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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 R*C  
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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。 L @b8,  
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模型 UE3#(:x A  
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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。 ]Z@+ |&@L  
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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. VW7 ?{EL7  
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光源 yM3]<~m  
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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。 lC/4CPKtV  
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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。 =xs{Ov=  
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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。 I|6wPV?  
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图2. 字母F光源的设定方法光 39W"G7n?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 (_}w4N#  
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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。 Y)x(+#  
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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。 2?]NQE9lA  
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图5. 视网膜重点采样规格设定
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脚本 9(%ptnya  
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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: JRMe( ,u  
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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。 0|0<[:(hc  
余下的脚本计算与屈光度有关的所有参数。 0Ywqv)gg  
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分析 e1e2Wk  
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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。 Wcy N, 5  
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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 83*"58  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. Z/ "jLfP  
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Dim entity As T_ENTITY p]d3F^*i  
Dim op As T_OPERATION VP4W~;UV|\  
Dim mat As T_MODELMATERIAL mQQ5>0^m  
Dim A As Double jgLCs)=5hV  
Dim pupilDiam As Double Bc {#ia  
Dim eID As Long l<7)uO^8  
Dim parID As Long 8oI)q4V  
Dim count As Integer @u./VK  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double `P&L. m]|  
Dim tlens As Double, nlens As Double lGa'Y  
Dim curv As Double, conic As Double Nl_Sgyx,\  
Dim ok As Long ~]71(u2  
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Sub Main X<4h"W6  
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    '用户输入对话框 Te`Z Qqb  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 I!y[7^R  
        TextBox 220,21,40,21,.TextBox1 'default: 0 >$]SYF29  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 x\vb@!BZ  
        OKButton 40,91,90,21 Lh~Ym<CeN  
        CancelButton 190,91,90,21 h' OLj#H  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 \2!v~&S  
        TextBox 220,49,40,21,.TextBox2 'default: 4 Gc) Zu`67  
    End Dialog .!kqIx*3  
    Dim dlg As UserDialog SSANt?\Z<  
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    ok = Dialog (dlg) yQ> *F  
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    If ok=0 Then    'cancel button was pressed $wa )e  
        Print "Execution cancelled." ?@ ei_<A{  
        End * pN,@ZV$  
    End If 4C&L%A  
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    'Assign accommodation and pupil diameter & use defaults if field left empty v_*E:E  
    If dlg.TextBox1 = "" Then C'ZF#Z  
        A = 0           'Default accommodation DiF=<} >x  
    Else ' vO+,-  
        A = CDbl(dlg.TextBox1) %=J<WA6\  
    End If W! FmC$Kc  
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    If dlg.TextBox2 = "" Then D/_=rAl1  
        pupilDiam = 4   'Default pupil diameter 1!. CfQi  
    Else ~y{(&7sM  
        pupilDiam = CDbl(dlg.TextBox2) @>'.F<:P<  
    End If M>df7.N7%P  
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    Print " " 5B{O!SNd  
    Print "Accommodation = " & A & " Diopters" apk06"/  
    Print "Pupil Diameter = " & pupilDiam & " mm" h3.wR]ut  
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    ' Calculate new parameters with accommodation e.eQZ5n~q`  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness C !81Km5  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens *7hr3x  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 8Z>ZjNG  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens @RKw1$BA  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens IMzhEm  
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    tlens = 3.767 + 0.04*A                  'Lens thickness Qz;2RELz  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction !8]W"@qb  
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    'Adjust parameters to account for accommodation &#Sg1$/+  
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    '************************************************************************* { hUbK+dKZ  
    'Aqueous thickness (Position of Lens) "V:B-q  
    '************************************************************************* Ow=`tv$l  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) Rxld$@~-(]  
    GetCustomElement eID, entity .H+`]qLkL  
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    parID = FindFullName( "Geometry.Arizona Eye" ) [vpZ3;  
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    ' Delete any shift(s) in z ( B$;'U<  
    count = 0 |r5|IA  
    While GetOperationCount(eID)>count bU1UNm`{C  
