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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 kI%%i>Y}  
    %vBhLaE  
    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。 *Vho?P6y\Y  
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    模型 [Y`,qB<B  
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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。 Q 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. _'#x^D  
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    光源 hR.@b*q?R  
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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。 -,["c9'3  
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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。 v!%5&: c3  
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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。 _D|^.)=U|  
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    图2. 字母F光源的设定方法光 Y6&wJ<   
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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 CpJ0m-7aIH  
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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。 ncx(pp  
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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。 _sbp6ZO_  
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    图5. 视网膜重点采样规格设定
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    脚本 N:9>dpP}O  
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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: /x1MPP>fu  
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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。 WQHd[2Z#e  
    余下的脚本计算与屈光度有关的所有参数。 Vrvic4  
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    分析 ){Ob,LEU&  
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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。 \Vl`YYjZ  
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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 ;.bm6(;  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. _.-;5M-  
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    Dim entity As T_ENTITY r$wxk 4%Rz  
    Dim op As T_OPERATION qL94SW;  
    Dim mat As T_MODELMATERIAL IVW1]y  
    Dim A As Double ~0b O}  
    Dim pupilDiam As Double 5MSB dO  
    Dim eID As Long _$>pw<  
    Dim parID As Long kEd@oC  
    Dim count As Integer \Y}3cE  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double _wdG|{px  
    Dim tlens As Double, nlens As Double l|hUw  
    Dim curv As Double, conic As Double q=lAb\i  
    Dim ok As Long 8?FbtBAn  
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    Sub Main sp* Vqd  
    xB !6_VlB  
        '用户输入对话框 %N#%|2B  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 V:G>G'Eh0  
            TextBox 220,21,40,21,.TextBox1 'default: 0 v|E"[P2e  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 =!Q7}z1QI  
            OKButton 40,91,90,21 ,E.' o=Z  
            CancelButton 190,91,90,21 PoIl>c1MS  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 N&[D>G]>v  
            TextBox 220,49,40,21,.TextBox2 'default: 4 v)_nWu  
        End Dialog DvM5 k  
        Dim dlg As UserDialog &* E+N[  
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        ok = Dialog (dlg) 1[ ]&(Pa  
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        If ok=0 Then    'cancel button was pressed |] Qg7m,O  
            Print "Execution cancelled." =f(cH152T  
            End aAy'\T$x.  
        End If x}twsc`  
    ",)Qc!^P$  
        'Assign accommodation and pupil diameter & use defaults if field left empty al`3Lu0  
        If dlg.TextBox1 = "" Then %_Yx<wR%  
            A = 0           'Default accommodation rS1fK1dy s  
        Else *:O.97q@h  
            A = CDbl(dlg.TextBox1) J6<rX[ yZe  
        End If t^ZV|s 1  
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        If dlg.TextBox2 = "" Then +t2SzQ j>  
            pupilDiam = 4   'Default pupil diameter &[&r2 >a  
        Else mE^o-9/  
            pupilDiam = CDbl(dlg.TextBox2) F_bF  
        End If HV/cc"  
    !pJeA)W;  
        Print " " +D1d=4  
        Print "Accommodation = " & A & " Diopters" TT9z_Q5~  
        Print "Pupil Diameter = " & pupilDiam & " mm" nhN);R~o"1  
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        ' Calculate new parameters with accommodation Gy[O)PEEh  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness "k Te2iS  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens \u&_sBLKV  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ~y$ !48o  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 6DZ),F,M  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens u0`%+:]0  
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        tlens = 3.767 + 0.04*A                  'Lens thickness Yhp]x   
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction y ?G_y  
    >q7BVF6V |  
        'Adjust parameters to account for accommodation :pRpv hm  
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        '************************************************************************* A6oq.I0  
        'Aqueous thickness (Position of Lens) =H<0o?8?c  
        '************************************************************************* b~BIz95  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) K 0hu:1l)  
        GetCustomElement eID, entity AfC>Q!-w  
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        parID = FindFullName( "Geometry.Arizona Eye" ) t!K*pM  
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        ' Delete any shift(s) in z OMk5{-8B  
        count = 0 `m.eM  
        While GetOperationCount(eID)>count U4G}DCU  
            GetOperation eID, count, op 3 DaQo0N  
            If op.Type="ShiftZ" Then N S#TW  
                DeleteOperation eID,count s6o>m*{  
                count=count-1 Qo =Kqv  
            End If $W;b{H=F  
            count=count+1 C[WCg9Av  
        Wend A?Wk  w f  
    P IXL6  
        'Set new shift in gN {'UDg  
        op.Type = "ShiftZ" p h[\)  
        op.val1 = taq ]xd^%q*  
        op.parent = parID bw&myzs  
        AddOperation eID, op g+PPW88P;  
        Print "Set aqueous humor thickness = " & taq-0.55 /# <pVgN  
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        '************************************************************************* &:=$wc  
        'Radius and conic constant of anterior lens @/UfD ye  
        '************************************************************************* (5^ZlOk3  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) [_xyl e  
        GetConic eID, entity, curv, conic Y\v-,xPm  
    ;W:6{9m ze  
        SetConic eID, entity, 1/Rant, CCant iq*A("pU  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant X bkb5EkA  
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        '************************************************************************* yg]2erR  
        'Radius and conic constant of posterior lens >"3>fche  
        '************************************************************************* @ \2#Dpr  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) irTv4ZE'+l  
        GetConic eID, entity, curv, conic M`D$!BJr  
    ^6p'YYj"5  
        SetConic eID, entity, 1/Rpost, CCpost Tp<k<uKD  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost >5T_g2pkv  
    `:M^8SYrL  
        '************************************************************************* nU`Lhh8y  
        'Lens thickness (Position of posterior lens surface) ji+{ :D  
        '************************************************************************* }jSj+*  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) (Y(E%  
    dRvin[R8  
        ' Delete any z-shift(s) .I$}KE)  
        count = 0 q6`G I6  
        While GetOperationCount(eID)>count }jF+`!*!  
