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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 >0I\w$L  
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    人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 `,)%<}  
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    模型 idNg&'   
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    模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 90!67Ap`x  
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    Table 1. AZ眼睛模型的定义
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    在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. 7DIFJJE'  
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    光源 =xM:8 hm  
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    多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 8Oo16LPD  
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    图1. 光源和提示信息使用
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    除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 dU#} Tk  
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    在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 w~WW2 w  
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    图2. 字母F光源的设定方法光 "ac$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 cGS7s 8U  
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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。 z460a[Wl  
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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。 oVeC@[U  
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    图5. 视网膜重点采样规格设定
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    脚本 Vi<F@ji  
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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: i" >kF@]c8  
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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。 a,KqTQB  
    余下的脚本计算与屈光度有关的所有参数。 {[[/*1r|  
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    分析 8U7X/L  
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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。 h"On9  
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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@y*~sG]  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. $Ce;}sM  
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    Dim entity As T_ENTITY "i~~Q'=7  
    Dim op As T_OPERATION uui3jZ:  
    Dim mat As T_MODELMATERIAL = K3NKPUI  
    Dim A As Double "E%3q3|"l  
    Dim pupilDiam As Double _vr;cjMI  
    Dim eID As Long 7r wNjY#  
    Dim parID As Long NLF6O9  
    Dim count As Integer Qs;MEt1  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ]TIBy "3  
    Dim tlens As Double, nlens As Double n_@cjO  
    Dim curv As Double, conic As Double s:Io5C(  
    Dim ok As Long n$y@a? al  
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    Sub Main > PONu]^  
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        '用户输入对话框 $gysy!2}.  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 #w&N) c>  
            TextBox 220,21,40,21,.TextBox1 'default: 0 Wtqv  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 w~}.c:B  
            OKButton 40,91,90,21 }WEF *4B!  
            CancelButton 190,91,90,21 tzdh3\6F  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 41NVF_R6J  
            TextBox 220,49,40,21,.TextBox2 'default: 4 .yb=I6D;<3  
        End Dialog ?$Ii_.  
        Dim dlg As UserDialog {x<yDDIv_  
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        ok = Dialog (dlg) ioJr2wq6  
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        If ok=0 Then    'cancel button was pressed 0=V -{  
            Print "Execution cancelled." d{:0R9  
            End #Iwxt3K  
        End If *W$bhC'w  
    dI) 9@UL  
        'Assign accommodation and pupil diameter & use defaults if field left empty ,'>O#kD  
        If dlg.TextBox1 = "" Then &@/25Y2  
            A = 0           'Default accommodation &AhkP=Yw  
        Else Tb<}GcwJ  
            A = CDbl(dlg.TextBox1) %3mh'Z -[f  
        End If B):hm  
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        If dlg.TextBox2 = "" Then SRek:S,  
            pupilDiam = 4   'Default pupil diameter ]Ofs, U^  
        Else Qs7*_=+h  
            pupilDiam = CDbl(dlg.TextBox2) B8.uzX'p  
        End If #7|73&u(  
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        Print " " R;`C;Rbf  
        Print "Accommodation = " & A & " Diopters" Q+a"Z^Z|  
        Print "Pupil Diameter = " & pupilDiam & " mm" se&Q\!&M  
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        ' Calculate new parameters with accommodation a+P Vi  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness k`h#.B J  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens p^*A&7d:P  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ,#Mt10e{  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens vfloha p  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens *m*sg64Zw  
    @"__2\ 0  
        tlens = 3.767 + 0.04*A                  'Lens thickness ,'&H`h54  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction osZ] R  
    _BHEK  
        'Adjust parameters to account for accommodation P9jPdls  
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        '************************************************************************* 2./;i>H[u  
        'Aqueous thickness (Position of Lens) hD9b2KZv  
        '************************************************************************* ndS8p]P&o(  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Usq.'y/ o  
        GetCustomElement eID, entity -T{G8@V0I  
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        parID = FindFullName( "Geometry.Arizona Eye" ) njckPpyb@  
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        ' Delete any shift(s) in z VCQo3k5 {  
        count = 0 {B[ }}wX$  
        While GetOperationCount(eID)>count ubUVxYD?  
