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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 &hZwZgV +3  
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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。 A{,n;;  
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    模型 "/%89 HMD  
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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。 Yx?aC!5M  
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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. zQuM !.  
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    光源 `6w#8}  
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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。 -Wo15O"  
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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。 H7IW"UkBR  
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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。 ( )|3  
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    图2. 字母F光源的设定方法光 |XcH]7Ai"  
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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 5:gj&jt;)7  
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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。 YF[$Q=7.  
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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。 ToU.mM?f^  
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    图5. 视网膜重点采样规格设定
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    脚本 5+L8\V9;  
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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: ( pD7  
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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。 QMb^&?;s  
    余下的脚本计算与屈光度有关的所有参数。 TG]}X\c+V|  
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    分析 /.ZaE+  
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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|.20w5  
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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 CKC0{J8g  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. 3ZN>9`  
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    Dim entity As T_ENTITY 0BXs&i-TP5  
    Dim op As T_OPERATION A\g%  
    Dim mat As T_MODELMATERIAL vzy!3Hiw  
    Dim A As Double Y-~;E3(  
    Dim pupilDiam As Double uQ1jwYK`7  
    Dim eID As Long E0jUewG  
    Dim parID As Long MCd F!{  
    Dim count As Integer d#7]hF  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double LaT8l?q q  
    Dim tlens As Double, nlens As Double =M7PvH'"  
    Dim curv As Double, conic As Double z"qv  
    Dim ok As Long &CO| Y(+  
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    Sub Main D"`[6EN[  
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        '用户输入对话框 I4ctxMVP  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 fO+U HSC  
            TextBox 220,21,40,21,.TextBox1 'default: 0 G{O\)gf  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 /x O{ .dr  
            OKButton 40,91,90,21 We\Y \*!v  
            CancelButton 190,91,90,21 d/4ubf+$k  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 i\vpGlx  
            TextBox 220,49,40,21,.TextBox2 'default: 4 A`Q >h{  
        End Dialog nHVPMi>  
        Dim dlg As UserDialog V0S6M^\DK  
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        ok = Dialog (dlg) !c."   
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        If ok=0 Then    'cancel button was pressed ~K%k 0kT  
            Print "Execution cancelled." ?4MSgu  
            End qkiJ HT  
        End If =kF? _KN  
    !^]q0x  
        'Assign accommodation and pupil diameter & use defaults if field left empty C|9[Al  
        If dlg.TextBox1 = "" Then pqOA/^ar  
            A = 0           'Default accommodation )FV6,  
        Else oFb\T iLu  
            A = CDbl(dlg.TextBox1) U-1VnX9m  
        End If A3<^ U  
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        If dlg.TextBox2 = "" Then Q|Nzbmwh  
            pupilDiam = 4   'Default pupil diameter JR!Q,7S2!N  
        Else VZt;P%1;h  
            pupilDiam = CDbl(dlg.TextBox2) T0s35z9  
        End If "wC0eDf  
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        Print " " xSx&79Ez<*  
        Print "Accommodation = " & A & " Diopters" - *r[  
        Print "Pupil Diameter = " & pupilDiam & " mm" cl@kRX<7'  
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        ' Calculate new parameters with accommodation FLK"|*A  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ?<Z)*CF)  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens K?$ 9N}+  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens fYb KmB  
    )\RzE[Cb  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens Av@& hD\  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens tN[St  
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        tlens = 3.767 + 0.04*A                  'Lens thickness zoR,RBU6  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 4u@yJ?U  
    ~K4k'   
        'Adjust parameters to account for accommodation K3a>^g  
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        '************************************************************************* Xs{/}wc.q;  
        'Aqueous thickness (Position of Lens) 6{cybD`Ef&  
        '************************************************************************* FrgW7`s[A  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) JqL<$mSep  
        GetCustomElement eID, entity 'Na|#tPYI  
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        parID = FindFullName( "Geometry.Arizona Eye" ) %j~9O~-  
