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infotek 2020-12-09 09:18

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。 =+/eLKG  
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模型 =@m &s^R  
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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。 :9O#ObFR  
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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. 6 )Hwt_b  
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光源 dq7x3v^"ZG  
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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。 ;'?l$ ._  
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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。 1QqYQafA  
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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。 _p# CwExuy  
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图2. 字母F光源的设定方法光 0)%YNaskj  
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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 -u&6X,Oq\u  
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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。 |M>eEE*F<  
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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。 sSOOXdnGG  
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图5. 视网膜重点采样规格设定
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脚本 9iXeBC  
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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: vbkI^+=,YY  
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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。 cmBB[pk\  
余下的脚本计算与屈光度有关的所有参数。 wi hH?~]  
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分析 'Hc-~l>D  
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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。 xgABpikC^  
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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 N<f"]  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. x HoKo  
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Dim entity As T_ENTITY 7 ]^M>#  
Dim op As T_OPERATION zBo1P(kek  
Dim mat As T_MODELMATERIAL (2$( ?-M  
Dim A As Double C2@,BCR  
Dim pupilDiam As Double e@c0WlWa  
Dim eID As Long Kpb#K[(]&  
Dim parID As Long 4?0vso*X<:  
Dim count As Integer 7Ok;Lt!x  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 0%,!jW{`  
Dim tlens As Double, nlens As Double i\1TOP|h  
Dim curv As Double, conic As Double #rxVd 7f  
Dim ok As Long umD!2 w  
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Sub Main eyefWn&  
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    '用户输入对话框 @[5xq  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 .}'qUPNR  
        TextBox 220,21,40,21,.TextBox1 'default: 0 b}0,\B%  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 VGtC)mG8)  
        OKButton 40,91,90,21 }tsYJlh5  
        CancelButton 190,91,90,21 szsk;a  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 >"gf3rioW  
        TextBox 220,49,40,21,.TextBox2 'default: 4 :{qv~&+C  
    End Dialog j]*j}%hz  
    Dim dlg As UserDialog OC1I&",Ai|  
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    ok = Dialog (dlg) n,=VQ Ou  
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    If ok=0 Then    'cancel button was pressed *\=.<|HZ  
        Print "Execution cancelled." gT$Ju88  
        End f:ZAG4B  
    End If ELBa}h;  
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    'Assign accommodation and pupil diameter & use defaults if field left empty kjEEuEv  
    If dlg.TextBox1 = "" Then g) p,5BADm  
        A = 0           'Default accommodation uvtF_P/  
    Else Y3r%B9~  
        A = CDbl(dlg.TextBox1) ,stN  
    End If Qi_>Mg`x  
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    If dlg.TextBox2 = "" Then Q@ 2i~Qo[  
        pupilDiam = 4   'Default pupil diameter b'J'F;zh>  
    Else  -QOw8vm  
        pupilDiam = CDbl(dlg.TextBox2) ,S'p %g  
    End If \cC%!4  
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    Print " " G"X8}:}  
    Print "Accommodation = " & A & " Diopters" la( <8  
    Print "Pupil Diameter = " & pupilDiam & " mm" =Vy`J)z9  
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    ' Calculate new parameters with accommodation `9)t[7  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness b8LoIY*  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens hGd<<\  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 70f Klp  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens >tO`r.5u9  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens bhkUKxd  
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    tlens = 3.767 + 0.04*A                  'Lens thickness w4W_iaU  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction x%+aKZ(m)  
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    'Adjust parameters to account for accommodation 58%#DX34M  
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    '************************************************************************* %CS@g.H=_  
    'Aqueous thickness (Position of Lens) Zm=(+ f  
    '************************************************************************* OR}c)|1  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 356>QW'm  
    GetCustomElement eID, entity {]E+~%Va  
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    parID = FindFullName( "Geometry.Arizona Eye" ) N@O8\oQG  
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    ' Delete any shift(s) in z 1AG=%F|.  