            GetOperation eID, count, op 6QAhVg: A  
            If op.Type="ShiftZ" Then f[wxt n'r  
                DeleteOperation eID,count VMH^jCFp  
                count=count-1 ,)ZI&BL5  
            End If Kjt\A]R%  
            count=count+1 do:IkjU~  
        Wend }No8to  
    #Fz/}lO  
        'Set new shift in /X%+z5  
        op.Type = "ShiftZ" y3OF+;E  
        op.val1 = taq ^MO})C  
        op.parent = parID $rm/{i_7  
        AddOperation eID, op T,h 9xl9i  
        Print "Set aqueous humor thickness = " & taq-0.55 il% u)NN  
    M< /  
        '************************************************************************* A\<W x/  
        'Radius and conic constant of anterior lens pD;fFLvN  
        '************************************************************************* q5{h@}|M  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Go(Td++HS  
        GetConic eID, entity, curv, conic i>e?$H,/  
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        SetConic eID, entity, 1/Rant, CCant Y`rli  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant J?C:@Q  
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        '************************************************************************* fwNj@fl_,e  
        'Radius and conic constant of posterior lens X}H?*'-  
        '************************************************************************* '}$$0S.DC  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 'OvM  
        GetConic eID, entity, curv, conic 0ZJj5<U  
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        SetConic eID, entity, 1/Rpost, CCpost PU8dr|!  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 9e Fj+  
    ~z)JO'Z$  
        '************************************************************************* [Qcht,\^v  
        'Lens thickness (Position of posterior lens surface) @Gt.J*!s/  
        '************************************************************************* J";4+wA7  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) fZrh_^yH  
    +QNsI2t;r  
        ' Delete any z-shift(s) )]kxLf#  
        count = 0 "SRS{-p0  
        While GetOperationCount(eID)>count bEln.)  
            GetOperation eID, count, op _@W1?;yD  
            If op.Type="ShiftZ" Then p<3<Zk 7~0  
                DeleteOperation eID,count \440gH`  
                count=count-1 1) 5$,+~lL  
            End If DTG-R>y^  
            count=count+1 k-^le|n9  
        Wend 51Vqbtj^  
    <w`EU[y_  
        'Set new z-shift iBI->xU[U  
        op.Type = "ShiftZ" UE/JV_/S;  
        op.val1 = tlens G"w [>m  
        op.parent = parID O_]hbXV0  
        AddOperation eID, op sUU[QP-  
        Print "Set lens thickness = " & tlens [+Fajo;0  
    d0-4KN2  
        '************************************************************************* > l]Ble  
        'Lens index of refraction  TD%&9$F  
        '************************************************************************* )/)[}wN;j  
        eID = FindMaterial( "Lens" ) Em !%3C1r  
        GetModelMaterial eID, mat p6V#!5Q  
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        mat.Nd = nlens YxrMr9>l1  
        SetModelMaterial eID, mat %-a;HGbZn  
        Print "Set lens index of refraction = " & nlens @T:J<,  
    "YaT1` Kr  
        '************************************************************************* hz*T"HJ]t  
        'Pupil diameter QO^V@"N  
        '************************************************************************* Qj|rNeM_  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) *ow`}Q  
    Q6D>(H#"0  
        'Adjust pupil diameter (trimming volume inner hole) R:$E'PSx  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" }0tHzw=#%e  
    d%.|MAE  
        ' Adjust pupil location to just in front of the lens KJ:z\N8eo  
        parID = FindFullName( "Geometry.Arizona Eye" ) 8|^&~Rl4  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) X</Sl>[8  
        count = 0 7'"qW"<  
        While GetOperationCount(eID)>count K_~kL0=4  
            GetOperation eID, count, op OGIv".~s4  
            If op.Type="ShiftZ" Then DP0@x+`k  
                DeleteOperation eID,count 1DcX$b  
                count=count-1 heL`"Y2'y>  
            End If `a83bF35  
            count=count+1 j#~~_VA~  
        Wend ^b$_I31D  
        op.Type = "ShiftZ" Wy}^5]R0E  
        op.val1 = taq-0.01 2x9.>nwhb  
        op.parent = parID @&Z^WN,x  
        AddOperation eID, op -gm5E qi  
    ZE-vroh  
        Print "Set pupil diameter = " & pupilDiam qxDMDMN  
    /]^Y\U^  
        'Update AZ Eye subassembly Description fge h;cD  
        eID = FindFullName( "Geometry.Arizona Eye" ) >}\s-/  
        GetEntity eID, entity Le:C8^  
        entity.Description = "Accommodation = " & A & "D" |9=A"092{  
        SetEntity eID, entity \pfa\, rW  
    T.3{}230<  
        Update 9 :Oz-b  
        Print "DONE!" vi *A 5  
         n1{[CCee@  
    End Sub PPH;'!>s"  
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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: %~x?C4L8  
    }6!/Nb  
    Accommodation = 4 Diopters >mX6;6FF  
    Pupil Diameter = 4 mm icIn>i<m  
    Set aqueous humor thickness = 2.81 |=*)a2  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 KILX?Pt[7  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 f)j*P<V  
    Set lens thickness = 3.927 %~PcJhz  
    Set lens index of refraction = 1.42672 | bRU=dg  
    Set pupil diameter = 4 cz1+ XpU  
    DONE! NS2vA>n8R  
     
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