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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。 ?`O^;f  
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模型 'ShK7j$  
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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。 3 5L0 CM  
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. >V]9<*c  
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光源 Nv6"c<(L=  
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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。 u3pFH(  
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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。 DZ`m{l3H  
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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。 "h7Dye  
图2. 字母F光源的设定方法光 4i+%~X@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 BpYxH#4  
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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。 ;YW@ 3F-h  
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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。 c/v|e&q  
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图5. 视网膜重点采样规格设定
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脚本 -V[x 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: !@N?0@$/  
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。 M6Np!0G  
余下的脚本计算与屈光度有关的所有参数。 p3{Ff5FZ  
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分析 \hBzP^*"n  
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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。 c:>&YGmhu  
图7. 字母F在视网膜上颜色分析
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脚本代码 ctjQBWE  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. ?# _{h  
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Dim entity As T_ENTITY P*~ vWYH9  
Dim op As T_OPERATION \]5I atli  
Dim mat As T_MODELMATERIAL $j<KXR  
Dim A As Double 7}6CUo  
Dim pupilDiam As Double [Z#Sj=z  
Dim eID As Long q^Oj/ws  
Dim parID As Long OHsA]7S  
Dim count As Integer pq&[cA_w  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double q#8yU\J|,  
Dim tlens As Double, nlens As Double jnT Tj l  
Dim curv As Double, conic As Double BI%XF 9{  
Dim ok As Long vB{i w}Hi!  
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Sub Main dr:x0>  
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    '用户输入对话框 18QqZ,t  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 CE c(2q+%i  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ] S[?tn  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 L+<h 5>6  
        OKButton 40,91,90,21 m6n%?8t  
        CancelButton 190,91,90,21 [xr^t1  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 )E>yoUhN  
        TextBox 220,49,40,21,.TextBox2 'default: 4 n-l_PhPQ`  
    End Dialog vIOGDI>  
    Dim dlg As UserDialog #fns3=/ H  
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    ok = Dialog (dlg) |vl~B|",  
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    If ok=0 Then    'cancel button was pressed Mh5> hD  
        Print "Execution cancelled." :=ek~s.UV  
        End 9*ZlNZ  
    End If /[\g8U{5B}  
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    'Assign accommodation and pupil diameter & use defaults if field left empty ;<m`mb4x[  
    If dlg.TextBox1 = "" Then /3~L#jS  
        A = 0           'Default accommodation |. 0~'  
    Else 5}ftiy[Yc  
        A = CDbl(dlg.TextBox1) w3);ZQ|  
    End If 4dPTrBQ?  
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    If dlg.TextBox2 = "" Then kexV~Q  
        pupilDiam = 4   'Default pupil diameter xwof[BnEZ  
    Else <%S)6cw(3  
        pupilDiam = CDbl(dlg.TextBox2) :e;6oC*"q  
    End If v>B412l  
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    Print " " FrXP"U}Y  
    Print "Accommodation = " & A & " Diopters" ,mp<<%{u  
    Print "Pupil Diameter = " & pupilDiam & " mm" iKJqMES  
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    ' Calculate new parameters with accommodation gI;"PkN  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness g}D)MlXRq  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens {Fw"y %a^  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens zH}3J}  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens P7XZ|Td4*  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ra T9  
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    tlens = 3.767 + 0.04*A                  'Lens thickness &3Zb?  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction :)lG}c  
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    'Adjust parameters to account for accommodation }]o8}$&(  
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    '************************************************************************* [StnKQ?"wz  
    'Aqueous thickness (Position of Lens) oR2?$KF   
    '************************************************************************* xyk%\&"7  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) W4^zKnH  
    GetCustomElement eID, entity hFi gY\$m  
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    parID = FindFullName( "Geometry.Arizona Eye" ) b},2A'X  
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    ' Delete any shift(s) in z jL\j$'KC  
    count = 0 Qq`S=:}~x  
    While GetOperationCount(eID)>count :kR>wX  
        GetOperation eID, count, op iv~R4;;)  
        If op.Type="ShiftZ" Then j*?8w(!  
