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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 ]F~5l?4u#  
    -uZ^UG!K  
    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。 Jz6PqU|=  
    b8Qm4b?:4  
    模型 2%I:s6r  
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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。 HFazqQ[  
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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. Smp+}-3O  
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    光源 >,v~,<3 i  
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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。  >Pu*MD;  
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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。 |Yx8Ez  
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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。 ]k Pco4  
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    图2. 字母F光源的设定方法光 ;WhB2/5v  
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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 #SdaTMLFf  
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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。 #df43_u  
    JjwuxZVr O  
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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。 \@xnC$dd/  
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    图5. 视网膜重点采样规格设定
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    脚本 I4*N  
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    内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: l*eA ?Qz  
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    图6. 用户对话框的创建与编辑
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    图7. 用户对话框编辑器
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    如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 AIeYy-f  
    余下的脚本计算与屈光度有关的所有参数。 0K!9MDT}*  
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    分析 myo/}58Nv  
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    屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 iPIA&)x}  
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    图7. 字母F在视网膜上颜色分析
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    脚本代码 #Ky0` n  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. Eg9502Bl~8  
    RHxd6Gs"  
    Dim entity As T_ENTITY dug RO[  
    Dim op As T_OPERATION G$Dg*<  
    Dim mat As T_MODELMATERIAL %6n;B|!  
    Dim A As Double Wj3H  y4  
    Dim pupilDiam As Double (*EN!-/  
    Dim eID As Long H$;\TG@,  
    Dim parID As Long /oI ''O%M  
    Dim count As Integer CI,-q i  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ua{eri[  
    Dim tlens As Double, nlens As Double C$5v:Fk  
    Dim curv As Double, conic As Double ^'h~#7s  
    Dim ok As Long %8ul}}d9  
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    Sub Main C?|gf?1p  
    ^,X+ n5q;m  
        '用户输入对话框 qj|GAGrQ2  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 +V) (,f1  
            TextBox 220,21,40,21,.TextBox1 'default: 0 $lv  g.u  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 < ;g0?M\  
            OKButton 40,91,90,21 DJbj@ 2W[  
            CancelButton 190,91,90,21 Y}Ov`ZM!r  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 T7,tJk,(  
            TextBox 220,49,40,21,.TextBox2 'default: 4 g5cR.]oz  
        End Dialog n_!&Wr^CX  
        Dim dlg As UserDialog U3Q'ZT  
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        ok = Dialog (dlg) ZpZ~[BtQ  
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        If ok=0 Then    'cancel button was pressed (d (whlF  
            Print "Execution cancelled." NO<myN+N  
            End 9uq| VU5  
        End If | zAey\  
    )TWf/L cp  
        'Assign accommodation and pupil diameter & use defaults if field left empty )j$Bo{  
        If dlg.TextBox1 = "" Then \/5 8#  
            A = 0           'Default accommodation |[qI2-el?  
        Else ( R0   
            A = CDbl(dlg.TextBox1) ,Pl[SMt!  
        End If 41:Z8YL(  
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        If dlg.TextBox2 = "" Then Ghj6&K%b0  
            pupilDiam = 4   'Default pupil diameter P }PSS#nn  
        Else &38Fj'l  
            pupilDiam = CDbl(dlg.TextBox2) a{HvrWs?Q  
        End If A*$vk2VWw  
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        Print " " M- -6oR7  
        Print "Accommodation = " & A & " Diopters" o~~_>V)W  
        Print "Pupil Diameter = " & pupilDiam & " mm" ~r{Nc j  
    w0.#/6  
        ' Calculate new parameters with accommodation ?6[>HX;  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness bkY7]'.bz&  
    >s{[d$  
        Rant = 12.0 - 0.4*A                     'Radius of anterior lens ^awl-CG  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens Ar\`OhR  
    l@^RbF['  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens UgUW4x'+  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ^EB}e15"  
    xX&*&RPZ  
        tlens = 3.767 + 0.04*A                  'Lens thickness KJ-D|N,8@^  
    ;mMn-+3<  
        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction x|Q6[Y  
    HO wJ 2L  
        'Adjust parameters to account for accommodation aC:rrS  
    '; qT  
        '************************************************************************* l\S..B +  
        'Aqueous thickness (Position of Lens) 10a=[\ Q  
        '************************************************************************* b)df V=  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) \^_F>M  
        GetCustomElement eID, entity T$+}Srb  
    "=Ziy4V  
        parID = FindFullName( "Geometry.Arizona Eye" ) d+/d)cu  
    }e82e  
        ' Delete any shift(s) in z \Oc3rJ(  
        count = 0 O ~"^\]\  
        While GetOperationCount(eID)>count `a<G7  
            GetOperation eID, count, op a ZfX |  
            If op.Type="ShiftZ" Then F35e/YfG  
                DeleteOperation eID,count :@pm gp  
                count=count-1 $bN%x/  
            End If )`L!eN  
            count=count+1 r*kk/ $,2  
        Wend t4,6`d?C  
    /+3|tb  
        'Set new shift in JNZKzyJ9K  
        op.Type = "ShiftZ" ;KnnAZJ  
        op.val1 = taq =LuA [g  
        op.parent = parID c|I{U[(U  
        AddOperation eID, op 9<xe%V=ki  
        Print "Set aqueous humor thickness = " & taq-0.55 1tD4 I  
    "--rz;+K  
        '************************************************************************* 2#sE\D  
        'Radius and conic constant of anterior lens jtd{=[STU  
        '************************************************************************* fIFB"toiPE  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) \l#=p+x5  
        GetConic eID, entity, curv, conic ^D\#*pIO  
    4$.4,4+  
        SetConic eID, entity, 1/Rant, CCant l_$~~z ~  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant &ts!D!Hj  
    }bHd U]$}  
        '************************************************************************* f\Pd#$3  
        'Radius and conic constant of posterior lens q7X /"Dfx  
        '************************************************************************* {y :/9  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ~uV.jh  
        GetConic eID, entity, curv, conic A/ GEDG ?  
