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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 %NH{%K,  
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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。 x!`~+f.6  
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模型 HxnWM\p  
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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。 ',l}$]y5  
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Table 1. AZ眼睛模型的定义
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在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. "~,3gNTzV  
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光源 s;Sv@=\  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 =C4!h'hz  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 2od 9Q=v~  
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在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 O <#H5/Tq  
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图2. 字母F光源的设定方法光 "8*5!anu-  
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图3. 字母F在视网膜上位置点列图
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视网膜的散射 ^b&U0k$R  
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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。 VI(2/**  
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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。 lr~c w#h*  
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图5. 视网膜重点采样规格设定
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脚本 >pj)va[Q  
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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: i"OY=iw-N  
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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。 ~`!{5:v  
余下的脚本计算与屈光度有关的所有参数。 Y8@TY?  
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分析 4) z*Vux  
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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。 dA[S@ysvG  
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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 'E_~>  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. HE.YfD)  
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Dim entity As T_ENTITY XFJz\'{  
Dim op As T_OPERATION D\ kd6  
Dim mat As T_MODELMATERIAL /~}<[6ZGCY  
Dim A As Double y8/+kn +  
Dim pupilDiam As Double Q/y"W,H#  
Dim eID As Long 54>gr1B  
Dim parID As Long 2e*"<>aeq  
Dim count As Integer K/IG6s;Xj  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double vi~NfD@s  
Dim tlens As Double, nlens As Double 0;n}{26a  
Dim curv As Double, conic As Double L3|~ i&k  
Dim ok As Long [;,Xp/  
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Sub Main 1qN+AT  
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    '用户输入对话框 zwJK|Sk  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1  ie4BE'  
        TextBox 220,21,40,21,.TextBox1 'default: 0 -0:Equ?pz  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ?A2jj`N1x  
        OKButton 40,91,90,21 !rPU5y*  
        CancelButton 190,91,90,21 jQ&82X%m  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 qg9VK'3o  
        TextBox 220,49,40,21,.TextBox2 'default: 4 `2PvE4]%p  
    End Dialog 6o=Q;Mezl  
    Dim dlg As UserDialog O]%Vh l  
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    ok = Dialog (dlg) l#^weXSlk  
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    If ok=0 Then    'cancel button was pressed ! w2BD^V-  
        Print "Execution cancelled." _}3NLAqg  
        End :WHbwu,L$  
    End If /^Ng7Mi!  
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    'Assign accommodation and pupil diameter & use defaults if field left empty pL pBP+i  
    If dlg.TextBox1 = "" Then SU>cJ*  
        A = 0           'Default accommodation f,0,:)  
    Else X(dHh O  
        A = CDbl(dlg.TextBox1) L6n<h  
    End If EB2 5N~7  
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    If dlg.TextBox2 = "" Then (c|Ry[$|  
        pupilDiam = 4   'Default pupil diameter %h "%G=:  
    Else (M nK \^Y  
        pupilDiam = CDbl(dlg.TextBox2) ' T%70)CM~  
    End If zelM}/d  
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    Print " " Eq6. s)10  
    Print "Accommodation = " & A & " Diopters" X\HP&;Wd  
    Print "Pupil Diameter = " & pupilDiam & " mm" gSt'<v  
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    ' Calculate new parameters with accommodation bC0DzBnM;  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Bl*.N9*  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens H&h"!+t(#  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens +hUz/G+3  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens CN!~(1v  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens WN3]xw3  
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    tlens = 3.767 + 0.04*A                  'Lens thickness >%i]p  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction D,&o=EU  
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    'Adjust parameters to account for accommodation {LoNp0i1a  
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    '************************************************************************* #!R=h|  
    'Aqueous thickness (Position of Lens) XG;Dj<Dm  
    '************************************************************************* [28Vf"#]  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) zIy&gOX  
    GetCustomElement eID, entity ,pR.HCR#Y  
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    parID = FindFullName( "Geometry.Arizona Eye" ) S7f"\[Aw  
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    ' Delete any shift(s) in z F%`O$uXA  
    count = 0 . E? a  
    While GetOperationCount(eID)>count =v49[i  
        GetOperation eID, count, op ;QqC c!b  
        If op.Type="ShiftZ" Then p n(y4we  
            DeleteOperation eID,count #bmbK{[  
            count=count-1 -i*]Sgese  
        End If 8 GW0w  
        count=count+1  [kL`'yi  
    Wend _8&a%?R@W  
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    'Set new shift in CjZIBMGc  
    op.Type = "ShiftZ" "s.s(TR8  
    op.val1 = taq S- JD}+ 9  
    op.parent = parID 9/$Cq  
    AddOperation eID, op Tjj-8cg  
    Print "Set aqueous humor thickness = " & taq-0.55 H.#zbKj  
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    '************************************************************************* (%SKTM  
    'Radius and conic constant of anterior lens X^7n/|%*.  
