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infotek 2023-04-27 08:29

Arizona眼睛模型

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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。 Vqb4 MWW  
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模型 7^ITedW@  
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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。 pD eqBO  
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. T7'njaLec  
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光源 .MXznz  
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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。 (lTM5qC  
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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。 =%%\b_\L  
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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。 3qXOsa7  
图2. 字母F光源的设定方法光 |ITp$  _S  
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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 [V|,O'X ~  
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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。 9gZMfP  
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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。 d(3F:dbk  
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图5. 视网膜重点采样规格设定
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脚本 L'BDS*  
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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: <Bn^+u\  
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。 I L 'i7p  
余下的脚本计算与屈光度有关的所有参数。 l"5$6h  
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分析 K_{f6c<  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 X^r5su?  
图7. 字母F在视网膜上颜色分析
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脚本代码 A[oLV"J6x5  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 'b:e`2fl  
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Dim entity As T_ENTITY 7!+kyA\}r^  
Dim op As T_OPERATION M$DJ$G|Z  
Dim mat As T_MODELMATERIAL *%l&'+   
Dim A As Double XSyCT0f08  
Dim pupilDiam As Double 6F6[w?   
Dim eID As Long 3 $ cDC8  
Dim parID As Long %Koc^ pb)  
Dim count As Integer )IPnSh/ <  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double S~d_SU~>`  
Dim tlens As Double, nlens As Double q>/# P5V  
Dim curv As Double, conic As Double JZ  Qkr  
Dim ok As Long S(9Xbw)T  
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Sub Main ?v-IN  
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    '用户输入对话框 @=,2{JF*6  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 0#lw?sv  
        TextBox 220,21,40,21,.TextBox1 'default: 0 )^7Y^u e  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 X|K"p(N  
        OKButton 40,91,90,21 5 WSu  
        CancelButton 190,91,90,21 GenkYtS  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1  *Dtwr  
        TextBox 220,49,40,21,.TextBox2 'default: 4 +(0Fab8g  
    End Dialog P*oKcq1R  
    Dim dlg As UserDialog s `HSTq2  
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    ok = Dialog (dlg) Zx,R6@l  
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    If ok=0 Then    'cancel button was pressed [SgWUP*  
        Print "Execution cancelled." <MZ$baK  
        End f ZL%H0&  
    End If q$z#+2u  
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    'Assign accommodation and pupil diameter & use defaults if field left empty #mlTN3   
    If dlg.TextBox1 = "" Then =]&?(Gq  
        A = 0           'Default accommodation  Q];gC{I  
    Else FL% GW:  
        A = CDbl(dlg.TextBox1) >8Wvz.Nq/  
    End If ]y3V ^W#  
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    If dlg.TextBox2 = "" Then 3p{N7/z(  
        pupilDiam = 4   'Default pupil diameter N]R<EBq  
    Else EbSH)aR  
        pupilDiam = CDbl(dlg.TextBox2) drP2% u  
    End If &I: [ 'l!  
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    Print " " ?Y+xuY/t  
    Print "Accommodation = " & A & " Diopters" Yq}7x1mm  
    Print "Pupil Diameter = " & pupilDiam & " mm" %^[45e  
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    ' Calculate new parameters with accommodation )QE7$|s  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness jIJVl \i]  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens U^vQr%ha  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens !Rk1q&U5  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens J~KWn.  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens dl;~-'0  
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    tlens = 3.767 + 0.04*A                  'Lens thickness s (|T@g  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction ~t[ #p:  
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    'Adjust parameters to account for accommodation C\Q3vG  
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    '************************************************************************* JL $6Fw;  
    'Aqueous thickness (Position of Lens) +jYO?uaT  
    '************************************************************************* Cnd70tbD )  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) r) Ts(#Z  
    GetCustomElement eID, entity ,/6V^K  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ]#R'hL%f  
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    ' Delete any shift(s) in z L,!?'.*/]  
    count = 0 -q' np0H  
    While GetOperationCount(eID)>count UfjLNe}wA  
        GetOperation eID, count, op 9|WBJ6  
        If op.Type="ShiftZ" Then TEz)d=  
            DeleteOperation eID,count (q`Jef  
