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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 7TaHE   
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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。 NkYU3[m$v  
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模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 kE*OjywN  
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Table 1. AZ眼睛模型的定义
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在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. -'F? |  
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光源 B 4my  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 7$/%c{o  
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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。 mO~A}/je  
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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。 A"W}l)+X  
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图2. 字母F光源的设定方法光 7]&ouT  
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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 ;~ , <8  
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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。 cJQ&#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。 CTOrBl$70  
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图5. 视网膜重点采样规格设定
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脚本 RLtIn!2OU  
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内置脚本使用对话框显示屈光度和光瞳直径的数值设置。使用FRED Basic脚本创建和使用对话框非常容易。图6显示了如何获取用户自定义对话框,如下图所示: )VoQ/ch<  
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图6. 用户对话框的创建与编辑
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图7. 用户对话框编辑器
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如果“OK”按钮按下,将会核对对话框下面的代码行,如果点击取消则脚本终止。然后输入的参数赋予变量,如果此处是保留为空白,则使用默认值。因此,如果没有值输入并点击“OK”按钮,则脚本是以屈光度为0,光瞳直径为4mm来运行的。 Z.v2 !u  
余下的脚本计算与屈光度有关的所有参数。 QTKN6P  
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分析 0*-nVC1  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 tUR9ti  
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图7. 字母F在视网膜上颜色分析
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脚本代码 KE k]<b=  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. { 95u^S=  
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Dim entity As T_ENTITY ?*ni5\y5o  
Dim op As T_OPERATION -jJw wOm  
Dim mat As T_MODELMATERIAL fvUD'sx  
Dim A As Double |loo ^!I  
Dim pupilDiam As Double pHpHvSI  
Dim eID As Long }[%d=NY  
Dim parID As Long n$S`NNO{]  
Dim count As Integer Bt\z0*t=s  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double zLa3Q\T  
Dim tlens As Double, nlens As Double XA%a7Xtni  
Dim curv As Double, conic As Double V7qc9Gd@I  
Dim ok As Long 5W29oz}-S  
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Sub Main !Ui"<0[,  
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    '用户输入对话框 Z;XiA<|  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 W18I"lHeh  
        TextBox 220,21,40,21,.TextBox1 'default: 0 J"TM[4^\Y  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 k5=VH5{S  
        OKButton 40,91,90,21 .}V&*-ep  
        CancelButton 190,91,90,21 nfV32D|3  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 l`}Ag8Q  
        TextBox 220,49,40,21,.TextBox2 'default: 4 d*A(L5;@  
    End Dialog =b* Is,R/  
    Dim dlg As UserDialog 't5 I%F  
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    ok = Dialog (dlg) .PhH|jrCW^  
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    If ok=0 Then    'cancel button was pressed S _B $-H|  
        Print "Execution cancelled." ^S'#)H-8C3  
        End H%*< t}  
    End If {MaFv  
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    'Assign accommodation and pupil diameter & use defaults if field left empty TBzOz:k  
    If dlg.TextBox1 = "" Then h6Vm;{ ~  
        A = 0           'Default accommodation g+-=/Ge  
    Else v GT#BS%  
        A = CDbl(dlg.TextBox1) UW%.G  
    End If :Gdfpz-{?  
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    If dlg.TextBox2 = "" Then 2+Tu"oG;rB  
        pupilDiam = 4   'Default pupil diameter _IK@K 6V1  
    Else MwlhL?  
        pupilDiam = CDbl(dlg.TextBox2) A?q9(n|A"  
    End If +foyPj!%  
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    Print " " =7Wr  
    Print "Accommodation = " & A & " Diopters" Nm 0kMq|h  
    Print "Pupil Diameter = " & pupilDiam & " mm" i'Oh^Y)E#  
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    ' Calculate new parameters with accommodation XU}|Ud562  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness a^*@j:[  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens qQ_o>+3VAy  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens -cjwa-9 ~  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens 3']yjj(gHr  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens '5Zt B<  
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    tlens = 3.767 + 0.04*A                  'Lens thickness 0wzq{~\{=_  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction zlh}8Es  
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    'Adjust parameters to account for accommodation ;(kU:b|j  
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    '*************************************************************************  4I> I  
    'Aqueous thickness (Position of Lens) \gh`P S-B  
    '************************************************************************* {&'u1yR  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 31n5n  
    GetCustomElement eID, entity u0md ^  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ?Afx{H7  
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    ' Delete any shift(s) in z GHMoT  
    count = 0 g2=5IU<  
    While GetOperationCount(eID)>count #Fua^]n  
        GetOperation eID, count, op u"%i3%Yjh  
        If op.Type="ShiftZ" Then {-sy,EYcw  
            DeleteOperation eID,count w%no6 ;  
            count=count-1 x+}6qfc$9k  
        End If !!=%ty  
        count=count+1 J^@0Ff;=5^  
    Wend D cN s`2  
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    'Set new shift in ])= k";76  
    op.Type = "ShiftZ" fz`+j -u  
    op.val1 = taq ^AWM/aY  
    op.parent = parID CW(]6s u{  
    AddOperation eID, op F<y5zqGy@  
    Print "Set aqueous humor thickness = " & taq-0.55 8F(_Vqu  
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    '************************************************************************* eCY gi7?  
