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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 lcV<MDS  
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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。 wM[~2C=vx  
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    模型 NA,C Z  
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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。 A8A ~!2V  
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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. >u%]6_[  
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    光源 fFjH "2WD  
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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。 jEXW  
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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。 7kKy\W  
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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。 9;%CHb&  
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    图2. 字母F光源的设定方法光 w<9>Q1(  
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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 U }Hwto`R  
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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。 (J"T]-[  
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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。 YJxw 'U >P  
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    图5. 视网膜重点采样规格设定
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    脚本 4;`Bj:.  
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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: ZV}X'qGaq  
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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。 TaJB4zB  
    余下的脚本计算与屈光度有关的所有参数。 6pE :A@  
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    分析 c':ezEaC  
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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。 #0b&^QL  
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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 nA>sHy  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. vtJV"h?e"3  
    iNCX:Y  
    Dim entity As T_ENTITY 8|twV35  
    Dim op As T_OPERATION h!&sNzX  
    Dim mat As T_MODELMATERIAL V's:>;  
    Dim A As Double yj@tV2  
    Dim pupilDiam As Double T)7TyE|"2g  
    Dim eID As Long V%HS\<$h  
    Dim parID As Long k6IG+:s  
    Dim count As Integer dEM ?~?  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double u}9fj  
    Dim tlens As Double, nlens As Double ghk5rl$   
    Dim curv As Double, conic As Double  H'RL62!  
    Dim ok As Long !rxp?V n -  
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    Sub Main t qOi x/  
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        '用户输入对话框 z*~YLT&  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 k7_I$ <YDj  
            TextBox 220,21,40,21,.TextBox1 'default: 0 F>|9 52  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 V'Y{v  
            OKButton 40,91,90,21 c)C5KaiPG  
            CancelButton 190,91,90,21 b`cYpcs  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 yeD_j/  
            TextBox 220,49,40,21,.TextBox2 'default: 4 fUag1d  
        End Dialog >',y  
        Dim dlg As UserDialog YTY%#"  
    !jS4!2'  
        ok = Dialog (dlg) [UPNd!sy  
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        If ok=0 Then    'cancel button was pressed .")b?#K  
            Print "Execution cancelled." OsW"CF2  
            End EiV=RdL  
        End If 5{ >0eFzG  
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        'Assign accommodation and pupil diameter & use defaults if field left empty j~ym<-[{a  
        If dlg.TextBox1 = "" Then &B-[oqC?  
            A = 0           'Default accommodation G=M] 8+h  
        Else m>Ux`Gp+  
            A = CDbl(dlg.TextBox1) sz09+4h#  
        End If AfWl6a?T8:  
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        If dlg.TextBox2 = "" Then 9rj('F & 1  
            pupilDiam = 4   'Default pupil diameter }(i(Ar-  
        Else c]Unbm^w  
            pupilDiam = CDbl(dlg.TextBox2) G_oX5:J*  
        End If C@dGWAG  
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        Print " " }X1.Wt=?  
        Print "Accommodation = " & A & " Diopters" *M!kA65'  
        Print "Pupil Diameter = " & pupilDiam & " mm" <A~GW 'HB  
    m^$5K's&  
        ' Calculate new parameters with accommodation UC9{m252  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 6c\DJD  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens SfI*bJo>V  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens \ZnN D1A  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens Fn,k!q  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens :4;S"p  
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        tlens = 3.767 + 0.04*A                  'Lens thickness ?R?Grw)`H  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 2,AaP*,  
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        'Adjust parameters to account for accommodation G*\sdBW!k  
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        '************************************************************************* F!CAitxd  
        'Aqueous thickness (Position of Lens) @%B4;c  
        '************************************************************************* Ex,JB +  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ,+-?Zv 2  
        GetCustomElement eID, entity '0Zm#g  
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        parID = FindFullName( "Geometry.Arizona Eye" ) w`#fH  
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        ' Delete any shift(s) in z  rA#s   
