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    [技术]Arizona眼睛模型 [复制链接]

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    只看楼主 倒序阅读 楼主  发表于: 2021-10-22
    简介 dtZE67KS  
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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。 E5</h"1  
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    模型 PL X>-7@  
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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。 y7/F _{  
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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. ICC%,$C~l  
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    光源 Jrxz'9qRG  
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    多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 h6~$/`&]b  
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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。 -' g*^  
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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。 rV6/Tdy  
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    图2. 字母F光源的设定方法光 h[o6-f<D  
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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 "ZwKk G  
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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。 !-<p,z  
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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。 #Tw@wfaq)  
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    图5. 视网膜重点采样规格设定
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    脚本 qz?mh4Oh  
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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: AN!s{7V3  
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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%q}IH#  
    余下的脚本计算与屈光度有关的所有参数。 SZaS;hhhHu  
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    分析 $odso;Hn  
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    屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 wLc4Dm*V  
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    图7. 字母F在视网膜上颜色分析
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    脚本代码 .*m>\>Gsgw  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. <sK4#!K  
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    Dim entity As T_ENTITY #@<9S{F  
    Dim op As T_OPERATION `x%'jPP1 ^  
    Dim mat As T_MODELMATERIAL Z}$TKO*u  
    Dim A As Double BauU{:Sh  
    Dim pupilDiam As Double F*"}aP$  
    Dim eID As Long okbQ<{9  
    Dim parID As Long 7}M2bH} \K  
    Dim count As Integer /|* Y2ETOr  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 93Co}@Y;Y+  
    Dim tlens As Double, nlens As Double '>r7V  
    Dim curv As Double, conic As Double i3rH'B -I.  
    Dim ok As Long Fu!RhsW5j  
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    Sub Main &=VDASEu  
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        '用户输入对话框 qkiI/nH3  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 _/i4MtM  
            TextBox 220,21,40,21,.TextBox1 'default: 0 'Lu__NfN  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 tH-C8Qxy  
            OKButton 40,91,90,21 X5 j1`t,  
            CancelButton 190,91,90,21 yUpgoX(6  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Q ]}Hd-  
            TextBox 220,49,40,21,.TextBox2 'default: 4 M5 <@~V/[  
        End Dialog EK4d_L]I  
        Dim dlg As UserDialog yu;P +G  
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        ok = Dialog (dlg) 6I%5Q4Ll  
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        If ok=0 Then    'cancel button was pressed #{?qNl8F*J  
            Print "Execution cancelled." 'FDef#P<  
            End v%q0OX>9X"  
        End If gHo?[pS%y  
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        'Assign accommodation and pupil diameter & use defaults if field left empty 1fpQLaT  
        If dlg.TextBox1 = "" Then V,cBk  
            A = 0           'Default accommodation Evedc*z~P  
        Else =>_\fNy  
            A = CDbl(dlg.TextBox1) lhqg$lb  
        End If C#Na&m  
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        If dlg.TextBox2 = "" Then INJEsz  
            pupilDiam = 4   'Default pupil diameter PpAu!2lt9  
        Else MRdduPrM%$  
            pupilDiam = CDbl(dlg.TextBox2) 2.l:O2<  
        End If @0/+_2MH-  
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        Print " " |&zz,+E  
        Print "Accommodation = " & A & " Diopters" MB]<Dyj,  
        Print "Pupil Diameter = " & pupilDiam & " mm" *-8&[D0  
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        ' Calculate new parameters with accommodation fTK3,s1=  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness UWd=!h^dt  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens wY[+ZT  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 7t0e r'VC  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens toBHkiuD  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 'Wm x)0)  
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        tlens = 3.767 + 0.04*A                  'Lens thickness v@ lM3_rbO  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction +l<5#pazx  
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        'Adjust parameters to account for accommodation k@k&}N0{  
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        '************************************************************************* 8|l\E VV6  
        'Aqueous thickness (Position of Lens) paCV!tP  
        '************************************************************************* P*3BB>FO   
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 1cpiHZa  
        GetCustomElement eID, entity qKr8)}h  
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        parID = FindFullName( "Geometry.Arizona Eye" ) h7lDHIQf  
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        ' Delete any shift(s) in z e#$]Y?,  
        count = 0 ;;6uw\6 O  
        While GetOperationCount(eID)>count -z)n?(pftm  
            GetOperation eID, count, op $QN"w L||  
            If op.Type="ShiftZ" Then 8 Hg+H=?  
