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infotek 2021-10-22 09:55

Arizona眼睛模型

简介 /dHF6yW  
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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。 ~TtiO#,t  
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模型  \=o-  
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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。 zuCSj~  
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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. rC5O")I<  
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光源 ssL\g`xe  
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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。 d;>QhoiL  
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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。 *1"+%Z^  
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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。 Dv6}bx(  
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图2. 字母F光源的设定方法光 qP ,EBE  
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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 HOi`$vX }N  
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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。 +[ZY:ZQ  
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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。 a9Vi];  
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图5. 视网膜重点采样规格设定
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脚本 N>E_%]Ch  
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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: )5H?Vh>36  
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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。 dWW.Y*339  
余下的脚本计算与屈光度有关的所有参数。 GX%g9f!O  
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分析 xx $cnG  
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屈光度为4,光瞳直径为4mm,字母F点在视网膜上所成的像。 DfB7*+x{  
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图7. 字母F在视网膜上颜色分析
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脚本代码 {)Xy%QV  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. {G-kNU  
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Dim entity As T_ENTITY !~Z"9(v'C  
Dim op As T_OPERATION m+9#5a-  
Dim mat As T_MODELMATERIAL 0 "#HJA44  
Dim A As Double vD4*&|8T#  
Dim pupilDiam As Double kcEeFG;DQ  
Dim eID As Long P {'b:C  
Dim parID As Long !m$jk2<  
Dim count As Integer 8k79&|  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double Z:gyz$9w  
Dim tlens As Double, nlens As Double ]'S^]  
Dim curv As Double, conic As Double !9x}  
Dim ok As Long ?ubro0F:  
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Sub Main rlD8D|ZG  
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    '用户输入对话框 kVL.PY\K  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 Ca\6vR  
        TextBox 220,21,40,21,.TextBox1 'default: 0 }7X%'Bg=M  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 ;kK/_%gN-G  
        OKButton 40,91,90,21 Ho%CDz z  
        CancelButton 190,91,90,21 .(vwIb8\_  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 11lsf/IP  
        TextBox 220,49,40,21,.TextBox2 'default: 4 v,t:+ !8  
    End Dialog ^}r1;W?n  
    Dim dlg As UserDialog j.YA 2mr  
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    ok = Dialog (dlg) F[0]/  
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    If ok=0 Then    'cancel button was pressed 1eKT^bgM  
        Print "Execution cancelled." ,0k;!YK  
        End snJ129}A  
    End If KmF]\:sMD  
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    'Assign accommodation and pupil diameter & use defaults if field left empty ?4B`9<j8%  
    If dlg.TextBox1 = "" Then nP$9CA  
        A = 0           'Default accommodation d'2A,B~_*  
    Else (w{j6).3Dj  
        A = CDbl(dlg.TextBox1) YK\X+"lB  
    End If c9Yrw^  
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    If dlg.TextBox2 = "" Then +n)9Tz5  
        pupilDiam = 4   'Default pupil diameter OKV8zO  
    Else 9B4&m|g  
        pupilDiam = CDbl(dlg.TextBox2) #1[u (<AS  
    End If =T_g}pu  
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    Print " " Ls%MGs9PI  
    Print "Accommodation = " & A & " Diopters" [!z,lY>  
    Print "Pupil Diameter = " & pupilDiam & " mm" j@9T.P1  
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    ' Calculate new parameters with accommodation _j3fAr(V  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness Z}QB.$&  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens ]?*wbxU0  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens z:;CX@)*  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens HV.t6@\};  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens =Uh$&m  
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    tlens = 3.767 + 0.04*A                  'Lens thickness g){<y~Mk  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction <q SC#[xu  
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    'Adjust parameters to account for accommodation "fI6Cpc  
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    '************************************************************************* 68 sB )R  
    'Aqueous thickness (Position of Lens) w@b)g  
    '************************************************************************* yw!{MO  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) 9UkBwS`  
    GetCustomElement eID, entity N0lC0 N?_J  
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    parID = FindFullName( "Geometry.Arizona Eye" ) +H.`MZ=  
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    ' Delete any shift(s) in z {FG j]*  
    count = 0 k\IbIv7?i  
    While GetOperationCount(eID)>count "{n&~H`  
        GetOperation eID, count, op RpK@?[4s  
        If op.Type="ShiftZ" Then G"6 !{4g  
            DeleteOperation eID,count zTp"AuNHN  
            count=count-1 _+,TT['57s  
        End If j6YOKJX  
        count=count+1 yr6V3],Tp  
    Wend <[phnU^ 8  
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    'Set new shift in q<J~~'  
    op.Type = "ShiftZ" :+Z%; Dc  
    op.val1 = taq a}d@ T  
    op.parent = parID ZoeD:xnh[  
    AddOperation eID, op C}X\|J  
    Print "Set aqueous humor thickness = " & taq-0.55 ),)lzN%!  
