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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 Xq`|'6]/  
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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。 FHpS?htRy  
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    模型 S;#S3?G  
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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。 7PG&G5  
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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. !yAlb#yu  
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    光源 {E *dDv  
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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。 A:$Qt%c  
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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。 ?+-uF }  
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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。 MY>mP  
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    图2. 字母F光源的设定方法光 r}k2n s9  
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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 wZ7Opm<nt  
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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。  ismx evD  
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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。 ? <b>2j  
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    图5. 视网膜重点采样规格设定
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    脚本 eUP.:(E  
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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: Zpfsh2`  
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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。 d/I,`  
    余下的脚本计算与屈光度有关的所有参数。 3[mVPV  
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    分析 W&E?#=*X  
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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。 a<%Ivqni  
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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 3>60_:+Zb  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. \F`%vZrKR  
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    Dim entity As T_ENTITY zx:Qz  
    Dim op As T_OPERATION h- )tWJ c  
    Dim mat As T_MODELMATERIAL WI@l2`X  
    Dim A As Double v|DgRPY  
    Dim pupilDiam As Double ft |W  
    Dim eID As Long nPlg5&E  
    Dim parID As Long Y3%_IwSJ|  
    Dim count As Integer Jz"Yb  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double IRWVoCc9/\  
    Dim tlens As Double, nlens As Double ?@n, 9!  
    Dim curv As Double, conic As Double b+b].,  
    Dim ok As Long >@Vap  
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    Sub Main F3)w('h9c  
    be^+X[  
        '用户输入对话框 jU~q~e7Te  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 HLYog+?  
            TextBox 220,21,40,21,.TextBox1 'default: 0 {tE9m@[AF  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 _JEe]  
            OKButton 40,91,90,21 _]oNbcbt(  
            CancelButton 190,91,90,21 _x+)Tv  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 B!J~ t8  
            TextBox 220,49,40,21,.TextBox2 'default: 4 X ? eCK,  
        End Dialog iX]tL:,~i  
        Dim dlg As UserDialog $, I%g<  
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        ok = Dialog (dlg) SM? rss.=  
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        If ok=0 Then    'cancel button was pressed 5/w4[d  
            Print "Execution cancelled." (FVHtZi7  
            End KE$I!$zO  
        End If zE,1zBS<  
    TzSEQ S{  
        'Assign accommodation and pupil diameter & use defaults if field left empty &9j*Y  
        If dlg.TextBox1 = "" Then TUy 25E  
            A = 0           'Default accommodation W!Qaa(o?  
        Else pB(|Y]3A  
            A = CDbl(dlg.TextBox1) g"}j  
        End If 8'<RPU}M  
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        If dlg.TextBox2 = "" Then 4:zyZu3fm  
            pupilDiam = 4   'Default pupil diameter !-tP\%'  
        Else Zb&5)&'X  
            pupilDiam = CDbl(dlg.TextBox2) /#Fz K  
        End If UlNx5l+k  
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        Print " " u{J\X$]  
        Print "Accommodation = " & A & " Diopters" f%[0}.wp  
        Print "Pupil Diameter = " & pupilDiam & " mm" }5b,u6  
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        ' Calculate new parameters with accommodation /mK."5-cm  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ~rfUqM]I   
    *8%nbR  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens e'dx Y(  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens } q?*13iy(  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens z km#w  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens G=( ja?d  
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        tlens = 3.767 + 0.04*A                  'Lens thickness 7W.z8>p  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction JTcE{i  
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        'Adjust parameters to account for accommodation N2uTWT>  
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        '************************************************************************* 8+mu'RZ X  
        'Aqueous thickness (Position of Lens) wl N l|+ K  
        '************************************************************************* INNTp[  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) J;5G]$s  
        GetCustomElement eID, entity :"Gd;~p.  
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        parID = FindFullName( "Geometry.Arizona Eye" ) pP)> x*1  
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        ' Delete any shift(s) in z k &6$S9  
        count = 0 =`EVg>+^  
        While GetOperationCount(eID)>count ]N^>>k  
            GetOperation eID, count, op mV;)V8'  
            If op.Type="ShiftZ" Then ' JAcN@q~z  
                DeleteOperation eID,count CyKupJ.Fq  
                count=count-1 N"Cd{3  
            End If lPA:ho/`:  
            count=count+1 zbZN-j#  
        Wend j&l2n2z  
    }>yQ!3/i  
        'Set new shift in ;mauA#vd  
        op.Type = "ShiftZ" 7Um3m yXU  
        op.val1 = taq ;\54(x}|K  
        op.parent = parID S{S.H?{F  
        AddOperation eID, op 1Gp| _8  
        Print "Set aqueous humor thickness = " & taq-0.55 xX~; /e&,  
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        '************************************************************************* f-5}`)`.+  
        'Radius and conic constant of anterior lens AiUK#I  
        '************************************************************************* JPM W|JT  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) js[H $  
        GetConic eID, entity, curv, conic +nKf ^rG  
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        SetConic eID, entity, 1/Rant, CCant @u1mC\G  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ;@/vKA3l.  
