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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。 !J71[4t  
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模型 TRq~n7Y7C  
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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。 ~*[}O)7#  
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. hW},%  
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光源 53T2w,?  
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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。 GS,pl9#V_  
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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。 ^$L/Mv+  
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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。 {e@1,19  
图2. 字母F光源的设定方法光 ZV U9t  
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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 a@a1/ 3  
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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。 #SXXYh-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。 Kaa*;T![  
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图5. 视网膜重点采样规格设定
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脚本 vuZ<'?Nm  
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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: xpxm9ySwu  
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。 QD<4(@c5|  
余下的脚本计算与屈光度有关的所有参数。 Dk-L4FS  
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分析 `R> O5Rv  
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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。 (+_J0i t  
图7. 字母F在视网膜上颜色分析
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脚本代码 ' 7A7HDJ  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. T42g4j/l~  
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Dim entity As T_ENTITY f h^_=R(/  
Dim op As T_OPERATION hvyN8We  
Dim mat As T_MODELMATERIAL JdHc'WtS!|  
Dim A As Double `O{Uz?#*x  
Dim pupilDiam As Double 2z\F m/Z.  
Dim eID As Long .%rR  
Dim parID As Long .{ -yveE  
Dim count As Integer yFt7fdl2  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ["}A#cO652  
Dim tlens As Double, nlens As Double iV&#5I  
Dim curv As Double, conic As Double _&/Zab5  
Dim ok As Long }'W^Ki$  
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Sub Main Bkc-iC}F  
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    '用户输入对话框 pqSE|3*l  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 DBUwf1=qj  
        TextBox 220,21,40,21,.TextBox1 'default: 0 u-_$?'l;~  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 k)py\  
        OKButton 40,91,90,21 -z$0S%2?  
        CancelButton 190,91,90,21 p L@zZK0  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ]3xa{ h~4  
        TextBox 220,49,40,21,.TextBox2 'default: 4 6bNW1]rD  
    End Dialog Q*.FUV&;  
    Dim dlg As UserDialog  >Gu0&  
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    ok = Dialog (dlg) Wts{tb  
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    If ok=0 Then    'cancel button was pressed yU"G|Ex  
        Print "Execution cancelled." <o+ 7U  
        End 4C%>/*%8>  
    End If k~f+LO  
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    'Assign accommodation and pupil diameter & use defaults if field left empty S I7B6c  
    If dlg.TextBox1 = "" Then :XSc#H4  
        A = 0           'Default accommodation Y:%)cUxA  
    Else e@=[+iJc  
        A = CDbl(dlg.TextBox1) Vb^s 'k  
    End If J'yN' 0  
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    If dlg.TextBox2 = "" Then *\KMkx  
        pupilDiam = 4   'Default pupil diameter 51qIo4$  
    Else ok s=|'&  
        pupilDiam = CDbl(dlg.TextBox2) d7J[.^\  
    End If |OZ>/l {  
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    Print " " 4AOS}@~W  
    Print "Accommodation = " & A & " Diopters" YeC,@d[  
    Print "Pupil Diameter = " & pupilDiam & " mm" xY0QGQca  
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    ' Calculate new parameters with accommodation >J3ja>Gw/  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ^HFU@/  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ;"Y;l=9_  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens v^W?o}W  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 9/daRq$  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens NzAtdcwR  
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    tlens = 3.767 + 0.04*A                  'Lens thickness Mc7<[a  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 7e4tUAiuU  
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    'Adjust parameters to account for accommodation V\K m% vP  
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    '************************************************************************* '%-xe3  
    'Aqueous thickness (Position of Lens) 8U2 wH  
    '************************************************************************* $qtU  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) _RaVnMJKX4  
    GetCustomElement eID, entity 3cfZ!E~^kc  
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    parID = FindFullName( "Geometry.Arizona Eye" ) jaO#><f  
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    ' Delete any shift(s) in z -{8Q= N  
    count = 0 [> &+*c  
    While GetOperationCount(eID)>count |t65# 1  
        GetOperation eID, count, op ( X 'FQ  
        If op.Type="ShiftZ" Then Ec*--]j*c  
            DeleteOperation eID,count /cL9 ?k;o  
            count=count-1 ADyNNMcx  
        End If F0BOhlK  
        count=count+1  Z|:_ c  
    Wend <[3lV)~t  
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    'Set new shift in RM^?&PM85  
    op.Type = "ShiftZ" lYZ@a4TA  
    op.val1 = taq =>:% n  
    op.parent = parID @%G'U&R{  
    AddOperation eID, op >^T,U0T])  
    Print "Set aqueous humor thickness = " & taq-0.55 >|_gT%]5  
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    '************************************************************************* vN0L( B  
    'Radius and conic constant of anterior lens g~Nij~/  
    '************************************************************************* yA !3XUi  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 0K$WSGB?6j  
    GetConic eID, entity, curv, conic ]O[+c*|w  
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    SetConic eID, entity, 1/Rant, CCant )-Mn"1ia  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant lk*0c {_L  
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    '************************************************************************* iO?gF  
    'Radius and conic constant of posterior lens tv@Z 5  
    '************************************************************************* } Jdh^t.  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) f#;ubfi"z  
    GetConic eID, entity, curv, conic zfP[1  
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    SetConic eID, entity, 1/Rpost, CCpost ~51kiQW  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost U5On-T5  
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    '************************************************************************* iJCY /*C}  
    'Lens thickness (Position of posterior lens surface) q*F~~J!P  
    '************************************************************************* Qe @A5#  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) >%n8W>^^4  
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    ' Delete any z-shift(s) q(ZB.  
