[技术]Arizona眼睛模型 [复制链接]

简介 HA9Nr.NqC@  
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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。 =,d* {m~A  
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模型 B221}t  
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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。 ZcTL#OTP  
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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. nGv23R(?G  
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光源 c{,y{2c]LT  
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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。 OY^n0Zof,  
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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。 K$<`4#i  
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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。 qIDWl{b<  

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视网膜的散射 *K+jsVDY  
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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。 Mhv1K|4s  
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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。 ~aJW"\{  
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脚本 'v\1:zi  
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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： s[G|q5n  
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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。 +{,N X  
余下的脚本计算与屈光度有关的所有参数。 g08*}0-k  
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分析 z5XYpi_;[  
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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。 :y+B;qw  
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脚本代码 `z9)YH  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 81GQijq  
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Dim entity As T_ENTITY *QbM*oH  
Dim op As T_OPERATION H$z>OS_6U  
Dim mat As T_MODELMATERIAL { 1+Cw?1d  
Dim A As Double q';&SR#"`K  
Dim pupilDiam As Double $|4cJ#;^L  
Dim eID As Long <8u>_
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Dim parID As Long UWQtvQ f  
Dim count As Integer K :1g"  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 8[8|*8xqs  
Dim tlens As Double, nlens As Double .)LZ`Ge3F  
Dim curv As Double, conic As Double YV5Yx-+3w$  
Dim ok As Long v6wRME;JA  
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Sub Main 0CPxIF&  
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    '用户输入对话框 CQ@LmTW[  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 2>F
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        TextBox 220,21,40,21,.TextBox1 'default: 0 }5Yj  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 u@<Pu@?xm  
        OKButton 40,91,90,21 PeO]lq  
        CancelButton 190,91,90,21 JZ`>|<W  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 cNe0x2Z$?  
        TextBox 220,49,40,21,.TextBox2 'default: 4 P+[QI U  
    End Dialog  b<[jaI0  
    Dim dlg As UserDialog 3^{8_^I  
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    ok = Dialog (dlg) +T9Q_e*  
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    If ok=0 Then    'cancel button was pressed \ jECSV|  
        Print "Execution cancelled." $j57LY|r  
        End }$l8d/_$[  
    End If GxxDY]!  
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    'Assign accommodation and pupil diameter & use defaults if field left empty m;dm|4L^  
    If dlg.TextBox1 = "" Then G3G/xC"  
        A = 0           'Default accommodation 59.$ULQVMY  
    Else &,J*_F<s2<  
        A = CDbl(dlg.TextBox1) Odm#wL~E  
    End If vB^uxdt|m  
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    If dlg.TextBox2 = "" Then bG"HD?A_  
        pupilDiam = 4   'Default pupil diameter >QXzMN}o  
    Else l09Fn>wa  
        pupilDiam = CDbl(dlg.TextBox2) )B6
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    End If <0#^7Z  
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    Print " " 7AFE-'S  
    Print "Accommodation = " & A & " Diopters" 2Zy_5>~  
    Print "Pupil Diameter = " & pupilDiam & " mm" kBo;h.[l  
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    ' Calculate new parameters with accommodation K}x_nW  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness o+NMA (  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ;J]25j]]  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens _pW_G1U  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens N>0LQ MI  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 8!&nKy<Y  
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    tlens = 3.767 + 0.04*A                  'Lens thickness Ry&q1j  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 3V?817&6z  
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    'Adjust parameters to account for accommodation <?YA,"~  
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    '************************************************************************* =Q-k'=6\  
    'Aqueous thickness (Position of Lens) ~O{W;Cyh  
    '************************************************************************* %t
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    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) P>(P2~$Y"  
    GetCustomElement eID, entity bHE7yv [  
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    parID = FindFullName( "Geometry.Arizona Eye" ) -p`L%xj\  
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    ' Delete any shift(s) in z ,X68xk.'  
    count = 0 OUI6 ax\[  
    While GetOperationCount(eID)>count iCP~
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        GetOperation eID, count, op Ow@v"L;jF!  
        If op.Type="ShiftZ" Then F)SPaC4  
            DeleteOperation eID,count ^]>aHz9  
            count=count-1 je%ldY]/@  
        End If m2xBS!fm  
        count=count+1 +6l]]*H  
    Wend 'N\&<dT>  
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    'Set new shift in X`:'i?(yj  
    op.Type = "ShiftZ" G>w+#{(  
    op.val1 = taq T_LLJ
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    op.parent = parID +BL{@,zr  
    AddOperation eID, op eh(<m8I  
    Print "Set aqueous humor thickness = " & taq-0.55 dz-y}J11  
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    '************************************************************************* E7nFb:zlV  
    'Radius and conic constant of anterior lens 8]bz(P#  
    '************************************************************************* 6ZOy&fd,Ty  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) xq[Yg15d%  
    GetConic eID, entity, curv, conic D."=k{r.  
