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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 3/,}&SX  
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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。 YQR[0Y&e=  
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    模型 =9:gW5F69  
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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。 S>s+ nqcP  
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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. vm =d?*cR  
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    光源 *y|zF6  
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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。 ehZ/J5  
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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。 nL]eGC  
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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。 w8`B}Dr23  
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    图2. 字母F光源的设定方法光 y-~_W 6\  
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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 I |"'  
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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。 Rt@O@oDI  
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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。 n|B<rx?v  
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    图5. 视网膜重点采样规格设定
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    脚本 $Xqc'4YOZ  
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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: 4P#4R B  
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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。 bEmzigN[  
    余下的脚本计算与屈光度有关的所有参数。 z|zEsDh;  
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    分析 0:c3aq&u  
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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。 |\94a  
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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 +x<OyjY5?]  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. s|X_:3\x  
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    Dim entity As T_ENTITY r~ 2q`l'>  
    Dim op As T_OPERATION ";DozPU  
    Dim mat As T_MODELMATERIAL p[)yn%uh  
    Dim A As Double TV`sqKW  
    Dim pupilDiam As Double  ^mN`!+  
    Dim eID As Long b1%w+*d<z  
    Dim parID As Long NLUiNfCR  
    Dim count As Integer q_[`PYT  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double [Mj5o<k;I  
    Dim tlens As Double, nlens As Double p(9[*0.};  
    Dim curv As Double, conic As Double U~dqxR"Q  
    Dim ok As Long FtlJ3fB@  
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    Sub Main B9H.8+~(  
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        '用户输入对话框 9#kk5)J  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 PfGiJ]:V-u  
            TextBox 220,21,40,21,.TextBox1 'default: 0 P/Y)Yx_(  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 9D;ono3  
            OKButton 40,91,90,21 ]cW Q9  
            CancelButton 190,91,90,21 :Y4Sdj  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Mky^X,r  
            TextBox 220,49,40,21,.TextBox2 'default: 4 H}(WL+7  
        End Dialog q Oa*JA`  
        Dim dlg As UserDialog vFeR)Ox's  
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        ok = Dialog (dlg) L=P8;Gj)  
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        If ok=0 Then    'cancel button was pressed 1[- `*Ph  
            Print "Execution cancelled." ,wy;7T>ODd  
            End `, 4YPjk^  
        End If 7Q,<h8N\5  
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        'Assign accommodation and pupil diameter & use defaults if field left empty D&]xKx  
        If dlg.TextBox1 = "" Then /;xrd\du  
            A = 0           'Default accommodation vG=Pi'4XXo  
        Else NGZtlNvh  
            A = CDbl(dlg.TextBox1) ,mz7!c9H^a  
        End If #Yy5@A}`o  
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        If dlg.TextBox2 = "" Then z]=Ks_7  
            pupilDiam = 4   'Default pupil diameter  UF@.  
        Else jwI1 I{x  
            pupilDiam = CDbl(dlg.TextBox2) v "[<pFj^  
        End If M. _5mZ{  
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        Print " " m |.0$+=  
        Print "Accommodation = " & A & " Diopters" [g{fz3 O6  
        Print "Pupil Diameter = " & pupilDiam & " mm" % 3fpIzm  
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        ' Calculate new parameters with accommodation ^PMA"!n8  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness ;6?,Yhk$h  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens :R3&R CTZ  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens Wu l8ej:  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens zB\ 8<97 C  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens  }"q#"s  
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        tlens = 3.767 + 0.04*A                  'Lens thickness C[+?gQJ[9  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction h,K&R8S  
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        'Adjust parameters to account for accommodation L$jii  
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        '************************************************************************* #;m^DX QZn  
        'Aqueous thickness (Position of Lens) [G[{?{  
        '************************************************************************* OSom-?|w  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) :JXcs39  
        GetCustomElement eID, entity ur]WNk8bN  
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        parID = FindFullName( "Geometry.Arizona Eye" ) R80|q#h,]  
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        ' Delete any shift(s) in z DnN+W  
        count = 0 ol_&epG;ST  
        While GetOperationCount(eID)>count ;zWiPnX}  
            GetOperation eID, count, op g7eI;Tpv  
            If op.Type="ShiftZ" Then Yt r*"-  
                DeleteOperation eID,count 1o)<23q`)  
                count=count-1 qzk]9`i1:  
            End If lHu/pSu@k  
            count=count+1 n9 Jev_!A  
        Wend %H}M[_f  
    +^$;oG  
        'Set new shift in nYj7r* e[  
        op.Type = "ShiftZ" 9g$fFO  
        op.val1 = taq j\.e6&5%SS  
        op.parent = parID &3*r-9BZ  
        AddOperation eID, op h@s i)5"  
        Print "Set aqueous humor thickness = " & taq-0.55 T{BGg  
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        '************************************************************************* 'qeUI}[  
        'Radius and conic constant of anterior lens YT@H^=  
        '************************************************************************* lDs C>L-F  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) gX* &RsF  
        GetConic eID, entity, curv, conic e JEcLK3u  
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        SetConic eID, entity, 1/Rant, CCant {|e7^_ke  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ?1X7jn`,+  
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        '************************************************************************* WkoYkkuzj  
        'Radius and conic constant of posterior lens fY|vq amA;  
        '************************************************************************* MOIVt) ZY  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) mn\GLR.  
