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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。 Ol;"}3*Z*  
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模型 gU?M/i2  
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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。 MI`<U:-lP  
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. j3[kG#  
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光源 p1IN%*IV+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。 $`L |  
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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。 41+@!`z7  
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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。 .la_u8A]  
图2. 字母F光源的设定方法光 .RbPO#(  
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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 V}h)e3X  
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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。 ) gxN' z  
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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。 ^+Vf*YY 8  
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图5. 视网膜重点采样规格设定
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脚本 %~N| RSec  
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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: `L3{y/U'  
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。 Yb'%J@T}  
余下的脚本计算与屈光度有关的所有参数。 |gfG\fL3V  
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分析 &E-q(3-  
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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。 2>xEE  
图7. 字母F在视网膜上颜色分析
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脚本代码 QPB ^%8  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. f~f)6XU|  
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Dim entity As T_ENTITY ?p>m ;Aq  
Dim op As T_OPERATION c(s: f@ 1  
Dim mat As T_MODELMATERIAL H9[0-Ur5  
Dim A As Double zo1 fUsK?  
Dim pupilDiam As Double 2 yRUw  
Dim eID As Long VD+v \X_  
Dim parID As Long  >Xxi2Vy  
Dim count As Integer IJLuu@kRm,  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double -CTLQyj)  
Dim tlens As Double, nlens As Double (:RYd6i  
Dim curv As Double, conic As Double c + aTO"  
Dim ok As Long b\UE+\a&  
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Sub Main 9{-H/YS\_s  
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    '用户输入对话框 -.5R.~@  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 @CKMJ^#|  
        TextBox 220,21,40,21,.TextBox1 'default: 0 g2YE^EKU~  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ,9$|"e&  
        OKButton 40,91,90,21 /'bX}H(dq  
        CancelButton 190,91,90,21 l(8@?t^;  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 *EFuK8 ;  
        TextBox 220,49,40,21,.TextBox2 'default: 4 Y"TrF(C  
    End Dialog }eSrJgF4M  
    Dim dlg As UserDialog jEL"Q?#  
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    ok = Dialog (dlg) JHJ]BMm  
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    If ok=0 Then    'cancel button was pressed !#PA#Q|cO  
        Print "Execution cancelled." UTO$L|K  
        End .lGN Fx  
    End If jM>;l6l  
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    'Assign accommodation and pupil diameter & use defaults if field left empty i4)]lWnd  
    If dlg.TextBox1 = "" Then $]4o!Z  
        A = 0           'Default accommodation RP9~n)h~b  
    Else ?v&2^d4C*F  
        A = CDbl(dlg.TextBox1)  ">q?(i\  
    End If UryHte  
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    If dlg.TextBox2 = "" Then .+5;AtN  
        pupilDiam = 4   'Default pupil diameter {]O.?Yru?  
    Else 3o#K8EL  
        pupilDiam = CDbl(dlg.TextBox2) Y0ACJ?|  
    End If SOluTFxUw  
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    Print " " &Zo+F]3d  
    Print "Accommodation = " & A & " Diopters" P8 R^46  
    Print "Pupil Diameter = " & pupilDiam & " mm" ozl>Au  
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    ' Calculate new parameters with accommodation '^tC|)  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Ib"fHLWA^!  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens )O>M~  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens va!fJ  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens B8>@q!G8P  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens fBKN?]BdN  
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    tlens = 3.767 + 0.04*A                  'Lens thickness }*7Gq  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction jm[f|4\  
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    'Adjust parameters to account for accommodation 0<nW nD,z  
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    '************************************************************************* g ~%IA.$c  
    'Aqueous thickness (Position of Lens) WmE4TL^8?  
    '************************************************************************* H^g&e$d0  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) uIR   
    GetCustomElement eID, entity ix 5\Y  
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    parID = FindFullName( "Geometry.Arizona Eye" ) @Suww@<  
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    ' Delete any shift(s) in z \psO$TxF=  
    count = 0  9-y<= )  
    While GetOperationCount(eID)>count H`7T;`Yb  
        GetOperation eID, count, op J$ &2GAi  
        If op.Type="ShiftZ" Then ^%qQ)>I=j  
            DeleteOperation eID,count }p*WH$!~  
            count=count-1 I<S*"[nV  
        End If 1(jx.W3  
        count=count+1 `-5gsJ  
    Wend #2%8@?_-M  
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    'Set new shift in 3H%bbFy  
    op.Type = "ShiftZ" _ + >V(,{G  
    op.val1 = taq ;>Z0e`=  
    op.parent = parID ZsGJ[  
    AddOperation eID, op ;z~j%L%b  
    Print "Set aqueous humor thickness = " & taq-0.55 ~2QD.(  
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    '************************************************************************* r`PD}6\  
    'Radius and conic constant of anterior lens kM3#[#6$!  
