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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 yL&F!+(/Ix  
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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。  Aki8#  
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模型 IX;u+B  
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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。 CD%wi:C%|  
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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. # 9Z];<g  
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光源 F)) +a&O  
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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。 Q/r9r*>z  
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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。 >V@-tT"^:  
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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。 *^ncb,1+i  
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图2. 字母F光源的设定方法光 QRhR.:M\  
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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 5`*S'W}\>  
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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。 HlgF%\@a+U  
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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。 4]u53`  
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图5. 视网膜重点采样规格设定
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脚本 SaMg)s~B  
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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: c?"#x-<1s  
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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。 \I1+J9Gl  
余下的脚本计算与屈光度有关的所有参数。 bEyZRG  
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分析 nAG2!2_8  
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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。 *=mtt^yZ  
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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 9'faH  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. L,M=ogdb  
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Dim entity As T_ENTITY &eKnLGKD  
Dim op As T_OPERATION vmm#UjwF3  
Dim mat As T_MODELMATERIAL C|bnUN  
Dim A As Double [KMW *pA7  
Dim pupilDiam As Double <SGO+1zt p  
Dim eID As Long IWERn v!  
Dim parID As Long b1JXC=*@  
Dim count As Integer "MQy>mD6  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double SB0Cq  
Dim tlens As Double, nlens As Double eG* <=.E  
Dim curv As Double, conic As Double $!%/Kk4M  
Dim ok As Long 9`]Gosz  
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Sub Main ^0p y  
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    '用户输入对话框 ad1I2  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 dU<\ FW_  
        TextBox 220,21,40,21,.TextBox1 'default: 0 T1 >xw4uo  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 #pO=\lJ,  
        OKButton 40,91,90,21 E j`  
        CancelButton 190,91,90,21 ZmeSm& hQ_  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 b5lZ||W.  
        TextBox 220,49,40,21,.TextBox2 'default: 4 ,|6 O}E&  
    End Dialog 0=O(+ yi  
    Dim dlg As UserDialog OV/H&fe  
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    ok = Dialog (dlg) ;]!QLO.bs^  
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    If ok=0 Then    'cancel button was pressed F|pM$Kd`  
        Print "Execution cancelled." m_YXTwwx  
        End #0>??]&r  
    End If /iURP-rl  
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    'Assign accommodation and pupil diameter & use defaults if field left empty Wd "<u2  
    If dlg.TextBox1 = "" Then M|8vP53=q  
        A = 0           'Default accommodation 55Z)*JMv  
    Else 0T,uH  
        A = CDbl(dlg.TextBox1) &iKy  
    End If QL/I/EgqC  
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    If dlg.TextBox2 = "" Then E$l4v>iA  
        pupilDiam = 4   'Default pupil diameter 9#(Nd, m})  
    Else JC6?*R  
        pupilDiam = CDbl(dlg.TextBox2) 1OI/!!t1$  
    End If h;" 9.  
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    Print " " ;IyA"C(i  
    Print "Accommodation = " & A & " Diopters" wNc.z*+O"H  
    Print "Pupil Diameter = " & pupilDiam & " mm" $fifx>!  
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    ' Calculate new parameters with accommodation K(jo[S  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness vYl2_\,Y?  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens PU8>.9x  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens .cks ){\  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 7pPaHX8  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens *G rYB6MT  
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    tlens = 3.767 + 0.04*A                  'Lens thickness /=5:@  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction :/A7Z<u,  
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    'Adjust parameters to account for accommodation zTBf.A;e7  
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    '************************************************************************* m3T=x =  
    'Aqueous thickness (Position of Lens) KBC?SxJSJc  
    '************************************************************************* Gxhr0'  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) sdp3geBYo  
    GetCustomElement eID, entity z] +&kNm  
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    parID = FindFullName( "Geometry.Arizona Eye" ) nh XVc((  
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    ' Delete any shift(s) in z |hl:!j.t  
    count = 0 E .N@qMn~  
    While GetOperationCount(eID)>count xeNj@\jdC5  
        GetOperation eID, count, op *Jwx,wF}4  
        If op.Type="ShiftZ" Then -UB XWl  
            DeleteOperation eID,count { )g $  
            count=count-1 3xIelTf*  
        End If %6.WGuO  
        count=count+1 ?lca#@f(  
    Wend {gz-w|7  
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    'Set new shift in )FpizoVq0  
    op.Type = "ShiftZ" V O\g"Yc  
    op.val1 = taq % * k`z#b  
    op.parent = parID 3 \}>nE  
    AddOperation eID, op FG!2h&k  
    Print "Set aqueous humor thickness = " & taq-0.55 xyD2<?dGUb  
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    '************************************************************************* q6PG=9d0B  
    'Radius and conic constant of anterior lens 5,R4:y ?cK  
    '************************************************************************* X5pb9zRq  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 5 ) q_Aro  
    GetConic eID, entity, curv, conic xx@[ecW  
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    SetConic eID, entity, 1/Rant, CCant VUi> ]v/e  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant eo*l^7  
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    '************************************************************************* s0O]vDTR,H  
    'Radius and conic constant of posterior lens Jmuyd\?,b  
    '************************************************************************* A.vf)hO  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) BCfmnE4%  
    GetConic eID, entity, curv, conic L} "bp  
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    SetConic eID, entity, 1/Rpost, CCpost U8.V Rn  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost h/Yxm2  
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    '************************************************************************* ~&aULY?)]  
