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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 aCH:#|B  
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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。 U>plv  
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模型 _;J9q}X  
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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。 yhkQFB%gv  
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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. R26tQbwE  
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光源 1{Alj27  
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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。 |3<ehvKy  
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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。 q5\LdI2  
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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。 jC Kt;lj  
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图2. 字母F光源的设定方法光 'MdE}  
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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 M%5$-;6~_  
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在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 +/>YH-P=  
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图4. 视网膜朗伯散射设定
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注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 F;Xq:e8  
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图5. 视网膜重点采样规格设定
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脚本 'y M:W cN  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: /XW0`FF  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 -R$FJb Id  
余下的脚本计算与屈光度有关的所有参数。 !Ub?eJp  
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分析 vS t=Ax3]  
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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。 HToN+z%w3H  
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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 JdYF&~  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. @[b:([  
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Dim entity As T_ENTITY 7n 95>as  
Dim op As T_OPERATION y yR8VO{  
Dim mat As T_MODELMATERIAL x5 ~E'~_  
Dim A As Double qCkg\)Ks5I  
Dim pupilDiam As Double 4p.{G%h  
Dim eID As Long [;#.DH]  
Dim parID As Long iM/0Yp-v'>  
Dim count As Integer K<w5[E9V.  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double XK/@!ud"`  
Dim tlens As Double, nlens As Double ?.A/E?Oc  
Dim curv As Double, conic As Double p;t!"I:`?  
Dim ok As Long dDn4nwH  
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Sub Main qf=[*ZY  
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    '用户输入对话框 ^-;Z8M  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 n03SX aU~V  
        TextBox 220,21,40,21,.TextBox1 'default: 0 3cFLU^  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 5'-9?-S"  
        OKButton 40,91,90,21 Iy4M MU  
        CancelButton 190,91,90,21 ;,})VoC\!  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 wXZY5-h4  
        TextBox 220,49,40,21,.TextBox2 'default: 4 i8 ):0  
    End Dialog DJ [#H  
    Dim dlg As UserDialog h_G7T1;L  
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    ok = Dialog (dlg) <({eOh5 N  
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    If ok=0 Then    'cancel button was pressed vhEs+ j  
        Print "Execution cancelled." `LU,uz  
        End gO%i5  
    End If /aa;M*Qp  
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    'Assign accommodation and pupil diameter & use defaults if field left empty |#jm=rT0y  
    If dlg.TextBox1 = "" Then r8?Lr-;  
        A = 0           'Default accommodation $K5s)!  
    Else \ g(#)f  
        A = CDbl(dlg.TextBox1) *K.7Zf0  
    End If FH21mwV  
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    If dlg.TextBox2 = "" Then 0a%ui2k  
        pupilDiam = 4   'Default pupil diameter "K!BJQ  
    Else 5nq-b@?L  
        pupilDiam = CDbl(dlg.TextBox2) uBkn y;  
    End If HbSx}bM_9  
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    Print " " 3&Rqz9W  
    Print "Accommodation = " & A & " Diopters" SfFR  
    Print "Pupil Diameter = " & pupilDiam & " mm" SW'KYzn  
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    ' Calculate new parameters with accommodation c qyh#uWe  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ^ED>{UiNI  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 6b01xu(A[  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens NS;8&  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ,VsCRp  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 1AV1W_"  
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    tlens = 3.767 + 0.04*A                  'Lens thickness bK1`a{  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 8HA=O ?Cg  
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    'Adjust parameters to account for accommodation cGp 6yf  
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    '************************************************************************* BVp.A]  
    'Aqueous thickness (Position of Lens) ;<<IXXKU  
    '************************************************************************* Li^!OHro.  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) oA@^N4PD  
    GetCustomElement eID, entity CWYJ<27v{  
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    parID = FindFullName( "Geometry.Arizona Eye" ) HbDB?s<  
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    ' Delete any shift(s) in z n7uD(cL  
    count = 0 K(<P" g(  
    While GetOperationCount(eID)>count 2Hwf:S'  
