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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 @jMo/kO/A  
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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。 ts@$*  
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    模型  ?f'`b<o  
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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。 L[*cbjt[  
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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. 2~g-k 3  
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    光源 is^R8a  
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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。 PZZPx<?N  
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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。 $t"QLsk0  
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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。 wG)[Ik6:  
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    图2. 字母F光源的设定方法光 i(.PkYkaq  
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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 pG)dF@  
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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。 eS ?9}TG|  
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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。 *,O3@,+>H  
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    图5. 视网膜重点采样规格设定
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    脚本 OT|0_d?bD  
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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: $/#[,1  
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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。 a+k3wzJ  
    余下的脚本计算与屈光度有关的所有参数。 Y|hd!C-x  
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    分析 ^ . A  
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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。 ~/aCzx~  
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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 =c&.I}^1L  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. XA.1Y)  
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    Dim entity As T_ENTITY 'BgR01w J  
    Dim op As T_OPERATION ""N~##)8  
    Dim mat As T_MODELMATERIAL /#eS3`48  
    Dim A As Double E|_8#xvb  
    Dim pupilDiam As Double gy|o#&e]%  
    Dim eID As Long /6y{ ?0S  
    Dim parID As Long !a!4^zqp  
    Dim count As Integer 3N2d@R  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double xy&*s\=:  
    Dim tlens As Double, nlens As Double $X\2h+ Os  
    Dim curv As Double, conic As Double ZzR0k  
    Dim ok As Long L|-|DOgw  
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    Sub Main aAn p7\7  
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        '用户输入对话框 x6Gl|e[jv  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 368 g> /#'  
            TextBox 220,21,40,21,.TextBox1 'default: 0 hV) `e"r\s  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 tBl (E  
            OKButton 40,91,90,21 z?|bs?HKS  
            CancelButton 190,91,90,21 )g3c-W=  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 P (Y\l  
            TextBox 220,49,40,21,.TextBox2 'default: 4 s+&0Z3+  
        End Dialog /"~UGn]R  
        Dim dlg As UserDialog t pxk8Ys  
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        ok = Dialog (dlg) S-7C'dc  
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        If ok=0 Then    'cancel button was pressed Clap3E|a  
            Print "Execution cancelled." 2 1+[9  
            End Qr6PkHU  
        End If V joVC$ZX  
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        'Assign accommodation and pupil diameter & use defaults if field left empty 7xG~4N<)]  
        If dlg.TextBox1 = "" Then 7<B-2g  
            A = 0           'Default accommodation hK{<&T  
        Else mZM7 4!4X  
            A = CDbl(dlg.TextBox1) f3>DmH#  
        End If H5UF r,t  
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        If dlg.TextBox2 = "" Then @+y,E-YTdV  
            pupilDiam = 4   'Default pupil diameter vO/3bu}  
        Else Y Ztd IG  
            pupilDiam = CDbl(dlg.TextBox2)  |*-<G3@  
        End If WoNY8 8hT  
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        Print " " *{Z=)k%  
        Print "Accommodation = " & A & " Diopters" ,LmP >Q.  
        Print "Pupil Diameter = " & pupilDiam & " mm" Wa&!1' @  
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        ' Calculate new parameters with accommodation %@TC- xx  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness aS\$@41"  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens |pq9i)e&  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens WA:r4V  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens SQx&4R.  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens n;>=QG -v  
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        tlens = 3.767 + 0.04*A                  'Lens thickness `QW=<Le?  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction L2~'Z'q  
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        'Adjust parameters to account for accommodation O.xtY @'"  
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        '************************************************************************* iy]?j$B$  
        'Aqueous thickness (Position of Lens) @_#\qGY  
        '************************************************************************* rcY &n^:  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) <l5m\A  
        GetCustomElement eID, entity #V#!@@c;?  
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        parID = FindFullName( "Geometry.Arizona Eye" ) AS;qJ)JfzQ  
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        ' Delete any shift(s) in z C4|OsC7J  
        count = 0 wp> z04  
        While GetOperationCount(eID)>count rK:cUW0]X  
            GetOperation eID, count, op 'U0W   
            If op.Type="ShiftZ" Then RU~ku{8?  
                DeleteOperation eID,count uhp.Yv@c  
                count=count-1 ;/JXn  
            End If LNHi }P~  
            count=count+1 \^RKb-6n  
        Wend _5x]BH6f  
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        'Set new shift in BHZhdm@),  
        op.Type = "ShiftZ" <1<xSr  
        op.val1 = taq WjM7s]ZRv  
        op.parent = parID .q[}e);)  
        AddOperation eID, op ylQj2B,CB  
        Print "Set aqueous humor thickness = " & taq-0.55 `<M>"~W  
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        '************************************************************************* P+OS  
        'Radius and conic constant of anterior lens :Q@/F;Z?  