    '************************************************************************* YyC$\HH6  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) $Eo-58<q  
    GetConic eID, entity, curv, conic m2Wi "X(I_  
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    SetConic eID, entity, 1/Rant, CCant ^C;ULUn3  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant H~W=#Cx  
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    '************************************************************************* KqXPxp^_Al  
    'Radius and conic constant of posterior lens Oo9'  
    '************************************************************************* ex|h&Vma2V  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ne=CN!=  
    GetConic eID, entity, curv, conic O?iLLfs  
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    SetConic eID, entity, 1/Rpost, CCpost [vxHsY3z  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost a!, X@5  
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    '************************************************************************* 2W;2._  
    'Lens thickness (Position of posterior lens surface) 1}OM"V  
    '************************************************************************* B9]bv]  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6Z{(.'Be  
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    ' Delete any z-shift(s) ZN!<!"~  
    count = 0 !'a <Dw5  
    While GetOperationCount(eID)>count LB^xdMXi  
        GetOperation eID, count, op U"L-1]L  
        If op.Type="ShiftZ" Then Bx|h)e9  
            DeleteOperation eID,count mnU8i=v0 A  
            count=count-1 0*6Q 8`I  
        End If +_ny{i`'  
        count=count+1 cpphnGj5  
    Wend 8*&YQId~  
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    'Set new z-shift YAd%d|Q  
    op.Type = "ShiftZ" n39EKH rm%  
    op.val1 = tlens 5JS*6|IbD{  
    op.parent = parID ."ytBF  
    AddOperation eID, op CM)V^k*  
    Print "Set lens thickness = " & tlens l$m}aQ%h  
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    '************************************************************************* 40 zO4  
    'Lens index of refraction 0KjCM4t  
    '************************************************************************* rv2;)3/*  
    eID = FindMaterial( "Lens" ) imyfki $B  
    GetModelMaterial eID, mat \og2\Oh&gH  
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    mat.Nd = nlens 877Kv);  
    SetModelMaterial eID, mat *TPWLR ^  
    Print "Set lens index of refraction = " & nlens T[2<_nn=  
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    '************************************************************************* A| y U'k  
    'Pupil diameter m,ur{B8 :  
    '************************************************************************* o+Q2lO5  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) IaO*{1re  
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    'Adjust pupil diameter (trimming volume inner hole) Yh{5O3(;  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" SZvC4lOn#  
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    ' Adjust pupil location to just in front of the lens m",G;VN  
    parID = FindFullName( "Geometry.Arizona Eye" ) Ho $+[K  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) n D}<zj$D2  
    count = 0 t;_1/ mt  
    While GetOperationCount(eID)>count 3A\Z ]L  
        GetOperation eID, count, op 3V<c4'O\W  
        If op.Type="ShiftZ" Then h;~NA}>  
            DeleteOperation eID,count D[{"]=-  
            count=count-1 A>\3FeU>UC  
        End If Bk5ft4v-  
        count=count+1 upFe{M@  
    Wend vgi`.hk  
    op.Type = "ShiftZ" 1yTw*vH F  
    op.val1 = taq-0.01 m3XT8F*&  
    op.parent = parID /bmkt@$-0  
    AddOperation eID, op S(0JBGC  
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    Print "Set pupil diameter = " & pupilDiam z2q!_ ~  
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    'Update AZ Eye subassembly Description boZ/*+t  
    eID = FindFullName( "Geometry.Arizona Eye" ) #;UoZJ B  
    GetEntity eID, entity FA;B :O@:'  
    entity.Description = "Accommodation = " & A & "D" C#RueDa.  
    SetEntity eID, entity ER:K^ Za  
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    Update v+CW([zAx#  
    Print "DONE!" milQxSpj  
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End Sub y8]vl;88yY  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: ^[v>B@p*{  
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Accommodation = 4 Diopters ^tVIPH.R  
Pupil Diameter = 4 mm `R*!GHro  
Set aqueous humor thickness = 2.81 4}] In/yA  
Set anterior lens radius = 10.4 and conic constant = -2.375869 !ED,'d%J  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 <f0yh"?6VH  
Set lens thickness = 3.927 :^]Fp UY  
Set lens index of refraction = 1.42672 M->#WGl\B  
Set pupil diameter = 4 VYrs4IFT$  
DONE!
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