        GetOperation eID, count, op d; \x 'h2  
        If op.Type="ShiftZ" Then mfLS< /A  
            DeleteOperation eID,count Y;S+2])R2  
            count=count-1 }Tn]cL{]C  
        End If 0o[p<<c*  
        count=count+1 /kyuL]6  
    Wend (`gqLPx[  
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    'Set new shift in <pRb#G"  
    op.Type = "ShiftZ" v]gJ 7x  
    op.val1 = taq 9}t2OJS*h"  
    op.parent = parID v#:#w.]-Y  
    AddOperation eID, op 0*W=u-|s6  
    Print "Set aqueous humor thickness = " & taq-0.55 yWu80C8 q  
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    '************************************************************************* qR!SwG44+  
    'Radius and conic constant of anterior lens SZH,I&8  
    '************************************************************************* /r Zj=  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) xlkEW&N&  
    GetConic eID, entity, curv, conic @rkNx@[~  
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    SetConic eID, entity, 1/Rant, CCant hf>JW[>Xo  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 5[[4A]#T  
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    '************************************************************************* mYXe0E#6  
    'Radius and conic constant of posterior lens s CSrwsbhv  
    '************************************************************************* jR\&2;T  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) F)) +a&O  
    GetConic eID, entity, curv, conic !HM{imT  
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    SetConic eID, entity, 1/Rpost, CCpost D#508{)  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost 6~V$0Y>]  
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    '************************************************************************* >V@-tT"^:  
    'Lens thickness (Position of posterior lens surface) =yOIP@  
    '************************************************************************* *^ncb,1+i  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) dGf{d7D  
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    ' Delete any z-shift(s) "zL<:TQ"  
    count = 0 ?8fa/e  
    While GetOperationCount(eID)>count ([iMOE[D3  
        GetOperation eID, count, op IIUoB!`  
        If op.Type="ShiftZ" Then {LVii}<  
            DeleteOperation eID,count "zJ1vIZY  
            count=count-1 9a"[-B:  
        End If Y~hBVz2g  
        count=count+1 !]7Z),s  
    Wend f"q='B9_T\  
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    'Set new z-shift 7NV1w*> /  
    op.Type = "ShiftZ" i5w  
    op.val1 = tlens \$}^u5Y  
    op.parent = parID L+7L0LbNU  
    AddOperation eID, op  Zm!T4pL  
    Print "Set lens thickness = " & tlens l4u_Z:<w  
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    '************************************************************************* r ,D T>  
    'Lens index of refraction p)RASIB  
    '************************************************************************* LJ`*&J   
    eID = FindMaterial( "Lens" ) $(K[W}  
    GetModelMaterial eID, mat SwpS6  
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    mat.Nd = nlens d4t %/Uh  
    SetModelMaterial eID, mat @v\Osp t=  
    Print "Set lens index of refraction = " & nlens "C&l7K;bp  
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    '************************************************************************* XT> u/Z)  
    'Pupil diameter .z4 fJx  
    '************************************************************************* 4*< x0  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) *cz nokq6  
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    'Adjust pupil diameter (trimming volume inner hole) @{3$H^  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 5P-7"g ca  
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    ' Adjust pupil location to just in front of the lens luRtuXn[8  
    parID = FindFullName( "Geometry.Arizona Eye" ) GM=r{F &  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) xCGa3X  
    count = 0 C?m2R(RF  
    While GetOperationCount(eID)>count s.`:9nj  
        GetOperation eID, count, op :6~Nq/hZB  
        If op.Type="ShiftZ" Then wO9|_.Z{  
            DeleteOperation eID,count 8Q ba4kgL  
            count=count-1 8 9o&KF]  
        End If z)p( l!  
        count=count+1 o.W:R Ux  
    Wend /5 yjON{  
    op.Type = "ShiftZ" yIy'"BCxM  
    op.val1 = taq-0.01 KK$t3e)  
    op.parent = parID A Gu#*,K  
    AddOperation eID, op mrWPTCD{  
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    Print "Set pupil diameter = " & pupilDiam l\g>@b  
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    'Update AZ Eye subassembly Description $2uk;&"?A=  
    eID = FindFullName( "Geometry.Arizona Eye" ) m1H|C3u8  
    GetEntity eID, entity NU[{ANbl  
    entity.Description = "Accommodation = " & A & "D" V&)Jvx}^  
    SetEntity eID, entity 4'u +%6+__  
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    Update Cge@A'2  
    Print "DONE!" Rr#Zcs!G  
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End Sub %PA#x36  
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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: @'n07 5)h  
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Accommodation = 4 Diopters Xb#!1hA  
Pupil Diameter = 4 mm ;B*im S10  
Set aqueous humor thickness = 2.81 r+ v?~m!  
Set anterior lens radius = 10.4 and conic constant = -2.375869 R|&jvG=|  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 0 PEg `Wq  
Set lens thickness = 3.927 $O nh2 ^  
Set lens index of refraction = 1.42672 7p1f*N[X  
Set pupil diameter = 4 @7S* ]  
DONE! >^Rkk {cc  
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