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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 +pJ;}+  
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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。 ?w1_.m|8u  
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模型 wxARD3%  
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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。 YBN. waL  
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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. o_p//S#q  
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光源 I.j`h2  
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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。 C_?L$3 U0  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 ~zFs/(k  
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在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 LbtcZ)D!  
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图2. 字母F光源的设定方法光 L$h.VQv+  
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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 Deq~"  
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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。 gk~.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。 QfB \h[A  
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图5. 视网膜重点采样规格设定
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脚本 Mi9A%ZmP  
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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: M~;mamTP  
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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。 3'O+  
余下的脚本计算与屈光度有关的所有参数。 g4P059  
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分析 U;:>vi3p  
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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。 /}r%DND'  
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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 gAC}  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. 0tm%Kd  
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Dim entity As T_ENTITY xaX3<V@S  
Dim op As T_OPERATION |dpOE<f[  
Dim mat As T_MODELMATERIAL 0K`3BuBs  
Dim A As Double bqN({p&  
Dim pupilDiam As Double 2J^6(vk  
Dim eID As Long 41mg:xW(J  
Dim parID As Long xvQJTR k  
Dim count As Integer Cp&lS=  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double QQ!%lbMK]  
Dim tlens As Double, nlens As Double L{ ?& .iA  
Dim curv As Double, conic As Double {f3)!Pei`J  
Dim ok As Long uO>$,s  
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Sub Main C;}~C:aJ  
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    '用户输入对话框 bdk"7N  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 ]T}G-  
        TextBox 220,21,40,21,.TextBox1 'default: 0 '0GCaL*Sd  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 mQtGE[  
        OKButton 40,91,90,21 ;&37mO/T  
        CancelButton 190,91,90,21 2)h i(  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 9XX&~GW/  
        TextBox 220,49,40,21,.TextBox2 'default: 4 \/la`D  
    End Dialog G$}\~dD  
    Dim dlg As UserDialog }H!c9Y  
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    ok = Dialog (dlg) HvN!_}[  
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    If ok=0 Then    'cancel button was pressed d3_aFs Q  
        Print "Execution cancelled." ! pR&&uG  
        End IUAx*R  
    End If ,>V|%tD'  
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    'Assign accommodation and pupil diameter & use defaults if field left empty $FZ~]Ef  
    If dlg.TextBox1 = "" Then "n," >  
        A = 0           'Default accommodation 9TBkVbqV  
    Else z J93EtlF  
        A = CDbl(dlg.TextBox1) ?<]BLkx  
    End If (BEGt '7  
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    If dlg.TextBox2 = "" Then v{$X2z_$w  
        pupilDiam = 4   'Default pupil diameter oS0l Tf\  
    Else  U2  
        pupilDiam = CDbl(dlg.TextBox2) QxH%4 )?  
    End If ]@vX4G/  
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    Print " " )."_i64  
    Print "Accommodation = " & A & " Diopters" NE,2jeZQ.  
    Print "Pupil Diameter = " & pupilDiam & " mm" ?>cx; "xF  
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    ' Calculate new parameters with accommodation K PSFy<  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness >0DQ<@ot:  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ? [l[y$9  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens /17Qhex  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens :f G5?])  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens NQz*P.q  
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    tlens = 3.767 + 0.04*A                  'Lens thickness <qT[  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction de1cl<  
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    'Adjust parameters to account for accommodation njtz,qt_;G  
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    '************************************************************************* Xyy;BO:  
    'Aqueous thickness (Position of Lens) JFH3)Q  
    '************************************************************************* FeoI+K A  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) $nF|n+m  
    GetCustomElement eID, entity ]$Pl[Vegy  
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    parID = FindFullName( "Geometry.Arizona Eye" ) 3u#bx1  
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    ' Delete any shift(s) in z dv -L!C  
    count = 0 :+NZW9_  
    While GetOperationCount(eID)>count pFgpAxl  
        GetOperation eID, count, op @W6:JO  
        If op.Type="ShiftZ" Then <}t~^E,  
            DeleteOperation eID,count FlGU1%]m  
            count=count-1 6D|[3rXr  
        End If ]xC#XYE:dy  
        count=count+1 }A jE- K{  
    Wend \~ m\pf?  
