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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。 q^h/64F  
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模型 Ho1V)T>  
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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。 >65\  
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. 5,?^SK|'x  
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光源 b-RuUfUn0  
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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。 Z1{>"o:@  
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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。 bu{dT8g'U  
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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。 "[0.a\ d<  
图2. 字母F光源的设定方法光 gv1y%(`|n(  
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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 e xkPu-[W  
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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。 QOY{j  
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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。 [Y.=bfV!  
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图5. 视网膜重点采样规格设定
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脚本 5 v^tPGg4  
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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: 45&Rl,2  
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。 Z\cD98B#  
余下的脚本计算与屈光度有关的所有参数。 y+KAL{AGK  
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分析 e^;%w#tEqI  
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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。 )_Z^oH ]<  
图7. 字母F在视网膜上颜色分析
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脚本代码 Hg$7[um  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. #\_ 8y`{x  
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Dim entity As T_ENTITY >P]gjYN  
Dim op As T_OPERATION 0Ua=&;/2  
Dim mat As T_MODELMATERIAL q@tym5  
Dim A As Double zQ#* O'-n  
Dim pupilDiam As Double %0 i)l|  
Dim eID As Long |(AFU3 ~  
Dim parID As Long (][-()YV  
Dim count As Integer .(3ec/i4CF  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double X?XB!D7[  
Dim tlens As Double, nlens As Double v\_\bT1  
Dim curv As Double, conic As Double {e q378d  
Dim ok As Long q^?a|l  
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Sub Main r=~K#:66  
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    '用户输入对话框 jOzi89  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ~Z!YB,)bp  
        TextBox 220,21,40,21,.TextBox1 'default: 0 klH?!r&  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 @b,6W wc  
        OKButton 40,91,90,21 Gp+\}<^ Z  
        CancelButton 190,91,90,21 +k~0&lZi  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 v1Q 78P  
        TextBox 220,49,40,21,.TextBox2 'default: 4 b%vIaP|]B  
    End Dialog boHbiE  
    Dim dlg As UserDialog +vxOCN4}v  
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    ok = Dialog (dlg) lfre-pS+  
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    If ok=0 Then    'cancel button was pressed r7L.W  
        Print "Execution cancelled." /'5d0' ,M  
        End ;Rpib[m  
    End If |:.Uw\z5'  
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    'Assign accommodation and pupil diameter & use defaults if field left empty R PoBF~>  
    If dlg.TextBox1 = "" Then t 7o4 aBl"  
        A = 0           'Default accommodation ,.}%\GhY  
    Else wc. =`Me  
        A = CDbl(dlg.TextBox1) x)GheM^  
    End If 9t6c*|60#n  
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    If dlg.TextBox2 = "" Then K&Bbjb_|  
        pupilDiam = 4   'Default pupil diameter Y;%LwDC  
    Else (CY D]n  
        pupilDiam = CDbl(dlg.TextBox2) CtV|oeJ  
    End If r-TrA$k  
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    Print " " MfHOn YV  
    Print "Accommodation = " & A & " Diopters" +L`}(yLJ)9  
    Print "Pupil Diameter = " & pupilDiam & " mm" {Dk!<w I)  
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    ' Calculate new parameters with accommodation ge:a{L  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Tjq1[Wq  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens BAY e:0  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens BxjSo^n  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens Y0T:%  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens IZ7o6Etti  
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    tlens = 3.767 + 0.04*A                  'Lens thickness IGQBTdPUa  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction X%j`rQk`  
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    'Adjust parameters to account for accommodation 8FMxn{k2  
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    '************************************************************************* GWWg3z.o"W  
    'Aqueous thickness (Position of Lens) yxHo0U  
    '************************************************************************* >Zs!  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) vI0,6fOd6  
    GetCustomElement eID, entity &1yJrj9y  
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    parID = FindFullName( "Geometry.Arizona Eye" ) #}+H  
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    ' Delete any shift(s) in z |-b\N6 }  
    count = 0 boGdZ2$h4  
    While GetOperationCount(eID)>count GdI,&| /  
        GetOperation eID, count, op *X/Vt$P  
        If op.Type="ShiftZ" Then ;!A8A4~nu  
            DeleteOperation eID,count I`X!M!dB)  
