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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 s6!&4=ZA  
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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。 I)` +:+P  
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模型 f9>pMfi:@  
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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。 ]nRf%Vi8g  
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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. ^1F zs(#.  
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光源 +kYp!00  
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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。 aBaiXv/*  
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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。 t(roj@!x_o  
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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。 (Ytr&gh;0  
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图2. 字母F光源的设定方法光 +l)t5Mg\  
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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 0F- +)S?M[  
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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。 psIo[.$rTk  
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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。 W>+`e]z  
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图5. 视网膜重点采样规格设定
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脚本 9"S iHp\)  
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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: ;Qt/(/  
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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。 EMr|#}]#s  
余下的脚本计算与屈光度有关的所有参数。 tpA-IL?KQw  
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分析 (:E@kpK  
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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。 xWY\,'+Q  
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图7. 字母F在视网膜上颜色分析
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脚本代码 \/ri|fm6l#  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. l}(HE+?  
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Dim entity As T_ENTITY Y[PC<-fyf  
Dim op As T_OPERATION F%lC%~-qh  
Dim mat As T_MODELMATERIAL 5-fASN.Lx  
Dim A As Double b1'849i'y=  
Dim pupilDiam As Double "S'Yn-  
Dim eID As Long 0w TOdCvmb  
Dim parID As Long R%2.N!8v  
Dim count As Integer Ici4y*`M  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double K^"l.V#J  
Dim tlens As Double, nlens As Double w]h8KNt  
Dim curv As Double, conic As Double JBc*m  
Dim ok As Long {y5 L  
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Sub Main "R)n1,0  
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    '用户输入对话框 xuqG)HthRS  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 |%XcI3@*  
        TextBox 220,21,40,21,.TextBox1 'default: 0 jbZTlG  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 {*8G<&  
        OKButton 40,91,90,21 C`qV+pV  
        CancelButton 190,91,90,21  ydY( *]  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 J1gnR  
        TextBox 220,49,40,21,.TextBox2 'default: 4 F"M/gy  
    End Dialog :,qvqh][  
    Dim dlg As UserDialog vA6onYjA  
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    ok = Dialog (dlg) ] FvGAG.*  
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    If ok=0 Then    'cancel button was pressed pQ^V<6z}  
        Print "Execution cancelled." u~ FVI  
        End |Axbx?  
    End If O.y ?q  
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    'Assign accommodation and pupil diameter & use defaults if field left empty BaP'y8dVN  
    If dlg.TextBox1 = "" Then S^D@8<6GJ  
        A = 0           'Default accommodation 1VG]|6f  
    Else }|8^+V&  
        A = CDbl(dlg.TextBox1) `h :!^"G  
    End If ui`EODhA(  
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    If dlg.TextBox2 = "" Then >e-0A  
        pupilDiam = 4   'Default pupil diameter (w"(RM~  
    Else *+6iXMwe  
        pupilDiam = CDbl(dlg.TextBox2) OA}; pQ9QN  
    End If {=&( { cS  
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    Print " " Pq{p\Qkj  
    Print "Accommodation = " & A & " Diopters" y>h9:q|  
    Print "Pupil Diameter = " & pupilDiam & " mm" J2oh#TGp  
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    ' Calculate new parameters with accommodation [%6)  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness xf7YIhL^*  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens {LA?v& b'  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 3PLA*n+%  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens PX23M|$!  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens K(lVAKiP]  
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    tlens = 3.767 + 0.04*A                  'Lens thickness |) &d9|]  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction @6R6.i5d  
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    'Adjust parameters to account for accommodation hz<TjWXv'  
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    '************************************************************************* !OPHS^L  
    'Aqueous thickness (Position of Lens) O/(vimx.#F  
    '************************************************************************* #v~dhx=R  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Ii/{xVMD  
    GetCustomElement eID, entity 1BEc"  
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    parID = FindFullName( "Geometry.Arizona Eye" ) z"7X.*]  
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    ' Delete any shift(s) in z c\ ZnGI\|  
    count = 0 N. nGez  
    While GetOperationCount(eID)>count fiU#\%uJg  
        GetOperation eID, count, op ; 5[W*,7s  
        If op.Type="ShiftZ" Then W 9}xfy09  
            DeleteOperation eID,count &{qKoI]  
            count=count-1 {wz_ngQ  
        End If {=gJGP/}_  
        count=count+1 .EjR<UU  
    Wend gk5Gf l  
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    'Set new shift in N6+^}2' *)  
    op.Type = "ShiftZ"  [Ne'2z  
    op.val1 = taq /S~ =qodS  
    op.parent = parID FK-q-PKO#.  
