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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 <ldid]o #  
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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。 q1N4X7<_  
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    模型 EsT0"{  
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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。 C$KaT3I  
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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. I?f"<5[0  
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    光源 CMC?R,d  
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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。 f?2zLE>u  
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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。 |C~Sr#6)7  
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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。 @)  
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    图2. 字母F光源的设定方法光 @; W<dJ<X  
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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 B#J{F  
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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。  UP\8w#~  
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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。 4#TnXxL  
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    图5. 视网膜重点采样规格设定
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    脚本 7 2`/d`  
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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: |d5ggf .w  
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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。 pMOD\J:l,  
    余下的脚本计算与屈光度有关的所有参数。 >Ja0hS{*  
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    分析 n1_ %Td  
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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。 $H4=QVj6  
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    图7. 字母F在视网膜上颜色分析
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    脚本代码 #U\$@4D  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. GX7VlI[  
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    Dim entity As T_ENTITY e,^pMg~  
    Dim op As T_OPERATION  /; +oz  
    Dim mat As T_MODELMATERIAL v<j2L"bj  
    Dim A As Double "@(58nk  
    Dim pupilDiam As Double O!o <P5X^  
    Dim eID As Long sb'lZFSP~s  
    Dim parID As Long -P2 @mx%  
    Dim count As Integer E{<?l 7t  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ^Wf S\M`  
    Dim tlens As Double, nlens As Double 8`a,D5U:  
    Dim curv As Double, conic As Double *JwFD^<j  
    Dim ok As Long U8E0~[y'  
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    Sub Main r;9z 5'  
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        '用户输入对话框 ZH% we  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Sq<3Rw  
            TextBox 220,21,40,21,.TextBox1 'default: 0 |%-YuD  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 cFw3Iw"JJ  
            OKButton 40,91,90,21 :|=- (z  
            CancelButton 190,91,90,21 :u AjV  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 9g96 d-  
            TextBox 220,49,40,21,.TextBox2 'default: 4 l4zw]AYk+X  
        End Dialog 5|5=Y/   
        Dim dlg As UserDialog \` &ej{  
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        ok = Dialog (dlg) )x)gHY8;  
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        If ok=0 Then    'cancel button was pressed CNq[4T'~A  
            Print "Execution cancelled." vpi l$Uq  
            End ]/a g*F  
        End If &h\7^=s.  
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        'Assign accommodation and pupil diameter & use defaults if field left empty 2g0K76=Co:  
        If dlg.TextBox1 = "" Then XYMxG:  
            A = 0           'Default accommodation RFB(d=o5S  
        Else IOX:yxj  
            A = CDbl(dlg.TextBox1) o7J{+V  
        End If \d:h$  
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        If dlg.TextBox2 = "" Then ,2,W^HJ  
            pupilDiam = 4   'Default pupil diameter %iX/y  
        Else (xbIUz.  
            pupilDiam = CDbl(dlg.TextBox2) i]dz}=j'  
        End If ;|;iCaD a+  
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        Print " " 1EQvcw #  
        Print "Accommodation = " & A & " Diopters" Q4=|@|U0  
        Print "Pupil Diameter = " & pupilDiam & " mm" 9Eu #lV  
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        ' Calculate new parameters with accommodation ^:+Rg}]W^  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Rh[Ibm56  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens %/Bvy*X&  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ~x\Cmu9`  
    d[S#Duz<&  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens }DbE4"^K7  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens k},>^qE  
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        tlens = 3.767 + 0.04*A                  'Lens thickness 6W$rY] h!  
    :SK<2<8h  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction xb]o dYGdW  
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        'Adjust parameters to account for accommodation + LS3T^  
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        '************************************************************************* r,Ds[s)B  
        'Aqueous thickness (Position of Lens) %2}C'MqS  
        '************************************************************************* \1]rlzXGUT  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) }s(C^0x  
        GetCustomElement eID, entity rpSr^slr  
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        parID = FindFullName( "Geometry.Arizona Eye" ) JdO)YlM-  
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        ' Delete any shift(s) in z ifvU"l  
        count = 0 .$P|^Zx,  
        While GetOperationCount(eID)>count =},{8fZ4  
            GetOperation eID, count, op 3(C :X1  
            If op.Type="ShiftZ" Then dHq#  
                DeleteOperation eID,count bs BZ E  
                count=count-1 bQ"N ;d)e  
            End If K?[)E3  
            count=count+1 6{8/P'@/Zz  
        Wend "9ue76  
    ,z G(u 1  
        'Set new shift in jWSb5#Pw  
        op.Type = "ShiftZ" yjFe'  
        op.val1 = taq BJgDo  
        op.parent = parID gJk[Ja  
        AddOperation eID, op 2kVp_=c  
        Print "Set aqueous humor thickness = " & taq-0.55 iE=P'"I  
    3}j1RYtz  
        '************************************************************************* 7 v~ro  
        'Radius and conic constant of anterior lens ^aHh{BQ%  
        '************************************************************************* QLn+R(r  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) Je@kiE  
        GetConic eID, entity, curv, conic kZv*rWAm  
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        SetConic eID, entity, 1/Rant, CCant FQ!Oxlq,Q  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant n]v7V&mj\  
    wFb@1ae\  
        '************************************************************************* GG+5/hU  
        'Radius and conic constant of posterior lens Z\'wm'  
        '************************************************************************* {>h97}P  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) y?Onb 3%  
        GetConic eID, entity, curv, conic :~D]; m  
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        SetConic eID, entity, 1/Rpost, CCpost Hd374U<8]T  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost tt{`\1q  
    R6<4"?*r  
        '************************************************************************* a,cC!   
