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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。 9 [I ro  
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模型 esu6iU@  
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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。 4 |5ekwk  
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. 329xo03-[  
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光源 O: BP35z_F  
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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。 wA~Nfn ^  
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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。 7R2)Klt  
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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。 F#<P FT4i  
图2. 字母F光源的设定方法光 u('OHPqq  
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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 1Ev+':%  
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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。 6aK--k  
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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。 }mGD`5[`  
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图5. 视网膜重点采样规格设定
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脚本 ]`kvq0Gyb  
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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: AP7W)S  
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"hR:'ts  
余下的脚本计算与屈光度有关的所有参数。 :58'U|  
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分析 MGz> ,c^wW  
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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。 ^0 lPv!2  
图7. 字母F在视网膜上颜色分析
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脚本代码 / IS WC   
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. \|t0~sRwh  
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Dim entity As T_ENTITY M(E_5@?3  
Dim op As T_OPERATION }"x*xN  
Dim mat As T_MODELMATERIAL |*NrS<"  
Dim A As Double 8'[wa  
Dim pupilDiam As Double T6r~OV5  
Dim eID As Long (R<4"QbE  
Dim parID As Long ~ 7Nyi dV;  
Dim count As Integer R"o,m  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double g DG m32  
Dim tlens As Double, nlens As Double c):*R ]=  
Dim curv As Double, conic As Double &s;^q  
Dim ok As Long x=#5\t9  
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Sub Main z\Y^x 9  
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    '用户输入对话框 ]+dl=SmF  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 vUs7#*  
        TextBox 220,21,40,21,.TextBox1 'default: 0 yj R O9  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 vxT"BvN  
        OKButton 40,91,90,21 Lp)8SmN  
        CancelButton 190,91,90,21 jGhg~-m  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 P$>kBW53  
        TextBox 220,49,40,21,.TextBox2 'default: 4 9p rsL#Fn  
    End Dialog Jwt I(>cI  
    Dim dlg As UserDialog _5w?v~65  
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    ok = Dialog (dlg) UjOhaj "h  
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    If ok=0 Then    'cancel button was pressed Z;'.pU~  
        Print "Execution cancelled." }t3FAy(%  
        End G)Bq?=P  
    End If VFSn!o:C  
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    'Assign accommodation and pupil diameter & use defaults if field left empty e=UVsYNx  
    If dlg.TextBox1 = "" Then i!oj&&  
        A = 0           'Default accommodation ?mR[A`J58  
    Else TK/'=8  
        A = CDbl(dlg.TextBox1) vW-`=30  
    End If sg"D;b:X  
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    If dlg.TextBox2 = "" Then \u-e\w  
        pupilDiam = 4   'Default pupil diameter X7d.Ie  
    Else }lTZq|;A  
        pupilDiam = CDbl(dlg.TextBox2) |kNGpwpI  
    End If &qP-x98E?  
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    Print " " eoe^t:5&  
    Print "Accommodation = " & A & " Diopters" u<shhb-  
    Print "Pupil Diameter = " & pupilDiam & " mm" &:I +]G/W  
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    ' Calculate new parameters with accommodation 6Hbf9,vI  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness )USC  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens i;hc]fYb=K  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens IPR tm!  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens jc.JX_/  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens rYFau1  
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    tlens = 3.767 + 0.04*A                  'Lens thickness {I-a;XBX  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction /4 LR0`A'  
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    'Adjust parameters to account for accommodation n?LIphc\  
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    '************************************************************************* ki~y@@3I  
    'Aqueous thickness (Position of Lens)  _7#tgZyv  
    '************************************************************************* IbJ[Og^Qyu  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 3[=`uO0\7  
    GetCustomElement eID, entity yLz,V}  
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    parID = FindFullName( "Geometry.Arizona Eye" ) h [IYA1/y  
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    ' Delete any shift(s) in z <@e+-$  
    count = 0 jfY{z=*]u  
    While GetOperationCount(eID)>count k<Tez{<  
        GetOperation eID, count, op >GznG[Ku  
        If op.Type="ShiftZ" Then *Cnq2=A]A  
            DeleteOperation eID,count E!I  
