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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 SS l8  
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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。 :DS2zA  
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模型 <Tj"GVZAEO  
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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。 S3%.-)ib  
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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. jhjW* F<u  
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光源 gb!@OZ c  
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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。 .FfwY 'V  
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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。 6xDl=*&%  
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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。 ,d9%Ce.$2  
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图2. 字母F光源的设定方法光 lOowMlf@2  
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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 %x cM_|AyR  
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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。 U5@TaGbx  
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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。 0`g}(}'L  
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图5. 视网膜重点采样规格设定
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脚本 LX(iuf+l  
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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: V,|Bzcz  
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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。 Xn ZX *Y]"  
余下的脚本计算与屈光度有关的所有参数。 }v'PY/d.  
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分析 }LHT#{+ 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。 Je4.9?Ch  
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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 u75)>^:I   
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. >zfZw"mEP  
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Dim entity As T_ENTITY 5u u2 _B_L  
Dim op As T_OPERATION yG4LQE  
Dim mat As T_MODELMATERIAL &[W3e3Asra  
Dim A As Double P98X[0&  
Dim pupilDiam As Double D<D k1  
Dim eID As Long $@:>7Y"  
Dim parID As Long KHc/x8^9  
Dim count As Integer #BT6bH08X  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double g.`t!6Hc  
Dim tlens As Double, nlens As Double :}3qZX  
Dim curv As Double, conic As Double !rsqr32]  
Dim ok As Long oZ*=7u  
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Sub Main v{rK_jq  
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    '用户输入对话框 u=v%7c2Mx}  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 zoJkDr=jn  
        TextBox 220,21,40,21,.TextBox1 'default: 0 =Zb"T5E  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 13_+$DhU-L  
        OKButton 40,91,90,21 >gOI]*!5  
        CancelButton 190,91,90,21 Edn$0D68u_  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 4f*Ua`E_  
        TextBox 220,49,40,21,.TextBox2 'default: 4 Y9co?!J 5M  
    End Dialog ]\9B?W(#  
    Dim dlg As UserDialog 1R+ )T'in  
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    ok = Dialog (dlg) \Zz= 4 j  
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    If ok=0 Then    'cancel button was pressed M:1F@\<  
        Print "Execution cancelled." sKG~<8M}  
        End lJ>QTZH!wW  
    End If l"pz )$eE  
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    'Assign accommodation and pupil diameter & use defaults if field left empty @<w9fzi  
    If dlg.TextBox1 = "" Then Mp=kZs/  
        A = 0           'Default accommodation TLL[F;uZ  
    Else O"s`-OM;n  
        A = CDbl(dlg.TextBox1) M@2Qn-I  
    End If 5dNf$a0E  
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    If dlg.TextBox2 = "" Then '*LN)E> d  
        pupilDiam = 4   'Default pupil diameter LG@c)H74  
    Else !wR{Y[Yu  
        pupilDiam = CDbl(dlg.TextBox2) fF-\TW  
    End If l^eNZ3:H  
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    Print " " D@b<}J>0'  
    Print "Accommodation = " & A & " Diopters" t ]I(98pY  
    Print "Pupil Diameter = " & pupilDiam & " mm" ':R3._tw\  
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    ' Calculate new parameters with accommodation /HJ(Wt q  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness =*>4Gh i  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens +D-+}&oW  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens \`%Y-!H+v  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens wyA(}iSq  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens (#l_YI -  
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    tlens = 3.767 + 0.04*A                  'Lens thickness =wR]X*Pan  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Lvj5<4h;  
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    'Adjust parameters to account for accommodation \gzwsT2&  
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    '************************************************************************* >8fz ?A  
    'Aqueous thickness (Position of Lens) v7OV;e a$  
    '************************************************************************* I7z]%Z  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) JO^ [@  
    GetCustomElement eID, entity >]Yha}6h  
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    parID = FindFullName( "Geometry.Arizona Eye" ) '%RK KA  
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    ' Delete any shift(s) in z aE cg_es  
    count = 0 *_K-T#  
    While GetOperationCount(eID)>count &@iF!D\u  
