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    [转载]FRED运用:Arizona眼睛模型 [复制链接]

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    只看楼主 倒序阅读 楼主  发表于: 2016-02-24
    简介 p%-;hL!  
    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。 G]T&{3g-.  
    o[aIQ|G  
    模型 U*\ 1d  
    jE!?;} P1  
    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。 V|)nU sU  
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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. ^K0oJg.E  
    4[rX\?^e  
    光源 :'Tq5kE  
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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。 #Yx /ubg6  
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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。 =\g K<Xh  
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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: 03  
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    图2. 字母F光源的设定方法光 s]Z++Lh<{  
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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 3u oIYY  
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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。 3w8v.J8q  
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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。 *~^M_wej  
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    图5. 视网膜重点采样规格设定
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    脚本 lh-zE5;  
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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: :8Ugz~i  
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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。 {i)FDdDGD  
    余下的脚本计算与屈光度有关的所有参数。 Thuwme  
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    分析 +K48c,gt?  
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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。 t]+h.  
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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 Oe&gTXo  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. &,'CHBM  
    ?-=<7 ~$  
    Dim entity As T_ENTITY j=Z;M1  
    Dim op As T_OPERATION w%~Mg3|  
    Dim mat As T_MODELMATERIAL m">2XGCn  
    Dim A As Double j5m]zh5\J=  
    Dim pupilDiam As Double <1E5[9 q  
    Dim eID As Long O[ug7\cl+  
    Dim parID As Long 6f&qtJQ<A  
    Dim count As Integer uM2 .?>`X  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double oA4<AJ2  
    Dim tlens As Double, nlens As Double ),Igu  
    Dim curv As Double, conic As Double *_eY +\j  
    Dim ok As Long 4^k+wQU  
    QoS]QY'bZ  
    Sub Main s[}cj+0  
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        '用户输入对话框 LuWY}ste  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 vpoJ{TPO  
            TextBox 220,21,40,21,.TextBox1 'default: 0 M+WN\.2pX  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 /;`-[   
            OKButton 40,91,90,21  5 c1{[  
            CancelButton 190,91,90,21 `A$zLqz)Vm  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 +,J!xy+~,  
            TextBox 220,49,40,21,.TextBox2 'default: 4 d8VFa'|  
        End Dialog u=ZZ;%Rvd  
        Dim dlg As UserDialog Duq.`XO  
    *P+8^t#Vp  
        ok = Dialog (dlg) h/7_IuD  
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        If ok=0 Then    'cancel button was pressed J+YoAf`hi  
            Print "Execution cancelled." 9.Yn]O  
            End 8\m[Nuq5  
        End If G,XUMZ  
    1Wz5Iv#Ez  
        'Assign accommodation and pupil diameter & use defaults if field left empty 0|FQIhVuY  
        If dlg.TextBox1 = "" Then .}3K9.hkr  
            A = 0           'Default accommodation +{cCKRm  
        Else sLW e \o  
            A = CDbl(dlg.TextBox1) ,<fs+oi  
        End If RT"JAJTi/  
    e4 -7&8N+  
        If dlg.TextBox2 = "" Then yOyuMZo6  
            pupilDiam = 4   'Default pupil diameter fi'\{!!3m^  
        Else :YNXS;>)!  
            pupilDiam = CDbl(dlg.TextBox2) eI+p  
        End If v.Xmrry  
    cTL W}4m%g  
        Print " " :{~TG]4M  
        Print "Accommodation = " & A & " Diopters" /y- 8dgv0a  
        Print "Pupil Diameter = " & pupilDiam & " mm" w s7LDY&(  
    jWh}cM=  
        ' Calculate new parameters with accommodation I1!m;5-c9k  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness K(Ak+&[  
    n(jrK9]  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens ;%4N@Z  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens "@rXN"4  
    }N@+bNh~  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens E 7"`D\*  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ^Dys#^  
    7z3YzQ=Kg  
        tlens = 3.767 + 0.04*A                  'Lens thickness JmbWEX|  
    Kj* $'('  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction -{eI6#z|\A  
    _+. )8   
        'Adjust parameters to account for accommodation J;Veza  
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        '************************************************************************* U46Z~B  
        'Aqueous thickness (Position of Lens) ^zR*s |1Q  
        '************************************************************************* :xsNn55b  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) SaA-Krn  
        GetCustomElement eID, entity *w6(nG'M{  
    Hs(U|BXU  
        parID = FindFullName( "Geometry.Arizona Eye" ) bw OG|\  
    VHx:3G  
        ' Delete any shift(s) in z ^(1S`z$  
        count = 0 w~WW2 w  