        'Lens thickness (Position of posterior lens surface) $_FZn'Db6  
        '************************************************************************* > H~6NBd5D  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) wVE:X3Ei  
    (6clq:c7j  
        ' Delete any z-shift(s) ) $#(ZL^m  
        count = 0 b2s~%}T  
        While GetOperationCount(eID)>count :".w{0l@  
            GetOperation eID, count, op +Vy_9I(4Z  
            If op.Type="ShiftZ" Then :XYy7xz<  
                DeleteOperation eID,count a:b^!H>#  
                count=count-1 a q kix"J  
            End If CV3DMA  
            count=count+1 ="3,}qR  
        Wend ^yJ:+m;6K  
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        'Set new z-shift n`.#59-Hx  
        op.Type = "ShiftZ" /AR]dcL@76  
        op.val1 = tlens ZF'HM@cfo  
        op.parent = parID Q6x%  
        AddOperation eID, op $H;+}VQ  
        Print "Set lens thickness = " & tlens >)3VbO  
    ] D6|o5  
        '************************************************************************* 2yxi= XWZ  
        'Lens index of refraction *Ru2:}?MpS  
        '************************************************************************* c{4R*|^  
        eID = FindMaterial( "Lens" ) "lrA%~3%[P  
        GetModelMaterial eID, mat HTR1)b  
    7=3O^=Q ^Q  
        mat.Nd = nlens .Q[yD<)Ubs  
        SetModelMaterial eID, mat R&Ci/  
        Print "Set lens index of refraction = " & nlens LwQH6 !;[  
    x5F@ad 9  
        '************************************************************************* jyQVSQ s  
        'Pupil diameter m8AAp1=  
        '************************************************************************* O] ZC+]}/  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Ue!Q."  
    $"fzBM?5  
        'Adjust pupil diameter (trimming volume inner hole) FW Y[=S  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Noz&noq  
    L[]BzsIv  
        ' Adjust pupil location to just in front of the lens |^ iA6)Q  
        parID = FindFullName( "Geometry.Arizona Eye" ) _l T0H u  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) h[Mdr  
        count = 0 DxfMqH[vs  
        While GetOperationCount(eID)>count 7Ud'd<  
            GetOperation eID, count, op ]]/lC  
            If op.Type="ShiftZ" Then }p{;^B  
                DeleteOperation eID,count c,$mWTC  
                count=count-1 e1uMR-Q  
            End If c[:Wf<% |  
            count=count+1 wko2M[  
        Wend '=#5(O%pp  
        op.Type = "ShiftZ" =YHt9fb$c  
        op.val1 = taq-0.01 Spo +@G  
        op.parent = parID xYwkFB$$*  
        AddOperation eID, op SUu >6'LN  
    *l-`<.  
        Print "Set pupil diameter = " & pupilDiam "K ?#,_  
    5~U:@Tp  
        'Update AZ Eye subassembly Description y ||@?Y  
        eID = FindFullName( "Geometry.Arizona Eye" ) ?4sJw:  
        GetEntity eID, entity ohsH2]C  
        entity.Description = "Accommodation = " & A & "D" vgo{]:Aj{  
        SetEntity eID, entity ?K<Z kYw?  
    7E\gxQ(vU  
        Update kwF]TO S  
        Print "DONE!" ugxw!cj  
         ^#w{/C/n  
    End Sub PkJcd->  
    +6376$dC  
    如果屈光度是4,光瞳直径是4,则会输出如下数据: 50,Y  
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    Accommodation = 4 Diopters nsl*Dm"*F  
    Pupil Diameter = 4 mm 1J'pB;.]s  
    Set aqueous humor thickness = 2.81 n^Vxi;F  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 :l`i4kx  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 ,R}Z=w#  
    Set lens thickness = 3.927 |[ocyUsxX  
    Set lens index of refraction = 1.42672 }P. K2ku  
    Set pupil diameter = 4 0I^Eo|  
    DONE! tN}c0'H  
     
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