    'Radius and conic constant of anterior lens 5@$b@jTd  
    '************************************************************************* ~;Ga65_6_  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) 1*eWo~G  
    GetConic eID, entity, curv, conic &#'[]V%^F  
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    SetConic eID, entity, 1/Rant, CCant 3 *G 7H  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant ':71;^zXf  
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    '************************************************************************* ;4E0%@R  
    'Radius and conic constant of posterior lens Vwp fkD`  
    '************************************************************************* DRLX0Ml]\  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 2\ /(!n  
    GetConic eID, entity, curv, conic zof>S>5>R7  
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    SetConic eID, entity, 1/Rpost, CCpost 3S-nsMs.  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost nT0FonK>  
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    '************************************************************************* T`{W$ 4XS  
    'Lens thickness (Position of posterior lens surface) &|7pu=  
    '************************************************************************* !2WRxM  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) zrjqB3R4@O  
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    ' Delete any z-shift(s) +*3\ C!  
    count = 0 7d?'~}j  
    While GetOperationCount(eID)>count v\#69J5.>)  
        GetOperation eID, count, op d18%zY>  
        If op.Type="ShiftZ" Then >3 Q%Yn  
            DeleteOperation eID,count %|[+\py$Q  
            count=count-1 (!Q^.C_m  
        End If ![Z'jC py  
        count=count+1 !o2lB^e8  
    Wend 6elmLDMni\  
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    'Set new z-shift zq g4@" p  
    op.Type = "ShiftZ" d#.9!m~.  
    op.val1 = tlens PNLtpixZ  
    op.parent = parID 87zsV/  
    AddOperation eID, op jE.U~D)2YF  
    Print "Set lens thickness = " & tlens 'G3B02*  
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    '************************************************************************* 8V%(SV  
    'Lens index of refraction _NAKVzo-  
    '************************************************************************* WRQJ6B  
    eID = FindMaterial( "Lens" ) XM$r,}B k  
    GetModelMaterial eID, mat 2E^zQ>;01  
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    mat.Nd = nlens /GNLZm^  
    SetModelMaterial eID, mat D^To:N 7U  
    Print "Set lens index of refraction = " & nlens &Ib8xwb:  
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    '************************************************************************* |D u.aN  
    'Pupil diameter 4A:@+n%3m  
    '************************************************************************* CRvUD.D  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) ? &ew$%  
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    'Adjust pupil diameter (trimming volume inner hole) *4Cq,o`o>  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" I~EQuQ>=  
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    ' Adjust pupil location to just in front of the lens y\b.0-z  
    parID = FindFullName( "Geometry.Arizona Eye" ) MK 7S*N1  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) /j!?qID  
    count = 0 >bWsUG9  
    While GetOperationCount(eID)>count k.>*!l0  
        GetOperation eID, count, op P]-d (N}/H  
        If op.Type="ShiftZ" Then %iY-}uhO  
            DeleteOperation eID,count SlI0p&2,  
            count=count-1 K:fK! /  
        End If 7Xm7{`jH  
        count=count+1 ~sk;6e)(2  
    Wend $;Lb|~  
    op.Type = "ShiftZ" S/& _  
    op.val1 = taq-0.01 A@#9X'C$^  
    op.parent = parID @ 'rk[S}A  
    AddOperation eID, op )s(J8J[b*L  
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    Print "Set pupil diameter = " & pupilDiam 703=.xj  
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    'Update AZ Eye subassembly Description 6*Jd8Bva\o  
    eID = FindFullName( "Geometry.Arizona Eye" ) 9*2A}dH  
    GetEntity eID, entity {`BC$V  
    entity.Description = "Accommodation = " & A & "D" kPF[E5  
    SetEntity eID, entity q[1:h  
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    Update iD#HB o  
    Print "DONE!" )h&s.k  
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End Sub ]0.? 1se  
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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: {X<mr~  
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Accommodation = 4 Diopters [R-4e; SRh  
Pupil Diameter = 4 mm 6?Ul)'  
Set aqueous humor thickness = 2.81 ?#ue:O1  
Set anterior lens radius = 10.4 and conic constant = -2.375869 2KMLpO&De  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 !fr /WxJ  
Set lens thickness = 3.927 P|YBCH  
Set lens index of refraction = 1.42672 <n< @ O5  
Set pupil diameter = 4 K-F@OSK'  
DONE! |\"vHt?@G  
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