        While GetOperationCount(eID)>count ]gDX~]f[  
            GetOperation eID, count, op P#qQde/y  
            If op.Type="ShiftZ" Then  @+!u{  
                DeleteOperation eID,count p-B |Gr|  
                count=count-1 /t_AiM,(  
            End If $WG<  
            count=count+1 3Hkb)Wu  
        Wend Mtq^6`JJ'  
    h|[oQ8)  
        'Set new shift in 01vKx)f  
        op.Type = "ShiftZ" '%[r9 w  
        op.val1 = taq g5~wdhpb  
        op.parent = parID WXCZ }l  
        AddOperation eID, op VU \{<j{  
        Print "Set aqueous humor thickness = " & taq-0.55 Ll0"<G2t  
    swG!O}29OX  
        '************************************************************************* #\gx.2W7  
        'Radius and conic constant of anterior lens gt Rs||  
        '************************************************************************* yIma7H@=L  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) @JpkG%eK  
        GetConic eID, entity, curv, conic R9O1#s^  
    Mt%=z9OLq9  
        SetConic eID, entity, 1/Rant, CCant aYcc2N%C  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant GJn ~x  
    p]J0A ^VV  
        '************************************************************************* E<L6/rG  
        'Radius and conic constant of posterior lens #iP5@:!Wm~  
        '************************************************************************* +X!QH/ 8  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 6Wc'5t3  
        GetConic eID, entity, curv, conic n@y*~sG]  
    7aJ:kumDZ  
        SetConic eID, entity, 1/Rpost, CCpost $Ce;}sM  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost -*~~ 00w  
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        '************************************************************************* l]z=0  
        'Lens thickness (Position of posterior lens surface) = K3NKPUI  
        '************************************************************************* "E%3q3|"l  
    ,_RPy2N  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) zOA2chy4  
    `E-cf7%  
        ' Delete any z-shift(s) X"O^4MnvI  
        count = 0 L~ e{Vv8UR  
        While GetOperationCount(eID)>count Fps:6~gD  
            GetOperation eID, count, op FP9FE `x  
            If op.Type="ShiftZ" Then XcM.<Dn3  
                DeleteOperation eID,count ($[)Tcq*~  
                count=count-1 -9^A,vX  
            End If Ygfv?  
            count=count+1 @&GfCg5Cb  
        Wend MNd[Xzm  
    wv&#lM(  
        'Set new z-shift Eg 8rgiU  
        op.Type = "ShiftZ" OmAa$L,'w  
        op.val1 = tlens lbiMB~rwI  
        op.parent = parID qfsu# R  
        AddOperation eID, op :V^|}C#  
        Print "Set lens thickness = " & tlens kyu PN<?  
    A,]%*kg2  
        '************************************************************************* Z$:iq  
        'Lens index of refraction to#N>VfD  
        '************************************************************************* A7=k 9|  
        eID = FindMaterial( "Lens" ) (?lKedA>2  
        GetModelMaterial eID, mat Vc$y ^|=  
    +'!Y[7|9iv  
        mat.Nd = nlens J:oAzBFpA  
        SetModelMaterial eID, mat OGn-~ #E  
        Print "Set lens index of refraction = " & nlens 22r$Ri_>  
    tLo_lLn*~%  
        '************************************************************************* &AhkP=Yw  
        'Pupil diameter Tb<}GcwJ  
        '************************************************************************* %3mh'Z -[f  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) B):hm  
    c@/K}  
        'Adjust pupil diameter (trimming volume inner hole) SRek:S,  
    `F4gal^ ^  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" !nt[J$.z^  
    g0>Q* x  
        ' Adjust pupil location to just in front of the lens #7|73&u(  
        parID = FindFullName( "Geometry.Arizona Eye" ) feG#*m2g  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) )k6kK}  
        count = 0 ^]ig*oS\`  
        While GetOperationCount(eID)>count se&Q\!&M  
            GetOperation eID, count, op C5x*t Q|  
            If op.Type="ShiftZ" Then ;T*o RS  
                DeleteOperation eID,count `$i/f(t6`  
                count=count-1 sX,S]:X  
            End If "ot# g"  
            count=count+1 >m# bj^F\  
        Wend ^b^}6L'Z  
        op.Type = "ShiftZ" eq,`T;  
        op.val1 = taq-0.01 aKC,{}f$m  
        op.parent = parID %hCd*[Z}j  
        AddOperation eID, op G*%:"qleT$  
    JUd Q Q  
        Print "Set pupil diameter = " & pupilDiam E8"$vl&c]  
    5Sx.'o$  
        'Update AZ Eye subassembly Description 'e:(61_  
        eID = FindFullName( "Geometry.Arizona Eye" ) ?3a:ntX h  
        GetEntity eID, entity /a?qtRw  
        entity.Description = "Accommodation = " & A & "D" YuFR*W;$  
        SetEntity eID, entity SaSj9\o  
    /M Z^;XG  
        Update Q?/qQ}nNw  
        Print "DONE!" "WZ|   
         7mtX/w9  
    End Sub M$UZn  
    a9y+FCA  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: tQ(4UHqa~  
    Nx=rw h  
    Accommodation = 4 Diopters IQeiT[TF  
    Pupil Diameter = 4 mm ppzQh1  
    Set aqueous humor thickness = 2.81 6os{q`/Q])  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 20cEE>  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 r1/9BTPKdJ  
    Set lens thickness = 3.927 hO; XJyv  
    Set lens index of refraction = 1.42672 -mw`f)?Ev  
    Set pupil diameter = 4 R'Uf#.  
    DONE! FwUgMR*xq  
    OxqkpK&  
    (文章来源:讯技光电)
     
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