[技术]Arizona眼睛模型 [复制链接]

简介 7yG%E  
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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。 [g==#[  
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模型 6ZjUC1  
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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。 5-4  
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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. ,jnaa(n  
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光源 6Po{tKU  
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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。 xJ^B.;>  
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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。 %f\j)qw  
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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。 {Zs EYUP  
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视网膜的散射 ^c}kVQ\g3  
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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。 t@2MEo  
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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。 cI6Td*vM  
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脚本 s=R^2;^  
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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：
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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。 dM -<aq  
余下的脚本计算与屈光度有关的所有参数。 ?5[$d{ Gjl  
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分析 1O2V!?P  
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屈光度为4，光瞳直径为4mm，字母F点在视网膜上所成的像。 ;e2D}  
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脚本代码 y?iW^>|?L=  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. gd0a,_`M  
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Dim entity As T_ENTITY 7a4Z~r27/  
Dim op As T_OPERATION [.;I}  
Dim mat As T_MODELMATERIAL x45F-w{  
Dim A As Double H@|m^1  
Dim pupilDiam As Double b6""q9S!  
Dim eID As Long VTO92Eo  
Dim parID As Long u`*1OqU  
Dim count As Integer HSACaTVK  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double [t?:CgI)E  
Dim tlens As Double, nlens As Double 'kJyE9*xU.  
Dim curv As Double, conic As Double ~'Korxa  
Dim ok As Long OP``+z>  
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Sub Main C)cuy7<  
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    '用户输入对话框 S`h yRw  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ] `;Fc8$  
        TextBox 220,21,40,21,.TextBox1 'default: 0 YCG$GD  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 DU@SXb  
        OKButton 40,91,90,21 %y+v0.aWH+  
        CancelButton 190,91,90,21 =|V#~p*  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 CSzu$Hnq  
        TextBox 220,49,40,21,.TextBox2 'default: 4 
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    End Dialog m&--$sr  
    Dim dlg As UserDialog q^}iXE~  
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    ok = Dialog (dlg) !3ji]q;uF  
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    If ok=0 Then    'cancel button was pressed 2t3)$\ylQp  
        Print "Execution cancelled." Dyj>dh-  
        End <,t6A?YoMP  
    End If ,/eAns`ZU  
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    'Assign accommodation and pupil diameter & use defaults if field left empty i&L!?6 5-f  
    If dlg.TextBox1 = "" Then 1Uc/r>u9  
        A = 0           'Default accommodation &3 x [0DV  
    Else :>3?|Z"Aj  
        A = CDbl(dlg.TextBox1) CeUC[cUQU  
    End If T?*f}J  
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    If dlg.TextBox2 = "" Then <SSkCw  
        pupilDiam = 4   'Default pupil diameter .6pVt_f0/  
    Else U ?6.UtNf  
        pupilDiam = CDbl(dlg.TextBox2) C|S~>4`  
    End If XrGP]k6.^  
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    Print " " =<r1sqf  
    Print "Accommodation = " & A & " Diopters" +o K*5 Y  
    Print "Pupil Diameter = " & pupilDiam & " mm" pE{Ecrc3|  
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    ' Calculate new parameters with accommodation CS;4ysNf  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness =DXN`]uN  

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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ~6#O5plKc  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens O-n JuZJgX  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens rb]?"lizi  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens |+Tq[5&R  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 5wC,:c[H7  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction Fzy5k?R  
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    'Adjust parameters to account for accommodation z6 .^a-sU5  
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    '************************************************************************* HnKXO  
    'Aqueous thickness (Position of Lens) gCx#&aXS  
    '************************************************************************* $-paY
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    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 9`7>"[=P  
    GetCustomElement eID, entity bv}e[y
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    parID = FindFullName( "Geometry.Arizona Eye" ) qTe@?j  
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    ' Delete any shift(s) in z 
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    count = 0 0CK3jdZ+X  
    While GetOperationCount(eID)>count HbJ^L:/  
        GetOperation eID, count, op A}(o1wuw  
        If op.Type="ShiftZ" Then dEZlJo@J  
            DeleteOperation eID,count <4582x,G  
            count=count-1 V+t's*9o3  
        End If wJh/tb=$o  
        count=count+1 k +Cwnp  
    Wend _Sl3)  
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    'Set new shift in ZWQ/BgKB  
    op.Type = "ShiftZ" ;?%_jB$P  
    op.val1 = taq P+DIo7VTX  
    op.parent = parID 6!wk5#  
    AddOperation eID, op -! ^D8^s  
    Print "Set aqueous humor thickness = " & taq-0.55 ]AX3ov6z9;  
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    '************************************************************************* S:1g(f*85  
    'Radius and conic constant of anterior lens #@F.wV0  
    '************************************************************************* ?/8V%PL~$  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) -B?cF9  
    GetConic eID, entity, curv, conic :TkMS
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    SetConic eID, entity, 1/Rant, CCant DKF '*  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant %^[D+1ULb  

