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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。 }Pw5*duq  
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模型 NWoZDsu  
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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。 av`b8cGg  
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. <`M Hra8  
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光源 <GoE2a4Va  
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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。 -$T5@  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 qqkZbsN  
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在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 2etlR  
图2. 字母F光源的设定方法光 FWD9!M K  
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图3. 字母F在视网膜上位置点列图
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视网膜的散射 9k83wACry  
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在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 5[Q44$a{  
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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。 FE_n+^|k<  
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图5. 视网膜重点采样规格设定
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脚本 G`)I _uO  
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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: !XtbZ-  
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。 3mBr nq]j>  
余下的脚本计算与屈光度有关的所有参数。 *, {b]6v  
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分析 SSH/q/  
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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。 Ay2|@1e  
图7. 字母F在视网膜上颜色分析
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脚本代码 Ke\?;1+  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. b[u_r,b  
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Dim entity As T_ENTITY ^pg5o)M  
Dim op As T_OPERATION #s]]\  
Dim mat As T_MODELMATERIAL KIuYWr7&  
Dim A As Double ETtK%%F0  
Dim pupilDiam As Double S&R~*  
Dim eID As Long qed; UyN  
Dim parID As Long )Wc#?K  
Dim count As Integer ~ xXB !K~C  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double t[^}/ S  
Dim tlens As Double, nlens As Double l+T\DZ  
Dim curv As Double, conic As Double uQ&xoDCB  
Dim ok As Long !E$S&zVMQ  
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Sub Main -R:1-0I$  
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    '用户输入对话框 .oSKSld  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 3[8'pQ!&  
        TextBox 220,21,40,21,.TextBox1 'default: 0 !'PPj_Hp]  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 |1t30_ /gS  
        OKButton 40,91,90,21 s+ 0$_&xR  
        CancelButton 190,91,90,21 N"2@y aN  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 w0 "h,{  
        TextBox 220,49,40,21,.TextBox2 'default: 4 `;i| %$TU  
    End Dialog mX"z$  
    Dim dlg As UserDialog "e(OO/EZS  
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    ok = Dialog (dlg) BD9` +9  
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    If ok=0 Then    'cancel button was pressed ~){*XJw6  
        Print "Execution cancelled." [#14atv  
        End e[{LNM{/#  
    End If Z\@vN[[  
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    'Assign accommodation and pupil diameter & use defaults if field left empty ;E##bdSCA  
    If dlg.TextBox1 = "" Then w8@ Ok_fj  
        A = 0           'Default accommodation KiCZEA  
    Else eo,m ^&  
        A = CDbl(dlg.TextBox1) N|Rlb5\  
    End If LkNfcBa_  
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    If dlg.TextBox2 = "" Then "qwRcuHY  
        pupilDiam = 4   'Default pupil diameter C~6aX/:  
    Else hbN*_[  
        pupilDiam = CDbl(dlg.TextBox2) ~A"ODLgU9  
    End If N*@bJ*0  
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    Print " " TmO\!`  
    Print "Accommodation = " & A & " Diopters" Iy e  
    Print "Pupil Diameter = " & pupilDiam & " mm" ?(ks=rRK  
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    ' Calculate new parameters with accommodation 2Ie50U  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Hm4lR{A  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens &_!BMzp4  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens ,`H=%#  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens #7'ww*+  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens @ZT25CD  
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    tlens = 3.767 + 0.04*A                  'Lens thickness :X@;XEol~  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction x}F.<`  
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    'Adjust parameters to account for accommodation x)V.^-  
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    '************************************************************************* pY-iz M L  
    'Aqueous thickness (Position of Lens) Ry/NfF=  
    '************************************************************************* #<se0CJB  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 0MPsF{Xw[  
    GetCustomElement eID, entity r+ vtKb  
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    parID = FindFullName( "Geometry.Arizona Eye" ) kv)LH{  
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    ' Delete any shift(s) in z 93YD\R+q  
    count = 0 =Jem.Ph  
    While GetOperationCount(eID)>count ZZlR:D  
        GetOperation eID, count, op xcoYo  
        If op.Type="ShiftZ" Then .W?POJT  
            DeleteOperation eID,count RV&2y=eb  
            count=count-1 vy-{BH  
        End If W*8D@a0 _  
        count=count+1 }H^#}  
    Wend &I d ^n  
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    'Set new shift in #=$4U!yL  
    op.Type = "ShiftZ" V <k_Q@K  
    op.val1 = taq ]kc_wFT<  
    op.parent = parID 3ON]c13  
    AddOperation eID, op $H5PB' b  
    Print "Set aqueous humor thickness = " & taq-0.55 `cZG&R  
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    '************************************************************************* +ES.O]?>  
    'Radius and conic constant of anterior lens >A1Yn]k  
    '************************************************************************* s"a*S\a;b  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) KAUYE^  
    GetConic eID, entity, curv, conic 6W#+U<  
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    SetConic eID, entity, 1/Rant, CCant JgK?j&!hs:  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant !!` zz  
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    '************************************************************************* Z{ p;J^:  
    'Radius and conic constant of posterior lens gR?3)m  
    '************************************************************************* R>Zn$%j\  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) $_)f|\s  
    GetConic eID, entity, curv, conic A+[wH(  
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    SetConic eID, entity, 1/Rpost, CCpost m"v` E7G  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost g%\e80~1(  
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    '************************************************************************* j^64:3  
    'Lens thickness (Position of posterior lens surface) MvRuW:  
    '************************************************************************* k $+&  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Ex*g>~e  
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    ' Delete any z-shift(s) $G=\i>R.  
