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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。 # 3.)H9  
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模型 U}P,EP%p  
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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。 r\mPIr|  
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. co]Gmg6p  
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光源 Xem| o&  
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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。 U)~#g'6:8  
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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。 q) _r3   
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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。 UH40~LxIma  
图2. 字母F光源的设定方法光 0eA5zFU7  
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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 G2@KI-  
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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。 qc-C>Ra  
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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。 q] ZSj J  
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图5. 视网膜重点采样规格设定
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脚本 NEg>lIu<~  
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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: Qi|?d7k0  
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。 dqwWfn1lt  
余下的脚本计算与屈光度有关的所有参数。 [iXi\Ex  
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分析 ~bFdJj 1*  
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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。 7uA\&/ ,  
图7. 字母F在视网膜上颜色分析
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脚本代码 a'^0.1  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. X=#It&m%s  
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Dim entity As T_ENTITY f:FpyCo=9  
Dim op As T_OPERATION G)4SWu0<t  
Dim mat As T_MODELMATERIAL ytob/tc  
Dim A As Double F b2p(.  
Dim pupilDiam As Double 1::LN(`<  
Dim eID As Long VB's  
Dim parID As Long i)8gCDc  
Dim count As Integer A{t"M-<  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double V:QdQ;c  
Dim tlens As Double, nlens As Double W\a!Q]pV  
Dim curv As Double, conic As Double 79a9L{gso  
Dim ok As Long g X8**g'  
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Sub Main l)%mqW%  
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    '用户输入对话框 uYY=~o[ Tw  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 pbFYiu+  
        TextBox 220,21,40,21,.TextBox1 'default: 0 8eN%sm  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 7NeDs$  
        OKButton 40,91,90,21 dGa@<hg  
        CancelButton 190,91,90,21 -@#Pc#  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 oN4G1U Kc  
        TextBox 220,49,40,21,.TextBox2 'default: 4 bbO+%-(X  
    End Dialog +!G4tA$g  
    Dim dlg As UserDialog D|"sE>  
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    ok = Dialog (dlg) {DSyV:   
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    If ok=0 Then    'cancel button was pressed 22PGWSQ  
        Print "Execution cancelled." OoE9W  
        End MHGjvSx  
    End If s5nB(L*Pjp  
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    'Assign accommodation and pupil diameter & use defaults if field left empty ?${V{=)*X'  
    If dlg.TextBox1 = "" Then 4YBf ~Pp  
        A = 0           'Default accommodation ZHb7+  
    Else '}@e5^oL  
        A = CDbl(dlg.TextBox1) jm4)gmC  
    End If ^z38<L=z"  
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    If dlg.TextBox2 = "" Then ;r%<2(  
        pupilDiam = 4   'Default pupil diameter n}+wd9J*!2  
    Else }Z^FEd"y  
        pupilDiam = CDbl(dlg.TextBox2) _ \_3s  
    End If :l4^iSf  
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    Print " " #&}%70R)  
    Print "Accommodation = " & A & " Diopters" gYRqqV  
    Print "Pupil Diameter = " & pupilDiam & " mm" =z+-l5Gu"  
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    ' Calculate new parameters with accommodation vY4WQbz(  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness #j\*Lc"Ur:  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ]~$c~*0g  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens  3&O% &  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens q$ bHO  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens (H'_KPK  
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    tlens = 3.767 + 0.04*A                  'Lens thickness o-L|"3 P  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction -Mr{+pf  
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    'Adjust parameters to account for accommodation hgF21Oj9  
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    '************************************************************************* TXA. 6e  
    'Aqueous thickness (Position of Lens) ^H f+du  
    '************************************************************************* 1!K !oY  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) z?8zFP  
    GetCustomElement eID, entity W ]a7&S  
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    parID = FindFullName( "Geometry.Arizona Eye" ) n P0Ziu'{  
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    ' Delete any shift(s) in z %Y#[% ~|(  
    count = 0 >^M!@=/?J  
    While GetOperationCount(eID)>count MBnK&GS  
        GetOperation eID, count, op |:!E HFr  
        If op.Type="ShiftZ" Then <|mE9u  
            DeleteOperation eID,count oVKsic?  
