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infotek 2020-12-09 09:18

Arizona眼睛模型

简介 $RYsqX\v  
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人眼光学模型可用来设计眼科用设备,光学系统注定了要与人眼一起使用。本文演示了这样一个模型:Arizona眼睛模型,在Jim Schwiegerling教授的书中有详细描述:《Field Guide to Visual and Ophthalmic Optics》。AZ眼睛模型达到了基于平均临床数据所决定的轴上和轴外像差等级。FRED文件包含了此眼睛模型及几个用来分析它的光源,并包括一个基于想要的屈光度来调整模型的内嵌脚本。 BihXYux*  
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模型 @} 61D  
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模型的定义如表1种所示,由半径、圆锥常数、折射率、阿贝数、到下一面的距离等一系列表面组成。一些参数由屈光度(A)来决定。 F|3 =Cl  
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Table 1. AZ眼睛模型的定义
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在FRED中使用0屈光度来创建的,光瞳加在了透镜的前面。材料是创建一个新的材料并选择类型“Model Material”,输入的参数是nd和vd. u49v,,WGw  
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光源 [_&\wHX  
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多个光源定义来分析该模型的不同特性。图1显示了所以的光源和提示信息告诉您他们可以用来做什么。 Z>)(yi9+  
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图1. 光源和提示信息使用
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除了“Letter F”之外的所有光源的光线位置设定在了孔径光阑位置处,并增加了pre-propagation distance= -8。尽管光线在光瞳处创建,规定的传输方向相对于光线位置在pre-propagation distance之后。这意味着光束沿着Z轴在眼睛的前面以平行光入射,而不是在光瞳处入射。 ccUq!1  
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在往下看是内置的脚本用来修改屈光度,使其为4(250mm),光源“Letter F”在视网膜处生成一个字母为F的图像。绿色的光线聚焦的非常好而红色和蓝色光线有一点的模糊。使用Positions Spot Diagram分析工具来观察最为合适。 Wgt[ACioN  
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图2. 字母F光源的设定方法光 +[MzF EE[  
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图3. 字母F在视网膜上位置点列图
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视网膜的散射 `Ns$HV  
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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。 ?F@0"qi  
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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。 )F\tU  
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图5. 视网膜重点采样规格设定
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脚本 @O7hY8",  
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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: *CHLs^)   
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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。 2qY`*Y.2  
余下的脚本计算与屈光度有关的所有参数。 zj ;'0Zu  
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分析 |U*wMYC  
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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。 }u=-Y'!#]  
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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 ,)u\G(N  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. \ /3Xb  
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Dim entity As T_ENTITY W}<'Y@[ ,  
Dim op As T_OPERATION g1JBssw&m  
Dim mat As T_MODELMATERIAL qVOlUH  
Dim A As Double 01n5]^.p  
Dim pupilDiam As Double #$&!)13  
Dim eID As Long lx8@;9fLy  
Dim parID As Long ('qu#.'  
Dim count As Integer ;aJBx  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double [b-wak})aD  
Dim tlens As Double, nlens As Double g$c\(isY;  
Dim curv As Double, conic As Double E2M|b  
Dim ok As Long VTOZ #*f  
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Sub Main ;++CMTza]  
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    '用户输入对话框 l6^IX0&p  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 eyq8wQT  
        TextBox 220,21,40,21,.TextBox1 'default: 0 ou;E@`h;x  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 EV}c,*);y  
        OKButton 40,91,90,21 J?d&+mt  
        CancelButton 190,91,90,21 6I0G.N  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 iElE-g@Ws  
        TextBox 220,49,40,21,.TextBox2 'default: 4 x7qVLpcL3z  
    End Dialog o1x IGP<  
    Dim dlg As UserDialog fiuF!<#;6  
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    ok = Dialog (dlg) N/ 7Q(^  
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    If ok=0 Then    'cancel button was pressed ;Kq/[$~0  
        Print "Execution cancelled." ?[ n{M  
        End p<5ED\;N;  
    End If ][b_l(r$?  