            DeleteOperation eID,count ^:{8z;w!(  
            count=count-1 nD BWm`kN  
        End If //2O#Fg{/  
        count=count+1 cj>UxU][eS  
    Wend QX<n^W  
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    'Set new shift in Qy"Jt]O  
    op.Type = "ShiftZ" y2_rm   
    op.val1 = taq Unb2D4&'  
    op.parent = parID s`bGW1#io  
    AddOperation eID, op 8j#S+=l>  
    Print "Set aqueous humor thickness = " & taq-0.55 6U*CR=4  
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    '************************************************************************* Q`9c/vPU  
    'Radius and conic constant of anterior lens Xs052c|s  
    '************************************************************************* K`K v.4  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) sWr;%<K  
    GetConic eID, entity, curv, conic x!_5 /  
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    SetConic eID, entity, 1/Rant, CCant DH?n~qKpC  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant Q&]|W Xv  
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    '************************************************************************* a*5KUj6/TL  
    'Radius and conic constant of posterior lens #]jl{K\f#X  
    '************************************************************************* "Wg,]$IvU  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Fa>f'VXx  
    GetConic eID, entity, curv, conic 'Eur[~k  
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    SetConic eID, entity, 1/Rpost, CCpost OK80-/8HI  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 'z8FU~oU  
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    '************************************************************************* O.B9w+G=  
    'Lens thickness (Position of posterior lens surface) )ovAGO  
    '************************************************************************* \PxT47[@e  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Q<V(#)*  
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    ' Delete any z-shift(s) \lQ3j8 U  
    count = 0 !ddyJJ^a  
    While GetOperationCount(eID)>count X3}eq|r9  
        GetOperation eID, count, op k 3m_L-  
        If op.Type="ShiftZ" Then zfKO)Itd  
            DeleteOperation eID,count ts,r,{  
            count=count-1 GmR3 a  
        End If We{@0K/O  
        count=count+1 z='%NZY  
    Wend U)8yd,qG[%  
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    'Set new z-shift m:h6J''<Z*  
    op.Type = "ShiftZ" v>wN O  
    op.val1 = tlens ,kJ7c;:i  
    op.parent = parID a|z-EKV  
    AddOperation eID, op 9s"st\u 4  
    Print "Set lens thickness = " & tlens T9V=#+8#"  
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    '************************************************************************* *Mhirz% iD  
    'Lens index of refraction /8e}c`  
    '*************************************************************************  "M5  
    eID = FindMaterial( "Lens" ) -E?:W`!  
    GetModelMaterial eID, mat ,)[9RgsE  
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    mat.Nd = nlens U}jGr=tu  
    SetModelMaterial eID, mat 9\.0v{&v  
    Print "Set lens index of refraction = " & nlens N-upNuv  
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    '************************************************************************* Yc]V+NxxQ  
    'Pupil diameter V#w$|2  
    '************************************************************************* |s! _;6  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) *gwaW!=  
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    'Adjust pupil diameter (trimming volume inner hole) Cy?]o?_?  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" o08g]a  
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    ' Adjust pupil location to just in front of the lens 'l^Bb#)"  
    parID = FindFullName( "Geometry.Arizona Eye" ) ;=,-C ;`  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) :o!Kz`J  
    count = 0 <5E'`T  
    While GetOperationCount(eID)>count P6GTgQ<'BA  
        GetOperation eID, count, op "j_iq"J  
        If op.Type="ShiftZ" Then 6#U~>r/  
            DeleteOperation eID,count >;4q  
            count=count-1 r[!~~yu/o  
        End If Jt5V{9:('  
        count=count+1 |V\{U j  
    Wend DD=X{{;D\"  
    op.Type = "ShiftZ" tAN!LI+w  
    op.val1 = taq-0.01 eWDXV-xD  
    op.parent = parID Zeg'\&w0s  
    AddOperation eID, op J-<P~9m~I  
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    Print "Set pupil diameter = " & pupilDiam 3q/Us0jr  
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    'Update AZ Eye subassembly Description W~mo*EJ'^  
    eID = FindFullName( "Geometry.Arizona Eye" ) w0g@ <( 3  
    GetEntity eID, entity @]n8*n  
    entity.Description = "Accommodation = " & A & "D" m[=SCH-;  
    SetEntity eID, entity iO*5ClB  
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    Update aaU4Jl?L  
    Print "DONE!" K uwhA-IL  
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End Sub t, %m-dU  
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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: G@DNV3Cc  
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Accommodation = 4 Diopters 1K3XNHF  
Pupil Diameter = 4 mm IB# ua:  
Set aqueous humor thickness = 2.81 ^4`x:6m  
Set anterior lens radius = 10.4 and conic constant = -2.375869 TI3xt-/  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 M%_*vD  
Set lens thickness = 3.927 /UunWZ u%  
Set lens index of refraction = 1.42672 "}_ J"%  
Set pupil diameter = 4 }'Ap@4  
DONE!
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