    count = 0 "4r5n8  
    While GetOperationCount(eID)>count zu;Yw=cM)  
        GetOperation eID, count, op `zep`j&8^  
        If op.Type="ShiftZ" Then M)b`~|Wt  
            DeleteOperation eID,count 6 a$%  
            count=count-1 +_`F@^R_   
        End If C-2n2OM.  
        count=count+1 Gn_v}31d%  
    Wend neZ_TT/3K  
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    'Set new z-shift s"Kp+tTWj  
    op.Type = "ShiftZ" x K_$^c.  
    op.val1 = tlens j5ui  
    op.parent = parID )}6:Ke)  
    AddOperation eID, op %/>_o{"hw  
    Print "Set lens thickness = " & tlens  m+vwp\0  
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    '************************************************************************* 0,/[r/=jT  
    'Lens index of refraction b,K1EEJ  
    '************************************************************************* 7,O^c +  
    eID = FindMaterial( "Lens" ) !BQ!] u  
    GetModelMaterial eID, mat T]i~GkD\  
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    mat.Nd = nlens S[ 2`7'XV  
    SetModelMaterial eID, mat j#~4JGZt  
    Print "Set lens index of refraction = " & nlens &V2G <gm0  
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    '************************************************************************* 1yE~#KpH  
    'Pupil diameter $~9U-B\  
    '************************************************************************* q$HBPR4h  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) kW(8i}bg  
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    'Adjust pupil diameter (trimming volume inner hole) v=W%|iZ  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" }M9'N%PU  
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    ' Adjust pupil location to just in front of the lens 82w< q(  
    parID = FindFullName( "Geometry.Arizona Eye" ) ll5Kd=3  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) \zoJr)  
    count = 0 |0 Zj/1<$  
    While GetOperationCount(eID)>count 8)H"w$jq  
        GetOperation eID, count, op <LLSUk/  
        If op.Type="ShiftZ" Then M.l;!U!}  
            DeleteOperation eID,count I]$kVa1iN  
            count=count-1 ^7_<rs   
        End If m.4y=69 &  
        count=count+1 q|6lw 74`  
    Wend 7"S|GEs:  
    op.Type = "ShiftZ" oF3#]6`;/  
    op.val1 = taq-0.01 %8$wod6  
    op.parent = parID I4") ;T3  
    AddOperation eID, op {uhw ^)v  
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    Print "Set pupil diameter = " & pupilDiam '<@PgO~  
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    'Update AZ Eye subassembly Description nH_A`m3%/  
    eID = FindFullName( "Geometry.Arizona Eye" ) 66BsUA.h  
    GetEntity eID, entity oZzE.Q1T  
    entity.Description = "Accommodation = " & A & "D" nGuF, 0j  
    SetEntity eID, entity `bxgg'V  
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    Update B)c.`cfr*\  
    Print "DONE!" Nd( $s[  
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End Sub lvFHr}W  
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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: ciXAyT cG  
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Accommodation = 4 Diopters $AX!L+<!  
Pupil Diameter = 4 mm 00 $W>Gr  
Set aqueous humor thickness = 2.81 eH6#'M4+\  
Set anterior lens radius = 10.4 and conic constant = -2.375869 \@80Z5?n  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 SWmdU]  
Set lens thickness = 3.927 b. t]p  
Set lens index of refraction = 1.42672 uS&bfx2  
Set pupil diameter = 4 5ax/jd~}  
DONE!
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