        '************************************************************************* {P_7AM  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) yTZ o4c "  
        GetConic eID, entity, curv, conic )c'E9ZuZ>d  
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        SetConic eID, entity, 1/Rant, CCant < *;GJ{  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant #(i pF  
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        '************************************************************************* (K84J*;  
        'Radius and conic constant of posterior lens `.3@Ki~$#  
        '************************************************************************* ?2dI8bG  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 4K? \5(b  
        GetConic eID, entity, curv, conic CS(2bj^6 D  
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        SetConic eID, entity, 1/Rpost, CCpost jC{KI!kPt  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost &);P|v`8  
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        '************************************************************************* u'>94Gm}  
        'Lens thickness (Position of posterior lens surface) 5r~jo7  
        '************************************************************************* !jSgpIp  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) @DY"~c cH  
    ubOXEkZ8N  
        ' Delete any z-shift(s) UXJblo#  
        count = 0 cBZEyy&  
        While GetOperationCount(eID)>count y1Z>{SDiq  
            GetOperation eID, count, op DZnqCu"J  
            If op.Type="ShiftZ" Then xy"'8uRi  
                DeleteOperation eID,count X:;x5'|  
                count=count-1 HK~SD:d  
            End If bE'{zU}o  
            count=count+1 ::$W .!Uv  
        Wend [3nWxFz$R  
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        'Set new z-shift dpylJ2  
        op.Type = "ShiftZ" vO~  Tx  
        op.val1 = tlens O#=%t  
        op.parent = parID *q k7e[IP  
        AddOperation eID, op ThI}~$Y  
        Print "Set lens thickness = " & tlens "#E<Leh'  
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        '************************************************************************* f pq|mY  
        'Lens index of refraction ftR& 5 !Wm  
        '************************************************************************* G:tY1'5  
        eID = FindMaterial( "Lens" ) 'hs4k|B  
        GetModelMaterial eID, mat 4Yi kC  
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        mat.Nd = nlens -9,~b9$  
        SetModelMaterial eID, mat s_VcC_A  
        Print "Set lens index of refraction = " & nlens jga\Ry=nw  
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        '************************************************************************* mY4pvpZw8  
        'Pupil diameter L-D4>+  
        '************************************************************************* _avf%OS  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) xn503,5G*7  
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        'Adjust pupil diameter (trimming volume inner hole) ~h;   
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" "IT7.!=@9  
    2(@2 z[eKr  
        ' Adjust pupil location to just in front of the lens ka\{?:r,8  
        parID = FindFullName( "Geometry.Arizona Eye" ) N\g=9o|Q  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) rD SYR\cg  
        count = 0 *S:~U  
        While GetOperationCount(eID)>count <a @7's  
            GetOperation eID, count, op Z6i~Dy3  
            If op.Type="ShiftZ" Then Z}uY%]  
                DeleteOperation eID,count 4hwb] Yz  
                count=count-1 5 k3m"*  
            End If ge GhM>G  
            count=count+1 :#^qn|{e  
        Wend NOXP}M  
        op.Type = "ShiftZ" ZxwrlaA  
        op.val1 = taq-0.01 s~A-qG>  
        op.parent = parID 208^Yu  
        AddOperation eID, op 8e*skL  
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        Print "Set pupil diameter = " & pupilDiam 4F#H$`:[  
    @`4T6eL5  
        'Update AZ Eye subassembly Description S7f.^8  
        eID = FindFullName( "Geometry.Arizona Eye" ) VbvP!<8  
        GetEntity eID, entity _90D4kGU  
        entity.Description = "Accommodation = " & A & "D" w>^(w<~Y  
        SetEntity eID, entity \j`0 f=z_  
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        Update H dqB B   
        Print "DONE!" {k_\1t(/  
         &`l\Q\_[@  
    End Sub [:cD  
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    如果屈光度是4,光瞳直径是4,则会输出如下数据: : "| /  
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    Accommodation = 4 Diopters <.n,:ir  
    Pupil Diameter = 4 mm 9,INyEyAL  
    Set aqueous humor thickness = 2.81 rz%~=Ca2j  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 )-)rL@s.  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 x:MwM?  
    Set lens thickness = 3.927 Jq &Hz$L|  
    Set lens index of refraction = 1.42672 yogavCD9b/  
    Set pupil diameter = 4 $45|^.b  
    DONE! ?pW1}: z  
     
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