            GetOperation eID, count, op GJ 'spgz  
            If op.Type="ShiftZ" Then 3kmeD".  
                DeleteOperation eID,count ^Jp*B;  
                count=count-1 o/^;@5\  
            End If !.fw,!}hOD  
            count=count+1 wHsB,2H  
        Wend 6Gn4asoA  
    /-0' Qa+*  
        'Set new z-shift Y@F  
        op.Type = "ShiftZ" lu UYo  
        op.val1 = tlens y,+[$u7h  
        op.parent = parID |)_-Bi;MW`  
        AddOperation eID, op ``?6=mO  
        Print "Set lens thickness = " & tlens >qT'z$  
    4}KU>9YRA  
        '************************************************************************* TF+ l5fv  
        'Lens index of refraction "r.2]R3  
        '************************************************************************* ^&c$[~W  
        eID = FindMaterial( "Lens" ) iz}sM>^  
        GetModelMaterial eID, mat kReG:  
    . gZZCf&?  
        mat.Nd = nlens ST8!i`Q$  
        SetModelMaterial eID, mat :cp   
        Print "Set lens index of refraction = " & nlens dYOF2si~%  
    A~-#@Z  
        '************************************************************************* "EftN5?/  
        'Pupil diameter f1+qXMs  
        '************************************************************************* 7el<5chZ  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) p {%t q$}.  
    #w3ru6*W  
        'Adjust pupil diameter (trimming volume inner hole) 6*1$8G`$8,  
    _LfHs1g4  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" \k&1*b?h  
    XKLF8~y8A  
        ' Adjust pupil location to just in front of the lens ?p8k{N(1  
        parID = FindFullName( "Geometry.Arizona Eye" ) I>w^2 (y  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) iH)Nk^   
        count = 0 7$b?m6fmK  
        While GetOperationCount(eID)>count W$\X~Q'0  
            GetOperation eID, count, op $T dC/#7  
            If op.Type="ShiftZ" Then 4u:0n>nJ1  
                DeleteOperation eID,count "zV']A>4H  
                count=count-1 V; 9 }7mw  
            End If )}X5u%woV  
            count=count+1 'm1.X-$V  
        Wend |PM m?2^R  
        op.Type = "ShiftZ" QdDtvJLf  
        op.val1 = taq-0.01 MguL$W&l  
        op.parent = parID {tzxA_  
        AddOperation eID, op E5x]zXy4  
    g_D-(J`IK,  
        Print "Set pupil diameter = " & pupilDiam $@87?Ab  
    kG3!(?:  
        'Update AZ Eye subassembly Description jL4>A$  
        eID = FindFullName( "Geometry.Arizona Eye" ) XNmQ?`.2'  
        GetEntity eID, entity <lld*IH  
        entity.Description = "Accommodation = " & A & "D" $U'3MEEw  
        SetEntity eID, entity g{DFS[h  
    [n:PNB  
        Update F RH&B5w  
        Print "DONE!" SgSk !lj  
         $Qq_qTJu?G  
    End Sub >rRf9wO1l  
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    如果屈光度是4,光瞳直径是4,则会输出如下数据: F_PTMl=Q|J  
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    Accommodation = 4 Diopters T]2U fi.  
    Pupil Diameter = 4 mm me'(lQ6^  
    Set aqueous humor thickness = 2.81 T7GQ^WnA  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 tBl#o ^  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 Z ps&[;R$-  
    Set lens thickness = 3.927 rdI]\UH  
    Set lens index of refraction = 1.42672 +2O=s<fp  
    Set pupil diameter = 4 #uWE2*')  
    DONE! !1-&Y'+  
     
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