        count = 0 zUQe0Gc.b^  
        While GetOperationCount(eID)>count v' 0!=r  
            GetOperation eID, count, op *]!l%Uf%  
            If op.Type="ShiftZ" Then fOW_h  
                DeleteOperation eID,count F"BL #g66  
                count=count-1 eUs-5 L  
            End If X8b#[40:  
            count=count+1 6F ;Or  
        Wend WD;)VsP  
    1 ;Ju]  
        'Set new shift in 0#=W#Jl>  
        op.Type = "ShiftZ" R9=K(pOT  
        op.val1 = taq lM&UFEl-\  
        op.parent = parID c!~T2t  
        AddOperation eID, op hZ o5p&b  
        Print "Set aqueous humor thickness = " & taq-0.55 bFn(w:1Q  
    #7C6yXb%  
        '************************************************************************* ^f0(aYWx  
        'Radius and conic constant of anterior lens U9F6d!:L7A  
        '************************************************************************* sy.:T]ZH  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) >t,O2~  
        GetConic eID, entity, curv, conic ]+lF=kkc %  
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        SetConic eID, entity, 1/Rant, CCant gUb "3g0  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant qzlER  
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        '************************************************************************* Fva]*5  
        'Radius and conic constant of posterior lens HqRCjD  
        '************************************************************************* [k ~C+FI  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) XC}1_VWs  
        GetConic eID, entity, curv, conic Xr2 Wa  
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        SetConic eID, entity, 1/Rpost, CCpost fU` T\  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost C,3T!\  
    6>lW5U^yA\  
        '************************************************************************* XJ\_ V[WA  
        'Lens thickness (Position of posterior lens surface) "Y(%oJS]D  
        '************************************************************************* ;3 dM@>5[  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) g6`.qyVfz'  
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        ' Delete any z-shift(s) `{WCrw6)  
        count = 0 kw;wlFU;  
        While GetOperationCount(eID)>count v'$ykZ!Z  
            GetOperation eID, count, op YiO3<}Uf  
            If op.Type="ShiftZ" Then ^Wk0*.wg  
                DeleteOperation eID,count WSSaZ9 =  
                count=count-1 cY^Y!.,  
            End If ,`+Bs&S 8  
            count=count+1 I'P.K| "R  
        Wend 3} l;  
    W -3w7^  
        'Set new z-shift wV?[3bEhM  
        op.Type = "ShiftZ" . *Z#cq0  
        op.val1 = tlens TiTYs  
        op.parent = parID " _mmR M  
        AddOperation eID, op 8db6(Q~P  
        Print "Set lens thickness = " & tlens i'9e K O  
    o` 2 5  
        '************************************************************************* R,XD6'Q  
        'Lens index of refraction oX2r?.j#M  
        '************************************************************************* 4bWfx _0W  
        eID = FindMaterial( "Lens" ) [!5l0{0  
        GetModelMaterial eID, mat i /C'0  
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        mat.Nd = nlens J511AoQ{R  
        SetModelMaterial eID, mat "NlRSc#  
        Print "Set lens index of refraction = " & nlens "_ Zh5 g  
    E=3#TBd  
        '************************************************************************* %jpH:-8'2  
        'Pupil diameter -<_+-t  
        '************************************************************************* +)% ,G@-`  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) *:k~g].Iz  
    j`Tm\!q  
        'Adjust pupil diameter (trimming volume inner hole) tYF$#Nor#k  
    qNhH%tYQ  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" |:{g?4Mi  
    #V,LNX)  
        ' Adjust pupil location to just in front of the lens 01'y^`\xQ  
        parID = FindFullName( "Geometry.Arizona Eye" ) ]U#JsMS  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) q=J9L Q  
        count = 0 }7otuO(pRo  
        While GetOperationCount(eID)>count g6HphRJ5s  
            GetOperation eID, count, op 5^bh.uF  
            If op.Type="ShiftZ" Then 7O]J^H+7  
                DeleteOperation eID,count Bi %Z2/  
                count=count-1 !>?4[|?n<  
            End If q|?`Gsr  
            count=count+1 `4se7{'UK`  
        Wend eUi> Mp  
        op.Type = "ShiftZ" NU BpIx&  
        op.val1 = taq-0.01 z&\Il#'\m+  
        op.parent = parID W` WLW8Qsw  
        AddOperation eID, op [%HYh7ua<  
    +qE,<c}}  
        Print "Set pupil diameter = " & pupilDiam X L{{7%j  
    [P(rY  
        'Update AZ Eye subassembly Description Vf@S8H  
        eID = FindFullName( "Geometry.Arizona Eye" ) B:B0p+$I  
        GetEntity eID, entity R?1idl)  
        entity.Description = "Accommodation = " & A & "D" ~NTDG  
        SetEntity eID, entity {Q}!NkF 1  
    OaX HJ^k  
        Update #JHy[!4  
        Print "DONE!" IptB.bYc  
         V.O<|tl.  
    End Sub u<BHf@AI  
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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: V,99N'o~x  
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    Accommodation = 4 Diopters z36brv<_'p  
    Pupil Diameter = 4 mm R (+h)#![  
    Set aqueous humor thickness = 2.81 Nv}U/$$S  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 Uqb]e?@  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 P]~N-xdV  
    Set lens thickness = 3.927 B<vvsp\X  
    Set lens index of refraction = 1.42672 [,.[gWA  
    Set pupil diameter = 4 KqT#zj  
    DONE! s{x*~M$vt  
     
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