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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 0{-`Th+h  
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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。 .F4oo=  
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    模型 *e%Dg{_  
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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。 XpR.rq$]  
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    Table 1. AZ眼睛模型的定义
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    在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. zwMQXI'k83  
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    光源 wu;7NatHx  
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    多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 XI]OA7Zis  
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    图1. 光源和提示信息使用
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    除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 :-$cdZ3E  
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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。 A * a{  
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    图2. 字母F光源的设定方法光 W"W@WG9X0  
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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 9@( O\xr  
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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。 Dm>T"4B`/  
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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。 ''$`;?t>  
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    图5. 视网膜重点采样规格设定
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    脚本 )W[KD,0+j  
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    内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: )o05Vda  
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    图6. 用户对话框的创建与编辑
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    图7. 用户对话框编辑器
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    如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 [P.@1mV  
    余下的脚本计算与屈光度有关的所有参数。 r$b:1C~  
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    分析 ;6DR .2}?>  
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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。 tfi2y]{A  
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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 p +u{W"I`  
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    Option Explicit     'Remove this to enable non-dimensioned variables to be used. VaD:  
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    Dim entity As T_ENTITY vS~AxeW/7R  
    Dim op As T_OPERATION ;yRwoTc)Y  
    Dim mat As T_MODELMATERIAL $-C6pZN(X  
    Dim A As Double k$9Gn9L%  
    Dim pupilDiam As Double ;s}-X_O<  
    Dim eID As Long d/0/$Bz}P  
    Dim parID As Long &M!4]p ow  
    Dim count As Integer yC9:sQ'k  
    Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double X;K8,A7`  
    Dim tlens As Double, nlens As Double *T.={>HE8  
    Dim curv As Double, conic As Double uf{SxEa  
    Dim ok As Long Ig40#pA  
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    Sub Main Ktg&G<%J0  
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        '用户输入对话框 9Q SUCN_  
        Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 }M"-5K}  
            TextBox 220,21,40,21,.TextBox1 'default: 0 iqU.a/~y  
            Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1  y)N.LS  
            OKButton 40,91,90,21 b&hF')_UOz  
            CancelButton 190,91,90,21 Y-}hNZn"{  
            Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 UD Iac;vT  
            TextBox 220,49,40,21,.TextBox2 'default: 4 w]]x[D]L  
        End Dialog :ofE8]  
        Dim dlg As UserDialog ,g<>`={kK+  
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        ok = Dialog (dlg) ,iA2s i  
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        If ok=0 Then    'cancel button was pressed F1Zk9%L%9$  
            Print "Execution cancelled." C%x(`S^/  
            End |Oj,S|Z:  
        End If _js2^<7v}  
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        'Assign accommodation and pupil diameter & use defaults if field left empty l(0&6ENyj  
        If dlg.TextBox1 = "" Then <.y^  
            A = 0           'Default accommodation I&Eg-96@  
        Else Tko CyD9  
            A = CDbl(dlg.TextBox1) hc@;}a\Y  
        End If 37ri b  
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        If dlg.TextBox2 = "" Then 0qaG#&!  
            pupilDiam = 4   'Default pupil diameter -\sKSY5{R  
        Else ^{6UAT~!R  
            pupilDiam = CDbl(dlg.TextBox2) &CPe$'FYI  
        End If ]R2Z-2  
    #!<+:y'S?  
        Print " " g-TX;(  
        Print "Accommodation = " & A & " Diopters" {~B4F}ES  
        Print "Pupil Diameter = " & pupilDiam & " mm" %n V@'3EI  
    .{Eg(1At  
        ' Calculate new parameters with accommodation BT*K,p  
        taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness OFPd6,(E  
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        Rant = 12.0 - 0.4*A                     'Radius of anterior lens Eb{4.17b  
        CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 6|(7G64{  
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        Rpost = -5.224557 + 0.2*A               'Radius of posterior lens se*pkgWbz  
        CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens cbg3bi  
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        tlens = 3.767 + 0.04*A                  'Lens thickness `P)64So-1  
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        nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction D$^7Xhk  
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        'Adjust parameters to account for accommodation H 29 _ /  
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        '************************************************************************* hTNYjXj  
        'Aqueous thickness (Position of Lens) 1<Ztk;$A  
        '************************************************************************* -7Y'6''~W.  
        eID = FindFullName( "Geometry.Arizona Eye.Lens" ) y&O_Jyg<  
        GetCustomElement eID, entity `A}{ I}xq  
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        parID = FindFullName( "Geometry.Arizona Eye" ) ph$&f0A6Xc  
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        ' Delete any shift(s) in z Q:xI} ]FM  
        count = 0 >5z`SZf  
        While GetOperationCount(eID)>count n6-!@RYr  
            GetOperation eID, count, op |H|eH~.yg&  
            If op.Type="ShiftZ" Then TJGKQyG$L  
                DeleteOperation eID,count {<V|Gr  
                count=count-1 ,:Y=,[n  
            End If 8aM% 9OU  
            count=count+1 mrB hvp""  
        Wend EXM/>PG  
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        'Set new shift in w]}cB+C+l#  
        op.Type = "ShiftZ"  OG<]`!"  
