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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 F<'@T,LVc  
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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。 9UD~$_<\  
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    模型 &yFt@g]  
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    模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 `WDN T0@M  
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    Table 1. AZ眼睛模型的定义
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    在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. Z4U8~i  
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    光源 &%QtUPvr9  
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    多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 7r=BGoA2E  
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    图1. 光源和提示信息使用
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    除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 vh8{*9+  
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    在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 /aa'ryl_%  
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    图2. 字母F光源的设定方法光 ]|cL+|':y  
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    图3. 字母F在视网膜上位置点列图
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    视网膜的散射 4%#C _pE9  
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    在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 gie}k)&M  
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    图4. 视网膜朗伯散射设定
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    注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 w{$t:l)2,  
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    图5. 视网膜重点采样规格设定
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    脚本 cE S3<`[K  
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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: Z/=x(I0  
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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。 RFyeA. N  
    余下的脚本计算与屈光度有关的所有参数。 uQ4WM  
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    分析 ;5 W|#{I  
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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。 3| 5Af  
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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 Lx&2)  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. <'H^}gQow  
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    Dim entity As T_ENTITY CA[-\>J7y  
    Dim op As T_OPERATION Hf P2o5-  
    Dim mat As T_MODELMATERIAL Qn> 0s  
    Dim A As Double pNFL;k+p}  
    Dim pupilDiam As Double @A(*&PU>j  
    Dim eID As Long :4|W;Lkd!  
    Dim parID As Long wkm;yCF+  
    Dim count As Integer Nq>74q]}n8  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double ; 2K_u  
    Dim tlens As Double, nlens As Double OF^v;4u  
    Dim curv As Double, conic As Double E )D*~2o/  
    Dim ok As Long VZNMom,Wr  
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    Sub Main f1F#U @U  
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        '用户输入对话框 d[ql7  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 =\Td~>  
            TextBox 220,21,40,21,.TextBox1 'default: 0 &d]%b`EXq  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 B5"(NJ;  
            OKButton 40,91,90,21 l0Wp%T  
            CancelButton 190,91,90,21 }9[E+8L1  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 2<Lnfc<^k  
            TextBox 220,49,40,21,.TextBox2 'default: 4 F"xD^<i  
        End Dialog ]8*#%^  
        Dim dlg As UserDialog Y85M$]e,  
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        ok = Dialog (dlg) `(A>7;]:  
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        If ok=0 Then    'cancel button was pressed _W]qV2j  
            Print "Execution cancelled." h32QEz-+  
            End (i4=}Kn2  
        End If g+h)s!$sB  
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        'Assign accommodation and pupil diameter & use defaults if field left empty zk8 s?$  
        If dlg.TextBox1 = "" Then /I|.^ Id|  
            A = 0           'Default accommodation -d? 9Acd  
        Else h?[3{Z^  
            A = CDbl(dlg.TextBox1) hmJ{'D1"  
        End If B:dk>$>uQ  
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        If dlg.TextBox2 = "" Then T% J;~|  
            pupilDiam = 4   'Default pupil diameter i_?";5B"  
        Else 7)sEW#d!  
            pupilDiam = CDbl(dlg.TextBox2) /7#KkMg  
        End If mB &nN+MV  
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        Print " " =pQA!u]QE  
        Print "Accommodation = " & A & " Diopters" NBzyP)2)  
        Print "Pupil Diameter = " & pupilDiam & " mm" 1SoKnfz{6  
    [|PVq#(  
        ' Calculate new parameters with accommodation /Y:1zLs%  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness v2R41*z,  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens sU"D%G  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 6@kKr  
    ],vUW#6$N  
        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens o, e y.  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens j&n][=PL  
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        tlens = 3.767 + 0.04*A                  'Lens thickness e6n1/TtqM  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction ncS.~F  
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        'Adjust parameters to account for accommodation ^zn j J\  
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        '************************************************************************* /MHqt=jP6  
        'Aqueous thickness (Position of Lens) 6||zwwk'.  
        '************************************************************************* 1;E[Ml  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) JJJlgr]#  
        GetCustomElement eID, entity gI rVrAV#  
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        parID = FindFullName( "Geometry.Arizona Eye" ) }}Ah-QU  
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        ' Delete any shift(s) in z J5Rr7=:*S  
        count = 0 NQefrof  
        While GetOperationCount(eID)>count [OJ@{{U%  
            GetOperation eID, count, op ^)=c74;;  
            If op.Type="ShiftZ" Then \z!*)v/{-  
                DeleteOperation eID,count A[L+w9  
                count=count-1 %jEdgD%xV  
            End If S%n5,vwE  
            count=count+1 5P_%Vp`B2  
        Wend N\b%+vR  
    rq'Cj<=Zj  
        'Set new shift in .QX|:]|n  
        op.Type = "ShiftZ" Ijq',@jE  
        op.val1 = taq s>`$]6wPa  
        op.parent = parID C$`z23E  
        AddOperation eID, op Ys,}L.  