            count=count-1 3(oZZz  
        End If ZE5-i@1  
        count=count+1 CUAg{]  
    Wend K8e4ax  
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    'Set new shift in \9&YV;Ct  
    op.Type = "ShiftZ" yt]Oj*nn0K  
    op.val1 = taq  r*~n`  
    op.parent = parID (ouRf;\6$8  
    AddOperation eID, op mtiO7w"M\7  
    Print "Set aqueous humor thickness = " & taq-0.55 dVY(V&p  
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    '************************************************************************* hlABu)B'1  
    'Radius and conic constant of anterior lens Z&?+&q r^  
    '************************************************************************* f(@"[-[  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) G}Qk!r  
    GetConic eID, entity, curv, conic uIVTs9\  
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    SetConic eID, entity, 1/Rant, CCant b |o`Q7Hj  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant -(%ar%~Zd  
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    '************************************************************************* 6Zl.Lh  
    'Radius and conic constant of posterior lens USHlb#*  
    '************************************************************************* YUP%K!k  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) { ="Su{i}}  
    GetConic eID, entity, curv, conic ;r0|_mnf  
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    SetConic eID, entity, 1/Rpost, CCpost rU2YMghE  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost !#_h2a  
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    '************************************************************************* l&e5_]+%  
    'Lens thickness (Position of posterior lens surface) $)kBz*C[  
    '************************************************************************* H L}sqcp  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) X*c_^g{  
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    ' Delete any z-shift(s) yP1Y3Tga=  
    count = 0 {m*V/tX  
    While GetOperationCount(eID)>count +*r**(-Dm  
        GetOperation eID, count, op )$Dcrrj  
        If op.Type="ShiftZ" Then pJ)+}vascR  
            DeleteOperation eID,count yccuTQvz  
            count=count-1 mV! @oNCK  
        End If K@$L~G  
        count=count+1 #sm_.?P  
    Wend 67K RM(S  
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    'Set new z-shift fW4cHB 9|  
    op.Type = "ShiftZ" _L `N^I.  
    op.val1 = tlens ?( dYW7S  
    op.parent = parID 3Q!J9t5dc  
    AddOperation eID, op n'&`9M['%d  
    Print "Set lens thickness = " & tlens +{=_|3(  
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    '************************************************************************* ou,=MpXx*  
    'Lens index of refraction Jv4D^>yj[  
    '************************************************************************* #.<F5  
    eID = FindMaterial( "Lens" ) r PRuSk-f  
    GetModelMaterial eID, mat !>Qc2&ZV  
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    mat.Nd = nlens 8t*%q+Z  
    SetModelMaterial eID, mat _ c(C;s3o  
    Print "Set lens index of refraction = " & nlens E23 Yk?"  
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    '************************************************************************* UmD-7Fd  
    'Pupil diameter "<jEI /  
    '************************************************************************* ,;=( )-  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 8HRPJSO~g  
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    'Adjust pupil diameter (trimming volume inner hole) ^]lwd"$  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" KZ<RDXVT  
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    ' Adjust pupil location to just in front of the lens s eZ<52f2  
    parID = FindFullName( "Geometry.Arizona Eye" ) mTuB*  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) b#I*~  
    count = 0 VgZaDd;  
    While GetOperationCount(eID)>count b-(UsY:  
        GetOperation eID, count, op o"ah\"#el  
        If op.Type="ShiftZ" Then g<T`F  
            DeleteOperation eID,count 1-NX>E5  
            count=count-1 MkNURy>n&  
        End If HT,kx  
        count=count+1 iZq@W3GL C  
    Wend rX>y>{w~  
    op.Type = "ShiftZ" 72`/xryY  
    op.val1 = taq-0.01 -IE P?NX  
    op.parent = parID ">vYEkZ3  
    AddOperation eID, op L5k>;|SA  
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    Print "Set pupil diameter = " & pupilDiam T;[c<gc/  
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    'Update AZ Eye subassembly Description lKhh=Pc2  
    eID = FindFullName( "Geometry.Arizona Eye" ) QH' [ (  
    GetEntity eID, entity 6[h$r/GXh"  
    entity.Description = "Accommodation = " & A & "D" &<P^Tvqq&  
    SetEntity eID, entity Qdr-GODx  
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    Update 5f*'wA  
    Print "DONE!" ,S0~:c:)  
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End Sub ExP25T  
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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: 'GzhZ`E6  
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Accommodation = 4 Diopters ,f0g|5yDf  
Pupil Diameter = 4 mm qD%&\ZT  
Set aqueous humor thickness = 2.81 $E,DxDT  
Set anterior lens radius = 10.4 and conic constant = -2.375869 ;1g-z]  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 0G\myv  
Set lens thickness = 3.927 w$;*~Qc  
Set lens index of refraction = 1.42672 Y7V&zF{  
Set pupil diameter = 4 Y$$?8xr ~  
DONE!
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