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infotek 2022-02-25 09:52

Arizona眼睛模型

简介 q}&+{dN\1  
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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。 A<[w'"  
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模型 hLyV'*}  
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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。 2bpFQ8q  
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.  8KzH -  
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光源 ZB,UQ~!Yr  
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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。 EmV ZqW  
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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。 t3.I ` Z  
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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。 NV3oJ0f&2  
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图2. 字母F光源的设定方法光 :-b-)*TC;  
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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 ~rbJtz  
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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。 Mwd.S  
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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。 *18J$  
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图5. 视网膜重点采样规格设定
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脚本 .@f )#2  
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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: 3;EBKGg|  
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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。 h &IF ?h  
余下的脚本计算与屈光度有关的所有参数。 D+Z,;XZ  
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分析 $b"Ex>  
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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。 /C[XC7^4'  
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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 (7}Zh|@W  
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  1. Option Explicit     'Remove this to enable non-dimensioned variables to be used. 8)&J oPN  
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    Dim entity As T_ENTITY ?} U l(  
    Dim op As T_OPERATION 2v1dSdX,W  
    Dim mat As T_MODELMATERIAL \1#!% I=.  
    Dim A As Double VI^~I;M^  
    Dim pupilDiam As Double N'0fB`:kz  
    Dim eID As Long =D?{d{JT  
    Dim parID As Long V?z-Dt C  
    Dim count As Integer H AMps[D[  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double H?dEgubg7]  
    Dim tlens As Double, nlens As Double ^p #bxN")  
    Dim curv As Double, conic As Double vjXCArS  
    Dim ok As Long `k'Dm:*`u4  
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    Sub Main 6T A2  
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        '用户输入对话框 R2nDK7j  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 0:k MnHn\  
            TextBox 220,21,40,21,.TextBox1 'default: 0 <e'l"3+9(  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 L~L]MC&  
            OKButton 40,91,90,21 K/XUF#^B]  
            CancelButton 190,91,90,21 !EO 2  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 {]:B80I;2  
            TextBox 220,49,40,21,.TextBox2 'default: 4 VufG7%S{  
        End Dialog ? 1b*9G%i  
        Dim dlg As UserDialog \b|Q`)TK  
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        ok = Dialog (dlg) ` oXL  
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        If ok=0 Then    'cancel button was pressed i]n ?zWo_h  
            Print "Execution cancelled." 7)v`l1  
            End +jz%:D  
        End If "0l7%@z*)q  
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        'Assign accommodation and pupil diameter & use defaults if field left empty {Ng HH]]O  
        If dlg.TextBox1 = "" Then 9mH+Ol#(  
            A = 0           'Default accommodation Rk52K*Dc  
        Else s$;IR c5!6  
            A = CDbl(dlg.TextBox1) t%>x}b"2T  
        End If DYvg^b  
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        If dlg.TextBox2 = "" Then vE+OL8V  
            pupilDiam = 4   'Default pupil diameter vH9Gf  
        Else q5(Z   
            pupilDiam = CDbl(dlg.TextBox2) f@= lK?Pfh  
        End If 0_5j(   
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        Print " " ]gGCy '*)  
        Print "Accommodation = " & A & " Diopters" w*s#=]6  
        Print "Pupil Diameter = " & pupilDiam & " mm" Ty>g:#bogI  
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        ' Calculate new parameters with accommodation }]?U. ]-  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness o+Kh2;$)  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens h 66X746  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens Sk,9<@  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens = g)G!  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ZIrJ"*QO=  
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        tlens = 3.767 + 0.04*A                  'Lens thickness |K6hY-uC  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction A/"p PO  
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        'Adjust parameters to account for accommodation f@a@R$y  
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        '************************************************************************* i\?P>:)  
        'Aqueous thickness (Position of Lens) Qvd$fY**  
        '************************************************************************* Z"fnjH  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) )pXw 3Fo  
        GetCustomElement eID, entity = A !;`G  
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        parID = FindFullName( "Geometry.Arizona Eye" ) rpT{0 >5  
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        ' Delete any shift(s) in z MrA&xM  
        count = 0 7+I2" Hy  
        While GetOperationCount(eID)>count 8HLcDS#  
