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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 Bs~~C8+  
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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。 Ma^jy.  
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模型 gmL~n7m:K  
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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。 +MoUh'/u  
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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. |#TU"$;  
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光源 /7AHd ;  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 pHeG{<^  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 wNf:_^|}  
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在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 hY"eGaoF"  
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图2. 字母F光源的设定方法光 ='7m$,{(Q[  
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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 uJ% <+I  
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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。 }LUvh  
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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。 x93@[B*%  
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图5. 视网膜重点采样规格设定
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脚本 >F$9&s&  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: U2VEFm6  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 #VQZ"7nI@  
余下的脚本计算与屈光度有关的所有参数。 A4j ,]hOD  
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分析 vXJs.)D7  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 zEQ]5>mG  
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图7. 字母F在视网膜上颜色分析
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脚本代码 +ai3   
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. xQ9t1b|{e  
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Dim entity As T_ENTITY _H| )g*]t  
Dim op As T_OPERATION d6i}xnmC  
Dim mat As T_MODELMATERIAL %NLd"SV  
Dim A As Double H1N@E}>|  
Dim pupilDiam As Double e~vO   
Dim eID As Long 5hE#y]pfN  
Dim parID As Long jFQy[k-B  
Dim count As Integer 6#=Iv X4  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double htB2?%S=T  
Dim tlens As Double, nlens As Double ]OpGD5jZ  
Dim curv As Double, conic As Double S'x ]c#  
Dim ok As Long W{NWF[l8O?  
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Sub Main XT^=v6^H  
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    '用户输入对话框 eF3NyL(A  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 5OdsT-y  
        TextBox 220,21,40,21,.TextBox1 'default: 0 =Uk #7U"P  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 |$ PA  
        OKButton 40,91,90,21 ~}OaX+!  
        CancelButton 190,91,90,21 '6D"QDZB  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 Uw4iWcC  
        TextBox 220,49,40,21,.TextBox2 'default: 4 eC/{c1C  
    End Dialog qO@vXuul,  
    Dim dlg As UserDialog 4K cEJlK5  
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    ok = Dialog (dlg) %DuPM6 6r  
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    If ok=0 Then    'cancel button was pressed <EnmH/C.  
        Print "Execution cancelled." ]ZLF=  
        End W[jg+|  
    End If Gs#9'3_U5  
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    'Assign accommodation and pupil diameter & use defaults if field left empty :[a*I6/^  
    If dlg.TextBox1 = "" Then bWL!=  
        A = 0           'Default accommodation J>X@g;  
    Else R&1>\t  
        A = CDbl(dlg.TextBox1) WrP+n  
    End If xWLZlUHEu  
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    If dlg.TextBox2 = "" Then /5 z+N(RFC  
        pupilDiam = 4   'Default pupil diameter m03dL^(   
    Else G)0 4'|W  
        pupilDiam = CDbl(dlg.TextBox2) 8 n[(\f:  
    End If D[^K0<-Z  
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    Print " " <xBL/e %  
    Print "Accommodation = " & A & " Diopters" j&ti "|2\  
    Print "Pupil Diameter = " & pupilDiam & " mm" *6JA&zj0B  
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    ' Calculate new parameters with accommodation ,{IDf  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness uP4yJ/]  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens  LcLHX  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 6O?zi|J[:  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens uou "s9  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens 0SD'&   
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    tlens = 3.767 + 0.04*A                  'Lens thickness b!t[PShw^  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction p` ~=v4;b  
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    'Adjust parameters to account for accommodation <Hv/1:k}  
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    '************************************************************************* [<r.M<3  
    'Aqueous thickness (Position of Lens) 2KO`+  
    '************************************************************************* x7B;\D#`i/  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) h5P ]`r  
    GetCustomElement eID, entity "E<+idoz  
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    parID = FindFullName( "Geometry.Arizona Eye" ) iB99.,o-&  
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    ' Delete any shift(s) in z @GXKqi  
    count = 0 q4X( _t  
    While GetOperationCount(eID)>count z,ryY'ua/I  
        GetOperation eID, count, op I>rTqOK  
        If op.Type="ShiftZ" Then _zbIS&4  
            DeleteOperation eID,count U=%(kOx  
            count=count-1 @?s>oSyV  
        End If ?9?A)?O<j~  
        count=count+1 =LY`K#  
    Wend Z=$-S(>J  
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    'Set new shift in FD!8o  
    op.Type = "ShiftZ" ;\|GU@K{hC  
    op.val1 = taq )cL(()N  
    op.parent = parID S~r75] "  
    AddOperation eID, op .dYv.[?hL  
    Print "Set aqueous humor thickness = " & taq-0.55 f5M;q;  
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    '************************************************************************* l(x0d  
    'Radius and conic constant of anterior lens @gqZiFM)  
    '************************************************************************* k|>yFc  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) wIAH,3!  