    count = 0 e-%7F]e  
    While GetOperationCount(eID)>count 1*!c X  
        GetOperation eID, count, op zH=/.31Q  
        If op.Type="ShiftZ" Then `r~`N`o5A  
            DeleteOperation eID,count ]Efh(Gb]  
            count=count-1 pjX%LsX\  
        End If ~zE 1'  
        count=count+1 Q8;x9o@p  
    Wend 0^<Skm27"  
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    'Set new z-shift jpYw#]Q  
    op.Type = "ShiftZ" @b ::6n/u  
    op.val1 = tlens a2c x  
    op.parent = parID =RW* %8C  
    AddOperation eID, op XI%RneuDr:  
    Print "Set lens thickness = " & tlens r%g <h T 8  
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    '************************************************************************* CU#L *kz  
    'Lens index of refraction ~4MtDf  
    '************************************************************************* 2p$n*|T&c  
    eID = FindMaterial( "Lens" ) dl*_ m3T  
    GetModelMaterial eID, mat m6bWmGn GC  
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    mat.Nd = nlens dJdD"xj  
    SetModelMaterial eID, mat ]97Xu_  
    Print "Set lens index of refraction = " & nlens 8Ehy9<  
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    '************************************************************************* SE-!|WR  
    'Pupil diameter lF; ziF  
    '************************************************************************* Ur_ S [I  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) "J]f0m=  
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    'Adjust pupil diameter (trimming volume inner hole) \S=XIf  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 5z9r S<  
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    ' Adjust pupil location to just in front of the lens jGk7=}nw  
    parID = FindFullName( "Geometry.Arizona Eye" ) bjM-Hd/K  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ppwd-^f3j  
    count = 0 |QnUK5D$  
    While GetOperationCount(eID)>count D 7Gd%  
        GetOperation eID, count, op ?Ia4H   
        If op.Type="ShiftZ" Then lEO?kn.:z  
            DeleteOperation eID,count r\A@&5#q  
            count=count-1 C $]5l; `  
        End If 7j@^+rkr3f  
        count=count+1 Tjd&^m  
    Wend M*g2VyZ  
    op.Type = "ShiftZ" "_ nX5J9  
    op.val1 = taq-0.01 c+szU}(f6(  
    op.parent = parID y-E1]4?})  
    AddOperation eID, op $?H]S]#|}.  
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    Print "Set pupil diameter = " & pupilDiam pd=7^"[};  
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    'Update AZ Eye subassembly Description 98D{{j92  
    eID = FindFullName( "Geometry.Arizona Eye" ) }U2[?  
    GetEntity eID, entity '4J&Gpx  
    entity.Description = "Accommodation = " & A & "D" EG F:xl  
    SetEntity eID, entity !&@2  
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    Update D"`%|`O  
    Print "DONE!" -(6eVI  
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End Sub }R`8h&J  
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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: "AT&!t[J  
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Accommodation = 4 Diopters 5/Ydv RB67  
Pupil Diameter = 4 mm  ]a78tTi  
Set aqueous humor thickness = 2.81 a^@+%?X  
Set anterior lens radius = 10.4 and conic constant = -2.375869 c eqFQ  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 cge-'/8w%  
Set lens thickness = 3.927  =Ov9Kf  
Set lens index of refraction = 1.42672 }j& O/ Up  
Set pupil diameter = 4 'g. :MQ8  
DONE!
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