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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 \v6 M:KR5/  
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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。 /%4_-Cpm  
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模型 cECi')  
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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。 `.#@@5e  
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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. hh~n#7w~IR  
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光源 OzT#1T1'c  
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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。 s cdtWA  
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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。 yMLOUUWa8x  
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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。 19(Dj&x  
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图2. 字母F光源的设定方法光 :)jJge&^p  
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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 Sd IX-k.  
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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。 JNWg|Qt  
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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。 5&CDHc7Oj  
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图5. 视网膜重点采样规格设定
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脚本 %Y4e9T".  
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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: +TeFt5[)h  
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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。 ,`td@Y  
余下的脚本计算与屈光度有关的所有参数。 =He. fEy  
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分析 |!d"*.Q@F  
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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。 __p_8P  
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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 tn/T6C^)  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. `PI(%N  
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Dim entity As T_ENTITY % U`xu.  
Dim op As T_OPERATION =Pe><k  
Dim mat As T_MODELMATERIAL h`MdKX$  
Dim A As Double RE46k`44  
Dim pupilDiam As Double @?B6aD|jE  
Dim eID As Long OIaYHA  
Dim parID As Long ul5|.C  
Dim count As Integer m.%`4L^`T  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 8{&["?  
Dim tlens As Double, nlens As Double !UV5zmS  
Dim curv As Double, conic As Double $*~Iu%Az  
Dim ok As Long Mxz,wfaH>  
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Sub Main {LE&ylE  
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    '用户输入对话框 ;Fl<v@9  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 X=p"5hhfn  
        TextBox 220,21,40,21,.TextBox1 'default: 0 B(HT.%r^A  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 |qjZ38;6  
        OKButton 40,91,90,21 0=U70nKr  
        CancelButton 190,91,90,21 aSaAC7sFk  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 ;q#]-^  
        TextBox 220,49,40,21,.TextBox2 'default: 4 T|'&K:[TJ  
    End Dialog b^V'BC3  
    Dim dlg As UserDialog "-i#BjZl/  
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    ok = Dialog (dlg) :.IN?X  
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    If ok=0 Then    'cancel button was pressed 8<PKKDgbfd  
        Print "Execution cancelled." QocQowz  
        End X:q_c=X  
    End If ['Z{@9  
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    'Assign accommodation and pupil diameter & use defaults if field left empty -wr(vE,  
    If dlg.TextBox1 = "" Then :\}U9QfCw  
        A = 0           'Default accommodation L`K;IV%;  
    Else M'jXve(=yF  
        A = CDbl(dlg.TextBox1) ]rX9MA6  
    End If H7IW"UkBR  
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    If dlg.TextBox2 = "" Then `bP?o  
        pupilDiam = 4   'Default pupil diameter T)\NkM&  
    Else INNAYQ  
        pupilDiam = CDbl(dlg.TextBox2) VuWib+fT  
    End If >BiRk%x  
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    Print " " q.oLmX  
    Print "Accommodation = " & A & " Diopters" n9}RW;N+u  
    Print "Pupil Diameter = " & pupilDiam & " mm" h`?k.{})M  
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    ' Calculate new parameters with accommodation v}`1)BUeF  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness 6v47 QW|'  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens _X%Dw  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens P/ aDd@j  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens k,_i#9 X  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens GXeAe}T  
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    tlens = 3.767 + 0.04*A                  'Lens thickness j+>Q#&h9  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction h3 @s2 fK  
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    'Adjust parameters to account for accommodation j.& ;c'V$.  
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    '************************************************************************* +qE']yzm!  