    AddOperation eID, op ,BGUIu6  
    Print "Set aqueous humor thickness = " & taq-0.55 ;9ChBA  
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    '************************************************************************* 2cGiE{  
    'Radius and conic constant of anterior lens 3a ZS1]/  
    '************************************************************************* +7_U( |gO  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" )  <|82)hO  
    GetConic eID, entity, curv, conic SlT>S1`rnG  
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    SetConic eID, entity, 1/Rant, CCant }'>mT,ytgk  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant @k'V`ZQF  
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    '************************************************************************* &u6n5-!v  
    'Radius and conic constant of posterior lens ^rjUye%EK  
    '************************************************************************* alNn(0MG  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Pq(LW(  
    GetConic eID, entity, curv, conic !V/7q'&t=  
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    SetConic eID, entity, 1/Rpost, CCpost E:A!tu$B  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost vW?/:  
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    '************************************************************************* oZl%0Uy?9I  
    'Lens thickness (Position of posterior lens surface) =i Dd{$  
    '************************************************************************* n^5Q f\o  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) G^dzE/ :  
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    ' Delete any z-shift(s) KQw>6)  
    count = 0 =d:3]M^  
    While GetOperationCount(eID)>count u3wd~.  
        GetOperation eID, count, op Odhr=Hs  
        If op.Type="ShiftZ" Then SK 5]7C2  
            DeleteOperation eID,count MpJ<.|h  
            count=count-1 IX<9_q  
        End If 87!m l  
        count=count+1 ^L7!lzyo  
    Wend '#,C5*`  
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    'Set new z-shift Xrpvq(]  
    op.Type = "ShiftZ" p1 HbD`ST  
    op.val1 = tlens m@w469&<(q  
    op.parent = parID cN&:V2,  
    AddOperation eID, op ];b+f@  
    Print "Set lens thickness = " & tlens mh SknyqT  
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    '************************************************************************* ({!H ()  
    'Lens index of refraction 0]=Bqyg  
    '************************************************************************* [cl+AV "  
    eID = FindMaterial( "Lens" ) tXZMr   
    GetModelMaterial eID, mat A^LS^!Jz  
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    mat.Nd = nlens <X1 lq9 lW  
    SetModelMaterial eID, mat ozl!vf# kv  
    Print "Set lens index of refraction = " & nlens y c 8 h}`  
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    '************************************************************************* 5 ddfdIp  
    'Pupil diameter ;)P=WS:=  
    '************************************************************************* *">CEQ[MT  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 0G33hIOS  
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    'Adjust pupil diameter (trimming volume inner hole) suGd&eP|  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" \+l_H4\`K  
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    ' Adjust pupil location to just in front of the lens M7 k WJ  
    parID = FindFullName( "Geometry.Arizona Eye" ) `ah|BV  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 6PS[OB{3  
    count = 0 >gM"*Laa?  
    While GetOperationCount(eID)>count C8|#  
        GetOperation eID, count, op Q6e7Z-8  
        If op.Type="ShiftZ" Then vH1,As  
            DeleteOperation eID,count @7.7+blS"H  
            count=count-1 ~kSO YvK$'  
        End If Fa v++z  
        count=count+1 NJ-Ji> w  
    Wend ^yq}>_  
    op.Type = "ShiftZ" v2p0EOS  
    op.val1 = taq-0.01 [C<K~  
    op.parent = parID 1,Mm+_)B  
    AddOperation eID, op 2k^rZ^^"  
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    Print "Set pupil diameter = " & pupilDiam u U>L (  
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    'Update AZ Eye subassembly Description %N`_g' r!  
    eID = FindFullName( "Geometry.Arizona Eye" ) k.o8!aCm  
    GetEntity eID, entity mU?~s7  
    entity.Description = "Accommodation = " & A & "D" S_OtY]gF  
    SetEntity eID, entity j6XHH&ZEb  
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    Update Th*}U&  
    Print "DONE!" +'MO$&6  
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End Sub '` 2MxRP  
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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: \b8#xT}  
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Accommodation = 4 Diopters m6$&yKQ-=h  
Pupil Diameter = 4 mm %Q &']  
Set aqueous humor thickness = 2.81 o$+R  
Set anterior lens radius = 10.4 and conic constant = -2.375869 bM:4i1Z  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 -o`K/f}d  
Set lens thickness = 3.927 u~Po5W/i  
Set lens index of refraction = 1.42672 [6JDS;MIN  
Set pupil diameter = 4 cg17e  
DONE! ~_N,zw{x  
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