        GetConic eID, entity, curv, conic  ww\2  
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        SetConic eID, entity, 1/Rpost, CCpost vE~<R  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 73!])!SVI  
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        '************************************************************************* 14y>~~3C4  
        'Lens thickness (Position of posterior lens surface) "2I{T  
        '************************************************************************* N/E=-&E8  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) #;'*W$Wk2  
    b/=>'2f  
        ' Delete any z-shift(s) `1R[J4e  
        count = 0 57$/Dn  
        While GetOperationCount(eID)>count /(i~Hpp  
            GetOperation eID, count, op iyMoLZ5  
            If op.Type="ShiftZ" Then 1_LGlu~&  
                DeleteOperation eID,count G:MQ_tfr&  
                count=count-1 oMN Qv%U  
            End If j*_#{niy:  
            count=count+1 m9Dg%\B  
        Wend <|:$_&(  
    VO*fC  
        'Set new z-shift AE%zqvp>  
        op.Type = "ShiftZ" NbUibxJ  
        op.val1 = tlens =Flr05}m  
        op.parent = parID 83{v_M  
        AddOperation eID, op I4zm{ 1g  
        Print "Set lens thickness = " & tlens JWQ.Efe  
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        '************************************************************************* }z2K"eGt  
        'Lens index of refraction sAP  YQ  
        '************************************************************************* JRw)~Tg @  
        eID = FindMaterial( "Lens" ) Ly6) ,[q~  
        GetModelMaterial eID, mat &s&Ha{(!w  
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        mat.Nd = nlens f<@`{oP@  
        SetModelMaterial eID, mat et6@);F  
        Print "Set lens index of refraction = " & nlens x4@IK|CE  
    L4Si0 K  
        '************************************************************************* 4[K6ZDBU  
        'Pupil diameter ;3sJ7%`v  
        '************************************************************************* iIg99c7/&9  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) )`m/vYKWL  
    P/dT;YhL  
        'Adjust pupil diameter (trimming volume inner hole) Za1VJ5-  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" l' a<k"  
    Hp3T2|uL  
        ' Adjust pupil location to just in front of the lens ':T6m=yv  
        parID = FindFullName( "Geometry.Arizona Eye" ) *lp{,  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) "H)D~K~ *  
        count = 0 &$_#{?dPt  
        While GetOperationCount(eID)>count T@DT|lTI  
            GetOperation eID, count, op AW`+lE'?  
            If op.Type="ShiftZ" Then x% Eu.jj  
                DeleteOperation eID,count mRY~)< !4&  
                count=count-1  xXZ {  
            End If &?yVLft  
            count=count+1 gz"I=9  
        Wend 0'^zIL#.  
        op.Type = "ShiftZ" b/'RJQSAc  
        op.val1 = taq-0.01 C)0JcM  
        op.parent = parID hjY)W;  
        AddOperation eID, op :8Jn?E (36  
    Q 1e hW  
        Print "Set pupil diameter = " & pupilDiam gA:N>w&<X  
    %!Ak]|[7  
        'Update AZ Eye subassembly Description E3o J;E  
        eID = FindFullName( "Geometry.Arizona Eye" ) n4Eqm33  
        GetEntity eID, entity -$_h]x* W  
        entity.Description = "Accommodation = " & A & "D" iY4FOt7\  
        SetEntity eID, entity \BxE0GGky  
    _#6ekl|%  
        Update h8tKYm  
        Print "DONE!" 1\BQq  
         %wS5m#n  
    End Sub EU-=\Y  
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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: c{s%kVOzg  
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    Accommodation = 4 Diopters Fm{`?!  
    Pupil Diameter = 4 mm [1gWc`#  
    Set aqueous humor thickness = 2.81 7\1bq&a<  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 tV,Y38e  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 Q[N6#C:(4  
    Set lens thickness = 3.927 RzLbPSTQ  
    Set lens index of refraction = 1.42672 )6:nJ"j#  
    Set pupil diameter = 4 _,;|,  
    DONE! f_GqJ7Gk]  
     
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