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infotek 2023-04-27 08:29

Arizona眼睛模型

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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。 );FS7R  
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模型 *JX;|S  
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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。 "%qzj93>  
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. $q$7^ r@  
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光源 `=UWqb(K_  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 _oG&OJ@  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 Hc^W%t~  
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在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 0@I S  
图2. 字母F光源的设定方法光 nUS| sh  
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图3. 字母F在视网膜上位置点列图
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视网膜的散射 w[tmCn+  
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在散射文件中,有一个名为“Retina surface”的72%的反射型朗伯散射,它为视网膜的散射提供了一个粗略的近似。为了模拟来自视网膜的散射,改变自定义元件“Eye ball” 下的视网膜的表面从“halt all” 到”Allow All”。并使几何中“plane”可追迹。 3ZEB  
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图4. 视网膜朗伯散射设定
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注意在视网膜的表面有散射重点采样规格定义,在“Scatter”标签的底部可获取该信息。“toward pupil”指定散射光朝向光瞳,半角度10度。 V!v:]E  
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图5. 视网膜重点采样规格设定
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脚本 kF(n!2"W  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: 'k;rH !R  
图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 g0R~&AN!g  
余下的脚本计算与屈光度有关的所有参数。 1 zw*/dp  
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分析 ~t9tnLc$  
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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。 A,sr[Pa@  
图7. 字母F在视网膜上颜色分析
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脚本代码 .X# `k  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. y;_% W  
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Dim entity As T_ENTITY , ]bB9tid  
Dim op As T_OPERATION zR2B- &]H  
Dim mat As T_MODELMATERIAL ]a5 f2lE  
Dim A As Double T5a*z}L5  
Dim pupilDiam As Double 4R18A=X  
Dim eID As Long (=7Cs  
Dim parID As Long Z#rB}  
Dim count As Integer 'yMF~r3J  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double &=VDASEu  
Dim tlens As Double, nlens As Double sI{ M  
Dim curv As Double, conic As Double nBk)WX&[K  
Dim ok As Long (sh)TBb5  
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Sub Main v`M3eh@$A  
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    '用户输入对话框 %Dwk  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 IiG6<|d8H  
        TextBox 220,21,40,21,.TextBox1 'default: 0 +HBd %1  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 =Xo =Qcr  
        OKButton 40,91,90,21 O)[1x4U  
        CancelButton 190,91,90,21 z CvKDlL  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 B)0i:"q  
        TextBox 220,49,40,21,.TextBox2 'default: 4 U&?v:&c#&n  
    End Dialog D8$G`~hD  
    Dim dlg As UserDialog V$ ps>  
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    ok = Dialog (dlg) ouuuc9x]  
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    If ok=0 Then    'cancel button was pressed xL\0B,]  
        Print "Execution cancelled." 2AMo:Jqv  
        End /pT =0=  
    End If Ymg|4 %O@  
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    'Assign accommodation and pupil diameter & use defaults if field left empty 1,% R;7J=g  
    If dlg.TextBox1 = "" Then Y\No4w ^|d  
        A = 0           'Default accommodation N<XNTf  
    Else NxsBX :XDn  
        A = CDbl(dlg.TextBox1) >U[j]V]  
    End If NfjE`  
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    If dlg.TextBox2 = "" Then 5yP\I+Fm  
        pupilDiam = 4   'Default pupil diameter  |'B7v i)  
    Else .=s&EEF  
        pupilDiam = CDbl(dlg.TextBox2) ;IZwTXu!S  
    End If [D\k^h  
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    Print " " /w}u3|L$  
    Print "Accommodation = " & A & " Diopters" e]zBf;9 J  
    Print "Pupil Diameter = " & pupilDiam & " mm" G;l_|8<t#\  
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    ' Calculate new parameters with accommodation % ~H=sjg  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness H" 3fT0  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens |R/%D%_g  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens "i[@P)  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens Al} B34.uh  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens ^LoUi1j  
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    tlens = 3.767 + 0.04*A                  'Lens thickness SC)g^E#  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction n<z [J=I  
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    'Adjust parameters to account for accommodation >JFO@O5  
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    '*************************************************************************  +|n*b  
    'Aqueous thickness (Position of Lens) ?kbiMs1;u  
    '************************************************************************* l~w2B>i)  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) f'EuY17w  
    GetCustomElement eID, entity Lr~=^{  
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    parID = FindFullName( "Geometry.Arizona Eye" ) 42$VhdG  
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    ' Delete any shift(s) in z 0=2@  
    count = 0  KY$)#i  
    While GetOperationCount(eID)>count 3q\,$*D.  
        GetOperation eID, count, op 5K>3My#  
        If op.Type="ShiftZ" Then uKUiV%p!  
