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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。 PG[O?l  
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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。 3nC#$L-   
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. q=% C (  
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光源 ^ O Xr: P  
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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。 To{G#QEgG  
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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。 uQtk|)T E  
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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。 {e[pSD6   
图2. 字母F光源的设定方法光 \R>5F\ 0  
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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 = EChH@3  
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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。 MD ?F1l"}%  
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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。 3auJ^B}  
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图5. 视网膜重点采样规格设定
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脚本 6n6VEwYj  
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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: <,4R2'  
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。 !ga (L3vf  
余下的脚本计算与屈光度有关的所有参数。 ,[}yf#8@J  
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分析 #u<o EDQ  
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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。 ]D) 'I`  
图7. 字母F在视网膜上颜色分析
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脚本代码 +/!=Ub[:U  
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Option Explicit     'Remove this to enable non-dimensioned variables to be used. d7_g u  
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Dim entity As T_ENTITY h\u0{!@}  
Dim op As T_OPERATION ,y8I)+  
Dim mat As T_MODELMATERIAL Z?~d']XD  
Dim A As Double +>!B(j\gx  
Dim pupilDiam As Double mj(&`HRs4  
Dim eID As Long lR@i`)'?U  
Dim parID As Long ZH;y>Z  
Dim count As Integer 4$?w D <  
Dim taq As Double, Rant As Double, CCant As Double, Rpost As Double, CCpost As Double `Ge+(1x  
Dim tlens As Double, nlens As Double 8G5) o`  
Dim curv As Double, conic As Double i#]aV]IT  
Dim ok As Long pe!dm}!h[  
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Sub Main AJ#m6`M+EK  
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    '用户输入对话框 uFm+Y]h  
    Begin Dialog UserDialog 320,126,"Input parameters" ' %GRID:10,7,1,1 g* \P6  
        TextBox 220,21,40,21,.TextBox1 'default: 0 znQ'm^h  
        Text 20,21,190,21,"Accommodation (in Diopters):",.Text1,1 aucZJjH  
        OKButton 40,91,90,21 2-$bh  
        CancelButton 190,91,90,21 uK;K{  
        Text 20,49,190,14,"Pupil diameter (4 mm default):",.Text2,1 (! 0j4'  
        TextBox 220,49,40,21,.TextBox2 'default: 4 V{T{0b" \U  
    End Dialog iBKb/Oi6  
    Dim dlg As UserDialog h5&/hBN  
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    ok = Dialog (dlg) y7M:b Uh  
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    If ok=0 Then    'cancel button was pressed 7>'uj7r]=  
        Print "Execution cancelled." "xDx/d8B  
        End w\o)bn  
    End If GP[6nw_'^  
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    'Assign accommodation and pupil diameter & use defaults if field left empty FpdDIa  
    If dlg.TextBox1 = "" Then ] Wx>)LT  
        A = 0           'Default accommodation 6Iv(  
    Else f=:3!k,S  
        A = CDbl(dlg.TextBox1) fjIcB+Z  
    End If 6WE&((r ^  
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    If dlg.TextBox2 = "" Then Ic[}V0dk  
        pupilDiam = 4   'Default pupil diameter Gh]_L+  
    Else $=PWT-GIR  
        pupilDiam = CDbl(dlg.TextBox2) G}!7tU  
    End If 4AY _#f5u  
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    Print " " =ze FK_S!  
    Print "Accommodation = " & A & " Diopters" }O,U2=Hw`]  
    Print "Pupil Diameter = " & pupilDiam & " mm" /OQK/ t63  
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    ' Calculate new parameters with accommodation XYqpI/s  
    taq = 0.55 + 2.97 - 0.04*A              'Aqueous thickness O!+nF]V4f  
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    Rant = 12.0 - 0.4*A                     'Radius of anterior lens 24T@N~\g  
    CCant = -7.518749 + 1.285720*A          'Conic constant of anterior lens 4meidKw]  
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    Rpost = -5.224557 + 0.2*A               'Radius of posterior lens ="uKWt6n'  
    CCpost = -1.353971 - 0.431762*A         'Conic constant of posterior lens Sao>P[#x  
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    tlens = 3.767 + 0.04*A                  'Lens thickness t6'61*)|0  
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    nlens = 1.42 + 0.00256*A - 0.00022*A^2  'Lens index of refraction ],;D2]<s  
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    'Adjust parameters to account for accommodation gw_|C|!P  
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    '************************************************************************* az0cS*@  
    'Aqueous thickness (Position of Lens) `IEq@Wr#$!  
    '************************************************************************* _9D|u<D  
    eID = FindFullName( "Geometry.Arizona Eye.Lens" ) :{[<g](  
    GetCustomElement eID, entity Dn~Z SrJ  
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    parID = FindFullName( "Geometry.Arizona Eye" ) ZlthYuJ  
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    ' Delete any shift(s) in z IE&_!ce  
    count = 0 DdBxqkh  
    While GetOperationCount(eID)>count PC*m% ?+  
        GetOperation eID, count, op ~O \}/I28  
        If op.Type="ShiftZ" Then rmOQ{2}  
            DeleteOperation eID,count BjM+0[HC  
            count=count-1 >@^<S_KVh  
        End If >&bv\R/  
        count=count+1 t,RyeS/  
    Wend Tdg6kkJ  
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    'Set new shift in S[v Rw]*  
    op.Type = "ShiftZ" M]c7D`%s  
    op.val1 = taq e#tIk;9Xz  
    op.parent = parID m7JPH7P@BM  
    AddOperation eID, op *5 e<\{!  