    n|{x\@VeF  
        SetConic eID, entity, 1/Rpost, CCpost 'os-+m@  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost "&7v.-Y k(  
    /\C9FGS  
        '************************************************************************* j_Dx4*v g  
        'Lens thickness (Position of posterior lens surface) IUI >/87u  
        '************************************************************************* 3vmZB2QG  
    {L3lQ8Z  
        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) rjfQ\W;}U  
    y_\vXY'  
        ' Delete any z-shift(s) cl^tX%  
        count = 0 ?e yo2:-$  
        While GetOperationCount(eID)>count b[H& vp  
            GetOperation eID, count, op )PR{ia64;<  
            If op.Type="ShiftZ" Then `y m^0x8  
                DeleteOperation eID,count MX  qH  
                count=count-1 *"4 OXyV  
            End If $Nnz |y  
            count=count+1 R$NH [Tz  
        Wend kE/>Ys@w  
    YS/{q~$t  
        'Set new z-shift (l9U7^S"{K  
        op.Type = "ShiftZ" ~^:/t<N  
        op.val1 = tlens .}2^YOmd  
        op.parent = parID ~M+|g4W%  
        AddOperation eID, op = R; 0Ed&b  
        Print "Set lens thickness = " & tlens YP+0 uZ[g  
    hE+6z%A8  
        '************************************************************************* @yqy$I   
        'Lens index of refraction rAk*~OK  
        '************************************************************************* ^D"}OQoh  
        eID = FindMaterial( "Lens" ) &QLCij5:  
        GetModelMaterial eID, mat [\eUCt F  
    $d4eGL2S  
        mat.Nd = nlens ~%(r47n  
        SetModelMaterial eID, mat NhXTt!S6C  
        Print "Set lens index of refraction = " & nlens *p p1U>,  
    |$^,e%bE  
        '************************************************************************* r(0I>|u  
        'Pupil diameter }G_ i+  
        '************************************************************************* QV7K~qi  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) wE;??'O'l  
    [K x_%Le  
        'Adjust pupil diameter (trimming volume inner hole) 8kX3.X`  
    d8/lEmv[  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" On d"Eq=r  
    H>a3\M  
        ' Adjust pupil location to just in front of the lens +u:8#!X$RD  
        parID = FindFullName( "Geometry.Arizona Eye" ) >J|I  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) rN8 ZQiJC  
        count = 0 !G Z2|~f9  
        While GetOperationCount(eID)>count p~DlZk"  
            GetOperation eID, count, op + .mIC:9  
            If op.Type="ShiftZ" Then B$_F)2%m;  
                DeleteOperation eID,count TdG[b1xN  
                count=count-1 ycIT=AFYqd  
            End If _|x%M}O},  
            count=count+1 _)ZAf% f?  
        Wend 0 A/GWSmF  
        op.Type = "ShiftZ" j"yL6Q9P  
        op.val1 = taq-0.01 3@\vU~=P:  
        op.parent = parID 7f~DD8R  
        AddOperation eID, op -|:7<$2#I  
    C5*j0}  
        Print "Set pupil diameter = " & pupilDiam UdT ~ h  
    ko>SnE|w#  
        'Update AZ Eye subassembly Description rM/*_0[`d  
        eID = FindFullName( "Geometry.Arizona Eye" ) \/. Of]YQ  
        GetEntity eID, entity rKP"|+^  
        entity.Description = "Accommodation = " & A & "D" #$e~ o}(r  
        SetEntity eID, entity Z#3wMK~  
    #sq-V,8  
        Update u3dhMnUn  
        Print "DONE!" ?,;|*A  
         VgN`' iC`I  
    End Sub dPPe_% Ilr  
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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: 9L*gxI>  
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    Accommodation = 4 Diopters /px*v<Aw1  
    Pupil Diameter = 4 mm j}X4#{jgC  
    Set aqueous humor thickness = 2.81 {uDL"~^\  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 J wRdr8q  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 _|g(BK2}  
    Set lens thickness = 3.927 \"<&8  
    Set lens index of refraction = 1.42672 \V+$2 :A  
    Set pupil diameter = 4 p}}}~ lC/  
    DONE! k'xnl"q  
     
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