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    '************************************************************************* C+]I@Go'Tk  
    'Radius and conic constant of anterior lens /{[o ~:'p  
    '************************************************************************* lk!@?  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) R/_&m$ZB  
    GetConic eID, entity, curv, conic omFz@  
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    SetConic eID, entity, 1/Rant, CCant \!(zrfP{(  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 43w}qY1  
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    '************************************************************************* 9$Y=orpWxr  
    'Radius and conic constant of posterior lens No$3"4wk  
    '************************************************************************* s*4dxnS_8  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) UBs4K*h|  
    GetConic eID, entity, curv, conic RNL9>7xV  
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    SetConic eID, entity, 1/Rpost, CCpost 1cDF!X]  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost +mPx8P&%  
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    '************************************************************************* TrNF=x>  
    'Lens thickness (Position of posterior lens surface) jCY %|  
    '************************************************************************* gIfh3D=yX  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) Ni>[D"|  
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    ' Delete any z-shift(s) [;N'=]`  
    count = 0 SJLis"8  
    While GetOperationCount(eID)>count 2!\D PX  
        GetOperation eID, count, op 2eogY#  
        If op.Type="ShiftZ" Then e.%nRhSs3  
            DeleteOperation eID,count rOYx b }1  
            count=count-1 xo)P?-  
        End If ]|@^1we  
        count=count+1 54,er$$V  
    Wend xk5 ]^yDp  
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    'Set new z-shift }vuARZ>  
    op.Type = "ShiftZ" Y2TtY;  
    op.val1 = tlens !Cs_F&l"j  
    op.parent = parID X2_=agEP  
    AddOperation eID, op y5r4&~04  
    Print "Set lens thickness = " & tlens l{9Y  
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    '************************************************************************* VTM/hJmwJ  
    'Lens index of refraction +q4O D$}  
    '************************************************************************* '"^'MXa  
    eID = FindMaterial( "Lens" ) bcyzhK=  
    GetModelMaterial eID, mat .}t e>]A*  
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    mat.Nd = nlens 0b>h$OU/  
    SetModelMaterial eID, mat x2EUr,7  
    Print "Set lens index of refraction = " & nlens .`lCWeHN  
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    '************************************************************************* Gt1U!dP  
    'Pupil diameter R-:2HRaA  
    '************************************************************************* {ax:RUQxy  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) !1k_PY5)  
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    'Adjust pupil diameter (trimming volume inner hole) H|*m$| $,  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" QZs!{sZ  
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    ' Adjust pupil location to just in front of the lens Ri{=]$  
    parID = FindFullName( "Geometry.Arizona Eye" ) _w{Qtj~s|  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) \RiP  
    count = 0 97]E1j]  
    While GetOperationCount(eID)>count @F eTz[  
        GetOperation eID, count, op ` A>@]d  
        If op.Type="ShiftZ" Then 6<]lW  
            DeleteOperation eID,count . vV|hSc  
            count=count-1 UZMd~|  
        End If 3<!7>]A  
        count=count+1 Wri<h:1  
    Wend )UR7i8]!0  
    op.Type = "ShiftZ" %;_MGae  
    op.val1 = taq-0.01 ZH8,K Y"  
    op.parent = parID  &HW9Jn  
    AddOperation eID, op fl(wV.Je|  
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    Print "Set pupil diameter = " & pupilDiam Q?vlfZR`8  
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    'Update AZ Eye subassembly Description ~a:  
    eID = FindFullName( "Geometry.Arizona Eye" ) _U(  
    GetEntity eID, entity l-Z4Mq6*L  
    entity.Description = "Accommodation = " & A & "D" "x-j~u?  
    SetEntity eID, entity DI>s-7  
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    Update 8=l%5r^cq  
    Print "DONE!" wp_0+$?s  
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End Sub *pq\MiD/  
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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: fVlB=8DNk&  
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Accommodation = 4 Diopters .]^?<bG  
Pupil Diameter = 4 mm s_Sk0}e  
Set aqueous humor thickness = 2.81 icgfB-1|i  
Set anterior lens radius = 10.4 and conic constant = -2.375869 uFE)17E  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 n S=W1zf  
Set lens thickness = 3.927 ~ }P,.QQ  
Set lens index of refraction = 1.42672 Hka2  
Set pupil diameter = 4 mt .sucT  
DONE! I,tud!p`  
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