    Print "Set aqueous humor thickness = " & taq-0.55 GGH;Z WSe  
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    '************************************************************************* ]3}feU+  
    'Radius and conic constant of anterior lens !Q!&CG5l  
    '************************************************************************* -TgUyv.  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Anterior" ) iAK/d)bq  
    GetConic eID, entity, curv, conic [eyb7\#   
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    SetConic eID, entity, 1/Rant, CCant *|oPxQCtK  
    Print "Set anterior lens radius = " & Rant & " and conic constant = " & CCant `qE4U4  
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    '************************************************************************* T8U[xu.>  
    'Radius and conic constant of posterior lens V7:\q^$  
    '************************************************************************* K5{{:NR$  
    eID = FindFullName( "Geometry.Arizona Eye.Lens.Posterior" ) 6J\q`q(W(  
    GetConic eID, entity, curv, conic \*uugw,\y  
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    SetConic eID, entity, 1/Rpost, CCpost PB+\jj  
    Print "Set posterior lens radius = " & Rpost & " and conic constant = " & CCpost >PIPp7C  
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    '************************************************************************* *<r%aeG$em  
    'Lens thickness (Position of posterior lens surface) ijF V<P  
    '************************************************************************* vO]J]][  
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    parID = FindFullName( "Geometry.Arizona Eye.Lens" ) 7,h3V=^)Q  
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    ' Delete any z-shift(s) "qS!B.rt:  
    count = 0 7H%_sw5S.  
    While GetOperationCount(eID)>count 3T1P$E" m  
        GetOperation eID, count, op bE d?^h  
        If op.Type="ShiftZ" Then ZOuR"9]  
            DeleteOperation eID,count 2 5Q+1  
            count=count-1 9<l-NU9 _  
        End If =UNT.]  
        count=count+1 `E W!-v)  
    Wend frc{>u~t  
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    'Set new z-shift Y%g "Y  
    op.Type = "ShiftZ" :G}DAUFN  
    op.val1 = tlens +*C^:^jA  
    op.parent = parID WNa3^K/W{  
    AddOperation eID, op IcFK,y%1  
    Print "Set lens thickness = " & tlens oIb) Rq!m  
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    '************************************************************************* f&c]LH _  
    'Lens index of refraction D#jX6  
    '************************************************************************* @Dj:4  
    eID = FindMaterial( "Lens" ) Xhse~=qA  
    GetModelMaterial eID, mat (B:uc_+  
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    mat.Nd = nlens 4fty~0i=z  
    SetModelMaterial eID, mat 59i]  
    Print "Set lens index of refraction = " & nlens >rw"Rd'  
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    '************************************************************************* rz.IoQo  
    'Pupil diameter u s`}  
    '************************************************************************* N@()F&e  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil.Iris" ) -NzTqLBn  
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    'Adjust pupil diameter (trimming volume inner hole) f=m/ -mAA  
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    SetTrimVolHole eID, pupilDiam/2, pupilDiam/2, 0, 0, "Cylinder" {y6C0A*  
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    ' Adjust pupil location to just in front of the lens h<Wg3o  
    parID = FindFullName( "Geometry.Arizona Eye" ) =/9<(Tt%m  
    eID = FindFullName( "Geometry.Arizona Eye.Pupil" ) o1k#."wHr  
    count = 0 p=B?/Sqa  
    While GetOperationCount(eID)>count -k{ Jp/-D  
        GetOperation eID, count, op Dtt-|_EMS  
        If op.Type="ShiftZ" Then (6R4 \8z2  
            DeleteOperation eID,count iyj3QLqE  
            count=count-1 %S`ik!K"I  
        End If Hf%_}Du /`  
        count=count+1 WNF9#oN|oT  
    Wend 9p`r7:  
    op.Type = "ShiftZ" B< hEx@  
    op.val1 = taq-0.01 {|6z+vR  
    op.parent = parID ]"sRS`0+  
    AddOperation eID, op W:O0}   
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    Print "Set pupil diameter = " & pupilDiam e$wt&^W  
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    'Update AZ Eye subassembly Description eYEc^nC,c)  
    eID = FindFullName( "Geometry.Arizona Eye" ) jczq `yW  
    GetEntity eID, entity fsvYU0L  
    entity.Description = "Accommodation = " & A & "D" zvr\36  
    SetEntity eID, entity :Jl Di>B  
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    Update 4seciz0?  
    Print "DONE!" H]Wp%"L  
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End Sub }V]eg,.BJ  
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如果屈光度是4,光瞳直径是4,则会输出如下数据: LgHJo-+>  
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Accommodation = 4 Diopters dJl^ADX[@  
Pupil Diameter = 4 mm nwf7M#3d  
Set aqueous humor thickness = 2.81 54q3R`y  
Set anterior lens radius = 10.4 and conic constant = -2.375869 vg(K$o{BT  
Set posterior lens radius = -4.424557 and conic constant = -3.081019 hhmGv9P  
Set lens thickness = 3.927 yd>}wHt  
Set lens index of refraction = 1.42672 )ooWQ-%P  
Set pupil diameter = 4 Ei~f`{i  
DONE!
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