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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。 2LiJ IO8N  
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模型 'hf#Q9W5  
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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。 f2`[skNj  
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. &j<B22t!  
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光源 %u, H2 *  
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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。 f1rP+l-C<  
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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。 `1=n H/E  
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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。 .D(H@3qA@  
图2. 字母F光源的设定方法光 I% ivY  
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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 W;4rhZEgd  
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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。  _/;vsQB  
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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。 C< 3` ]l  
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图5. 视网膜重点采样规格设定
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脚本 2F%2K?$`Ej  
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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: mEeD[dMN  
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。 Hb55RilC  
余下的脚本计算与屈光度有关的所有参数。 rE$0a-d2B  
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分析 uH="l.u  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 |L[/]@|  
图7. 字母F在视网膜上颜色分析
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脚本代码 :d}I`)&  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. `v?XFwnV`  
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Dim entity As T_ENTITY )-VpDW!%_  
Dim op As T_OPERATION ]dIcW9a  
Dim mat As T_MODELMATERIAL r&+8\/{  
Dim A As Double (SGX|,5X7  
Dim pupilDiam As Double i ]x_W@h  
Dim eID As Long 3w!8PPl  
Dim parID As Long RT`.S uN  
Dim count As Integer zW#P ~zS  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double v+d} _rCT  
Dim tlens As Double, nlens As Double uaghB,i'n  
Dim curv As Double, conic As Double A\ARjSdb  
Dim ok As Long {6Y|Z>  
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Sub Main [GQn1ZLc  
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    '用户输入对话框 M5 \flE2  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 jKr\mb  
        TextBox 220,21,40,21,.TextBox1 'default: 0 4N6JKS  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 wtM1gYl^  
        OKButton 40,91,90,21 >|zMN$:  
        CancelButton 190,91,90,21 (;VlK#rnC  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ES,T[  
        TextBox 220,49,40,21,.TextBox2 'default: 4 sU Er?TZ  
    End Dialog B']-4X{SGa  
    Dim dlg As UserDialog EDAtC  
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    ok = Dialog (dlg) FQTAkkA_!  
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    If ok=0 Then    'cancel button was pressed 6mV-+CnYC  
        Print "Execution cancelled." :'`y}'  
        End ?_ 476A  
    End If moS0y?N  
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    'Assign accommodation and pupil diameter & use defaults if field left empty sGFvSW  
    If dlg.TextBox1 = "" Then S^s|/!>  
        A = 0           'Default accommodation 9$k0  
    Else S5o,\wT  
        A = CDbl(dlg.TextBox1) uwl_TDc>%  
    End If %lq[,6?>5  
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    If dlg.TextBox2 = "" Then &R5zt]4d&  
        pupilDiam = 4   'Default pupil diameter O NVhB  
    Else TB}6iIe  
        pupilDiam = CDbl(dlg.TextBox2) {x{~%)-  
    End If igx~6G*  
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    Print " " ) >te|@}o  
    Print "Accommodation = " & A & " Diopters" "7q!u,u  
    Print "Pupil Diameter = " & pupilDiam & " mm" ui RO,B}z  
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    ' Calculate new parameters with accommodation \VpN:RI  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness EDT9O  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens o_8Wnx^  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ?lE&o w  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 3{)!T;Wd  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens fUMjLA|*I<  
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    tlens = 3.767 + 0.04*A                  'Lens thickness e@Mg9VwDc  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction B"YN+So  
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    'Adjust parameters to account for accommodation 4VF4 8  
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    '************************************************************************* 7KesfH?  
    'Aqueous thickness (Position of Lens) !(Ymc_s  
    '************************************************************************* 5S<Rz)1r  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) JC0#pU;  
    GetCustomElement eID, entity >AFQm  
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    parID = FindFullName( "Geometry.Arizona Eye" )  !2kM  
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    ' Delete any shift(s) in z 5vFM0  
    count = 0 IL go:xQ  
    While GetOperationCount(eID)>count f&j\gYWq  
        GetOperation eID, count, op 3! #|hI>f  
        If op.Type="ShiftZ" Then }uNj#Uf  
            DeleteOperation eID,count 3[j,d]\|  
            count=count-1 jzJQ/ZFS  
        End If Iprt ZqiL  
        count=count+1 IsmZEVuC  
    Wend _aYhW{wW  
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    'Set new shift in A!,c@Kv 3  
    op.Type = "ShiftZ" 0BNH~,0u  
    op.val1 = taq {yv_Ni*6!  
