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    [技术]Arizona眼睛模型 [复制链接]

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    离线infotek
     
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    只看楼主 倒序阅读 楼主  发表于: 2021-10-22
    简介 7H6Ts8^S  
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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。 dAI^P/y%  
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    模型 [?]N GTr#  
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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。 ? x%s j  
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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. !dqC6a  
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    光源 RNT9M:w  
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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。 QK-aH1r  
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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。 -)V0D,r$[  
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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。 2q?/aw ;Z  
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    图2. 字母F光源的设定方法光 ` H'G"V  
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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 #VQZ"7nI@  
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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。 SoIK<*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。 iq;\},  
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    图5. 视网膜重点采样规格设定
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    脚本 m$8siF{<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: '(]Wtx%9"  
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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。 B:zx 9  
    余下的脚本计算与屈光度有关的所有参数。 v`h>5#_[  
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    分析 pMU\f  
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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。  exWQ~&  
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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 VwR\"8r3  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. '(K4@[3t  
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    Dim entity As T_ENTITY jOhAXe;~X{  
    Dim op As T_OPERATION 2a@X-Di  
    Dim mat As T_MODELMATERIAL ^gVQ6=z%  
    Dim A As Double b:(+d"S  
    Dim pupilDiam As Double ~ <1s[Hu  
    Dim eID As Long $1=7^v[U  
    Dim parID As Long FBE|pG7  
    Dim count As Integer MR "f)  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double 0Gu77&  
    Dim tlens As Double, nlens As Double [n9l[dN  
    Dim curv As Double, conic As Double *zRig|k!H  
    Dim ok As Long ZK4V-?/[6  
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    Sub Main aT^ $'_ G  
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        '用户输入对话框 5bb#{?2i  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 5c5!\g~'  
            TextBox 220,21,40,21,.TextBox1 'default: 0 F2YBkwI  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 P$'PB*5d|  
            OKButton 40,91,90,21 gj;gl ="3  
            CancelButton 190,91,90,21 aG1Fj[,  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 s(_z1  
            TextBox 220,49,40,21,.TextBox2 'default: 4 C b'|  
        End Dialog wPU5L*/*i  
        Dim dlg As UserDialog qiOtbH=  
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        ok = Dialog (dlg) WvU[9ME^)  
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        If ok=0 Then    'cancel button was pressed aPJTH0u  
            Print "Execution cancelled." X au %v5r  
            End YusmMsN?  
        End If |X{j^JP 5  
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        'Assign accommodation and pupil diameter & use defaults if field left empty )d[n-Si  
        If dlg.TextBox1 = "" Then Jk{SlH3'  
            A = 0           'Default accommodation )pI( <  
        Else 3MX#}_7A  
            A = CDbl(dlg.TextBox1) QXj#Brp  
        End If (bm> )U=  
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        If dlg.TextBox2 = "" Then WG,Il/  
            pupilDiam = 4   'Default pupil diameter C32*RNG?U  
        Else e&ti(Q=  
            pupilDiam = CDbl(dlg.TextBox2) sssw(F  
        End If XK~HfA?  
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        Print " " b!t[PShw^  
        Print "Accommodation = " & A & " Diopters" e!Z}aOeE  
        Print "Pupil Diameter = " & pupilDiam & " mm" p` ~=v4;b  
    )h ,v(Rxa  
        ' Calculate new parameters with accommodation 6b*xhu\  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness &fRz6Hd  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens i&(1 <S>P  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens FVNTE +LW  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens vo E t\H  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens v2gk1a &  
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        tlens = 3.767 + 0.04*A                  'Lens thickness (e_<~+E  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction o w(9dB&E  
    0.m-}  
        'Adjust parameters to account for accommodation bOU"s>?  
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        '************************************************************************* [qY yr  
        'Aqueous thickness (Position of Lens) NPv.7,  
        '************************************************************************* #P!<u Lc%  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) lpPPI+|4N  
        GetCustomElement eID, entity \v+>qY<q  
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        parID = FindFullName( "Geometry.Arizona Eye" ) N, u]2,E  