            count=count-1 \DBoe :0~  
        End If +*'  
        count=count+1 SjD,  
    Wend !Sr^4R+Z  
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    'Set new shift in  {Uxa h  
    op.Type = "ShiftZ" ov: h4  
    op.val1 = taq w,TyV%b[_  
    op.parent = parID c:I1XC  
    AddOperation eID, op ^-{ 1]G:  
    Print "Set aqueous humor thickness = " & taq-0.55 J7$1+|"  
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    '************************************************************************* RrKAgw  
    'Radius and conic constant of anterior lens #n%?}  
    '************************************************************************* 58zs% +F  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ?GqFtNz  
    GetConic eID, entity, curv, conic zOYkkQE3mJ  
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    SetConic eID, entity, 1/Rant, CCant *V#v6r7<Y/  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Fn$/ K  
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    '************************************************************************* L(TO5Y]  
    'Radius and conic constant of posterior lens YS=|y}Q|7d  
    '************************************************************************* xP*9UXZ4P  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) hY+3PNiI@  
    GetConic eID, entity, curv, conic d='z^vHK  
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    SetConic eID, entity, 1/Rpost, CCpost 5&7)hMppI  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost }<7Dyn,  
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    '************************************************************************* 8=gr F  
    'Lens thickness (Position of posterior lens surface) dvxD{UH  
    '************************************************************************* P]!$MOt  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) wOE_2k  
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    ' Delete any z-shift(s) 5FqUFzVqsl  
    count = 0 "F>-W \%  
    While GetOperationCount(eID)>count <y'B !d#  
        GetOperation eID, count, op g3n^ <[E  
        If op.Type="ShiftZ" Then ?"+' OOqik  
            DeleteOperation eID,count Noz+\O\  
            count=count-1 2#_9x7g+  
        End If z/ T|  
        count=count+1 I@cKiB  
    Wend G+4a%?JH  
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    'Set new z-shift RL~|Kr<7J  
    op.Type = "ShiftZ" ^T'+dGU`  
    op.val1 = tlens ^q"p 8   
    op.parent = parID $>'}6?C.  
    AddOperation eID, op 9;dP7o  
    Print "Set lens thickness = " & tlens o;FjpZ  
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    '************************************************************************* :d/Z&LXD  
    'Lens index of refraction 8>j+xbw  
    '************************************************************************* SZg+5MD;X  
    eID = FindMaterial( "Lens" ) )U<4ul  
    GetModelMaterial eID, mat ~FZLA}  
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    mat.Nd = nlens C,]Q/6'>  
    SetModelMaterial eID, mat -iBu:WyY$  
    Print "Set lens index of refraction = " & nlens 9foQ0#R  
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    '************************************************************************* _<;#=l  
    'Pupil diameter )~d2`1zGS  
    '************************************************************************* ,~K_rNNZ  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 3I:DL#f  
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    'Adjust pupil diameter (trimming volume inner hole) PG<N\  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 1Od: I}@  
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    ' Adjust pupil location to just in front of the lens ddnWr"_  
    parID = FindFullName( "Geometry.Arizona Eye" ) HxZ4t  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) >ID 3oi  
    count = 0 l[ @\!;|  
    While GetOperationCount(eID)>count DLS-WL  
        GetOperation eID, count, op 8H;TPa  
        If op.Type="ShiftZ" Then Syp|s3u;  
            DeleteOperation eID,count ]Wd{4(b  
            count=count-1 <@*mFq0,  
        End If 2d.I3z:[  
        count=count+1 BC@"WlD  
    Wend IZAbW  
    op.Type = "ShiftZ" DVTzN(gO*~  
    op.val1 = taq-0.01 J)jiI>  
    op.parent = parID 9\Xl 3j!  
    AddOperation eID, op ACyQsmqm:  
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    Print "Set pupil diameter = " & pupilDiam @Zq,mPaR$  
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    'Update AZ Eye subassembly Description VKik8)/.  
    eID = FindFullName( "Geometry.Arizona Eye" ) "g=ux^+X\  
    GetEntity eID, entity E\V>3rse  
    entity.Description = "Accommodation = " & A & "D" Jr''S}@|x  
    SetEntity eID, entity 6_XX[.%  
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    Update H>DJ-lG(  
    Print "DONE!" Ce_Z &?  
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End Sub 'Y vW|Iq  
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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,D'Hl6(%  
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Accommodation = 4 Diopters Ix *KL=MG  
Pupil Diameter = 4 mm ![vc/wuf  
Set aqueous humor thickness = 2.81 S0 yPg9v  
Set anterior lens radius = 10.4 and conic constant = -2.375869 t?0=;.D  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 p:4vjh=1h  
Set lens thickness = 3.927  )bK<t  
Set lens index of refraction = 1.42672 p!Gf ^  
Set pupil diameter = 4 $C[YqZO  
DONE!
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