    op.parent = parID Td ade+  
    AddOperation eID, op Siq]Ii0F;>  
    Print "Set aqueous humor thickness = " & taq-0.55 0cSm^a  
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    '*************************************************************************  V~VUl)  
    'Radius and conic constant of anterior lens _CPj] m{  
    '************************************************************************* gg.]\#3g  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) @ <3E `j'p  
    GetConic eID, entity, curv, conic L pq)TE#  
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    SetConic eID, entity, 1/Rant, CCant Z^]jy>dj  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 5kGQf  
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    '************************************************************************* =@ acg0  
    'Radius and conic constant of posterior lens e]nP7TIU  
    '************************************************************************* T;5VNRgpI  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) rrR"2WuGO  
    GetConic eID, entity, curv, conic l9C `:g  
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    SetConic eID, entity, 1/Rpost, CCpost |fywqQFq  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost cHt4L]n8n  
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    '************************************************************************* 4evNZ Q  
    'Lens thickness (Position of posterior lens surface) 0J^Z)U>j  
    '************************************************************************* ysZ(*K n(?  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) wm^1Fn--  
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    ' Delete any z-shift(s) c]Gs{V]\  
    count = 0  pdm(7^  
    While GetOperationCount(eID)>count Xq )7Im}?  
        GetOperation eID, count, op )^BZ,e  
        If op.Type="ShiftZ" Then +pq) 7  
            DeleteOperation eID,count ? A;RTM  
            count=count-1 k-a1^K3  
        End If G62;p#  
        count=count+1 rHjDf[5+  
    Wend Op8Gj  `  
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    'Set new z-shift p2Gd6v.t  
    op.Type = "ShiftZ" f[D%(  
    op.val1 = tlens %E/#h8oN{  
    op.parent = parID &OZx!G^Z  
    AddOperation eID, op \pkK >R  
    Print "Set lens thickness = " & tlens y\j[\UZKO  
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    '************************************************************************* C$ K?4$  
    'Lens index of refraction JBA{i45x  
    '************************************************************************* 7D,nxx(`  
    eID = FindMaterial( "Lens" ) A4|7^Ay  
    GetModelMaterial eID, mat u$[&'D6  
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    mat.Nd = nlens (SQGl!Lai0  
    SetModelMaterial eID, mat b$0;fEvIJn  
    Print "Set lens index of refraction = " & nlens X.>~DT%0Lm  
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    '************************************************************************* "=K3sk  
    'Pupil diameter J/D~]U  
    '************************************************************************* =BN<)f^*s  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) Xs|d#WbX  
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    'Adjust pupil diameter (trimming volume inner hole) -(e=S^36  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" wLiPkW  
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    ' Adjust pupil location to just in front of the lens Ek_&E7  
    parID = FindFullName( "Geometry.Arizona Eye" ) !<=(/4o&P  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) {`k&Q +gY  
    count = 0 k"%JyO8Y  
    While GetOperationCount(eID)>count ^`M%g2x  
        GetOperation eID, count, op N.+A-[7,W  
        If op.Type="ShiftZ" Then Ct?xTFb  
            DeleteOperation eID,count j@#RfVx  
            count=count-1 cUP1Uolvn  
        End If \!jz1`]&{  
        count=count+1 -hfkF+=U'  
    Wend g"Hl 30o  
    op.Type = "ShiftZ" ?D7zty+}^  
    op.val1 = taq-0.01 B5+Q%)52  
    op.parent = parID 5(\/ b<#  
    AddOperation eID, op AxH`4=3<  
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    Print "Set pupil diameter = " & pupilDiam UroC8Tm  
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    'Update AZ Eye subassembly Description {S-M]LE  
    eID = FindFullName( "Geometry.Arizona Eye" ) 'LuxF1>  
    GetEntity eID, entity ^K::g)  
    entity.Description = "Accommodation = " & A & "D" vol (%wB  
    SetEntity eID, entity 9@lG{9id?  
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    Update wj0_X;L  
    Print "DONE!" I(kEvfxc"  
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End Sub w;(=w N\  
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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: b;*'j9ly  
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Accommodation = 4 Diopters ;5$ GJu(  
Pupil Diameter = 4 mm of7p~{3H  
Set aqueous humor thickness = 2.81 uVhzJu.  
Set anterior lens radius = 10.4 and conic constant = -2.375869 nO'C2)bBSG  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 YM NLn9  
Set lens thickness = 3.927 FIAmAZH}_  
Set lens index of refraction = 1.42672  u+z  
Set pupil diameter = 4 ^*UtF9~%n  
DONE!
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