    '************************************************************************* ak$D1#hY  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ` 3h,Cy^  
    GetConic eID, entity, curv, conic RLR\*dL1  
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    SetConic eID, entity, 1/Rant, CCant 33OkY C%e  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant $_Q]3"U  
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    '************************************************************************* cNiNLwc  
    'Radius and conic constant of posterior lens =H/ 5  
    '************************************************************************* *:8,w?Nt  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ?#Y1E~N  
    GetConic eID, entity, curv, conic NQIbav^5  
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    SetConic eID, entity, 1/Rpost, CCpost H-jxH,mJmW  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ~en'E  
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    '************************************************************************* QR {>]I  
    'Lens thickness (Position of posterior lens surface) iE,/x^&,&  
    '************************************************************************* rL|9Xru  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) M=#g_*d  
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    ' Delete any z-shift(s) g-DFcwO,V  
    count = 0 &{ZTtK&JF  
    While GetOperationCount(eID)>count O ~D]C  
        GetOperation eID, count, op Z=zD~ka  
        If op.Type="ShiftZ" Then 37 d-!  
            DeleteOperation eID,count 7O<K?;I  
            count=count-1 2aJ_[3p/h]  
        End If {"mb)zr  
        count=count+1 |G(I,EPag  
    Wend !a^'Jbb  
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    'Set new z-shift yt#~n _  
    op.Type = "ShiftZ" /PZxF  
    op.val1 = tlens To =JE}jzo  
    op.parent = parID (\H^ KEy  
    AddOperation eID, op 9F2MCqvcm  
    Print "Set lens thickness = " & tlens ]:svR@E  
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    '************************************************************************* +%? \#EQJ  
    'Lens index of refraction f J+  
    '************************************************************************* W4$F\y  
    eID = FindMaterial( "Lens" ) l^R1XBP  
    GetModelMaterial eID, mat  |Fe*t  
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    mat.Nd = nlens S#N4!"  
    SetModelMaterial eID, mat D| g{]nO  
    Print "Set lens index of refraction = " & nlens dyVfDF  
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    '************************************************************************* M"5S  
    'Pupil diameter `ZGKM>q`  
    '************************************************************************* nHl{'|~  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) S^_F0</U,  
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    'Adjust pupil diameter (trimming volume inner hole) RuWu#tk  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" <`d;>r=4z  
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    ' Adjust pupil location to just in front of the lens sZI$t L<j  
    parID = FindFullName( "Geometry.Arizona Eye" ) S3ZI C\2  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) Ir6g"kwCKq  
    count = 0 l(d3N4iz  
    While GetOperationCount(eID)>count C=&;4In  
        GetOperation eID, count, op Vr hd\  
        If op.Type="ShiftZ" Then `Hd~H  
            DeleteOperation eID,count U:uF rb,  
            count=count-1 v)<|@TD)  
        End If WT jy"p*  
        count=count+1 1"~$(@oxG  
    Wend Wd?=RO`a  
    op.Type = "ShiftZ" 0gH;y+\=*  
    op.val1 = taq-0.01 DeTLh($\  
    op.parent = parID ahg]OWn#  
    AddOperation eID, op K[l5=)G0L  
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    Print "Set pupil diameter = " & pupilDiam F&a)mpFv3c  
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    'Update AZ Eye subassembly Description b{}ao  
    eID = FindFullName( "Geometry.Arizona Eye" ) 3o`c`;H%p  
    GetEntity eID, entity 2#R8}\  
    entity.Description = "Accommodation = " & A & "D" 3ICMH  
    SetEntity eID, entity ="de+S8W  
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    Update UeU`U  
    Print "DONE!" "mc ]^ O  
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End Sub r*{`_G=1  
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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: [wn! <#~v  
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Accommodation = 4 Diopters (: @7IWZf@  
Pupil Diameter = 4 mm F~?|d 0  
Set aqueous humor thickness = 2.81 \WxBtpbQ B  
Set anterior lens radius = 10.4 and conic constant = -2.375869 I-m Bj8^;  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 aole`PD,l  
Set lens thickness = 3.927 ~8U0(n:^  
Set lens index of refraction = 1.42672 ##nC@h@  
Set pupil diameter = 4 RKy!=#;17  
DONE! kY{;(b3Q  
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