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    '************************************************************************* !@ {sM6U  
    'Radius and conic constant of posterior lens X!m lC51  
    '************************************************************************* L+}<gQJ(  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Zn[ppsz|  
    GetConic eID, entity, curv, conic %< `D'V@  
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    SetConic eID, entity, 1/Rpost, CCpost .br6x^\<  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost W||&Xb  
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    '************************************************************************* }
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    'Lens thickness (Position of posterior lens surface) o7@C$R_#  
    '************************************************************************* <T&v\DN  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) !s:e  
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    ' Delete any z-shift(s) F~eY'~&H}  
    count = 0 8|zOgn{  
    While GetOperationCount(eID)>count KC)}Mzt6_  
        GetOperation eID, count, op b
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        If op.Type="ShiftZ" Then <_#2+7Qs  
            DeleteOperation eID,count E;[Uhh|78!  
            count=count-1 [bRE=Zr$Ry  
        End If Ov^##E  
        count=count+1 dCeLW  
    Wend "p7nngn~  
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    'Set new z-shift NpaS2q-d  
    op.Type = "ShiftZ" u@CQ+pnf:(  
    op.val1 = tlens W/AF  
    op.parent = parID eTuKu(0 E  
    AddOperation eID, op keFH CC  
    Print "Set lens thickness = " & tlens [c;#>UQMf  
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    '************************************************************************* T^(> 8/O  
    'Lens index of refraction .ws86stFSb  
    '************************************************************************* *l=(?Pe<  
    eID = FindMaterial( "Lens" ) EC 1|$Co  
    GetModelMaterial eID, mat aYDo0?kF'  
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    mat.Nd = nlens ,[)l>!0\H  
    SetModelMaterial eID, mat uxB`  
    Print "Set lens index of refraction = " & nlens Fk^N7EJ:$  
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    '************************************************************************* tRZ4\Bu  
    'Pupil diameter {M5t)-  
    '*************************************************************************
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    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) -J8Hsqf@  
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    'Adjust pupil diameter (trimming volume inner hole) O1S7t)ag  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" {ywwJ  
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    ' Adjust pupil location to just in front of the lens QXN_ ?E,g/  
    parID = FindFullName( "Geometry.Arizona Eye" ) O9ps?{g  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) sRA2O/yKCE  
    count = 0 _OyQ:>M6P  
    While GetOperationCount(eID)>count EK Vcz'w  
        GetOperation eID, count, op \2e^
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        If op.Type="ShiftZ" Then c!/+0[  
            DeleteOperation eID,count kS8?N`2}LV  
            count=count-1 %1.F;-GdsW  
        End If zX4RqI  
        count=count+1 e6Y>Bk  
    Wend yCvtglAJ4  
    op.Type = "ShiftZ" ,(pp+hNq  
    op.val1 = taq-0.01 y<E];ub  
    op.parent = parID zh*D2/r  
    AddOperation eID, op _p*8ke  
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    Print "Set pupil diameter = " & pupilDiam :C(/yg  
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    'Update AZ Eye subassembly Description )Wr_*>xj  
    eID = FindFullName( "Geometry.Arizona Eye" ) .Zv~a&GE  
    GetEntity eID, entity ?VmgM"'md  
    entity.Description = "Accommodation = " & A & "D" mXOI"B9Sq  
    SetEntity eID, entity (8)9S6  

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    Update t4[q:[1  
    Print "DONE!" %,_ZVgh0  
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End Sub o+'|j#P  
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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： !>n!Q*\(Ov  
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Accommodation = 4 Diopters rZJJ\ , |  
Pupil Diameter = 4 mm 45sEhs[$  
Set aqueous humor thickness = 2.81 C2"^YRN,  
Set anterior lens radius = 10.4 and conic constant = -2.375869 uC^)#Y\"  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 suwR`2  
Set lens thickness = 3.927 +w^,!gA&  
Set lens index of refraction = 1.42672 g"1V]  
Set pupil diameter = 4 ,"(G  
DONE! uBx\xeI