    'Lens thickness (Position of posterior lens surface) I_m3|VCa|t  
    '************************************************************************* bcq&yL'D  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 8@[S,[  
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    ' Delete any z-shift(s) R< L =&I  
    count = 0 ]$u C~b   
    While GetOperationCount(eID)>count f^-ot@w  
        GetOperation eID, count, op !1Hs;K  
        If op.Type="ShiftZ" Then OxPl0-]t  
            DeleteOperation eID,count hF{gN3v5  
            count=count-1 0l3[?YtXc  
        End If %AN,cE*  
        count=count+1 iZLy#5(St  
    Wend ]>Ym   
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    'Set new z-shift #UE}JR3g  
    op.Type = "ShiftZ" nE +H)%p  
    op.val1 = tlens ufe |I  
    op.parent = parID k'_f?_PBu  
    AddOperation eID, op _Vl~'+e  
    Print "Set lens thickness = " & tlens 'A>?aUq]:  
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    '************************************************************************* c4u/tt.)  
    'Lens index of refraction <(@Z#%O9)  
    '************************************************************************* Xt:$H6 y  
    eID = FindMaterial( "Lens" ) Do77V5  
    GetModelMaterial eID, mat -uxU[E  
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    mat.Nd = nlens L2p?] :-  
    SetModelMaterial eID, mat 'pT13RFD  
    Print "Set lens index of refraction = " & nlens {?Nm"#  
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    '************************************************************************* (5@H<c^6  
    'Pupil diameter ">G*hS  
    '************************************************************************* 4 ob?M:S  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) O\ _ro.  
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    'Adjust pupil diameter (trimming volume inner hole) E}KGZSj  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" (6B;  
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    ' Adjust pupil location to just in front of the lens 5'NNwc\  
    parID = FindFullName( "Geometry.Arizona Eye" ) 'YB[4Q /0  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) tT!' qL.*  
    count = 0 vQ* RrHG?c  
    While GetOperationCount(eID)>count O Bcz'f~  
        GetOperation eID, count, op "9r$*\wOf  
        If op.Type="ShiftZ" Then aoZ| @x  
            DeleteOperation eID,count 5q*s_acQ  
            count=count-1 QRvyaV  
        End If >I0;MNX  
        count=count+1 p:TE##  
    Wend /='0W3+o*L  
    op.Type = "ShiftZ" $K!Jm7O\  
    op.val1 = taq-0.01 S9Oz5_x  
    op.parent = parID (D%vN&F  
    AddOperation eID, op f*<Vq:N=\  
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    Print "Set pupil diameter = " & pupilDiam _qR?5;v  
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    'Update AZ Eye subassembly Description  {ibu 0  
    eID = FindFullName( "Geometry.Arizona Eye" ) haBmwq(f  
    GetEntity eID, entity Cyd/HTNh<  
    entity.Description = "Accommodation = " & A & "D" 4VZI]3K,  
    SetEntity eID, entity l99Lxgx=  
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    Update  t1 YB  
    Print "DONE!" )M.s<Y  
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End Sub OA*O =  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: W,NqevXo:  
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Accommodation = 4 Diopters /M%>M]  
Pupil Diameter = 4 mm t*9 gusmG  
Set aqueous humor thickness = 2.81 9:4S[mz/hD  
Set anterior lens radius = 10.4 and conic constant = -2.375869 3s/1\m%  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 ",3v%$ >  
Set lens thickness = 3.927 &RYdSXM  
Set lens index of refraction = 1.42672 CdF;0A9.3  
Set pupil diameter = 4 u0Wt"d-=  
DONE! Vt(Wy  
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