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    [技术]Arizona眼睛模型 [复制链接]

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    离线infotek
     
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    只看楼主 倒序阅读 楼主  发表于: 2021-10-22
    简介 kUx&pYv  
    :K82sCy%5  
    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。 )2q~u%9n  
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    模型 ?rX]x8iP  
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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。 RPnRVJ&"Z  
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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. {%v-(  
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    光源 f ).1]~  
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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。 e(F42;$$  
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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。 O#EV5FeF.  
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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。 Fk;o E'"D  
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    图2. 字母F光源的设定方法光 fEE /-}d  
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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 Hy"x  
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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。 kU-t7'?4  
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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。 /y7M lU9  
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    图5. 视网膜重点采样规格设定
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    脚本 e^YHJ>@  
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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: Uawpfgc}  
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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。 LLWB  
    余下的脚本计算与屈光度有关的所有参数。 H xV#WoYKj  
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    分析 X7UuwIIP  
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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。 Fhz*&JC#  
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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 6<,dRn  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. -"Y{$/B  
    Ko&hj XHx  
    Dim entity As T_ENTITY I]Tsz'T!9  
    Dim op As T_OPERATION ?.c;oS|  
    Dim mat As T_MODELMATERIAL WD;Y~|  
    Dim A As Double @''GPL@  
    Dim pupilDiam As Double t&5%?QyM  
    Dim eID As Long Sx:Ur>?hd5  
    Dim parID As Long Nfe>3uQK  
    Dim count As Integer SYeadsvF  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 2>-S-;i  
    Dim tlens As Double, nlens As Double D47R  
    Dim curv As Double, conic As Double "x941 }  
    Dim ok As Long N$Y" c*  
    P X;Ed*y  
    Sub Main 2Nxm@B` {  
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        '用户输入对话框 1iL 'V-y  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 [U#72+K  
            TextBox 220,21,40,21,.TextBox1 'default: 0 ,y9iKkg  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 -16K7yk  
            OKButton 40,91,90,21 P^MOx4  
            CancelButton 190,91,90,21 H* ,,^  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 OI} &m^IOo  
            TextBox 220,49,40,21,.TextBox2 'default: 4 Tj~IaU  
        End Dialog ;v17K  
        Dim dlg As UserDialog Obw?_@X  
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        ok = Dialog (dlg) bW#@OrsS  
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        If ok=0 Then    'cancel button was pressed ?Y:x[pOe  
            Print "Execution cancelled." 5#3W5z  
            End zPEg  
        End If PqNFyQkl  
    0Iud$Lu  
        'Assign accommodation and pupil diameter & use defaults if field left empty m`4R]L]  
        If dlg.TextBox1 = "" Then x# ~ x;)  
            A = 0           'Default accommodation 3:"]Rn([P  
        Else 3$vRW.c\q  
            A = CDbl(dlg.TextBox1) \ JG8KE=j  
        End If P+MA*:  
    m6eZ_ &+u  
        If dlg.TextBox2 = "" Then %2'A pp  
            pupilDiam = 4   'Default pupil diameter >$gG/WD?KR  
        Else 6#}93Dgv4  
            pupilDiam = CDbl(dlg.TextBox2) c8)/:xxl  
        End If >Sa*`q3J  
    W$JebW<z(  
        Print " " `<^VR[Mx  
        Print "Accommodation = " & A & " Diopters" $&|y<Y=  
        Print "Pupil Diameter = " & pupilDiam & " mm" oRN-xng  
    }MR1^  
        ' Calculate new parameters with accommodation C\_zdADUb%  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness a m-b!l!q^  
    gADmN8G=  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens H@X oqgI  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens U(&oj e  
    N-lGa@ j  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens EG'[`<*h  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ~5ZvOX6L2  
    Xf =XBoN|  
        tlens = 3.767 + 0.04*A                  'Lens thickness W$dn_9W  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 4vK8kkW1  
    E}CiQUx  
        'Adjust parameters to account for accommodation E< 4l#Z<  
    Xqp|VbDca  
        '************************************************************************* >idBS  
        'Aqueous thickness (Position of Lens) ;vhyhP.oM  
        '************************************************************************* wI M{pK  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) RO\gax  
        GetCustomElement eID, entity L+B?~_*  
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        parID = FindFullName( "Geometry.Arizona Eye" ) d "BW/%m|g  