            count=count-1 ?YO =J  
        End If 8_IOJ]:w  
        count=count+1 a}Fk x  
    Wend U$A7EFK'  
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    'Set new shift in 0Ox|^V  
    op.Type = "ShiftZ" $,;S\JmWP  
    op.val1 = taq kWs+2j  
    op.parent = parID iTLW<wG  
    AddOperation eID, op 1O9p YW5J  
    Print "Set aqueous humor thickness = " & taq-0.55 r9] rN  
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    '************************************************************************* o'eI(@{F=  
    'Radius and conic constant of anterior lens 2>$F0 M  
    '************************************************************************* JEsLF{  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) F:;!) H*  
    GetConic eID, entity, curv, conic whY~=lizn  
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    SetConic eID, entity, 1/Rant, CCant CzSZ>E$%U  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant If-,c^i  
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    '************************************************************************* 7?MB8tJ5r4  
    'Radius and conic constant of posterior lens m4"N+_j  
    '************************************************************************* feI./E  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) G'O/JM  
    GetConic eID, entity, curv, conic 5pM&h~M  
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    SetConic eID, entity, 1/Rpost, CCpost `S\zqF<  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost ~!ZmF(:  
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    '************************************************************************* tyEPU^PM  
    'Lens thickness (Position of posterior lens surface) hj&fQ}X  
    '************************************************************************* N-2([v  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) /mn-+u`K  
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    ' Delete any z-shift(s) X(k{-|9]  
    count = 0 &|.hkR2k  
    While GetOperationCount(eID)>count WR/o @$/  
        GetOperation eID, count, op 46bl>yk9<  
        If op.Type="ShiftZ" Then 7v_i>_m]  
            DeleteOperation eID,count D<U 9m3  
            count=count-1 bVoU|`c  
        End If >ZT& `E  
        count=count+1 HDmx@E.@  
    Wend #bT8QbJ(  
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    'Set new z-shift bLgL0}=n  
    op.Type = "ShiftZ" ~:>AR` 9G  
    op.val1 = tlens 7tSJniB  
    op.parent = parID D|d4:;7  
    AddOperation eID, op 7]Al*)  
    Print "Set lens thickness = " & tlens i;o}o *=  
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    '************************************************************************* U4>O\sU  
    'Lens index of refraction LY]nl3{E  
    '************************************************************************* VF)uu[ f9  
    eID = FindMaterial( "Lens" ) TUh&d5a9H  
    GetModelMaterial eID, mat DY9fF4[9a  
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    mat.Nd = nlens [X,A'Q  
    SetModelMaterial eID, mat QyPg |#T2>  
    Print "Set lens index of refraction = " & nlens VeZey)Q  
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    '************************************************************************* X rF3kz!44  
    'Pupil diameter ^=EjadVQ  
    '************************************************************************* o=pt_!i/  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) 5Go0}'*%  
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    'Adjust pupil diameter (trimming volume inner hole) !;%y$$gxh  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" )^4hQ3BS  
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    ' Adjust pupil location to just in front of the lens )kYOHS  
    parID = FindFullName( "Geometry.Arizona Eye" ) 3{"byfO#%  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) ! ja[ 4.  
    count = 0 _%Bz,C8  
    While GetOperationCount(eID)>count ?O??cjiA@  
        GetOperation eID, count, op N{8"s&  
        If op.Type="ShiftZ" Then 4qhWm"&CM  
            DeleteOperation eID,count ) Qq'Wp3i  
            count=count-1 y&"!m }  
        End If g\U/&.}DN  
        count=count+1 B2 c@kru  
    Wend Ln. 9|9  
    op.Type = "ShiftZ" 845 W>B  
    op.val1 = taq-0.01 ~-TOsRvxR  
    op.parent = parID J$Fnm\  
    AddOperation eID, op 38~PWKt  
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    Print "Set pupil diameter = " & pupilDiam MIq"Wy|Zs  
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    'Update AZ Eye subassembly Description Yi(1^'Bi  
    eID = FindFullName( "Geometry.Arizona Eye" ) G"T\=cQz  
    GetEntity eID, entity _%y4q%#  
    entity.Description = "Accommodation = " & A & "D" q$[n`w-  
    SetEntity eID, entity ;+ azeW ^  
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    Update GIT #<+"  
    Print "DONE!" !Xj#@e  
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End Sub 5t\HJ`C1Z  
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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: 6<X%\[)n  
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Accommodation = 4 Diopters gAt~?HvW6  
Pupil Diameter = 4 mm 03=5Nof1  
Set aqueous humor thickness = 2.81 _X4!xbP  
Set anterior lens radius = 10.4 and conic constant = -2.375869 yto[8;)_  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 K R,z^9  
Set lens thickness = 3.927 48O~Jx,  
Set lens index of refraction = 1.42672 ? }yfKU`  
Set pupil diameter = 4 2N5`'  
DONE!
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