        op.val1 = taq 6`PGV+3j  
        op.parent = parID MrygEC 5  
        AddOperation eID, op y`P7LC  
        Print "Set aqueous humor thickness = " & taq-0.55 fqp7a1qQl  
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        '************************************************************************* K|' ]Hje\  
        'Radius and conic constant of anterior lens (Gb{ckzs  
        '*************************************************************************  ^O\1v  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) l9Cy30O6  
        GetConic eID, entity, curv, conic 0i1?S6]d-  
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        SetConic eID, entity, 1/Rant, CCant ?9.?w-Q'  
        Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant s_e#y{ {C2  
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        '************************************************************************* Y(;[L`"  
        'Radius and conic constant of posterior lens TbUkqABm  
        '************************************************************************* tYxlM!  
        eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) Ra,on&OP`*  
        GetConic eID, entity, curv, conic ^ZZ@!Udy  
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        SetConic eID, entity, 1/Rpost, CCpost # T#FUI1p  
        Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost '{_tDboY  
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        '************************************************************************* vf'jz`Z  
        'Lens thickness (Position of posterior lens surface) \V7x3*nA  
        '************************************************************************* p<.!::*%(  
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        parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ZkG##Jp\>  
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        ' Delete any z-shift(s) ^{,}, i  
        count = 0 Y-9j2.{  
        While GetOperationCount(eID)>count I,q~*d  
            GetOperation eID, count, op e}@J?tJK.L  
            If op.Type="ShiftZ" Then @!tmUme1c  
                DeleteOperation eID,count ,wy:RVv@e  
                count=count-1 w@D@,q'x  
            End If :=KGQ3V~eK  
            count=count+1 t5[JN:an  
        Wend `>HthK  
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        'Set new z-shift ku8Z;ONeH  
        op.Type = "ShiftZ"  6}ewBAq%  
        op.val1 = tlens 60gn`s,,  
        op.parent = parID R}YryzV5  
        AddOperation eID, op zL=I-fVq  
        Print "Set lens thickness = " & tlens Jrrk$0H^~  
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        '************************************************************************* -CNv=vj 3  
        'Lens index of refraction Hqy>!1 !  
        '************************************************************************* &~6O;}\  
        eID = FindMaterial( "Lens" ) l`G:@}P>G  
        GetModelMaterial eID, mat Y2~{qY  
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        mat.Nd = nlens tg4&j$  
        SetModelMaterial eID, mat E<_6O Cz  
        Print "Set lens index of refraction = " & nlens O[J+dWyp  
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        '************************************************************************* !,WRXE&j  
        'Pupil diameter X=}0+W  
        '************************************************************************* 2{qG  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ]nGA1S{  
    Q^;\!$:M  
        'Adjust pupil diameter (trimming volume inner hole) f\_Q+!^  
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        SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" "K=)J'/n  
    `t"Kq+  
        ' Adjust pupil location to just in front of the lens %&S]cEw  
        parID = FindFullName( "Geometry.Arizona Eye" ) l"g%vS,;`  
        eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) $G.|5sEk  
        count = 0 9%veUvY  
        While GetOperationCount(eID)>count alD|-{Bf  
            GetOperation eID, count, op =?x=CEW  
            If op.Type="ShiftZ" Then PhdL@Mr  
                DeleteOperation eID,count @Kb~!y@G  
                count=count-1 En%o7^W++  
            End If k18V4ATE]  
            count=count+1 qWK7K%-$ E  
        Wend v Cr$miZ  
        op.Type = "ShiftZ" )^xmy6k  
        op.val1 = taq-0.01 5Wjp_^!e  
        op.parent = parID &~i &~AJ  
        AddOperation eID, op <\ c8q3N  
    LB0=V0|  
        Print "Set pupil diameter = " & pupilDiam p =O1aM  
    {[iQRYD0|  
        'Update AZ Eye subassembly Description !7|9r$  
        eID = FindFullName( "Geometry.Arizona Eye" ) b8Sl3F?-~  
        GetEntity eID, entity Sv",E@!f  
        entity.Description = "Accommodation = " & A & "D" uQ)]g  
        SetEntity eID, entity LZ$!=vg4  
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        Update =,9'O/br  
        Print "DONE!" 3mpjSL  
         $l0w{m!P  
    End Sub 2sq<"TlQXI  
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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: 6f1Y:qK'@  
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    Accommodation = 4 Diopters WVFy ZpB  
    Pupil Diameter = 4 mm ax}Xsk_  
    Set aqueous humor thickness = 2.81 g_=ZcGC  
    Set anterior lens radius = 10.4 and conic constant = -2.375869 6FAP *V;  
    Set posterior lens radius = -4.424557 and conic constant = -3.081019 1EB`6_>y  
    Set lens thickness = 3.927 [Y+ bW#'  
    Set lens index of refraction = 1.42672 `UPmr50Wq  
    Set pupil diameter = 4 HX^ P9jXT  
    DONE! YzVLa,[  
     
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