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    SetConic eID, entity, 1/Rant, CCant })Yv9],6  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant @0NJ{  
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    '************************************************************************* X(*!2uS  
    'Radius and conic constant of posterior lens Y3Oz'%B  
    '************************************************************************* %w ) +V  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) V5p0h~PK  
    GetConic eID, entity, curv, conic tU@zhGb  
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    SetConic eID, entity, 1/Rpost, CCpost tg\|?  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost e,gyQjJR  
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    '************************************************************************* )OP){/   
    'Lens thickness (Position of posterior lens surface) :Ht;0|[H  
    '************************************************************************* r.yK,  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) F #`=oM$5  
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    ' Delete any z-shift(s) &7>zURv  
    count = 0 HrM$NRhu  
    While GetOperationCount(eID)>count FX}Gt=  
        GetOperation eID, count, op 2C=Q8ayvX  
        If op.Type="ShiftZ" Then 8sOQ
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            DeleteOperation eID,count *O~e T  
            count=count-1 G~,:2 o3  
        End If vXE0%QE'Q  
        count=count+1 iE].&>w  
    Wend b:W-l?  
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    'Set new z-shift sG7u}r  
    op.Type = "ShiftZ" Cu;5RSr2Z  
    op.val1 = tlens 78 f$6J q  
    op.parent = parID !l@zT}i??  
    AddOperation eID, op jgv`>o%<W  
    Print "Set lens thickness = " & tlens 9=`Wp6Gmn  
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    '************************************************************************* L%"LlSg  
    'Lens index of refraction YJV%a  
    '************************************************************************* dT|vYK}\  
    eID = FindMaterial( "Lens" ) |{>ER,<-  
    GetModelMaterial eID, mat yx38g ca  
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    mat.Nd = nlens h^UKT`9vt  
    SetModelMaterial eID, mat IxZb$h[  
    Print "Set lens index of refraction = " & nlens C1kYl0zR[  
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    '************************************************************************* baV>N[F&  
    'Pupil diameter Fh$slow4!  
    '************************************************************************* }_9,w;M$  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" )
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    'Adjust pupil diameter (trimming volume inner hole)
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" >Gml4vGK  
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    ' Adjust pupil location to just in front of the lens k <iTjI*N  
    parID = FindFullName( "Geometry.Arizona Eye" ) m0n)dje  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) T;TA7{B  
    count = 0 Z<[<n0o1  
    While GetOperationCount(eID)>count bNs4 5hDP  
        GetOperation eID, count, op <7SpEVQ  
        If op.Type="ShiftZ" Then x!LQxoNF  
            DeleteOperation eID,count a8k;(/  
            count=count-1 `{k"8#4:qA  
        End If Hb} X-6N  
        count=count+1 W!Hm~9fz  
    Wend {9Y
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    op.Type = "ShiftZ" Dl(3wgA  
    op.val1 = taq-0.01 @hQlrq5c  
    op.parent = parID ~c^>54  
    AddOperation eID, op XR2~Q)@  
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    Print "Set pupil diameter = " & pupilDiam 9vUO
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    'Update AZ Eye subassembly Description ^z1&8k"[^  
    eID = FindFullName( "Geometry.Arizona Eye" ) X+L) -d  
    GetEntity eID, entity DI
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    entity.Description = "Accommodation = " & A & "D" 3$.deYa$R  
    SetEntity eID, entity ^k5ll=}  
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    Update {"oxJ`z4  
    Print "DONE!" An;MVA  
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End Sub U*Ge<(v$  
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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： \$0F-=w`8  
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Accommodation = 4 Diopters mMsTyM-f  
Pupil Diameter = 4 mm Bjk]ZU0T  
Set aqueous humor thickness = 2.81 Tc8un.  
Set anterior lens radius = 10.4 and conic constant = -2.375869 kB?al#`  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 w0w G-R ?  
Set lens thickness = 3.927 m'
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Set lens index of refraction = 1.42672 3vcO!6Z5  
Set pupil diameter = 4 O+g3X5f+  
DONE! rSXh;\MfB4