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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 ==`K$rM  
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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。 P\KP)bkC  
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模型 1U.se` L  
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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。 3]WIN_h  
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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. o1YX^-<[F  
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光源 R<{bb'  
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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。 bPEf2Z G4  
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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。 zm) ]cq  
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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。 |8PUmax  
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图2. 字母F光源的设定方法光 DvHcT] l>5  
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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 @'j=oTT  
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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。 3Ba>a(E  
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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。 Iq0_X7:{QI  
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图5. 视网膜重点采样规格设定
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脚本 $'*@g1v Y  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: 2Un~ Iy  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 _" W<>  
余下的脚本计算与屈光度有关的所有参数。 e^Q$Tog<  
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分析 0H,1"~,w]  
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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。 JUXIE y^  
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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 Nl3 x BM%  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 4wh_ iO  
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Dim entity As T_ENTITY &cztUM(  
Dim op As T_OPERATION Q1J./C}  
Dim mat As T_MODELMATERIAL ["|AD,$%  
Dim A As Double *c4uCI:0t  
Dim pupilDiam As Double yG|^-O}L  
Dim eID As Long rq?:I:0  
Dim parID As Long i <0H W  
Dim count As Integer J/S 47J~  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Ac;rMwXk#  
Dim tlens As Double, nlens As Double c9imfA+e  
Dim curv As Double, conic As Double LWE[]1=  
Dim ok As Long 3-#|6khqt  
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Sub Main /3->TS  
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    '用户输入对话框 =xcA4"k  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 P.Pw .[:3  
        TextBox 220,21,40,21,.TextBox1 'default: 0 <6^MVaD  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 y%)5r}S^  
        OKButton 40,91,90,21 EM]~yn!+  
        CancelButton 190,91,90,21 ^(y=DJ7  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Fq/?0B8  
        TextBox 220,49,40,21,.TextBox2 'default: 4 hV|pH)Nu{  
    End Dialog #TZf\0\!  
    Dim dlg As UserDialog T)wc{C9w  
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    ok = Dialog (dlg) UH/)4Wg  
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    If ok=0 Then    'cancel button was pressed YfL|FsCh  
        Print "Execution cancelled." _h>S7-X  
        End ._@Scd  
    End If tn\Y:  
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    'Assign accommodation and pupil diameter & use defaults if field left empty vRa|lGeW  
    If dlg.TextBox1 = "" Then _"n1"%Ns  
        A = 0           'Default accommodation 9t@^P^}=\m  
    Else vw=OGjT_>m  
        A = CDbl(dlg.TextBox1) u4TU"r("A  
    End If ~01 o  
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    If dlg.TextBox2 = "" Then p48M7OV  
        pupilDiam = 4   'Default pupil diameter F{}mlQg  
    Else =g4^tIYq  
        pupilDiam = CDbl(dlg.TextBox2) , f9V`Pz)  
    End If *0]E4]ZO  
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    Print " " kG_ K&,;@  
    Print "Accommodation = " & A & " Diopters" Ug>yTc_(7  
    Print "Pupil Diameter = " & pupilDiam & " mm" )&:4//}a  
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    ' Calculate new parameters with accommodation ^$qr6+  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ,73 kh  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens s\ft:a@  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens -=BQVJ_dK{  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens %T@3-V_  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ixF '-  
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    tlens = 3.767 + 0.04*A                  'Lens thickness \Z9+U:n  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction H.|v ^e  
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    'Adjust parameters to account for accommodation 8 tMfh  
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    '************************************************************************* ^@?-YWt   
    'Aqueous thickness (Position of Lens) M{I8b<hY  
    '************************************************************************* .;j}:<  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) ~]X4ru5,4  
    GetCustomElement eID, entity kBolDPvBG  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ; (I(TG  
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    ' Delete any shift(s) in z pN# \  
    count = 0 *olV Y/'O  
    While GetOperationCount(eID)>count |9>?{ B\a  
        GetOperation eID, count, op  fp!Ba  
        If op.Type="ShiftZ" Then !K a!f1  
            DeleteOperation eID,count Zwj\Hz.  