    GetConic eID, entity, curv, conic rYV]<[?~7  
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    SetConic eID, entity, 1/Rant, CCant QiA}0q3]0  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant c ?<)!9:  
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    '************************************************************************* W=g'Xu!|!2  
    'Radius and conic constant of posterior lens f.j<VKF}  
    '************************************************************************* yX*$PNL5w  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) / j "}e_Q  
    GetConic eID, entity, curv, conic [QMN0#(h  
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    SetConic eID, entity, 1/Rpost, CCpost Nk7=[y#z  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost i@D4bd9lR  
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    '************************************************************************* =mX26l`B  
    'Lens thickness (Position of posterior lens surface) R<I#. KD  
    '************************************************************************* DC_uh  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) ab9ecZ  
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    ' Delete any z-shift(s) _R]0S  
    count = 0 z3 ^_C`(F  
    While GetOperationCount(eID)>count <7)sS<I  
        GetOperation eID, count, op *@^@7`W  
        If op.Type="ShiftZ" Then (#6Fg|f4Y  
            DeleteOperation eID,count nVoWER:  
            count=count-1 R#YeE`K  
        End If ~}{_/8'5  
        count=count+1 Vp1ct06^  
    Wend 7l/ZRz }1  
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    'Set new z-shift `#W+pO  
    op.Type = "ShiftZ" NCT:!&  
    op.val1 = tlens a {x3FQ  
    op.parent = parID )l! /7WKY  
    AddOperation eID, op {U>N*&_`  
    Print "Set lens thickness = " & tlens vw:GNpg'R6  
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    '************************************************************************* %rhZH^2  
    'Lens index of refraction f34/whD65  
    '************************************************************************* yEjiMtQll]  
    eID = FindMaterial( "Lens" ) f|_\GVW  
    GetModelMaterial eID, mat fwA8=o SZd  
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    mat.Nd = nlens j `!Ge  
    SetModelMaterial eID, mat ){)-}M  
    Print "Set lens index of refraction = " & nlens co\Il]`R/  
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    '************************************************************************* cK\ u  
    'Pupil diameter PW5)") z  
    '************************************************************************* =NY55t.  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 479X5Cl  
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    'Adjust pupil diameter (trimming volume inner hole) ,W[J@4.  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" ;a>u7rw  
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    ' Adjust pupil location to just in front of the lens )=iv3nF?6N  
    parID = FindFullName( "Geometry.Arizona Eye" ) / yBrlf  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) 1|w@f&W"  
    count = 0 <"K*O9 nst  
    While GetOperationCount(eID)>count })70S8k  
        GetOperation eID, count, op vR!g1gI23  
        If op.Type="ShiftZ" Then $+n6V2^K)7  
            DeleteOperation eID,count /i27F2NQm  
            count=count-1 U/kQwrM  
        End If vOz1& |;D  
        count=count+1 A-uIZ zC  
    Wend h/{1(c}  
    op.Type = "ShiftZ" T^`; wD  
    op.val1 = taq-0.01  iKd+AzT  
    op.parent = parID 3+uL@LXd  
    AddOperation eID, op OqciZ@#5n  
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    Print "Set pupil diameter = " & pupilDiam ;>5`Y8s6  
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    'Update AZ Eye subassembly Description MYjc6@=cR  
    eID = FindFullName( "Geometry.Arizona Eye" ) 8 I_  
    GetEntity eID, entity gELG/6l  
    entity.Description = "Accommodation = " & A & "D" 2yg6hR  
    SetEntity eID, entity &*7KQd  
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    Update :EQ{7Op`  
    Print "DONE!" -j]k^  
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End Sub 7pY :.iVO  
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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: h ':ZF  
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Accommodation = 4 Diopters =(7nl#o  
Pupil Diameter = 4 mm G'G8`1Nj  
Set aqueous humor thickness = 2.81 U7 D!w$4  
Set anterior lens radius = 10.4 and conic constant = -2.375869 0&]1s  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 7LrmI~P  
Set lens thickness = 3.927 37jxl+  
Set lens index of refraction = 1.42672 0]  
Set pupil diameter = 4 fM"*;LN!N  
DONE! ]r|oNGD)G  
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