            DeleteOperation eID,count "K6&dk jY  
            count=count-1 4;yKOQD|  
        End If !Prg_6 `  
        count=count+1 &8Cu#^3  
    Wend Q ayPo]O  
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    'Set new shift in YNKHN2E8  
    op.Type = "ShiftZ" !Qu"BF   
    op.val1 = taq -#u=\8  
    op.parent = parID Z>:NPZODf  
    AddOperation eID, op e>+i>/Fn{h  
    Print "Set aqueous humor thickness = " & taq-0.55 f e\$@-  
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    '************************************************************************* Y']\Jq{OS  
    'Radius and conic constant of anterior lens {Aw#?#GPW  
    '************************************************************************* v_+{'F  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) }YGV\Nu  
    GetConic eID, entity, curv, conic ! >(7+B3E*  
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    SetConic eID, entity, 1/Rant, CCant !Xf5e*1IS  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant .sha&  
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    '************************************************************************* *2p t%eav  
    'Radius and conic constant of posterior lens =_JjmTy;a  
    '************************************************************************* ?+@n3]`0  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) B+P(M!m3  
    GetConic eID, entity, curv, conic } gyj0  
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    SetConic eID, entity, 1/Rpost, CCpost /M1ob:m  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost %9KldcQ}~  
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    '************************************************************************* q9KHmhUD  
    'Lens thickness (Position of posterior lens surface) X5zDpi|Dq  
    '************************************************************************* BKCA <  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) lA| 5E?  
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    ' Delete any z-shift(s) ~7*.6YnI  
    count = 0 q/4J.j L  
    While GetOperationCount(eID)>count \ub7`01  
        GetOperation eID, count, op BTqS'NuT  
        If op.Type="ShiftZ" Then ZCMw3]*  
            DeleteOperation eID,count $v4.sl:x  
            count=count-1 T"{>t  
        End If Qp)v?k ]  
        count=count+1 vOn`/5-  
    Wend M8kPj8}{  
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    'Set new z-shift g0xuxK;9c  
    op.Type = "ShiftZ" ~ (|5/ p7t  
    op.val1 = tlens >c1qpk/  
    op.parent = parID GFj{K  
    AddOperation eID, op |7'df&CA  
    Print "Set lens thickness = " & tlens n,vct<&z@  
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    '************************************************************************* T,,WoPU8t  
    'Lens index of refraction ^cOUQ33  
    '************************************************************************* 1-8mFIK  
    eID = FindMaterial( "Lens" ) y`Wty@  
    GetModelMaterial eID, mat  ~^NtO  
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    mat.Nd = nlens jD$,.AVvz  
    SetModelMaterial eID, mat RuL i,'u  
    Print "Set lens index of refraction = " & nlens R/~p>apg8  
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    '************************************************************************* faE t6  
    'Pupil diameter l5S aT,%  
    '************************************************************************* Q- cFtu-w  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) .?8;qA  
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    'Adjust pupil diameter (trimming volume inner hole) *RI]?j%B  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 8zZvht*  
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    ' Adjust pupil location to just in front of the lens FvaUsOy "  
    parID = FindFullName( "Geometry.Arizona Eye" ) lp.ldajN  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) k0OYJ/  
    count = 0 <wk!hTm W  
    While GetOperationCount(eID)>count hi_NOx  
        GetOperation eID, count, op EuZ<quwWg  
        If op.Type="ShiftZ" Then :i0uPh\0  
            DeleteOperation eID,count kjTduZ/3 "  
            count=count-1 Y xr>"KH6a  
        End If Tm~" IB*  
        count=count+1 T;Lkaxsn  
    Wend 0!4Ts3qn1  
    op.Type = "ShiftZ" ;"a=gr  
    op.val1 = taq-0.01 I,E?h?6Y  
    op.parent = parID *z5.vtfu!  
    AddOperation eID, op U\g/2dM  
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    Print "Set pupil diameter = " & pupilDiam xs{3pkTYD  
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    'Update AZ Eye subassembly Description NxkGOAOE  
    eID = FindFullName( "Geometry.Arizona Eye" ) bg!/%[ {M  
    GetEntity eID, entity ahJ`T*)HY  
    entity.Description = "Accommodation = " & A & "D" u }#(.)a:  
    SetEntity eID, entity R|6Cv3:  
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    Update 1auIR/=-  
    Print "DONE!" W\>fh&!)  
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End Sub 35h 8O,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: :N:yLd} &  
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Accommodation = 4 Diopters BOX{]EOj  
Pupil Diameter = 4 mm 'f#{{KA  
Set aqueous humor thickness = 2.81 R"-mKT}  
Set anterior lens radius = 10.4 and conic constant = -2.375869 d?y4GkK  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 ?k+xSV  
Set lens thickness = 3.927 +cJL7=V&  
Set lens index of refraction = 1.42672 Jz\%%C  
Set pupil diameter = 4 qSM|hHDo)  
DONE!
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