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        ' Delete any shift(s) in z 7Wv.-LD6  
        count = 0 ?!m\|'s-  
        While GetOperationCount(eID)>count %J'/cmR&  
            GetOperation eID, count, op qu#xc0?  
            If op.Type="ShiftZ" Then >r X$E<B\  
                DeleteOperation eID,count ,ye[TQ\,M  
                count=count-1 Slo^tqbG  
            End If Bi9Q8#lh  
            count=count+1 YeT{<9p  
        Wend k)z>9z%D  
    *Dq ++  
        'Set new shift in DXj>u9*%  
        op.Type = "ShiftZ" %Unwh1VG  
        op.val1 = taq `uLr^G=;  
        op.parent = parID c ?<)!9:  
        AddOperation eID, op ;t9!< L  
        Print "Set aqueous humor thickness = " & taq-0.55 L[:A Ue  
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        '************************************************************************* A ?tna6W:  
        'Radius and conic constant of anterior lens #c' B2Jn  
        '************************************************************************* A *:| d~  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) "] 2^O  
        GetConic eID, entity, curv, conic |<3x`l-`  
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        SetConic eID, entity, 1/Rant, CCant GL>YJ%  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant k:V9_EI=  
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        '************************************************************************* o=!_.lDF:  
        'Radius and conic constant of posterior lens E;`^`T40  
        '************************************************************************* 6d5J*y2  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 1D)0\#><  
        GetConic eID, entity, curv, conic :Hb`vH3 x  
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        SetConic eID, entity, 1/Rpost, CCpost K2Ro0  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost y:Gn58\o  
    }^Sk.:;n3  
        '************************************************************************* ]8"U)fzmc.  
        'Lens thickness (Position of posterior lens surface) aso8,mpZuA  
        '************************************************************************* 7jxx,#I:  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 8G$BQ  
    wA 7\K~fHV  
        ' Delete any z-shift(s) fUCjC*#1  
        count = 0 Ad,n+%"e  
        While GetOperationCount(eID)>count :81d~f7  
            GetOperation eID, count, op $8(QBZq  
            If op.Type="ShiftZ" Then Tc"J(GWG  
                DeleteOperation eID,count SmDNN^GR  
                count=count-1 :_xfi9L~W0  
            End If x%k@&d;z  
            count=count+1 8PVjNS/  
        Wend pl[@U<8aw  
    6&;GC<].(y  
        'Set new z-shift )\D{5j  
        op.Type = "ShiftZ" N<b2xT  
        op.val1 = tlens LauGT* z!  
        op.parent = parID xR kw+  
        AddOperation eID, op Xm|~1 k_3  
        Print "Set lens thickness = " & tlens ?%~^PHgZ|  
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        '************************************************************************* rp"5176  
        'Lens index of refraction jTg~]PQ^  
        '************************************************************************* uD?G\"L i  
        eID = FindMaterial( "Lens" ) oj{CNa  
        GetModelMaterial eID, mat 479X5Cl  
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        mat.Nd = nlens \\13n4fAv  
        SetModelMaterial eID, mat )qMbk7:v\  
        Print "Set lens index of refraction = " & nlens {irc~||4  
    } LC  
        '************************************************************************* {Ak 4GL  
        'Pupil diameter n6t@ e^  
        '************************************************************************* <'UGYY\wg0  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) VoUo!t:(+  
    R ai 0 4  
        'Adjust pupil diameter (trimming volume inner hole) ))Z>$\<:  
    G{4s~Pco[Q  
        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 45wtl/^9  
    "@hd\w{.  
        ' Adjust pupil location to just in front of the lens Q~0>GOq*  
        parID = FindFullName( "Geometry.Arizona Eye" ) T\$i=,_$  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) A-uIZ zC  
        count = 0 %1jcY0zEQ  
        While GetOperationCount(eID)>count |LbAW /9a  
            GetOperation eID, count, op <B0 f  
            If op.Type="ShiftZ" Then lqMr@ :t  
                DeleteOperation eID,count rq!*unJ  
                count=count-1 NZ i3U  
            End If $Z;/Sh  
            count=count+1 2IM 31 .  
        Wend :8oJG8WH  
        op.Type = "ShiftZ" %c\k LSe  
        op.val1 = taq-0.01 _ h#I}uJ~  
        op.parent = parID of_y<dd[G  
        AddOperation eID, op I-g/ )2  
    0mUVa=)D  
        Print "Set pupil diameter = " & pupilDiam =c*l!."0  
    7p2xst  
        'Update AZ Eye subassembly Description /u.ZvY3,  
        eID = FindFullName( "Geometry.Arizona Eye" ) jy2gR1~  
        GetEntity eID, entity 0'Ho'wDb  
        entity.Description = "Accommodation = " & A & "D" LOi}\O8  
        SetEntity eID, entity .S-)  
    Kd^.>T-  
        Update J=$\-  
        Print "DONE!" =(7nl#o  
         b=/'c Q  
    End Sub U7 D!w$4  
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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: P][jB  
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    Accommodation = 4 Diopters 9!uiQ  
    Pupil Diameter = 4 mm PgK7CG7G  
    Set aqueous humor thickness = 2.81 _7;:*'>a4  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 jmk Ou5@  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 "t.` /4R2w  
    Set lens thickness = 3.927 =gQ9>An  
    Set lens index of refraction = 1.42672 -GCo`PR?b  
    Set pupil diameter = 4 Su2{nNC>  
    DONE! ;mk[!  
     
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