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        '************************************************************************* %Hpz^<`  
        'Radius and conic constant of posterior lens 8C4v  
        '************************************************************************* p K hV<MFB  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) NGAjajB  
        GetConic eID, entity, curv, conic - -ZSl  
    %-O[%Dy  
        SetConic eID, entity, 1/Rpost, CCpost G]E-2 _t7  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Uq=!>C8  
    gVN&?`k*?  
        '************************************************************************* +<7a$/L?4  
        'Lens thickness (Position of posterior lens surface) OcZ8:`=%  
        '************************************************************************* K)nn;j=  
    &-(p~[|  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) +7$zL;ph=n  
    Pi'[d7o  
        ' Delete any z-shift(s) D`@*udn=  
        count = 0 ^ jT1q_0  
        While GetOperationCount(eID)>count Wu U_R E  
            GetOperation eID, count, op JAS!eF  
            If op.Type="ShiftZ" Then 0 ChdFf7  
                DeleteOperation eID,count ?T7ndXX  
                count=count-1 YnwP\Arfq  
            End If 95^-ptO{1`  
            count=count+1 -n]E\"  
        Wend Y5\=5r/  
    )kt,E}609  
        'Set new z-shift O_|p{65  
        op.Type = "ShiftZ" nhI1`l&  
        op.val1 = tlens {PQ!o^7y  
        op.parent = parID )jm u*D5N  
        AddOperation eID, op &/{x7;e  
        Print "Set lens thickness = " & tlens hgI;^ia  
    I>%@[h,+  
        '************************************************************************* tN&_f==e  
        'Lens index of refraction FW,@.CX  
        '************************************************************************* ehr,+GX  
        eID = FindMaterial( "Lens" ) {+x;J4  
        GetModelMaterial eID, mat @1tv/W  
    )NCSO b  
        mat.Nd = nlens x[1( cj  
        SetModelMaterial eID, mat 6dQ]=];  
        Print "Set lens index of refraction = " & nlens JB(P-Y#yyA  
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        '************************************************************************* Q??nw^8Hi  
        'Pupil diameter VQ'DNv| 9  
        '************************************************************************* MP%pEUomev  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 2[TssJQ  
    ZY{zFg9  
        'Adjust pupil diameter (trimming volume inner hole) -?PXj)<  
    d ~3G EK  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" c(!8L\69V}  
    }q<%![%  
        ' Adjust pupil location to just in front of the lens # `b5kqQm  
        parID = FindFullName( "Geometry.Arizona Eye" ) 2kQa3Pan  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) q3$;lLsb;j  
        count = 0 7) e#b  
        While GetOperationCount(eID)>count AZ& ]@Ao  
            GetOperation eID, count, op ?R\:6x<  
            If op.Type="ShiftZ" Then u<a =TPAU  
                DeleteOperation eID,count }5a$Ka-  
                count=count-1 [I4&E >  
            End If # vBS7ba  
            count=count+1 KvfZj  
        Wend ,?ci+M)  
        op.Type = "ShiftZ" BHEZ<K[U   
        op.val1 = taq-0.01 b.sRB1  
        op.parent = parID P},d`4Ty@  
        AddOperation eID, op YMTB4|{  
    Ceco^Mw  
        Print "Set pupil diameter = " & pupilDiam _M9-n  
    1pHt3Vc(G  
        'Update AZ Eye subassembly Description K_t! P  
        eID = FindFullName( "Geometry.Arizona Eye" ) _$YT*o@0J  
        GetEntity eID, entity Q ^z&;%q1  
        entity.Description = "Accommodation = " & A & "D" M~#% [?iU  
        SetEntity eID, entity CxW-lU3G`  
    O]N 8Q H  
        Update =x3ZQA  
        Print "DONE!" 9;k!dM  
         SB\T iH/  
    End Sub )Y:9sd8g7  
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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: y&8kORz;?  
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    Accommodation = 4 Diopters x0dO ^D  
    Pupil Diameter = 4 mm b+qdl`V d  
    Set aqueous humor thickness = 2.81 sU }.2k  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 6fr@y=s2:  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 #pm0T1+jW  
    Set lens thickness = 3.927 soi.`xE  
    Set lens index of refraction = 1.42672 {^qp~0  
    Set pupil diameter = 4 N&'05uWY}  
    DONE! f}U@e0Lsb  
     
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