            count=count-1 grzmW4Cw  
        End If bs?\ )R5/  
        count=count+1 rzIWQFv  
    Wend @jm+TW  
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    'Set new shift in oI/_WY[t  
    op.Type = "ShiftZ" 7PMz6  
    op.val1 = taq Rw{' O]Q*  
    op.parent = parID j \jMN*dmV  
    AddOperation eID, op 1F,U^O  
    Print "Set aqueous humor thickness = " & taq-0.55 c-(RjQ~M5  
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    '************************************************************************* BInSS*L  
    'Radius and conic constant of anterior lens J<"K`|F  
    '************************************************************************* * @]wT'  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) C/Tk`C&  
    GetConic eID, entity, curv, conic CLzF84@W=  
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    SetConic eID, entity, 1/Rant, CCant SoM,o]s#y  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant H\oxj,+N  
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    '************************************************************************* E> GmFw  
    'Radius and conic constant of posterior lens <Y7j'n  
    '************************************************************************* U1y!R<qlp  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) t2)uJN`a$X  
    GetConic eID, entity, curv, conic 6Q7=6  
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    SetConic eID, entity, 1/Rpost, CCpost ]pBEoktp  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 9DhM 9VU  
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    '************************************************************************* ~6kF`}5  
    'Lens thickness (Position of posterior lens surface) e8("G[P >  
    '************************************************************************* fYy w2"  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ,]wQ]fpt  
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    ' Delete any z-shift(s) r4/b~n+*  
    count = 0 z0 /+P  
    While GetOperationCount(eID)>count Yc]k<tQ  
        GetOperation eID, count, op OP=brLGu0  
        If op.Type="ShiftZ" Then t;VMtIW+E  
            DeleteOperation eID,count )jgz(\KZ  
            count=count-1 -c?x5/@3  
        End If  VQH48{X  
        count=count+1 ^g6v#]&WA  
    Wend b'+Wf#.]f0  
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    'Set new z-shift 1/?Wa  
    op.Type = "ShiftZ" WLXt@dK*u  
    op.val1 = tlens ,dQ*0XO!  
    op.parent = parID e8 ]CB  
    AddOperation eID, op GBb8 }lx  
    Print "Set lens thickness = " & tlens 13/,^?  
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    '************************************************************************* WuY#Kx~2  
    'Lens index of refraction !Z2h ?..O  
    '************************************************************************* 5A`>3w{3n  
    eID = FindMaterial( "Lens" ) [>?|wQy>=  
    GetModelMaterial eID, mat 6O{QmB0KK  
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    mat.Nd = nlens .jqil0#)Y"  
    SetModelMaterial eID, mat W)r|9G8T  
    Print "Set lens index of refraction = " & nlens A,EG0yb  
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    '************************************************************************* -{OJM|W+  
    'Pupil diameter i=n;rT  
    '************************************************************************* PU.j(0  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 8/R$}b><  
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    'Adjust pupil diameter (trimming volume inner hole) }rmr0Bh  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" Xk%eU>d  
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    ' Adjust pupil location to just in front of the lens -FZNk}  
    parID = FindFullName( "Geometry.Arizona Eye" ) h!(# /  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) .$cX:"_Mk  
    count = 0 `$1A;wg<  
    While GetOperationCount(eID)>count G2wSd'n*y  
        GetOperation eID, count, op x'}z NEXI  
        If op.Type="ShiftZ" Then H?r~% bh  
            DeleteOperation eID,count vqT) =ZC1  
            count=count-1 <ndY6n3  
        End If +pq=i  
        count=count+1 ?H_@/?  
    Wend /!Ag/SmS!9  
    op.Type = "ShiftZ" YR\(*LJL  
    op.val1 = taq-0.01 8u)>o* :  
    op.parent = parID /V+7:WDj  
    AddOperation eID, op [g"nu0sOK  
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    Print "Set pupil diameter = " & pupilDiam "kcix!}&  
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    'Update AZ Eye subassembly Description ux^rF  
    eID = FindFullName( "Geometry.Arizona Eye" ) =jm\8sl~~  
    GetEntity eID, entity mvpcRe <  
    entity.Description = "Accommodation = " & A & "D" &k*oG: J3  
    SetEntity eID, entity <n k/w5nKL  
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    Update oc-&}R4=  
    Print "DONE!" :_HdOm  
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End Sub a6 :hH@,  
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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: %=K[C  
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Accommodation = 4 Diopters Y#9bM $x7  
Pupil Diameter = 4 mm GK6~~ga=  
Set aqueous humor thickness = 2.81 AwuhF PG  
Set anterior lens radius = 10.4 and conic constant = -2.375869 =`(W^&|  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 6j1C=O@S  
Set lens thickness = 3.927 cna%;f.  
Set lens index of refraction = 1.42672 \goiW;b  
Set pupil diameter = 4 nZYO}bv\  
DONE!
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