        GetOperation eID, count, op :+!b8[?Z  
        If op.Type="ShiftZ" Then ra2q. H  
            DeleteOperation eID,count r=aQ S5  
            count=count-1 Qf]!K6eR  
        End If /U]5#'i  
        count=count+1 U.(_n  
    Wend rP4@K%F9jB  
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    'Set new shift in >C3 9`1  
    op.Type = "ShiftZ"  N&.p\T&t  
    op.val1 = taq n #/m7  
    op.parent = parID u;g}N'"  
    AddOperation eID, op 1<|I[EI  
    Print "Set aqueous humor thickness = " & taq-0.55 0O4mA&&!oK  
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    '************************************************************************* fZgU@!z  
    'Radius and conic constant of anterior lens sTyGi1  
    '************************************************************************* $7YLU{0  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) ^umAfk5r?H  
    GetConic eID, entity, curv, conic /WVMT]T6^,  
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    SetConic eID, entity, 1/Rant, CCant 3 2D/%dHC  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant kzXW<V9  
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    '************************************************************************* <~w#sIh  
    'Radius and conic constant of posterior lens blv6  
    '************************************************************************* ]:fHvx_?`7  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) |D:0BATRP  
    GetConic eID, entity, curv, conic w2[R&hJ  
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    SetConic eID, entity, 1/Rpost, CCpost iX p8u**  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost W0k q>s4  
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    '************************************************************************* m=V2xoMw6  
    'Lens thickness (Position of posterior lens surface) e: tp7w 4  
    '************************************************************************* h+@t8Q;gGw  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) "(qO}&b>  
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    ' Delete any z-shift(s) I|H mbTXa  
    count = 0 >w2u  
    While GetOperationCount(eID)>count +\chHOsw  
        GetOperation eID, count, op gEu\X|7'  
        If op.Type="ShiftZ" Then 6:pN?|=6X  
            DeleteOperation eID,count VuW19-G  
            count=count-1 |t_2AV  
        End If {r)M@@[  
        count=count+1 *TkABUL  
    Wend ]\lw^.%  
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    'Set new z-shift D=Y HJ>-wB  
    op.Type = "ShiftZ" HZ3<}`P_W  
    op.val1 = tlens ~fe0Ba4  
    op.parent = parID RJSgts "F  
    AddOperation eID, op J:a^''  
    Print "Set lens thickness = " & tlens H@:@zD!G[  
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    '************************************************************************* ] W_T(C*  
    'Lens index of refraction CiSG=obw  
    '************************************************************************* PdZSXP4;k  
    eID = FindMaterial( "Lens" ) I_rVeMw=  
    GetModelMaterial eID, mat >smaR^m  
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    mat.Nd = nlens yS""*8/  
    SetModelMaterial eID, mat j3>< J  
    Print "Set lens index of refraction = " & nlens .B*)A.   
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    '************************************************************************* g d-fJ._1  
    'Pupil diameter RZZB?vx  
    '************************************************************************* q'q{M-U<  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) I f(_$>  
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    'Adjust pupil diameter (trimming volume inner hole) ilP&ctn6+c  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" C0M{zGT>}  
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    ' Adjust pupil location to just in front of the lens c LJCLKJ  
    parID = FindFullName( "Geometry.Arizona Eye" ) ]+8,@%="  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) M<nn+vy`  
    count = 0  e(^O8  
    While GetOperationCount(eID)>count nL? B  
        GetOperation eID, count, op XV&3h>5  
        If op.Type="ShiftZ" Then |8B[yr.b  
            DeleteOperation eID,count '};Xb|msU  
            count=count-1 O_ c K 4  
        End If 2+.m44>Ti  
        count=count+1 Q%a4g  
    Wend #?9o A4Q  
    op.Type = "ShiftZ" R~i<*  
    op.val1 = taq-0.01 \3l;PY  
    op.parent = parID Vk"QcW  
    AddOperation eID, op +vP1DXtj(  
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    Print "Set pupil diameter = " & pupilDiam a'Z"Yz^Eo  
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    'Update AZ Eye subassembly Description MAXdgL[]  
    eID = FindFullName( "Geometry.Arizona Eye" ) 4{Iz\:G:{/  
    GetEntity eID, entity R?W8l5CIk  
    entity.Description = "Accommodation = " & A & "D" ~4M]SX1z  
    SetEntity eID, entity zri<'W  
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    Update jHd~yCq  
    Print "DONE!" .f}I$ "2  
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End Sub X7G6y|4;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: Jd |hwvwFe  
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Accommodation = 4 Diopters <AVpFy  
Pupil Diameter = 4 mm G~JQcJFj  
Set aqueous humor thickness = 2.81 8wBns)wy@  
Set anterior lens radius = 10.4 and conic constant = -2.375869 A1|:$tED+2  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 . &e,8  
Set lens thickness = 3.927 NM4 n  
Set lens index of refraction = 1.42672 M1^pW 63  
Set pupil diameter = 4 Uz0mSfBp  
DONE! Gqs8$[o  
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