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        ' Delete any shift(s) in z ~l;yr @  
        count = 0 We[<BJ o4  
        While GetOperationCount(eID)>count kqjxJ5  
            GetOperation eID, count, op cZPbD;e:  
            If op.Type="ShiftZ" Then l :f9Ih  
                DeleteOperation eID,count }K#iCby4  
                count=count-1 rd|@*^k  
            End If }".\ 4B$n  
            count=count+1 =4YbVA+(  
        Wend _bN))9 3  
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        'Set new shift in "r5'lQI  
        op.Type = "ShiftZ" }`+O$0A  
        op.val1 = taq .d<~a1k  
        op.parent = parID Y9z:xE  
        AddOperation eID, op dM);LT8@  
        Print "Set aqueous humor thickness = " & taq-0.55 wxdh?sQ  
    :6\-9m8JM  
        '************************************************************************* ^4n2 -DvG  
        'Radius and conic constant of anterior lens BZ]&uD|f  
        '************************************************************************* m]+X }|  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ;`X`c  
        GetConic eID, entity, curv, conic jldcvW  
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        SetConic eID, entity, 1/Rant, CCant >=Rd3dgDG  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant X=S}WKu  
    7)ES!C   
        '************************************************************************* DzX6U[=  
        'Radius and conic constant of posterior lens *@b~f&Lx6  
        '************************************************************************* ~FK+bF?%  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) oT9XJwqnv  
        GetConic eID, entity, curv, conic Mt7X<?GZm  
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        SetConic eID, entity, 1/Rpost, CCpost 8EW`*+%=  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ":(Cpf0  
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        '************************************************************************* "9MX,}X*  
        'Lens thickness (Position of posterior lens surface) J8`1V `$  
        '************************************************************************* m\R@.jkZ  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) D 9@<#2-  
    Z.cG`Km*  
        ' Delete any z-shift(s) AR[M8RA  
        count = 0 qB` 0^V  
        While GetOperationCount(eID)>count 6 ^6uK  
            GetOperation eID, count, op <+mO$0h"r  
            If op.Type="ShiftZ" Then )nbyV a  
                DeleteOperation eID,count MO(5-R`  
                count=count-1 6i?kkULBS  
            End If 0X}w[^f  
            count=count+1 l ")o!N?  
        Wend Bt`r6v;\  
    ;r2b@x:<_  
        'Set new z-shift *I;Mp  
        op.Type = "ShiftZ" ;Kq<',u~  
        op.val1 = tlens i >/@]2  
        op.parent = parID ":ws~Zep  
        AddOperation eID, op ,M9hb<:m  
        Print "Set lens thickness = " & tlens 4=#QN  
    swe8  
        '************************************************************************* @)M.u3{\  
        'Lens index of refraction YRT}fd>R&  
        '************************************************************************* 8 )2u@sx%  
        eID = FindMaterial( "Lens" ) vr]dRStr  
        GetModelMaterial eID, mat v2dSC(hRZ  
    :;gwdZ  
        mat.Nd = nlens 7zOvoQ}  
        SetModelMaterial eID, mat fjeE.  
        Print "Set lens index of refraction = " & nlens ROI$;B(  
    qgY(S}V  
        '************************************************************************* 5E!|on  
        'Pupil diameter h11bK'TIv  
        '************************************************************************* &b#NF1Q.  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) rt4|GVa  
    N'1[t  
        'Adjust pupil diameter (trimming volume inner hole) 3ks|  
    Y_ u7 0@`  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" k? _$h<Y  
    I[YfF  
        ' Adjust pupil location to just in front of the lens ^gVbVz[17  
        parID = FindFullName( "Geometry.Arizona Eye" ) 8B(Q7Qj  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) (j\UoKLRt  
        count = 0 X wn|.  
        While GetOperationCount(eID)>count OTr!?xi  
            GetOperation eID, count, op r;s3(@[,@  
            If op.Type="ShiftZ" Then i_Q4bhVj  
                DeleteOperation eID,count b9!J}hto,  
                count=count-1 pz z`4VS:  
            End If EC&19  
            count=count+1 '"NdT7*+  
        Wend Hwi7oXP  
        op.Type = "ShiftZ" Zi'8~iEH  
        op.val1 = taq-0.01 @C6DOB  
        op.parent = parID d(cYtM,P  
        AddOperation eID, op LB 5EGw  
    r4qV}-E  
        Print "Set pupil diameter = " & pupilDiam r_2VExk  
    kO O~%|1CP  
        'Update AZ Eye subassembly Description w+ )GM  
        eID = FindFullName( "Geometry.Arizona Eye" ) z K]%qv]  
        GetEntity eID, entity 7*W$GCd8  
        entity.Description = "Accommodation = " & A & "D" 'Rf#1ls#  
        SetEntity eID, entity (inwKRH  
    SOY#, Zu  
        Update ~<Qxw>S#  
        Print "DONE!" E~U|v'GCd  
         >WG91b<Xq  
    End Sub MkIO0&0O  
    [aVJYr2  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: H<3b+Sg  
    [}Yci:P_ +  
    Accommodation = 4 Diopters -cC(d$y  
    Pupil Diameter = 4 mm # SOj4W  
    Set aqueous humor thickness = 2.81 )qQg n]  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 h.0&)t\q"  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 dtXJ<1:  
    Set lens thickness = 3.927 <i @jD  
    Set lens index of refraction = 1.42672 fXR_)d  
    Set pupil diameter = 4 GeR -k9  
    DONE! ~]s"PV:|  
     
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