                DeleteOperation eID,count "&G/T ?4  
                count=count-1 Bg x'9p/  
            End If TJ6*t!'*X  
            count=count+1 r\'A i6  
        Wend M_/7D|xl/T  
    Y)*#)f  
        'Set new shift in \/zq7j  
        op.Type = "ShiftZ" keL&b/@  
        op.val1 = taq v$?+MNks  
        op.parent = parID mwHB(7YS,  
        AddOperation eID, op jaII r06  
        Print "Set aqueous humor thickness = " & taq-0.55 PNgY >=Y  
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        '************************************************************************* <Tzrj1"Q3  
        'Radius and conic constant of anterior lens 0zmE>/O+  
        '************************************************************************* ;- ~B)M_S`  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) g?goZPZB  
        GetConic eID, entity, curv, conic 8lvV4yb  
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        SetConic eID, entity, 1/Rant, CCant gY/"cq  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant nP$Ky1y G  
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        '************************************************************************* C~,a!qY  
        'Radius and conic constant of posterior lens 5F)C  jQ  
        '************************************************************************* #Z?A2r!1  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) {FeDvhv  
        GetConic eID, entity, curv, conic a*lh)l<KV  
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        SetConic eID, entity, 1/Rpost, CCpost _.tVSV p  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost iVhJ t#_b  
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        '************************************************************************* |W,& Hl7  
        'Lens thickness (Position of posterior lens surface) e^6)Zz1\  
        '************************************************************************* P{kur} T  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) tqE6>"jD  
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        ' Delete any z-shift(s) ^ Edfv5  
        count = 0 N)uSG&S:  
        While GetOperationCount(eID)>count x nsLf?>]  
            GetOperation eID, count, op dk[!V1x4\  
            If op.Type="ShiftZ" Then }7|1  
                DeleteOperation eID,count )B"jF>9)[  
                count=count-1 [kVS O  
            End If hZ?Rof  
            count=count+1 6iVxc|Ia  
        Wend SoW9p^HJ  
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        'Set new z-shift ?PuBa`zDE  
        op.Type = "ShiftZ" X9v.1s,  
        op.val1 = tlens $v4.sl:x  
        op.parent = parID T"{>t  
        AddOperation eID, op !#], hok8X  
        Print "Set lens thickness = " & tlens eBZXI)pPh  
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        '************************************************************************* kyR:[+je  
        'Lens index of refraction 2e+UM$  
        '************************************************************************* 2J7:\pR^  
        eID = FindMaterial( "Lens" ) jwc)Lj}  
        GetModelMaterial eID, mat >K_(J/&p  
    %". HaI]  
        mat.Nd = nlens l: HTk4$0  
        SetModelMaterial eID, mat xK *b1CB  
        Print "Set lens index of refraction = " & nlens N({MPO9  
    yr)G]K[/  
        '************************************************************************* sJB;3"~  
        'Pupil diameter bkOv2tZ  
        '************************************************************************* <Th6r.#?  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) u 1J0$  
    ^n*)7K[  
        'Adjust pupil diameter (trimming volume inner hole) |^&b8  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" kvL=> A  
    @E&J_un  
        ' Adjust pupil location to just in front of the lens G,&<<2{(f;  
        parID = FindFullName( "Geometry.Arizona Eye" ) 5Yg'BkEr  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) @6Y?\Wx$w  
        count = 0 >8~.wXyoC  
        While GetOperationCount(eID)>count D$w6V  
            GetOperation eID, count, op nHM~  
            If op.Type="ShiftZ" Then k :(SCHf  
                DeleteOperation eID,count #3i3G(mQ  
                count=count-1 "3X2VFwoJ  
            End If R{C(K(5/  
            count=count+1 Vh'P&W?[  
        Wend |B?cVc0  
        op.Type = "ShiftZ" L7n D|  
        op.val1 = taq-0.01 ;,hwZZA  
        op.parent = parID F|'>NL-=  
        AddOperation eID, op kjTduZ/3 "  
    Y xr>"KH6a  
        Print "Set pupil diameter = " & pupilDiam 8r*E-akuyr  
    T;Lkaxsn  
        'Update AZ Eye subassembly Description \ ZgE  
        eID = FindFullName( "Geometry.Arizona Eye" ) &C `Gg<  
        GetEntity eID, entity iN bIp"W  
        entity.Description = "Accommodation = " & A & "D" QE^$=\l0  
        SetEntity eID, entity 9 &$y}Y  
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        Update :vmH]{R  
        Print "DONE!" 'j`=if  
         "|x^|n8i  
    End Sub J4k=A7^N  
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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: J9\Cm!H  
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    Accommodation = 4 Diopters bZ dNibN  
    Pupil Diameter = 4 mm eQ$Y0qH1E  
    Set aqueous humor thickness = 2.81 KI.q@zO6|  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 j b!x:  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 b:U$x20n$  
    Set lens thickness = 3.927 +jAGGv^)  
    Set lens index of refraction = 1.42672 b_$4V3TA  
    Set pupil diameter = 4 FI)17i$  
    DONE! ^%d\qd`   
     
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