    count = 0 pY_s*0_  
    While GetOperationCount(eID)>count *Ho/ZYj3  
        GetOperation eID, count, op |tv"B@`  
        If op.Type="ShiftZ" Then R,9[hNHWGs  
            DeleteOperation eID,count iXj o[Rz^C  
            count=count-1 6U[4%(  
        End If ([-|}  
        count=count+1 Pcu#lWC$  
    Wend TjQvAkT  
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    'Set new shift in <$F\Nk|x  
    op.Type = "ShiftZ" nBHnkbKoy  
    op.val1 = taq 'XzXZJ[uq  
    op.parent = parID L=q+|j1>  
    AddOperation eID, op 6oLwfTy  
    Print "Set aqueous humor thickness = " & taq-0.55 ]u4Hk?j~<  
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    '************************************************************************* ;9~6_@,@o  
    'Radius and conic constant of anterior lens  .&9 i  
    '************************************************************************* PH> b-n  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) '@jXbN  
    GetConic eID, entity, curv, conic %{/%mJoX  
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    SetConic eID, entity, 1/Rant, CCant Y$Q|J4z  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant O~59FuL  
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    '************************************************************************* U5-@2YcH  
    'Radius and conic constant of posterior lens i&vaeP25)  
    '************************************************************************* ynw5-aS3  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) lY{FSGp  
    GetConic eID, entity, curv, conic 8F:e|\SB#  
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    SetConic eID, entity, 1/Rpost, CCpost H|ER  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost jS+AGE?5e  
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    '************************************************************************* j'aHF#_  
    'Lens thickness (Position of posterior lens surface) a)S+8uU  
    '************************************************************************* oyNSh8c7c  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) &Ch#-CUE/  
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    ' Delete any z-shift(s) /Nr*`l  
    count = 0 Pt&(npjN,  
    While GetOperationCount(eID)>count ZR$'u%+g'  
        GetOperation eID, count, op Gg~QAsks   
        If op.Type="ShiftZ" Then #7ov#_2Jd  
            DeleteOperation eID,count j:,NE(DF  
            count=count-1 CBDG./  
        End If u{FDdR9<  
        count=count+1 +<}0|Xl&  
    Wend FJ %  
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    'Set new z-shift "Vr[4&`  
    op.Type = "ShiftZ" KAsS [  
    op.val1 = tlens {q<03d~9|G  
    op.parent = parID ,(.MmP`  
    AddOperation eID, op <L{(Mj%Z  
    Print "Set lens thickness = " & tlens Iw<jT|y)  
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    '************************************************************************* lip[n;Ir>  
    'Lens index of refraction Q2A7mGN  
    '************************************************************************* h.!}3\Y  
    eID = FindMaterial( "Lens" ) u(OW gbA3  
    GetModelMaterial eID, mat A<6%r7&B'  
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    mat.Nd = nlens r}0\}~'?c  
    SetModelMaterial eID, mat "Tm[t?FMbe  
    Print "Set lens index of refraction = " & nlens ,R$u?c0>'&  
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    '************************************************************************* 7T"XPV|W6  
    'Pupil diameter / }Rz=&  
    '************************************************************************* Cn>ADWpT&  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) aA'|Rg,  
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    'Adjust pupil diameter (trimming volume inner hole) u7xDau(c  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" "+zCS|   
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    ' Adjust pupil location to just in front of the lens \`ZW* EtPI  
    parID = FindFullName( "Geometry.Arizona Eye" ) YPzU-:3  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) .i^7|o:  
    count = 0 1yV: qp  
    While GetOperationCount(eID)>count U`o^mtW.  
        GetOperation eID, count, op (;%|-{7e-  
        If op.Type="ShiftZ" Then A/7X9ir  
            DeleteOperation eID,count h(qQsxIOhS  
            count=count-1 x Au/  
        End If *xE,sj+(  
        count=count+1 lpRR&  
    Wend 5@hNnh16  
    op.Type = "ShiftZ" or k=`};  
    op.val1 = taq-0.01 |ou b!fG4  
    op.parent = parID [xh*"wT#g  
    AddOperation eID, op k<RZKwQc  
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    Print "Set pupil diameter = " & pupilDiam cpt<WK}  
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    'Update AZ Eye subassembly Description ( Y+N@d  
    eID = FindFullName( "Geometry.Arizona Eye" ) |v[Rp=?]  
    GetEntity eID, entity : L_BG)dM  
    entity.Description = "Accommodation = " & A & "D" _/S?#   
    SetEntity eID, entity 3+J0!FVla  
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    Update -`f04_@>d  
    Print "DONE!" ]#/4Y_d  
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End Sub kAM1TWbaVQ  
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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: 9s}Kl($  
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Accommodation = 4 Diopters s4%(>Q  
Pupil Diameter = 4 mm W$qd/'%  
Set aqueous humor thickness = 2.81 {B*W\[ns  
Set anterior lens radius = 10.4 and conic constant = -2.375869 ^v9|%^ug  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 Omi^>c4G  
Set lens thickness = 3.927 FuX 8v  
Set lens index of refraction = 1.42672 xsjO)))f  
Set pupil diameter = 4 J ti(b*~  
DONE! PuxK?bwC  
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