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    'Set new shift in E! d?@Xr@  
    op.Type = "ShiftZ" lC/1,Z/M  
    op.val1 = taq OL]P(HRm]~  
    op.parent = parID DmU,}]#:  
    AddOperation eID, op @W}cM  
    Print "Set aqueous humor thickness = " & taq-0.55 'yxN1JF  
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    '************************************************************************* [As9&]Bv5  
    'Radius and conic constant of anterior lens 9$[6\jMh  
    '************************************************************************* Ak3cE_*Y/  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) uN>JX/-  
    GetConic eID, entity, curv, conic cq]JD6937  
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    SetConic eID, entity, 1/Rant, CCant 9gq+,g>E_  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant =~zsah6N  
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    '************************************************************************* Hb}O/G$a*  
    'Radius and conic constant of posterior lens ebno:)  
    '************************************************************************* `-t8ag 3  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) P.bxq50  
    GetConic eID, entity, curv, conic YP E1s  
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    SetConic eID, entity, 1/Rpost, CCpost >~@O\n-t  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost S[ch/  
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    '************************************************************************* _%g L  
    'Lens thickness (Position of posterior lens surface) fGZ56eH:  
    '************************************************************************* YRg"{[+#]k  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) {p\ll  
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    ' Delete any z-shift(s) w*?SGW  
    count = 0 lfvt9!SJ+/  
    While GetOperationCount(eID)>count cWtuI(.  
        GetOperation eID, count, op T@wgWE<0y_  
        If op.Type="ShiftZ" Then >|X )  
            DeleteOperation eID,count &F- \t5X=i  
            count=count-1 ai%*s&0/Y  
        End If O22Q g  
        count=count+1 BG|m5f  
    Wend 5P Zzaz<  
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    'Set new z-shift x~Y{ {  
    op.Type = "ShiftZ" YMN=1Zuj?  
    op.val1 = tlens |kY}G3/  
    op.parent = parID Vv54;Js9  
    AddOperation eID, op oyB gF\  
    Print "Set lens thickness = " & tlens gY'-C  
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    '************************************************************************* )J*M{Gm6i  
    'Lens index of refraction N5[^W`Qf  
    '************************************************************************* l-Be5?|{_  
    eID = FindMaterial( "Lens" ) 2&"qNpPtE  
    GetModelMaterial eID, mat ;,8 )%[  
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    mat.Nd = nlens WNY:HH  
    SetModelMaterial eID, mat y2W|,=Vd  
    Print "Set lens index of refraction = " & nlens 0~~yYo&  
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    '************************************************************************* _9g-D9  
    'Pupil diameter 8.,d`~  
    '************************************************************************* oXjoQ  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ?7>"ZGDe>  
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    'Adjust pupil diameter (trimming volume inner hole) C}#$wge  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" @R-11wP)M  
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    ' Adjust pupil location to just in front of the lens 5(gWK{R)*  
    parID = FindFullName( "Geometry.Arizona Eye" ) M8V c5  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 2X<%BFsE  
    count = 0 |kH.o=  
    While GetOperationCount(eID)>count SJ91(K  
        GetOperation eID, count, op 'hE'h?-7  
        If op.Type="ShiftZ" Then a:8 MoH4  
            DeleteOperation eID,count )=#e*1!b  
            count=count-1 =A!r ZG  
        End If ]#Cc7wa  
        count=count+1 Uks%Mo9on  
    Wend [YP{%1*RM  
    op.Type = "ShiftZ" 3&>0'h  
    op.val1 = taq-0.01 oYdE s&qq  
    op.parent = parID $*VZa3B\  
    AddOperation eID, op {,i-V57-h  
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    Print "Set pupil diameter = " & pupilDiam GeDI\-  
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    'Update AZ Eye subassembly Description {G0=A~  
    eID = FindFullName( "Geometry.Arizona Eye" ) YA@MLZm  
    GetEntity eID, entity NT0n [o^  
    entity.Description = "Accommodation = " & A & "D" PtYG%/s  
    SetEntity eID, entity Y)DAR83  
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    Update 9/! 1J  
    Print "DONE!" m~ 5"q%;  
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End Sub F~i ~%f,  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: e pp04~  
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Accommodation = 4 Diopters #CPLvg#  
Pupil Diameter = 4 mm (BFwE@1"  
Set aqueous humor thickness = 2.81 =6qTz3t  
Set anterior lens radius = 10.4 and conic constant = -2.375869 ;@T0wd_i|  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 0 zK{)HZ  
Set lens thickness = 3.927 /!2`pv  
Set lens index of refraction = 1.42672 -$?t+ "/E  
Set pupil diameter = 4 h}! 9?:E  
DONE! D HT^.UM28  
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