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        ' Delete any shift(s) in z 0)YbI!  
        count = 0 v8>v.}y  
        While GetOperationCount(eID)>count fQWIw  
            GetOperation eID, count, op ]u-SL md  
            If op.Type="ShiftZ" Then F0~k1TDw  
                DeleteOperation eID,count vv6$>SU  
                count=count-1 RhF>T&Q  
            End If K*K1(_x=  
            count=count+1 39 e;  
        Wend \^+ILYO:$  
    \8uo{#cL8  
        'Set new shift in > 1L=,M  
        op.Type = "ShiftZ" '2J0>Bla  
        op.val1 = taq XA0 (f*  
        op.parent = parID JL}\*  
        AddOperation eID, op rgIrr5  
        Print "Set aqueous humor thickness = " & taq-0.55 2J;`m_oP  
    \a "Ct'  
        '************************************************************************* { PlK@#UN  
        'Radius and conic constant of anterior lens (A k\Lm  
        '************************************************************************* [~5p>'  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) KYJ1}5n  
        GetConic eID, entity, curv, conic b yg0.+e0  
    {TSY|D2  
        SetConic eID, entity, 1/Rant, CCant k>4qkigjc  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant <Pqv;WI|R  
    !.-tW7   
        '************************************************************************* rt]S\  
        'Radius and conic constant of posterior lens iY[+Ywh  
        '************************************************************************* : 2V^K&2L  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) I"L;L?\S  
        GetConic eID, entity, curv, conic B,$l4m4  
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        SetConic eID, entity, 1/Rpost, CCpost Z{-Lc68  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost )\/ =M*  
    hPm>tV2X  
        '************************************************************************* z,;;=V6j  
        'Lens thickness (Position of posterior lens surface) 3{raKM6F  
        '************************************************************************* 33l>{(y  
    hi{%pi&!T  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ! U0z"  
    e]+OO g&  
        ' Delete any z-shift(s) 3EFD%9n  
        count = 0 )9"oL!2h  
        While GetOperationCount(eID)>count 8``;0}'PC  
            GetOperation eID, count, op S[M4ukYK  
            If op.Type="ShiftZ" Then u.|~   
                DeleteOperation eID,count UP1?5Q=H]Q  
                count=count-1 d<p2/aA  
            End If Y8s;w!/  
            count=count+1 rp! LP#*  
        Wend s}x>J8hK  
    bPD)D'Hs  
        'Set new z-shift IxSV?k   
        op.Type = "ShiftZ" hAR? t5c  
        op.val1 = tlens ZwI 1* f  
        op.parent = parID GrEs1M1]*  
        AddOperation eID, op To"dG& h  
        Print "Set lens thickness = " & tlens g9tu %cIkR  
    QezSJ io  
        '************************************************************************* wJ"ev.A)  
        'Lens index of refraction *DeTqO65  
        '************************************************************************* oVkq2  
        eID = FindMaterial( "Lens" ) uF(k[[qaiN  
        GetModelMaterial eID, mat ,4F,:w  
    uZjI?Z.A  
        mat.Nd = nlens Z_z#QX>=D  
        SetModelMaterial eID, mat 0A$SYF$O+[  
        Print "Set lens index of refraction = " & nlens B+VuUt{S  
    z MdC  
        '************************************************************************* 60B-ay0e$b  
        'Pupil diameter mMw;0/n  
        '************************************************************************* 97~K!'/^+y  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) +H'\3^C-  
    a<Uqyilm  
        'Adjust pupil diameter (trimming volume inner hole) Q}vbm4)[  
    83;IyvbL  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" s"#]L44N  
    /0==pLa4  
        ' Adjust pupil location to just in front of the lens QXQ  
        parID = FindFullName( "Geometry.Arizona Eye" ) |O (G nsZ  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Vewzo1G2  
        count = 0 =MSu3<y,  
        While GetOperationCount(eID)>count R2^iSl%pj  
            GetOperation eID, count, op 7kz-V.  
            If op.Type="ShiftZ" Then LHi6:G"Y(  
                DeleteOperation eID,count P^IY: -s  
                count=count-1 981!2*  
            End If )SiY(8y  
            count=count+1 {+=i?  
        Wend $L{7%]7QC  
        op.Type = "ShiftZ" 7:o+iP46  
        op.val1 = taq-0.01 f=ib9WbR#  
        op.parent = parID Dd/}Ya(Gi  
        AddOperation eID, op 7%CIt?Z%  
    zqGYOm$r  
        Print "Set pupil diameter = " & pupilDiam oh&Y< d0  
    L>nO:`>h  
        'Update AZ Eye subassembly Description D@hmO]5c  
        eID = FindFullName( "Geometry.Arizona Eye" ) JuJ5qIal  
        GetEntity eID, entity V\zsDP  
        entity.Description = "Accommodation = " & A & "D"  U42\.V0  
        SetEntity eID, entity .BL:h&h|y  
    O,9X8$5H-a  
        Update E^syrEz  
        Print "DONE!" C4_t_N  
         */U$sZQ)  
    End Sub s^PmnFR  
    @3 "DBJ  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: (46U|P(v  
    s1=u{ET  
    Accommodation = 4 Diopters +{ab1))/  
    Pupil Diameter = 4 mm ^ wQcB  
    Set aqueous humor thickness = 2.81 r}@< K  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 [+DNM 2A  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 GTFl}t  
    Set lens thickness = 3.927 0*{p Oe/u  
    Set lens index of refraction = 1.42672 >@Khm"/T  
    Set pupil diameter = 4 bX{PSjD  
    DONE! a}D&$yz2  
     
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