            count=count-1 F<SMU4]YdG  
        End If t\44 Pu%  
        count=count+1 =^ur@E  
    Wend xo{3r\u?}  
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    'Set new shift in d*3;6ZLy  
    op.Type = "ShiftZ" 5bU[uT,`6  
    op.val1 = taq 9x;CJhX  
    op.parent = parID ^q``f%Xt  
    AddOperation eID, op P.^%8L  
    Print "Set aqueous humor thickness = " & taq-0.55 <Stfqa6FJ  
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    '************************************************************************* p)l>bC?3  
    'Radius and conic constant of anterior lens 9pAklD4  
    '************************************************************************* =xwA'D9]  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) mqL&bmT  
    GetConic eID, entity, curv, conic I*c B Ha  
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    SetConic eID, entity, 1/Rant, CCant pzcV[E1  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant QC@nRy8%  
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    '************************************************************************* `I*W}5  
    'Radius and conic constant of posterior lens ,<iJ#$: Sx  
    '************************************************************************* ul[edp_  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) EHpIbj;n  
    GetConic eID, entity, curv, conic tXj28sh$  
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    SetConic eID, entity, 1/Rpost, CCpost TAfLC)  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost vY|{CBGbd  
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    '************************************************************************* s;oDwT1  
    'Lens thickness (Position of posterior lens surface) bvyX(^I[q  
    '************************************************************************* #H9J/k_  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) s7j#Yg  
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    ' Delete any z-shift(s) !uaV6K  
    count = 0 a/ d'(]  
    While GetOperationCount(eID)>count ZJUTtiD  
        GetOperation eID, count, op z?o1 6o-:  
        If op.Type="ShiftZ" Then a<AT;Tc  
            DeleteOperation eID,count s^5KFK1  
            count=count-1 R7~H}>uaF  
        End If Y=RdxCCx4  
        count=count+1 J:s^F n  
    Wend 0*?/s\>PS;  
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    'Set new z-shift AhjK*nJF  
    op.Type = "ShiftZ" );4lM%]eb  
    op.val1 = tlens _ _x2xtrH  
    op.parent = parID Gb)!]:8  
    AddOperation eID, op t;wfp>El  
    Print "Set lens thickness = " & tlens SplEY!.k  
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    '************************************************************************* 3yNILj  
    'Lens index of refraction y+3< ] N  
    '************************************************************************* pqaQ%|<  
    eID = FindMaterial( "Lens" ) 8Ar5^.k  
    GetModelMaterial eID, mat W<Ms0  
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    mat.Nd = nlens }9n{E-bj*  
    SetModelMaterial eID, mat tvNh@it:F  
    Print "Set lens index of refraction = " & nlens r;3{%S._  
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    '************************************************************************* CD$0Z  
    'Pupil diameter bMT1(edm  
    '*************************************************************************  _N`:NOM  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) VCOz?Y*  
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    'Adjust pupil diameter (trimming volume inner hole) N[$bP)h7  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" QR'yZ45n4  
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    ' Adjust pupil location to just in front of the lens -Y]ue*k{  
    parID = FindFullName( "Geometry.Arizona Eye" ) ;{Cr+lqTJ  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) bZ!*s  
    count = 0 >Mml+4<5  
    While GetOperationCount(eID)>count oj.f uJD  
        GetOperation eID, count, op p4m9@ \gn  
        If op.Type="ShiftZ" Then F:"CaDk  
            DeleteOperation eID,count j^DoILw  
            count=count-1 " 9=F/o9  
        End If *P4G}9B|9:  
        count=count+1 <5qXC.{Cyp  
    Wend O*MC"%T  
    op.Type = "ShiftZ" 9NCo0!Fb  
    op.val1 = taq-0.01 y%.^| G  
    op.parent = parID U=_O*n?N-d  
    AddOperation eID, op (n'Mf  
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    Print "Set pupil diameter = " & pupilDiam 20[_eu)  
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    'Update AZ Eye subassembly Description Ns.b8Y  
    eID = FindFullName( "Geometry.Arizona Eye" ) JA!O,4  
    GetEntity eID, entity B j!{JcM-^  
    entity.Description = "Accommodation = " & A & "D" .ztO._J7f  
    SetEntity eID, entity 5mNd5IM  
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    Update ]Bo !v*12  
    Print "DONE!" ?m3,e&pB5  
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End Sub lp`raN No  
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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: VEAf,{)Q  
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Accommodation = 4 Diopters &Q7vY  
Pupil Diameter = 4 mm c`]_Q1'30w  
Set aqueous humor thickness = 2.81 m'h`%0Tc  
Set anterior lens radius = 10.4 and conic constant = -2.375869 }K\] M@  
Set posterior lens radius = -4.424557 and conic constant = -3.081019  M1>< K:  
Set lens thickness = 3.927 >;Er[Rywr  
Set lens index of refraction = 1.42672 0)/L+P5  
Set pupil diameter = 4 0 rbMT`Hy  
DONE! \$o5$/oU(  
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