    'Aqueous thickness (Position of Lens) &z ksRX  
    '************************************************************************* |cu`f{E2]  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) (Jpm KO  
    GetCustomElement eID, entity ~07RFR  
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    parID = FindFullName( "Geometry.Arizona Eye" ) j`9Nwa  
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    ' Delete any shift(s) in z Xiju"Cup"  
    count = 0 SsRVd^=;x  
    While GetOperationCount(eID)>count  q)oN 2-  
        GetOperation eID, count, op eBvW#Hzp  
        If op.Type="ShiftZ" Then vf_OQ4'G,  
            DeleteOperation eID,count k`@w(HhS  
            count=count-1 4WG=m}X  
        End If {G.jB/  
        count=count+1 u:5IjOb2^  
    Wend sY^lQN  
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    'Set new shift in uQ1jwYK`7  
    op.Type = "ShiftZ" 8r^j P.V  
    op.val1 = taq f !!P  
    op.parent = parID K P6PQgc  
    AddOperation eID, op <?4cWp|i  
    Print "Set aqueous humor thickness = " & taq-0.55 #NM JZ  
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    '************************************************************************* oT!/J  
    'Radius and conic constant of anterior lens `U#Po_hq  
    '************************************************************************* %O_t`wz  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) vnVZJ}]w\  
    GetConic eID, entity, curv, conic oVEAlBm^v  
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    SetConic eID, entity, 1/Rant, CCant ex0oAt^  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant D+hB[*7Fs  
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    '************************************************************************* @ AggznA8  
    'Radius and conic constant of posterior lens bN!u}DnN  
    '************************************************************************* "B?R| Xg  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) &/DOO ^  
    GetConic eID, entity, curv, conic )O -cw7 >  
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    SetConic eID, entity, 1/Rpost, CCpost g~|y$T  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost , | <jjq)  
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    '************************************************************************* <L2GUX36#  
    'Lens thickness (Position of posterior lens surface) 5Abz 5-^KH  
    '************************************************************************* b_ZNI0Hp@  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ]'6'<S  
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    ' Delete any z-shift(s) Vp\80D&  
    count = 0 MyqiBGTb  
    While GetOperationCount(eID)>count iA&oLu[y3  
        GetOperation eID, count, op *F|i&2  
        If op.Type="ShiftZ" Then C|9[Al  
            DeleteOperation eID,count u(8~4P0w  
            count=count-1 v10mDr  
        End If gINwvzW{  
        count=count+1 _~:j3=1&n  
    Wend )ph30B  
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    'Set new z-shift e7lo!( >#  
    op.Type = "ShiftZ" gUu&Vy\  
    op.val1 = tlens nZ541o@t9  
    op.parent = parID 48:liR  
    AddOperation eID, op yr%yy+(.k  
    Print "Set lens thickness = " & tlens 98h :X%  
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    '************************************************************************* t[/\KG8  
    'Lens index of refraction ,RR;VKj  
    '************************************************************************* F68},N>vr@  
    eID = FindMaterial( "Lens" ) U{HyxZ|q<  
    GetModelMaterial eID, mat \ hrBq^I  
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    mat.Nd = nlens 6W]OpM  
    SetModelMaterial eID, mat >,kL p|gA  
    Print "Set lens index of refraction = " & nlens O(WEgz  
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    '************************************************************************* J1nXAh)J  
    'Pupil diameter "k/;`eAP  
    '************************************************************************* GA(OK-WUd  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) .zQ4/  
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    'Adjust pupil diameter (trimming volume inner hole) SgyqmYTvZw  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" =7FE/S  
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    ' Adjust pupil location to just in front of the lens x`Vy<h 33  
    parID = FindFullName( "Geometry.Arizona Eye" ) l#tS.+B7  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) i<'{Y  
    count = 0 A>4l/  
    While GetOperationCount(eID)>count >F,$;y52  
        GetOperation eID, count, op u):X>??  
        If op.Type="ShiftZ" Then UIO6|*ka  
            DeleteOperation eID,count 7qW.h>%WE  
            count=count-1 v!nm &"  
        End If qK<aZ%V  
        count=count+1 u4go*#  
    Wend  =|^X$H  
    op.Type = "ShiftZ" /;zZnF\ e  
    op.val1 = taq-0.01 }P05eI  
    op.parent = parID M|1eqR%x-?  
    AddOperation eID, op V#p G; ,  
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    Print "Set pupil diameter = " & pupilDiam 0Ei\VVK>  
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    'Update AZ Eye subassembly Description '~ jy  
    eID = FindFullName( "Geometry.Arizona Eye" ) ztRWIkI q  
    GetEntity eID, entity VC/R)%@%  
    entity.Description = "Accommodation = " & A & "D" plzE  
    SetEntity eID, entity /&~nM  
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    Update U;x99Go:  
    Print "DONE!" {KF7j63  
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End Sub e-nWD  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: ]s1TJw [B  
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Accommodation = 4 Diopters {Bav$kw;?e  
Pupil Diameter = 4 mm 'e+-,CGdY\  
Set aqueous humor thickness = 2.81 FCsyKdM  
Set anterior lens radius = 10.4 and conic constant = -2.375869 QT7w::ht  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 z'5;f;  
Set lens thickness = 3.927 zv$=*  
Set lens index of refraction = 1.42672 HV]~=Bw2I  
Set pupil diameter = 4 a7QlU=\  
DONE! k@'?"CP\Xq  
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