        Print "Set aqueous humor thickness = " & taq-0.55 /zZ$<mVG  
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        '************************************************************************* \M^L'Mkj  
        'Radius and conic constant of anterior lens w6>'n }  
        '************************************************************************* S N_!o2F2  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) =1 g  
        GetConic eID, entity, curv, conic y05(/NH>  
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        SetConic eID, entity, 1/Rant, CCant $(v1q[ig  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant `btw*{.[  
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        '************************************************************************* [G:wPp.y  
        'Radius and conic constant of posterior lens $7~ k#_#PC  
        '************************************************************************* ?,e7v.b  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) ]5IG00`  
        GetConic eID, entity, curv, conic q:N"mp<%  
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        SetConic eID, entity, 1/Rpost, CCpost |GgFdn`>  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost v,w/g|  
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        '************************************************************************* s>d@=P>R  
        'Lens thickness (Position of posterior lens surface) ?H8w/{J   
        '************************************************************************* ?2hoY  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) tWL3F?wd  
    9d{iq"*R  
        ' Delete any z-shift(s) "3CQ0  
        count = 0 7eb^^a?  
        While GetOperationCount(eID)>count f?: o  
            GetOperation eID, count, op -1t"(v  
            If op.Type="ShiftZ" Then qk~ni8  
                DeleteOperation eID,count B4AV ubMbe  
                count=count-1 O o9 ePw7  
            End If 0/?V _  
            count=count+1 '6i"pJ0%  
        Wend Arh0m. w  
    @!/w'k 8  
        'Set new z-shift PY=(|2tb4  
        op.Type = "ShiftZ" I3uS?c  
        op.val1 = tlens 82#7TX4  
        op.parent = parID mk?&`_X1  
        AddOperation eID, op 4Z>KrFO  
        Print "Set lens thickness = " & tlens {J3;4p-&  
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        '************************************************************************* 8Z{&b,Y4L  
        'Lens index of refraction c6gRXp'ID  
        '************************************************************************* 9%aBW7@SK  
        eID = FindMaterial( "Lens" ) B-`d7c5  
        GetModelMaterial eID, mat bmN'{09@  
    $/</J]2`;  
        mat.Nd = nlens j4H]HGHv  
        SetModelMaterial eID, mat CDcZ6.f  
        Print "Set lens index of refraction = " & nlens 7Pspx'u  
    /bm$G"%d  
        '************************************************************************* @ht= (Jk9  
        'Pupil diameter T+p ?VngF  
        '************************************************************************* $%9.qy\8  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) [5Zs%!Z;8N  
    ?&?gQ#\N_J  
        'Adjust pupil diameter (trimming volume inner hole) #DjSS.iW  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" @{16j# 'R  
    Vg9n b  
        ' Adjust pupil location to just in front of the lens Htd-E^/  
        parID = FindFullName( "Geometry.Arizona Eye" ) x]o~ %h$  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 5.!iVyN  
        count = 0 UMsJg7~  
        While GetOperationCount(eID)>count jA@jsv  
            GetOperation eID, count, op n$B SO  
            If op.Type="ShiftZ" Then |r2 U4 ^  
                DeleteOperation eID,count k?-GI[@X  
                count=count-1 2LS03 27  
            End If AA[(rw  
            count=count+1 :D(4HXHK%  
        Wend 297X).  
        op.Type = "ShiftZ" LbX>@2(&  
        op.val1 = taq-0.01 @H%)!f]zWt  
        op.parent = parID E`68Z/%  
        AddOperation eID, op JL0>-kg  
    >*/\Pg6^  
        Print "Set pupil diameter = " & pupilDiam A2 'W  
    :u$nH9kwv  
        'Update AZ Eye subassembly Description 7,0^|P  
        eID = FindFullName( "Geometry.Arizona Eye" ) .bcoH  
        GetEntity eID, entity )`;Q]?D   
        entity.Description = "Accommodation = " & A & "D" 1b*Me'  
        SetEntity eID, entity 49S*f  
    ;!H<W[  
        Update XV)<Oavs  
        Print "DONE!" 9K~0:c  
         T](N ^P  
    End Sub _XLGXJ[B  
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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: >fG=(1"  
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    Accommodation = 4 Diopters J_PAWW  
    Pupil Diameter = 4 mm Wtl/xA_  
    Set aqueous humor thickness = 2.81 BPgY_f  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 OCR`1  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 (C{l4  
    Set lens thickness = 3.927 ?\|QDJXY  
    Set lens index of refraction = 1.42672 )UBU|uYR\  
    Set pupil diameter = 4 zx<:1nF,]  
    DONE! KtTlc#*KU  
     
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