            GetOperation eID, count, op ^L<*ggw  
            If op.Type="ShiftZ" Then q:1_D>  
                DeleteOperation eID,count k98}Jx7J)"  
                count=count-1 AQ 5CrYb  
            End If 5PQs1B  
            count=count+1 '.wyfSH@  
        Wend Y(]&j`%  
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        'Set new shift in \k|ZbCWg  
        op.Type = "ShiftZ" &,Xs=Lv mq  
        op.val1 = taq $v6dB {%Qu  
        op.parent = parID :>[;XT<  
        AddOperation eID, op h,V#V1>Hu  
        Print "Set aqueous humor thickness = " & taq-0.55 oIM]  
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        '************************************************************************* z.[ Ok  
        'Radius and conic constant of anterior lens a]465FY  
        '************************************************************************* M#qZ0JT4  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) uj-q@IKe  
        GetConic eID, entity, curv, conic <'4DMZ-G  
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        SetConic eID, entity, 1/Rant, CCant ?~a M<rcZ  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant T@]vjXd![  
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        '************************************************************************* +*Cg2`  
        'Radius and conic constant of posterior lens x=qACoq  
        '************************************************************************* 8fdK|l w  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Q H%{r4  
        GetConic eID, entity, curv, conic Iy](?b  
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        SetConic eID, entity, 1/Rpost, CCpost gtHk1 9  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost X!n-nms  
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        '************************************************************************* m)q;eQs  
        'Lens thickness (Position of posterior lens surface) 'sm+3d  
        '************************************************************************* d& @KGJ  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) m4n J9<-  
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        ' Delete any z-shift(s) zk4yh%Cd_  
        count = 0 Fa9]!bW  
        While GetOperationCount(eID)>count ^AD/N|X^  
            GetOperation eID, count, op q5[%B K  
            If op.Type="ShiftZ" Then hSD)|  
                DeleteOperation eID,count S&V5zB""n  
                count=count-1 z1LATy  
            End If E<a~ `e  
            count=count+1 CPGXwM=   
        Wend 1H @GwQ|<=  
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        'Set new z-shift HqU"i Y>b  
        op.Type = "ShiftZ" awXL}m[_!  
        op.val1 = tlens xGqe )M>8?  
        op.parent = parID ''wWw(2O  
        AddOperation eID, op F#iLMO&Q  
        Print "Set lens thickness = " & tlens A"C%.InZ  
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        '************************************************************************* Gn;eh~uw;l  
        'Lens index of refraction W?'!}g(~  
        '************************************************************************* FQ?H%UcW  
        eID = FindMaterial( "Lens" ) 0sq/_S  
        GetModelMaterial eID, mat bs]ret$?(q  
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        mat.Nd = nlens (>>pla^  
        SetModelMaterial eID, mat 5D]%E?ag  
        Print "Set lens index of refraction = " & nlens 'mug,jM  
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        '************************************************************************* .$4DK*  
        'Pupil diameter 4%p5X8|\ih  
        '************************************************************************* _hMVv&$  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Tc\^=e^N?  
    r#]gAG4t\  
        'Adjust pupil diameter (trimming volume inner hole) q`}Q[Li  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" &6MGPh7T  
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        ' Adjust pupil location to just in front of the lens ez86+  
        parID = FindFullName( "Geometry.Arizona Eye" ) J*,Ed51&7  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) %o#D"  
        count = 0 p0$K.f| ^  
        While GetOperationCount(eID)>count &N*S   
            GetOperation eID, count, op -j]r\EVKS  
            If op.Type="ShiftZ" Then #JO#PV%  
                DeleteOperation eID,count xwT"Q=|kW  
                count=count-1 ',6QL4qV/  
            End If xv 7^  
            count=count+1 `Xmf4  
        Wend zG@9-s* L  
        op.Type = "ShiftZ" @'R4zJ&+S  
        op.val1 = taq-0.01  O\]CfzR  
        op.parent = parID V>A@Sw  
        AddOperation eID, op * 2T&pX  
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        Print "Set pupil diameter = " & pupilDiam N iNZh;  
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        'Update AZ Eye subassembly Description AWQwpaj-  
        eID = FindFullName( "Geometry.Arizona Eye" ) i3;Z:,A4NN  
        GetEntity eID, entity LD_aJ^(d  
        entity.Description = "Accommodation = " & A & "D" 1uMnlimr  
        SetEntity eID, entity |mk$W$h  
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        Update YV{^S6M  
        Print "DONE!" @/anJrt  
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    End Sub !S%XIq}FX  
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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: !&SUoa  
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    Accommodation = 4 Diopters )5d&K8@  
    Pupil Diameter = 4 mm '$1-A%e$1  
    Set aqueous humor thickness = 2.81 t ~U&a9&Z  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 ,O 3"r;  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 cy^6g? ew  
    Set lens thickness = 3.927 >\} 2("bv  
    Set lens index of refraction = 1.42672 \RMYaI^+;  
    Set pupil diameter = 4 XuR!9x^5  
    DONE!
silence唯爱 2022-02-25 13:53
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