-5<S@8  
    op.Type = "ShiftZ" oFC)  
    op.val1 = tlens USPTpjt8R  
    op.parent = parID >cR)?P/o  
    AddOperation eID, op ,?-\ x6  
    Print "Set lens thickness = " & tlens k9si| '  
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    '************************************************************************* tj1JB%  
    'Lens index of refraction Q(@IK&v  
    '************************************************************************* 9w4sSj`  
    eID = FindMaterial( "Lens" ) -_^c6!i  
    GetModelMaterial eID, mat ;</Lf=+Vm  
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    mat.Nd = nlens u<tk G B  
    SetModelMaterial eID, mat `NNf&y)y  
    Print "Set lens index of refraction = " & nlens sd0r'jb  
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    '************************************************************************* EeQ5vqU  
    'Pupil diameter Rm>^tu -  
    '************************************************************************* +8P,s[0<R_  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) WE!vSZ3R  
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    'Adjust pupil diameter (trimming volume inner hole) &xS a7FY  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" =tdSq"jh  
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    ' Adjust pupil location to just in front of the lens zY9 H%  
    parID = FindFullName( "Geometry.Arizona Eye" ) 15H6:_+=0  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) L2z2}U=<  
    count = 0 t}p@:'  
    While GetOperationCount(eID)>count +C{p%`<  
        GetOperation eID, count, op 6LUC!Sh  
        If op.Type="ShiftZ" Then `sHuM*  
            DeleteOperation eID,count r0dDHj~F  
            count=count-1 ^HA %q8| n  
        End If ?pGkk=,KB  
        count=count+1 \F6LZZ2Lv  
    Wend '\DSTr:N  
    op.Type = "ShiftZ" H#d:kilNy  
    op.val1 = taq-0.01 d5j_6X  
    op.parent = parID O}ejWP8>  
    AddOperation eID, op Jobiq]|>  
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    Print "Set pupil diameter = " & pupilDiam Xa 9TS"  
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    'Update AZ Eye subassembly Description Es5p}uh.[Y  
    eID = FindFullName( "Geometry.Arizona Eye" ) ]`=X'fED  
    GetEntity eID, entity j ) vlM+  
    entity.Description = "Accommodation = " & A & "D" ZU&"73   
    SetEntity eID, entity tykB.2f  
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    Update E@)\Lc~  
    Print "DONE!" 3K0tC=  
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End Sub IO$z%r7  
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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: hsLzj\)6  
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Accommodation = 4 Diopters #VbVs l  
Pupil Diameter = 4 mm 2ef;NC.&n  
Set aqueous humor thickness = 2.81 ,d,\-x-+/  
Set anterior lens radius = 10.4 and conic constant = -2.375869 Y}R}-+bD/  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 LJzH"K[Gg6  
Set lens thickness = 3.927 gQWd&)'muf  
Set lens index of refraction = 1.42672 2(YPz|~W  
Set pupil diameter = 4 vR7HF*8  
DONE!
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