        GetOperation eID, count, op pr,1Wp0l  
        If op.Type="ShiftZ" Then -Tkd@  
            DeleteOperation eID,count &?Z)V-1H  
            count=count-1 ?G>TaTiK#  
        End If E!~2\qKT  
        count=count+1 q.b4m 'J  
    Wend dQ|Ht[ s=  
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    'Set new shift in l}-`E@w  
    op.Type = "ShiftZ" =bg&CZV T  
    op.val1 = taq ?_j6})2zY  
    op.parent = parID z*~ PYAt  
    AddOperation eID, op 0#{]!>R  
    Print "Set aqueous humor thickness = " & taq-0.55 Yg,lJ!q  
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    '************************************************************************* jMWwu+w  
    'Radius and conic constant of anterior lens vMdhNOU  
    '************************************************************************* &c9Fw:f;  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) FRQ("6(  
    GetConic eID, entity, curv, conic k8wi-z[dV  
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    SetConic eID, entity, 1/Rant, CCant X6*y/KG N  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 14YV#o:  
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    '************************************************************************* >upUY(3&  
    'Radius and conic constant of posterior lens j~f 7WJ  
    '************************************************************************* SWO!E  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) y* Q-4_%,  
    GetConic eID, entity, curv, conic "v(]"L  
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    SetConic eID, entity, 1/Rpost, CCpost 2pNJWYW"  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 5 ^J8<s@_  
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    '************************************************************************* I"<. h'  
    'Lens thickness (Position of posterior lens surface) K}3"KC  
    '************************************************************************* [Q_| 6Di  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 5f@YrTO[@  
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    ' Delete any z-shift(s) A?k,}~  
    count = 0 9,>Y  
    While GetOperationCount(eID)>count )mVYqlU"  
        GetOperation eID, count, op ^K8a#-  
        If op.Type="ShiftZ" Then t\d;}@bl  
            DeleteOperation eID,count 5nqdY*  
            count=count-1 l"y9XO|  
        End If pYUkd!K"  
        count=count+1 }gRLW2&mR>  
    Wend g}r5ohqC#  
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    'Set new z-shift WREGRy  
    op.Type = "ShiftZ" Jd6Q9~z#  
    op.val1 = tlens 8&hn$~ate  
    op.parent = parID 5MU@g*gj,C  
    AddOperation eID, op >Nl~"J|]q  
    Print "Set lens thickness = " & tlens \1 D,Kx;Cb  
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    '************************************************************************* ,8 ?*U]}  
    'Lens index of refraction sn`?Foh  
    '*************************************************************************  HcS^3^Y  
    eID = FindMaterial( "Lens" ) ([o:_5/8I  
    GetModelMaterial eID, mat >(KUYX?p  
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    mat.Nd = nlens y+R$pzX  
    SetModelMaterial eID, mat m?G+#k;K  
    Print "Set lens index of refraction = " & nlens t1s@Ub5);I  
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    '************************************************************************* 9gayu<J  
    'Pupil diameter tzJtd  
    '************************************************************************* )X$n'E  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) `&7? +s  
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    'Adjust pupil diameter (trimming volume inner hole) yE{UV>ry  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" q`zR6  
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    ' Adjust pupil location to just in front of the lens }gaKO 5  
    parID = FindFullName( "Geometry.Arizona Eye" ) ~36XJ  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Z9bPj8d  
    count = 0 vG:,oB}  
    While GetOperationCount(eID)>count u)>*U'bM  
        GetOperation eID, count, op B%;+8]  
        If op.Type="ShiftZ" Then 0k]N%!U  
            DeleteOperation eID,count |<icx8hbr  
            count=count-1 -bQvJ`iF  
        End If 0_izTke  
        count=count+1 (I g *iJ%2  
    Wend nwH|Hs riU  
    op.Type = "ShiftZ" Ia" Mi+{  
    op.val1 = taq-0.01 hV>Ey^Ty  
    op.parent = parID J3^Ir [  
    AddOperation eID, op NPabM(<`  
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    Print "Set pupil diameter = " & pupilDiam v>l?d27R  
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    'Update AZ Eye subassembly Description w=2 X[V}  
    eID = FindFullName( "Geometry.Arizona Eye" ) r${a S@F  
    GetEntity eID, entity >.>5%  
    entity.Description = "Accommodation = " & A & "D" 'iK*#b8l  
    SetEntity eID, entity Q"uu&JC  
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    Update 0C_Qp%Z  
    Print "DONE!" I !~Omr@P  
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End Sub <{j9|mt  
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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: !{\c`Z<#  
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Accommodation = 4 Diopters Hq8.O/Y"=  
Pupil Diameter = 4 mm ZrBxEf$f  
Set aqueous humor thickness = 2.81 ${3OQG  
Set anterior lens radius = 10.4 and conic constant = -2.375869 b2H6}s"=w  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 4 -W?u51"  
Set lens thickness = 3.927 &2^V<(19  
Set lens index of refraction = 1.42672 ['j,S<Bu~  
Set pupil diameter = 4 $!lxVZ>  
DONE! ) 'KHUa9  
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