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    'Assign accommodation and pupil diameter & use defaults if field left empty V=)0{7-9  
    If dlg.TextBox1 = "" Then P`JO6O:&  
        A = 0           'Default accommodation =+K2`=y;WF  
    Else 1bW[RK;GE  
        A = CDbl(dlg.TextBox1) dd+[FU  
    End If 0G-M.s}A  
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    If dlg.TextBox2 = "" Then 7X \azL  
        pupilDiam = 4   'Default pupil diameter qDR`)hle  
    Else Lq#>N_72W0  
        pupilDiam = CDbl(dlg.TextBox2) E'|@hL-jn  
    End If ?]i.Zi\[f  
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    Print " " f9A^0A?c  
    Print "Accommodation = " & A & " Diopters" ~*WSH&ip  
    Print "Pupil Diameter = " & pupilDiam & " mm" fmuAX w>  
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    ' Calculate new parameters with accommodation "i+fO&LpZ  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness %kM|Hk3d  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens qA4w*{JN  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens $vlc@]~d`&  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens < I}O_:%  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens !!NVx\a  
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    tlens = 3.767 + 0.04*A                  'Lens thickness iHKWz)0  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction 2rS|V|d  
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    'Adjust parameters to account for accommodation mlolSD;7  
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    '************************************************************************* wYTF:Ou^5~  
    'Aqueous thickness (Position of Lens) V~rF`1+5N  
    '************************************************************************* sq6|J])GgU  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) .Rq|F  
    GetCustomElement eID, entity [12^NEt  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ~HbZRDcJc  
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    ' Delete any shift(s) in z 8$ SA"c)  
    count = 0 *,w9#?2x  
    While GetOperationCount(eID)>count Mz}yf5{f  
        GetOperation eID, count, op l1X& Nw1W  
        If op.Type="ShiftZ" Then xngK_n  
            DeleteOperation eID,count G.KZZ-=_4  
            count=count-1 VGLE5lP X  
        End If E|!rapa  
        count=count+1 bAIo5lr  
    Wend VH&6Tm1  
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    'Set new shift in 9p ;)s  
    op.Type = "ShiftZ" !C&!Wj  
    op.val1 = taq 2=pVX  
    op.parent = parID cwK 6$Ax  
    AddOperation eID, op B2UQO4[w  
    Print "Set aqueous humor thickness = " & taq-0.55 R8 1z|+c|_  
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    '************************************************************************* ht8%A 1|  
    'Radius and conic constant of anterior lens Ip}(!D|  
    '************************************************************************* C^]y iR-U  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) `&2AN%Xz  
    GetConic eID, entity, curv, conic /6_>d $  
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    SetConic eID, entity, 1/Rant, CCant S:qML]RO  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant 9;3f`DK@2k  
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    '************************************************************************* eJ0PSW/4l  
    'Radius and conic constant of posterior lens Rg! [ic !  
    '************************************************************************* }5#<`8  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) uQ4WM  
    GetConic eID, entity, curv, conic r0=Aru5n  
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    SetConic eID, entity, 1/Rpost, CCpost 3RpDIl`0  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost Bor_Kib  
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    '************************************************************************* Q>s>@hw  
    'Lens thickness (Position of posterior lens surface) &E.ckWf  
    '************************************************************************* U#v??Sl  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 6AgevyVG  
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    ' Delete any z-shift(s) A@^e 4\  
    count = 0 {4"!~W  
    While GetOperationCount(eID)>count @;m7u  
        GetOperation eID, count, op [4,=%ez  
        If op.Type="ShiftZ" Then Mfjj+P  
            DeleteOperation eID,count < \]o#w*:  
            count=count-1 7_>No*[  
        End If 9I*zgM!F  
        count=count+1 ws:@Pe4AF  
    Wend |eIEqq.Eb  
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    'Set new z-shift )&[S*g  
    op.Type = "ShiftZ" 0ts] iQ7  
    op.val1 = tlens .L'>1H]B  
    op.parent = parID mXnl-_  
    AddOperation eID, op B5"(NJ;  
    Print "Set lens thickness = " & tlens DYlu`j_ux  
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    '************************************************************************* H8j#rC#&pm  
    'Lens index of refraction ,.Ac= "f  
    '************************************************************************* U1<EAGo|  
    eID = FindMaterial( "Lens" ) >x0"gh  
    GetModelMaterial eID, mat -AcLh0pc  
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    mat.Nd = nlens FCxLL"))  
    SetModelMaterial eID, mat r(./00a  
    Print "Set lens index of refraction = " & nlens e_6VPVa  
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    '************************************************************************* 4bD^Kc 4\  
    'Pupil diameter Uu xbN-u  
    '************************************************************************* f Co-ony  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) cA_77#<8  
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    'Adjust pupil diameter (trimming volume inner hole) fMRBGcg7Dc  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" 0,*clvH\;  
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    ' Adjust pupil location to just in front of the lens kxU <?0  
    parID = FindFullName( "Geometry.Arizona Eye" ) -miWXEe@l  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) fNOsB^Y  
    count = 0 /7#KkMg  
    While GetOperationCount(eID)>count 1qXqQA  
        GetOperation eID, count, op T-x1jC!B'  
        If op.Type="ShiftZ" Then T4n.C~  
            DeleteOperation eID,count q B-9&X  
            count=count-1 4G;FpWQm  
        End If |UvM [A|+  
        count=count+1 NQzpgf|h  
    Wend ')%Kv`hz  
    op.Type = "ShiftZ" $ )ps~  
    op.val1 = taq-0.01 -:IG{3fnu  
    op.parent = parID p?S:J`q  
    AddOperation eID, op ^b=]=w  
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    Print "Set pupil diameter = " & pupilDiam <I .p{Z  
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    'Update AZ Eye subassembly Description b(wzn`Z%Et  
    eID = FindFullName( "Geometry.Arizona Eye" ) tpw0j CVu  
    GetEntity eID, entity w5,p9f}.  
    entity.Description = "Accommodation = " & A & "D" Ek\f x*Lz  
    SetEntity eID, entity Am=D kkP%  
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    Update ')_Gm{A#p  
    Print "DONE!" k{ >rI2;  
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End Sub c$aTl9e  
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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: z[:UPPbW  
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Accommodation = 4 Diopters |0nbO2}  
Pupil Diameter = 4 mm P~n I6/r1  
Set aqueous humor thickness = 2.81 @7 xb/&N  
Set anterior lens radius = 10.4 and conic constant = -2.375869 NQS@i'W=g  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 8`E9a  
Set lens thickness = 3.927 2Wz/s 0`  
Set lens index of refraction = 1.42672 R:S Fj!W1  
Set pupil diameter = 4 #W`>vd}  
DONE! |0:&d w?*!  
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